Preamp Tubes? - Who, What, When, Where, Why, and How? - Page 58

RiverRatt · 10-13-2009, 11:48 PM

Marty, I found some info on Google about the 2210 - it only has 3 preamp tubes. V4 and V5 are the reverb driver and the PI.

ProfChaos · 10-14-2009, 12:27 AM

Quote:

Originally Posted by joshuaaewallen

Hey All! I'm still a bit new to the Marshall Forum, but already I have seen quite a bit of discussion regarding the selection and operation of power amp tubes. But... I would really like to get some feed back regarding the selection of preamp tubes.

I rarely play out, and quite frankly seldom have opportunity to turn my TSL122 up past 1 or 2. I am aware of the fact that because of this, I will be getting most of my tone from my preamp section, and not from the power amp. That being the case I would like to know more about how preamp tubes effect my sound.

I play mainly classic rock ranging from AC/DC to Def Leppard. Clearly I love distorted guitar tone, but I also love the way my TSL122 sounds on the clean channel. So...

What I am hoping for is feedback from you more experienced members of the forum regarding such topics as: How will different tubes change my sound to better suit my style of playing? What tonal qualities do different preamp tubes have? What is a good starting point for finding the right tubes for me? Can I "mix-and-match" preamp tubes? How long do preamp tubes last? How often should I replace them?

Please, do share your thoughts on this subject. I am eager to know what your experiences have been. Thanks in advance for your responses!

I play a Model 6100 30th Anniversary head--the EL34 version. In that amp, I prefer to spend the extra dough and go with Mullard 12AX7 pre-amp tubes. The new Mullard 12AX7 (re-issue) tubes are very friendly to overdriven tone--as in the pentode (Mesa Boogie-like) 100-watt setting of the 30th Anniversary head.

Even so, I would caution against merely replacing all your 12AX7 tubes willy-nilly; be sensitive to and aware of which tube came from which tube socket: The last 12AX7 (V4?) in the pre-amp of your Marshall is what is known as a "Matched Phase Inverter" (MPI); it is a "Special Application" tube. The MPI-tube drives the first stage of the power amp. More specifically, it is critical in the "push-pull" Class AB Marshall power amp that the MPI that drives the power amp be balanced for equal sine wave output on both negative and positive voltage cycles of the tube. (The specially balanced MPI tube averts a really weird, wobbly effect that would occur if the tube were not tuned to provide equal output at both negative and positive voltage cycles.)

Lastly, I might be wrong, but it seems to me that, in characterizing your sound as "distorted guitar tone," you might be confusing the terms "distortion" and "overdrive." Unless you use a "stomp box" pedal like a Pro-Co "Ratt" or an ElectroHarmonix "Big Muff Pie," you likely mean "overdrive," and not "distortion." (The yellow and red LED channel indicators represent different levels of overdrive--as in yellow = "Crunch," as in moderately overdriven, and red = [soaring] "Lead," as in heavily overdriven.)
As a flexible--yet general--rule, distortion = stinky-bad; overdrive = oh-so-good.

The overdrive effect is what gives the Marshall its crunch and the Boogie its bite.

cheers,
--Professor Chaos

Madaxeman · 10-14-2009, 08:04 AM

I know a tech who swears that you're better off with an unbalanced valve as a phase inverter. He reckons certain guitar amps sound worse with a balanced PI.

With preamp valves in general, I swap em around until I find a combination that works.
Right now in my Jubilee 2554 I'm running Siemens EL34's and Shuguang 7th/8th Gen in V3, Mullard ECC83 in V2 and a Pope/Amperex ECC83 in V1.

wegman · 10-14-2009, 08:58 AM

Quote:

Originally Posted by MartyStrat54

I'm not real familiar with the 2210. I forgot that the PI tube is listed with the power section. I'm always fascinated with Marshall amps that have a lot of preamp tubes (like the 6100). If the 5th tube is the phase inverter, do you know what the other tubes do? I mean I would assume that V1 and V2 are your gain stage tubes, but then what does V3 do? I'm assuming again that V4 is the tone stack/cathode follower tube. That leaves V3 as "another gain tube?" Who says an 800 doesn't have any gain?

Let me know about those tube positions if you know what they are.

I found this on line. It has all the positions listed and what they do in many Marshall amps. Don't let the link name fool you. If you scroll down to about a 1/4 of the way they have all the amps listed.

Marshall Amplifiers, Pre-1990

ProfChaos · 10-14-2009, 09:59 AM

Quote:

Originally Posted by Madaxeman

I know a tech who swears that you're better off with an unbalanced valve as a phase inverter. He reckons certain guitar amps sound worse with a balanced PI.

With preamp valves in general, I swap em around until I find a combination that works.
Right now in my Jubilee 2554 I'm running Siemens EL34's and Shuguang 7th/8th Gen in V3, Mullard ECC83 in V2 and a Pope/Amperex ECC83 in V1.

