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

joshuaaewallen · 01-29-2009, 10:07 PM

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!

Patill · 01-30-2009, 12:37 AM

preamp tubes last A LOT longer than power amp tubes because they don´t get that hot. A broken Preamp tube is mostly a production mistake.

Tubes in microphones for example stay there their whole life usually, there is no socket to change them.

I don´t know how they will affect your sound, but that´s very hard to tell anyway.

steelhorse · 01-30-2009, 12:38 AM

yep, yep and yep! Have fun with it and explore the different tonal palettes available, you never know what you might stumble across!

Depending on the manufacturer, the type of tube (standard, high gain, high gain/balanced, gold pin etc.) and the position, pre amp tubes can make a big difference in tone.

joshuaaewallen · 02-01-2009, 06:59 AM

Quote:

Originally Posted by steelhorse

yep, yep and yep! Have fun with it and explore the different tonal palettes available, you never know what you might stumble across!

Depending on the manufacturer, the type of tube (standard, high gain, high gain/balanced, gold pin etc.) and the position, pre amp tubes can make a big difference in tone.

Are there any good resources to help gain some insight into the tone characteristics of different tubes prior to actually buying a bunch of different tubes and juts blindly experimenting?

Eag · 02-01-2009, 03:38 PM

Quote:

Originally Posted by joshuaaewallen

Are there any good resources to help gain some insight into the tone characteristics of different tubes prior to actually buying a bunch of different tubes and juts blindly experimenting?

Plenty of good sources. One decision you will be making is whether you are going to go with new production, NOS, or both. Next you will want to assess your amp's tone and decide what you want to change. Is the tone too bright? Too dark? Too fizzy? Too much gain? Not enough gain? Too smooth? Too gritty? There are preamp tubes which will address any of these tonal points. For example, in new production tubes, JJ 12ax7s are generally regarded as rather dark in tone which can be nice for taming a bright and brassy plexi....the list goes on and on and on....

jcmjmp · 02-01-2009, 04:04 PM

Quote:

Originally Posted by joshuaaewallen

Are there any good resources to help gain some insight into the tone characteristics of different tubes prior to actually buying a bunch of different tubes and juts blindly experimenting?

Vacuum tubes @ thetubestore. New and NOS electron tubes for any amplifier.

http://thetubestore.com/12ax7review.html

They have some basic reviews of their preamp tubes. Its a good starting point.

joshuaaewallen · 02-09-2009, 08:34 PM

Quote:

Originally Posted by jcmjmp

Vacuum tubes @ thetubestore. New and NOS electron tubes for any amplifier.

12AX7 Tube Type Review

They have some basic reviews of their preamp tubes. Its a good starting point.

Thanks guys... I will definitely be doin' some research into this. I am really exited about the possibilities!

The Mick · 02-13-2009, 05:46 PM

One of the best things you can do for your amp and yourself is search the thrift stores for old cabinet stereos from the 50's they were very popular. I have found many with the original Telefunken 12ax7's in them. Dealing with the big cabinet is a pain but for the Telefunken's at the price of the stereo it's worth all the hassle.

Eag · 02-13-2009, 09:17 PM

Quote:

Originally Posted by The Mick

One of the best things you can do for your amp and yourself is search the thrift stores for old cabinet stereos from the 50's they were very popular. I have found many with the original Telefunken 12ax7's in them. Dealing with the big cabinet is a pain but for the Telefunken's at the price of the stereo it's worth all the hassle.

+1

Someone gave me an old Revere talkie movie projector dated 1954. It had two Black Plate RCA 12ax7 and one Amperex EL84 in it.

(I also swiped the way-cool bakelite knobs off of it.)

joshuaaewallen · 02-18-2009, 02:51 PM

Hello All...