When "he reckons certain guitar amps sound worse with a balanced PI," he is almost certainly not talking about the Marshall 6100 30th Anniversary head with EL34's: When I unwittingly replaced the Matched Phase Inverter in my 30th Anniversary head by plugging in a new 12AX7 Groove Tubes Mullard reissue, the amp sounded awful, at both the triode and pentode settings. It might be that your friend is arriving at a balanced phase inverter effect by mixing and matching the 12AX7's (ECC83's) leading up to the matched phase inverter. Whatever the case with your friend, the MPI is the Most Important Tube in Your Amp; this tube immediately precedes the bias circuit, and it drives the push-pull circuit of the four power amp output tubes. Any issues with the matched phase inverter get multiplied through the stages of gain in the power amp.

More specifically, the PDF drawing of the Marshall 6100's power amp shows that V7a and V7b (a matched-phase triode pair) drive all else in the power amp. This is why some audiophile engineers and technicians refer to the matched phase inverter as the "most important tube in your amplifier."

cheers,

--Professor Chaos

solarburnDSL50 · 10-14-2009, 10:36 AM

I don't buy into putting a matched or balanced tube into the PI slot on a guitar amp. HIFI amps are another story...

Here is a little excerpt from a guy on this subject:

Some simple and more "HIFI" PI's have what's called unity gain, which means no gain at all. Most guitar amps that are based on Fender/Marshall designs use a type of PI called a "long-tailed phase inverter", which has BAGS of gain!

In hifi applications it's common to design a "balanced" PI. This means that each PI output, while out of phase to each other will be exactly balanced so that when the output waves are combined in the output transformer things will be perfectly even on each side of the combined wave. This helps give the lowest distortion and the most "hifi" sound.

Tube stores will sell you 12AX7's that have been matched and balanced, meaning that since this tube consists of two triode amplifiers contained in one glass tube when you use it as a PI each triode will more perfectly provide that same gain, "balanced" output.

Unless you're a purist jazz player, who the heck wants a hifi guitar sound?

Most guitar amps also adjust parts values in the PI stage to provide reasonable balancing but being a bit off actually provides a better tone!

There are a lot of hifi technical ideas that crop up from tube stores wanting to make more money from guitar players that aren't really appropriate. They only make sense in a hifi application. Myself, I would never bother with a balanced PI tube in a guitar amp but in a tube hifi amp it's not a bad idea. Even then, it's easy to get too anal and nitpicky. The human ear is physically incapable of detecting much less than 2-3% distortion. To quibble about .1% vs .2% is frankly ridiculous!

RiverRatt · 10-14-2009, 11:11 AM

Quote:

Originally Posted by solarburnDSL50

I don't buy into putting a matched or balanced tube into the PI slot on a guitar amp.

Me either. I'm finding that I like a higher gain 12AX7 in the PI spot. Quite a change from my old days of nothing but 12AT7s.

MartyStrat54 · 10-14-2009, 01:46 PM

Quote:

Originally Posted by RiverRatt

Marty, I found some info on Google about the 2210 - it only has 3 preamp tubes. V4 and V5 are the reverb driver and the PI.

That's cool, a tube reverb driver. So is V3 the tone stack and cathode follower?

I looked at Dr. Tube last night and they have a horrible GIF photo for the 2210. However, it does look like V3 may be the TS and CF.

wegman · 10-14-2009, 01:48 PM

Lead models 2205, 2210, 4210, 4211, 4212
V1 is the first preamp. Recommend a low-noise type with a coiled heater, such as NOS 7025s or ECC83s. JJ ECC83s and Sovtek 12AX7LPSs or EHs are suitable. NOS 5751s recommended if lower gain is desired.

V2 is the driver and cathode follower for the tone controls. A low noise tube is not critical, however the heater-cathode insulation must be good quality. NOS JAN 12AX7s are recommended for this position. We understand that some technicians recommend Ei or JJ ECC83s for this duty.

V3 is the mix amplifier after the master volume control. A low noise tube is not needed here. Any 12AX7 of good quality will work, although guitarists picky about their tone may prefer a top-grade NOS version.

V4 is the reverb driver and recovery amplifier. A low noise tube is not critical. This position is very hard on the cathode, due to high current. NOS JAN 12AX7s are recommended for this position.

V5 is the phase inverter. A low noise tube is not critical, however the heater-cathode insulation must be good quality. NOS JAN 12AX7s are recommended for this position. We understand that some technicians recommend Ei or JJ ECC83s for this duty.

Power tubes are 2 x EL34 in 50-watt models, 4 x EL34 in 100-watt models (2210, 4211). These models were designed for 6550s, and can also accept KT88s or EL34s. Bias adjustment is MANDATORY

MartyStrat54 · 10-14-2009, 03:06 PM

Continuing on about a balanced PI. This thread is immensely long and over the course of many months we have experimented with unbalanced PI tubes and found them to be highly acceptable in all of our amp. The Marshall amp is built with components that are + or - 20 per cent. With that in mind, we look at the tolerance of the first and second gain stages. These gain stages have a lot of "slack" to them. They are not perfect and they are not "matched." As mentioned by SolarBurn, if you have a Hi Fi amp and it is built to higher tolerances, there is a good chance that it is also a Class A or High Class AB amp. Because it's "stereo," you would want to try to balance the gain out so the left and right speakers were of the same volume. That would be the only reason to "match" the PI tube in a Hi Fi amp. Remember, your ears cannot detect imperfections below a certain dB level or below a certain level of distortion..

I used to fall for the balanced PI and it is just a rip-off by those who push them. Some guitarists actually use a highly mismatched PI tube, because they get "their" sound out of that sort of tube. Harmonica players do this to their amps as well. They get more complicated harmonics from the amp.

Several of us have used all sorts of tubes in V4. High gain, lop-sided, low gain, near matched and they all seem to do the job. Now by doing these tests we realized that a real high gain tube (to high for V1 or V2) will work in the PI and it does affect the overall gain of the amp. Not by much, but there is a difference between running a medium gain tube in the PI and a very high gain tube in the PI. Conclusion? A whole lot of gain makes very little change in this slot.

The other thing is that these are all 12AX7 type tubes. Since we've covered the PI issue, it then allows us to roll the tubes in whatever slot we please. We are experienced rollers. We are mainly interested in V1 and V2. We have carefully selected tubes that we think work best in V3 and V4. This allows us to concentrate on the tonal qualities of Amperex, Telefunken, Mullard and Black Plate tubes.

I appreciate your comments and yes, the 6100 is a unique amp. However, I know how it works and it is still a basic Marshall as far as the power amp goes. It is of the same design as almost every modern Marshall. Your 6100 has a lot of preamp tubes which in a ways can be expensive when it comes time to change them. Marshall figured out how to make multi-channel amps with a smaller amount of tubes...but the amp section is still the same.

MartyStrat54 · 10-14-2009, 03:19 PM

Quote:

Originally Posted by wegman

V3 is the mix amplifier after the master volume control. A low noise tube is not needed here. Any 12AX7 of good quality will work, although guitarists picky about their tone may prefer a top-grade NOS version.

I looked at the Dr. Tube schematic last night and saw how V3 was being used. Because it says a low noise tube is not needed here, I suspect that mix amplifier could possibly be the same as the tone stack. This would use one half of the tube. I assume that the other half is the cathode follower. The bottom line is that your amp has these circuits and it takes a 12AX7 to drive them.

Other than your tube reverb driver, your amp appears to have the classic four tube arrangement.

MartyStrat54 · 10-15-2009, 03:53 PM

Things are getting a little slow around here. I think it's time to launch a new theme here. It's October...how about something scary like Count Telefunken? Yeah, everybody is starting to really show some interest in these fine tubes.

Here is a picture of a Tele Smooth, Tele Ribbed and Tele/RFT Smooth. I was wrong when I stated earlier about the RFT's construction. It is for the most part identical in every way. The Smooth Tele on the left has a red tip. Telefunken would paint the tips blue or red to designate them as medical or test equipment approved.

The vast majority of hi fi users will claim that the smoothie is the better Tele. I have used all three and the differences are not worth mentioning. I will say that a stronger gain Tele has a different sound over a lower gain one. By this I mean a 21-22 versus a 25-24. Out of all the Tele's I have, only three measure in the upper twenties. I am getting 12 more in and some of them are going to be V2's as I have dealt with this seller before.

I am looking forward to using an Amperex 7025 in V1 and a 29-28 Tele in V2. That ought to sound awesome.

Well ghosts and goblins, it's time to let those Tele's wail in your high gain amp. Please don't overdo it.

I went back and looked at the RFT's and they all have a thicker, longer tip at the top of the bottle like the one in the picture. Also, notice the dark base on the RFT.

solarburnDSL50 · 10-15-2009, 04:15 PM

I'm looking forward to giving one of these a spin in V1. Should be ghoulish for sure!

Well at least with my playing...

RiverRatt · 10-15-2009, 04:56 PM

Here's my triple threat. Left to right: 1966 Mullard (GE 6681), Raytheon black plate, and the Telefunken (Fisher) smooth plate.

MartyStrat54 · 10-15-2009, 06:16 PM

Pay close attention to the year of that 6681. It's 1966. That is the year all of the crazy shit started to happen. Alan...I have never seen a "pinched top" 6681. You have got some spooky tubes.

Anyway, that's one hell of a power trio you have.

solarburnDSL50 · 10-15-2009, 06:34 PM

Yep, that's a tri-fecta of tone. Just look how sexy that BP is.

MartyStrat54 · 10-15-2009, 08:06 PM

Quote:

Originally Posted by solarburnDSL50

Yep, that's a tri-fecta of tone. Just look how sexy that BP is.

Yes, they are a thing of beauty. They sound damn good as well.