Can anyone tell me on a TSL122 which preamp tube effects which part of the signal chain in the preamp?

joshuaaewallen · 03-13-2009, 12:33 PM

Anyone?

spikei · 03-13-2009, 06:17 PM

its quite a complicated one, i can tell you the v4 is phase inverter, i have seen a thread some were. do a search you will find it.

big dooley · 03-13-2009, 06:53 PM

V1 and V2 are the gain stages
V3 tone stack / cathode follower
V4 PI

joshuaaewallen · 03-13-2009, 07:05 PM

So... Since the four pre-amp tubes "cascade" gain and tone qualities from one tube to the next... Starting with V1 going up to V4... Am I better off going w/ a lower gain more harmonically rich style 12AX7 then increasing the gain in my tube type as I work up to V4 or am I better off to start w/ a high gain 12AX& and move from there into lower gain 12AX7's? The intent being to not lose my overall high gain, but to also create a more harmonically rich tone, not just high gain w/out any soul. Know what ah mean, Vern?

MartyStrat54 · 03-13-2009, 07:19 PM

Quote:

Originally Posted by big dooley

V1 and V2 are the gain stages
V3 tone stack / cathode follower
V4 PI

That is correct and this applies only to modern Marshalls using four ECC83/12AX7's in the circuit.

Please note that the preamp tube is actually two identical circuits inside of one glass envelope. However, in the real world, they might not be that identical. When replacing tubes, it is nice to have a tube tester, because it will tell you how close each half is matched. It is imperative to use a close matched 12AX7 on V4, the phase inverter. On V1 I put a tube that exhibits high gain and V2 gets a similar treatment (You may not want as much gain, so you could use a tube that measures on the low side. I have used 12AX7's that only read 60 per cent in V1 and V2 and the owners are thrilled with the sound they get.) V3 isn't as critical, but I still put a good tube in it anyway.

I like the sound of almost any NOS tube. It's a joy to be running tubes in your amp with 1955 date codes. Telefunkens, RCA Gray and Black Plates, Sylvania's, GE's and Raytheon's are all good tubes (as long as they test in an acceptable range).

I have all GE 12Ax7's (1964 date codes) in my DSL401 with Canadian made RCA Black Plate EL84's. What a monster! Total difference in tonal qualities versus the stock OE tubes.

I wish I could bring some of my tubes and my tester up to where you live and we could have some fun dialing in your TSL122. However, you know if you have a question you can contact me here or by PM.

Marty

joshuaaewallen · 03-13-2009, 07:37 PM

Quote:

Originally Posted by MartyStrat54

... It is imperative to use a close matched 12AX7 on V4, the phase inverter. On V1 I put a tube that exhibits high gain and V2 gets a similar treatment (You may not want as much gain, so you could use a tube that measures on the low side. I have used 12AX7's that only read 60 per cent in V1 and V2 and the owners are thrilled with the sound they get.) V3 isn't as critical, but I still put a good tube in it anyway...

Thank you! Now that is what I have been looking for. I know that there is going to be a certain amount of experimentation no matter what, but up to this point I really have had no clue where to start. So reading this really rocks!

Quote:

Originally Posted by MartyStrat54

... I like the sound of almost any NOS tube. It's a joy to be running tubes in your amp with 1955 date codes. Telefunkens, RCA Gray and Black Plates, Sylvania's, GE's and Raytheon's are all good tubes (as long as they test in an acceptable range).

I have all GE 12Ax7's (1964 date codes) in my DSL401 with Canadian made RCA Black Plate EL84's. What a monster! Total difference in tonal qualities versus the stock OE tubes.

I wish I could bring some of my tubes and my tester up to where you live and we could have some fun dialing in your TSL122. However, you know if you have a question you can contact me here or by PM.

Marty

What kind of differences in tone qualities between the different tubes you have tried?

Quote:

Originally Posted by joshuaaewallen

... 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 guess I am hoping someone out there with more experience will just say... "So you're playing this guitar, this amp, and you like this style of music.. Why don't you try this... (such-n-such combination of pre-amp)" Then I have, to my mind, a good starting point for experimentation.

joshuaaewallen · 03-13-2009, 07:44 PM

Quote:

Originally Posted by big dooley

V1 and V2 are the gain stages
V3 tone stack / cathode follower
V4 PI

Thanks! That's uber helpful! You guys rock.

MartyStrat54 · 03-14-2009, 02:47 PM

I posted the following on a different thread that had expanded into tube usage. I thought I would go ahead and post it here since it contains info on preamp tubes.

Marty

************************************************** **********

The gain stages are V1 and V2. One thing a 401 shares with its big brothers are four preamp tubes. What these four tubes do has been posted on other threads, so I won't go into detail about them all. However, keep in mind that an ECC83/12AX7 is a high-mu twin triode. It contains two gain stages per tube and that means your amp has four gain stages and that's a lot. In theory, a 12AX7 has a gain factor of 100, but when it is placed in the amp, it looses some of its gain due to the resistance of the circuit. A tube that will give you more gain is a 12BZ7. It is a direct replacement for a 12AX7 and has a gain of 100 as well. However, it has half the plate resistance so it maintains more gain when placed into a circuit, such as V1. I know several players who did this and they love the way it sounds. Note: I would only use a 12BZ7 in V1. Adding more could make the amp feedback and squeal at moderate volume levels.

Some people want less gain. This allows the volume controls to be cranked more and therefore you get more power tube distortion (the 12BZ7 will give you more preamp gain and preamp distortion). The tubes of choice are a 12AT7 with a gain factor of 70, a 12AU7 with a gain factor of only 17 and a 5751 (which is a low noise, lower gain 12AX7) with a gain factor of 70. Other 12xx7 tubes with a 9A pin layout are: 12AX7A, 12AD7, 12DF7, 12DT7, 7025 (Ultra quiet, high gain 12AX7), and 12DM7. There are many more and some of these other tubes might work. I'm only listing what are known to be direct replacements for an ECC83/12AX7 tube. Note: If you want a super clean channel, I would recommend a 5751 or a 7025. This is what I use in V1. However the 5751 can be bought for less money than a 7025. The 7025 is very quiet, but has a gain factor of 100 like a 12AX7.

I you want to try a 12BZ7, the only place you can find them are on Ebay. I haven't seen any tube dealers that sell them (or they were out of stock). These tubes are usually new old stock (NOS) tubes and are in great condition.

joshuaaewallen · 03-14-2009, 03:59 PM

V4 is the one in the metal shield / tube, correct?

joshuaaewallen · 03-14-2009, 04:23 PM

Quote:

Originally Posted by MartyStrat54

... A tube that will give you more gain is a 12BZ7. It is a direct replacement for a 12AX7 and has a gain of 100 as well. However, it has half the plate resistance so it maintains more gain when placed into a circuit, such as V1. I know several players who did this and they love the way it sounds. Note: I would only use a 12BZ7 in V1. Adding more could make the amp feedback and squeal at moderate volume levels....

How much squealing are we talking? Could this possibly be used to create controlled feedback?

Quote:

Originally Posted by MartyStrat54

... Some people want less gain. This allows the volume controls to be cranked more and therefore you get more power tube distortion (the 12BZ7 will give you more preamp gain and preamp distortion)...

... Pre-Amp distortion sounds more like my cup of tea. I never have opportunity to crank up enough to actually get power amp distortion. Plus I am theorizing that the split EL84/EL34 power section might help w/ that anyway...

Quote:

Originally Posted by MartyStrat54

Note: If you want a super clean channel, I would recommend a 5751 or a 7025. This is what I use in V1. However the 5751 can be bought for less money than a 7025. The 7025 is very quiet, but has a gain factor of 100 like a 12AX7.

I you want to try a 12BZ7, the only place you can find them are on Ebay. I haven't seen any tube dealers that sell them (or they were out of stock). These tubes are usually new old stock (NOS) tubes and are in great condition.