MartyStrat54 · 10-15-2009, 08:18 PM

You know it never ceases to amaze me. I won't mention who, but a forum member was asking for tube help. I always try to steer them here, but some folks get intimidated by the volume of pages in this thread.

So I give this guy the benefit of the doubt and give him four or so replies. I just read his latest post. He bought Groove Tubes and JJ preamps and if I remember, GT power tubes. Right across the board of what I told him not to get. Can't give out anymore or you'll know who he is.

Well Ha-Fucking-Ha...I hope you enjoy your new tone pony.

wegman · 10-15-2009, 08:43 PM

You know I was a run of the mill mild mannored Joe till I found this thread. Now I am looking for old tubes like a junkie looking to score. I have been asking everyone I know if they have any old tubes. It turns out a guy I work with used to repair TV's and old electronics. I told him what I was looking for and he knew right away what it was. He said he is going to look around and see if he has anything. If he does it is mine.

If I come across anything interesting I will post it.

Let's say this guy comes up with something. Any words of wisdom before I go popping a 40 year old tube in my Marshall?

I mean it sounds like crap right now but at least it works.

MartyStrat54 · 10-15-2009, 09:07 PM

Putting a bad preamp tube is not going to hurt the amp and you will know right away that it's bad. Without a tester, all you can do is roll them. I wish you the very best and I hope the guy loads you down with some nice 12AX7's. What you will hope for is White Label RCA, 59-66 Raytheon Black Plates, any tube that says 5751, 12AT7, 6681 or 7025. Any thing with a black plate, GE, RCA or Sylvania.

If you score, try to get some clear pics up (I suck at it myself, but some of it is my digital camera) and then we can tell you what you have.

RiverRatt · 10-15-2009, 09:47 PM

Quote:

Originally Posted by MartyStrat54

Pay close attention to the year of that 6681. It's 1966. That is the year all of the crazy shit started to happen. Alan...I have never seen a "pinched top" 6681. You have got some spooky tubes.

Anyway, that's one hell of a power trio you have.

It's just a plain ol' Mullard. It has a 163 code and the date code is B6K1. The GE code looks like UY with what looks like 183-5 under that. GE must have needed to fill an order or something. I tried it in V1 with the Tele in V2. It wasn't as good as either one with the Raytheon BP in V2.

I still think the Arcturus 12AZ7 is the coolest-looking tube I have. The logo is very intricate. It's clearly a Raytheon short black plate. Whether its a Ray 12AZ7 or a 12AT7 is anybody's guess, but the construction looks just like that relabeled Tung-Sol AT7 I sent you. Was it any good, BTW?

RiverRatt · 10-15-2009, 09:56 PM

Quote:

Originally Posted by wegman

You know I was a run of the mill mild mannored Joe till I found this thread. Now I am looking for old tubes like a junkie looking to score. I have been asking everyone I know if they have any old tubes. It turns out a guy I work with used to repair TV's and old electronics. I told him what I was looking for and he knew right away what it was. He said he is going to look around and see if he has anything. If he does it is mine.

If I come across anything interesting I will post it.

Let's say this guy comes up with something. Any words of wisdom before I go popping a 40 year old tube in my Marshall?

I mean it sounds like crap right now but at least it works.

Wegman, it's an addiction. I've driven 50 miles on a rumor that there might be some tubes around. Don't forget to raid old Hi-Fi sets from the mid-1950's to the mid-1960's. I bought one turntable/AM/FM stereo box that had a Mullard EZ81 recto, a couple of good 12AT7s and these two Sonotone ECC83 clear tops that nobody can identify but sound great. I'm thinking they are RCAs until I find conclusive evidence. Console sets are good, too. I've got a sweet 6BQ5 (EL84) that I pulled from an old TV chassis in a barn. You never know where goodies will turn up.

Good luck with the TV guy. TV sets use a lot of oddball tubes, but occasionally you'll find a gem. If you're going to be a successful hunter, you need to study ALL the different numbers that are basically the same tube. There are a lot more than you'd think. And don't believe every tube substitution chart you see on the internet. Some tubes will work, but have a different pinout and require some voodoo to use.

wegman · 10-15-2009, 10:20 PM

Marty, RiverRatt

Thanks for all the information. I really appreciate it. I didn't realize there were other tubes that would work. I asked him to look for 12AX7s/ECC83s. He knew right away they were pre-amp tubes. I was not schooled enough to tell him to look for others.

I will tell him to be on the look out for some of the others you guys mentioned.

I am like a little kid at Christmas. I can't wait to go to work tomorrow.

RiverRatt · 10-15-2009, 11:53 PM

Here's a list that has some substitutions. One thing to realize is that while, for example, all the substitutions they have listed for the 12AX7 tube type will work, but may have different gain characteristics. Also the power tubes they have listed would not substitute without some changes to the bias resistors at least, but any of the tubes you see listed here would be good to look for. The 6CA7 = EL34 = KT77. I don't know why they put all those others as subs.

Tube Substitution Table

Also, any 12A_7 will substitute for any other, but as above, they have different gain levels. 12BZ7s are an interesting 12AX7 substitution, too. In the second gain stage, they can really make a Marshall sound hot-rodded. A 12BH7 will behave about like a 12AT7.

solarburnDSL50 · 10-16-2009, 03:39 AM

I'm just giving a quick blip here but I got the EH6CA7's in. PV was 475v and biased em' to 75% PD and spanked my plank!

I give them a

on both gain and clean channels but I still need to open them up the rest of the way and that means I have to wait until the father-in-law goes out to breakfast. Its a bitch having to wait for this to happen. The rest of the family deals with me but I won't blow him out of the house. I'm not that mean. The kids they just go play outside. The wife lets it happen. I give her props for that. Doesn't mean I like her though...

Anyways I won't give my seal of approval until I light the chubby bottles up for some high volume torture sessions...poor neighbors.

Just to jog people's memory on what they are like. From the Tubestore:

At last something to replace the hole left since the EI 6CA7 went out of stock. These tubes sound every bit as good as the old EI tubes and are probably my favorite tubes for Hiwatt guitar amplifiers. It’s like they were made for each other. These tubes are like EL34’s on steroids. They handle high voltage and current without problems. As mentioned, there is nothing like a Hiwatt head powered by 6CA7 tubes and driving a 4x12 cab loaded with Fane speakers. This is classic rock tone at its finest. It’s the sound of Pete Townsend and The Who. The 6CA7 has more headroom than an EL34 and by the time you get it really crunchy sounding your pants are flapping in the breeze. Just the right amount of compression for great thick rock tone. Biasing levels can be dialed in from warm to hot without causing significant tonal changes. The EH is well constructed and should not pose any noise problems. If using these tubes in more reasonable systems the EH 6CA7 is capable of some really nice clean tones thanks to that extra headroom. If you want early Van Halen, these are not the tubes for you. If you want something loud and proud, you want to put the EH 6CA7 in your amp.

solarburnDSL50 · 10-16-2009, 10:43 AM

Quote:

Originally Posted by MartyStrat54

You know it never ceases to amaze me. I won't mention who, but a forum member was asking for tube help. I always try to steer them here, but some folks get intimidated by the volume of pages in this thread.

So I give this guy the benefit of the doubt and give him four or so replies. I just read his latest post. He bought Groove Tubes and JJ preamps and if I remember, GT power tubes. Right across the board of what I told him not to get. Can't give out anymore or you'll know who he is.

Well Ha-Fucking-Ha...I hope you enjoy your new tone pony.

JJ's and GT's freek'n rule Broham!!!!!!!!!!! I've got to have it now! No time to stop and think. JJ's and Gt's for me man. I ain't got no time for you old tube talk'n crappers!

BELCH!

wegman · 10-16-2009, 12:21 PM

Quote:

Originally Posted by wegman

Marty, RiverRatt

Thanks for all the information. I really appreciate it. I didn't realize there were other tubes that would work. I asked him to look for 12AX7s/ECC83s. He knew right away they were pre-amp tubes. I was not schooled enough to tell him to look for others.

I will tell him to be on the look out for some of the others you guys mentioned.

I am like a little kid at Christmas. I can't wait to go to work tomorrow.

Well I scored a couple tubes. One is a 12BH7A Sylvania and the other is a
12AU7 and I can't tell who the mafacturer is.

So I can just pop these in and try them out?

solarburnDSL50 · 10-16-2009, 12:27 PM

Quote:

Originally Posted by wegman

Well I scored a couple tubes. One is a 12BH7A Sylvania and the other is a
12AU7 and I can't tell who the mafacturer is.

So I can just pop these in and try them out?

The 12AU7 will have a gain factor of 20 as opposed to a 12AX7 which is at 100. So you will notice a sizable difference between the 2. If I used that 12AU7 in V1 it would neuter my overall gain on my DSL just to give an example.

Don't know bout the 12BH7A.

Here is a table to look at:

http://thetubestore.com/gainfactor.html

RiverRatt · 10-16-2009, 01:35 PM

You won't hurt anything by giving them a try, but odds are you won't like them in your guitar amp. The 12BH7 has about the same gain as a 12AT7 and might could be used as a phase inverter, but the 12AU7 will neuter an amp in just about any spot.

Both of these tubes can be (and are) used in low-watt guitar amplifiers as a power tube. There's a 1-watt amp project at AX84.com called the Firefly that uses a 12AU7 output tube, and I've been reading that Blackstar makes a low-watt amp that uses the 12BH7.

MartyStrat54 · 10-16-2009, 02:43 PM

Joe...

I'm glad you like you new CP Power Tubes. Hey...maybe they finally got it right. Now I won't put them on the same level as a dual getter, black plate, Fat Boy. These tubes can take more power than any other 6CA7's, EL34's and KT77's. There are even some that are more rare than a regular Fat Boy. However, if these tubes can handle the plate power of my 602's (500VDC+), I will have to look strongly at them.

My main thing is I want to hear your review with the tubes at volume.

10-13-2009, 11:48 PM	#1711 (permalink)
RiverRatt Senior Member Join Date: May 2008 Location: Between Memphis and Nashville Posts: 517	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Marty, I found some info on Google about the 2210 - it only has 3 preamp tubes. V4 and V5 are the reverb driver and the PI.

10-14-2009, 08:04 AM	#1713 (permalink)
Madaxeman Junior Member Join Date: Oct 2009 Location: Southampton UK Posts: 6	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? I know a tech who swears that you're better off with an unbalanced valve as a phase inverter. He reckons certain guitar amps sound worse with a balanced PI. With preamp valves in general, I swap em around until I find a combination that works. Right now in my Jubilee 2554 I'm running Siemens EL34's and Shuguang 7th/8th Gen in V3, Mullard ECC83 in V2 and a Pope/Amperex ECC83 in V1.

10-14-2009, 01:48 PM	#1719 (permalink)
wegman Senior Member Join Date: Oct 2009 Posts: 138	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Lead models 2205, 2210, 4210, 4211, 4212 V1 is the first preamp. Recommend a low-noise type with a coiled heater, such as NOS 7025s or ECC83s. JJ ECC83s and Sovtek 12AX7LPSs or EHs are suitable. NOS 5751s recommended if lower gain is desired. V2 is the driver and cathode follower for the tone controls. A low noise tube is not critical, however the heater-cathode insulation must be good quality. NOS JAN 12AX7s are recommended for this position. We understand that some technicians recommend Ei or JJ ECC83s for this duty. V3 is the mix amplifier after the master volume control. A low noise tube is not needed here. Any 12AX7 of good quality will work, although guitarists picky about their tone may prefer a top-grade NOS version. V4 is the reverb driver and recovery amplifier. A low noise tube is not critical. This position is very hard on the cathode, due to high current. NOS JAN 12AX7s are recommended for this position. V5 is the phase inverter. A low noise tube is not critical, however the heater-cathode insulation must be good quality. NOS JAN 12AX7s are recommended for this position. We understand that some technicians recommend Ei or JJ ECC83s for this duty. Power tubes are 2 x EL34 in 50-watt models, 4 x EL34 in 100-watt models (2210, 4211). These models were designed for 6550s, and can also accept KT88s or EL34s. Bias adjustment is MANDATORY __________________ Ian St Ian says "If your not playing Gibson and Marshall your a wanker!" Marshall JCM 800 2210 (1989) Marshall MG CD10 (hi guys!) Gibson Les Paul Custom (1981) Mackie 24x8 mixing console Alesis ADAT HD 24 digital recorder Shure KSM 27

10-14-2009, 03:06 PM	#1720 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,583	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Continuing on about a balanced PI. This thread is immensely long and over the course of many months we have experimented with unbalanced PI tubes and found them to be highly acceptable in all of our amp. The Marshall amp is built with components that are + or - 20 per cent. With that in mind, we look at the tolerance of the first and second gain stages. These gain stages have a lot of "slack" to them. They are not perfect and they are not "matched." As mentioned by SolarBurn, if you have a Hi Fi amp and it is built to higher tolerances, there is a good chance that it is also a Class A or High Class AB amp. Because it's "stereo," you would want to try to balance the gain out so the left and right speakers were of the same volume. That would be the only reason to "match" the PI tube in a Hi Fi amp. Remember, your ears cannot detect imperfections below a certain dB level or below a certain level of distortion.. I used to fall for the balanced PI and it is just a rip-off by those who push them. Some guitarists actually use a highly mismatched PI tube, because they get "their" sound out of that sort of tube. Harmonica players do this to their amps as well. They get more complicated harmonics from the amp. Several of us have used all sorts of tubes in V4. High gain, lop-sided, low gain, near matched and they all seem to do the job. Now by doing these tests we realized that a real high gain tube (to high for V1 or V2) will work in the PI and it does affect the overall gain of the amp. Not by much, but there is a difference between running a medium gain tube in the PI and a very high gain tube in the PI. Conclusion? A whole lot of gain makes very little change in this slot. The other thing is that these are all 12AX7 type tubes. Since we've covered the PI issue, it then allows us to roll the tubes in whatever slot we please. We are experienced rollers. We are mainly interested in V1 and V2. We have carefully selected tubes that we think work best in V3 and V4. This allows us to concentrate on the tonal qualities of Amperex, Telefunken, Mullard and Black Plate tubes. I appreciate your comments and yes, the 6100 is a unique amp. However, I know how it works and it is still a basic Marshall as far as the power amp goes. It is of the same design as almost every modern Marshall. Your 6100 has a lot of preamp tubes which in a ways can be expensive when it comes time to change them. Marshall figured out how to make multi-channel amps with a smaller amount of tubes...but the amp section is still the same. __________________ MARTY 2009 Gibson Explorer-Hell Raising Machine 1989 Fender Strat Plus USA 2008 Fender Tele USA 2004 Schecter Elite w/DiMarzio's TSL100 with custom 4x12 cab. TSL122 with Man 'O War Speakers. TSL602 #1 with JBL D123 Speakers and 602 #2 with Altec 417 Speakers. "Oh so sweet my friends." DSL401 #1 with Red Fang Speaker and 401 #2 with JBL D123 Speaker. Tubes: Let's just say they are NOS that kick ass. Last edited by MartyStrat54; 10-14-2009 at 08:30 PM. Reason: Multiple spelling errors.

10-15-2009, 03:53 PM	#1722 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,583	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Things are getting a little slow around here. I think it's time to launch a new theme here. It's October...how about something scary like Count Telefunken? Yeah, everybody is starting to really show some interest in these fine tubes. Here is a picture of a Tele Smooth, Tele Ribbed and Tele/RFT Smooth. I was wrong when I stated earlier about the RFT's construction. It is for the most part identical in every way. The Smooth Tele on the left has a red tip. Telefunken would paint the tips blue or red to designate them as medical or test equipment approved. The vast majority of hi fi users will claim that the smoothie is the better Tele. I have used all three and the differences are not worth mentioning. I will say that a stronger gain Tele has a different sound over a lower gain one. By this I mean a 21-22 versus a 25-24. Out of all the Tele's I have, only three measure in the upper twenties. I am getting 12 more in and some of them are going to be V2's as I have dealt with this seller before. I am looking forward to using an Amperex 7025 in V1 and a 29-28 Tele in V2. That ought to sound awesome. Well ghosts and goblins, it's time to let those Tele's wail in your high gain amp. Please don't overdo it. I went back and looked at the RFT's and they all have a thicker, longer tip at the top of the bottle like the one in the picture. Also, notice the dark base on the RFT. __________________ MARTY 2009 Gibson Explorer-Hell Raising Machine 1989 Fender Strat Plus USA 2008 Fender Tele USA 2004 Schecter Elite w/DiMarzio's TSL100 with custom 4x12 cab. TSL122 with Man 'O War Speakers. TSL602 #1 with JBL D123 Speakers and 602 #2 with Altec 417 Speakers. "Oh so sweet my friends." DSL401 #1 with Red Fang Speaker and 401 #2 with JBL D123 Speaker. Tubes: Let's just say they are NOS that kick ass.

10-15-2009, 04:56 PM	#1724 (permalink)
RiverRatt Senior Member Join Date: May 2008 Location: Between Memphis and Nashville Posts: 517	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Here's my triple threat. Left to right: 1966 Mullard (GE 6681), Raytheon black plate, and the Telefunken (Fisher) smooth plate.

10-15-2009, 06:16 PM	#1725 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,583	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Pay close attention to the year of that 6681. It's 1966. That is the year all of the crazy shit started to happen. Alan...I have never seen a "pinched top" 6681. You have got some spooky tubes. Anyway, that's one hell of a power trio you have. __________________ MARTY 2009 Gibson Explorer-Hell Raising Machine 1989 Fender Strat Plus USA 2008 Fender Tele USA 2004 Schecter Elite w/DiMarzio's TSL100 with custom 4x12 cab. TSL122 with Man 'O War Speakers. TSL602 #1 with JBL D123 Speakers and 602 #2 with Altec 417 Speakers. "Oh so sweet my friends." DSL401 #1 with Red Fang Speaker and 401 #2 with JBL D123 Speaker. Tubes: Let's just say they are NOS that kick ass.

10-15-2009, 08:18 PM	#1728 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,583	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? You know it never ceases to amaze me. I won't mention who, but a forum member was asking for tube help. I always try to steer them here, but some folks get intimidated by the volume of pages in this thread. So I give this guy the benefit of the doubt and give him four or so replies. I just read his latest post. He bought Groove Tubes and JJ preamps and if I remember, GT power tubes. Right across the board of what I told him not to get. Can't give out anymore or you'll know who he is. Well Ha-Fucking-Ha...I hope you enjoy your new tone pony. __________________ MARTY 2009 Gibson Explorer-Hell Raising Machine 1989 Fender Strat Plus USA 2008 Fender Tele USA 2004 Schecter Elite w/DiMarzio's TSL100 with custom 4x12 cab. TSL122 with Man 'O War Speakers. TSL602 #1 with JBL D123 Speakers and 602 #2 with Altec 417 Speakers. "Oh so sweet my friends." DSL401 #1 with Red Fang Speaker and 401 #2 with JBL D123 Speaker. Tubes: Let's just say they are NOS that kick ass.

10-15-2009, 08:43 PM	#1729 (permalink)
wegman Senior Member Join Date: Oct 2009 Posts: 138	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? You know I was a run of the mill mild mannored Joe till I found this thread. Now I am looking for old tubes like a junkie looking to score. I have been asking everyone I know if they have any old tubes. It turns out a guy I work with used to repair TV's and old electronics. I told him what I was looking for and he knew right away what it was. He said he is going to look around and see if he has anything. If he does it is mine. If I come across anything interesting I will post it. Let's say this guy comes up with something. Any words of wisdom before I go popping a 40 year old tube in my Marshall? I mean it sounds like crap right now but at least it works. __________________ Ian St Ian says "If your not playing Gibson and Marshall your a wanker!" Marshall JCM 800 2210 (1989) Marshall MG CD10 (hi guys!) Gibson Les Paul Custom (1981) Mackie 24x8 mixing console Alesis ADAT HD 24 digital recorder Shure KSM 27

10-15-2009, 09:07 PM	#1730 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,583	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Putting a bad preamp tube is not going to hurt the amp and you will know right away that it's bad. Without a tester, all you can do is roll them. I wish you the very best and I hope the guy loads you down with some nice 12AX7's. What you will hope for is White Label RCA, 59-66 Raytheon Black Plates, any tube that says 5751, 12AT7, 6681 or 7025. Any thing with a black plate, GE, RCA or Sylvania. If you score, try to get some clear pics up (I suck at it myself, but some of it is my digital camera) and then we can tell you what you have. __________________ MARTY 2009 Gibson Explorer-Hell Raising Machine 1989 Fender Strat Plus USA 2008 Fender Tele USA 2004 Schecter Elite w/DiMarzio's TSL100 with custom 4x12 cab. TSL122 with Man 'O War Speakers. TSL602 #1 with JBL D123 Speakers and 602 #2 with Altec 417 Speakers. "Oh so sweet my friends." DSL401 #1 with Red Fang Speaker and 401 #2 with JBL D123 Speaker. Tubes: Let's just say they are NOS that kick ass.

10-15-2009, 10:20 PM	#1733 (permalink)
wegman Senior Member Join Date: Oct 2009 Posts: 138	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Marty, RiverRatt Thanks for all the information. I really appreciate it. I didn't realize there were other tubes that would work. I asked him to look for 12AX7s/ECC83s. He knew right away they were pre-amp tubes. I was not schooled enough to tell him to look for others. I will tell him to be on the look out for some of the others you guys mentioned. I am like a little kid at Christmas. I can't wait to go to work tomorrow. __________________ Ian St Ian says "If your not playing Gibson and Marshall your a wanker!" Marshall JCM 800 2210 (1989) Marshall MG CD10 (hi guys!) Gibson Les Paul Custom (1981) Mackie 24x8 mixing console Alesis ADAT HD 24 digital recorder Shure KSM 27

10-15-2009, 11:53 PM	#1734 (permalink)
RiverRatt Senior Member Join Date: May 2008 Location: Between Memphis and Nashville Posts: 517	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Here's a list that has some substitutions. One thing to realize is that while, for example, all the substitutions they have listed for the 12AX7 tube type will work, but may have different gain characteristics. Also the power tubes they have listed would not substitute without some changes to the bias resistors at least, but any of the tubes you see listed here would be good to look for. The 6CA7 = EL34 = KT77. I don't know why they put all those others as subs. Tube Substitution Table Also, any 12A_7 will substitute for any other, but as above, they have different gain levels. 12BZ7s are an interesting 12AX7 substitution, too. In the second gain stage, they can really make a Marshall sound hot-rodded. A 12BH7 will behave about like a 12AT7.

10-16-2009, 01:35 PM	#1739 (permalink)
RiverRatt Senior Member Join Date: May 2008 Location: Between Memphis and Nashville Posts: 517	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? You won't hurt anything by giving them a try, but odds are you won't like them in your guitar amp. The 12BH7 has about the same gain as a 12AT7 and might could be used as a phase inverter, but the 12AU7 will neuter an amp in just about any spot. Both of these tubes can be (and are) used in low-watt guitar amplifiers as a power tube. There's a 1-watt amp project at AX84.com called the Firefly that uses a 12AU7 output tube, and I've been reading that Blackstar makes a low-watt amp that uses the 12BH7.

10-16-2009, 02:43 PM	#1740 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,583	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Joe... I'm glad you like you new CP Power Tubes. Hey...maybe they finally got it right. Now I won't put them on the same level as a dual getter, black plate, Fat Boy. These tubes can take more power than any other 6CA7's, EL34's and KT77's. There are even some that are more rare than a regular Fat Boy. However, if these tubes can handle the plate power of my 602's (500VDC+), I will have to look strongly at them. My main thing is I want to hear your review with the tubes at volume. __________________ MARTY 2009 Gibson Explorer-Hell Raising Machine 1989 Fender Strat Plus USA 2008 Fender Tele USA 2004 Schecter Elite w/DiMarzio's TSL100 with custom 4x12 cab. TSL122 with Man 'O War Speakers. TSL602 #1 with JBL D123 Speakers and 602 #2 with Altec 417 Speakers. "Oh so sweet my friends." DSL401 #1 with Red Fang Speaker and 401 #2 with JBL D123 Speaker. Tubes: Let's just say they are NOS that kick ass.

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