Ok... We know I like my preamp distortion... How do I balance this rock-n-roll fantasy with my love of a sweet clean channel? Since you prescribe the V1 position be changed for clean and distortion? I can honestly say that as-is, the TSL122 has a pretty amazing clean channel which is very surprising for a multi-channel amp. What do you think?

MartyStrat54 · 03-14-2009, 06:43 PM

V1 is the shielded tube with the metal cover on it. It is the first tube in the preamplification chain and it is imperative that it does not pick up any RF or other radiation or else it will send it down the line and V2 will amplify any unwanted noise from V1. That is why my first choice for V1 is a RCA 7025.

You may want to try a 12BZ7 in your rig. It won't hurt anything and you may like it. If you run two 12BZ7's you would probably get into a situation where the tubes would squeal (not in control, but out of control). I haven't ever heard of anyone using two, just one in the V1 position.

V3 and V4 are part of the amp circuit and V1 and V2 are in the gain stages. It is V4's job to perfectly "flip" the AC signal prior to going to the power tubes. That's why you want a closely matched tube to perform this. V3 is in the cathode follower circuit/tone stack. Again, part of a circuit in the amp.

Now this is to see if you are reading or not. I posted pictures of my amps. Did you see them? Well it is under a thread called, "About Time I Posted My Gear...Some Of It Anyway." in Marshall Amps. I want to post more pictures of my gear, but I do not know how to paste a picture directly to the thread. How the hell do you do it? I had to use TinyPics.com to host my pictures and you have to click on a link. I want my pictures to be right there on the page without any clicking. Please respond here, or you can email me at meospeak@aol.com.

Thanks, Marty

joshuaaewallen · 03-14-2009, 08:14 PM

HI Marty,

Another great post, as usual. Apparently I had the order of V1-4 mixed up, but gradually, thanks to all these great posts, I am starting to comprehend how things work w/ regard to my amp. Thank you!

Pictures. Easy peezy. Obviously you will be logged into the forum to start with, so...

1st: I like to upload my gear pics right to my Marshall forum profile (you can create an album)(I think it's simpler this way). You can see mine at Marshall Amp Forum - joshuaaewallen's Albums. When you do this, each picture in your album has it's own URL (web address).

2nd: Create a post or thread.

3rd: Write what you want in your post. Wherever you would like a picture to appear in your post click on the symbol above the text window that looks like a post card.

This pops up a window asking for a URL for the picture you want to paste. Now simply paste the URL from the picture you want to post onto the box and click 'ok'.

4th: Enjoy your expert quality post.

Ok... So this post isn't 'expert' by any means, but... Hopefully it helps. Lemme know if you need more help.

Do you use instant messenger? That may speed up the process...

MartyStrat54 · 03-14-2009, 11:58 PM

Holy cow! You went the full Monte didn't you. My God, you even copied the Windows page for me. Well, I found out how to do this. I don't know why the other web hosting company didn't work. I went from TinyPics.com to PhotoBucket.com and it worked with PhotoBucket. It is nice to know that I can store my pics in "My Album." That's what I'll do from now on. Thanks for your help.

Marty

joshuaaewallen · 03-15-2009, 08:23 AM

A picture is worth a thousand words... So I always try to go that route in the hopes that it will clarify anything that my own inept directions may be lacking...

joshuaaewallen · 03-15-2009, 08:40 AM

Quote:

Originally Posted by MartyStrat54

... It is V4's job to perfectly "flip" the AC signal prior to going to the power tubes. That's why you want a closely matched tube to perform this...

So... Apparently... Thinking I was changing out V1, I actually changed out V4... Smooth move.

But fortunately enough it seems to have helped switching out the Fender Branded 12ax7 with the JJ... Seems a bit less harsh to my ears now...

Here's a question... I was looking on eBay for a 12BZ7 tube, and there appears to be quite a price spectrum out there, and a variety of NOS manufacturers. Is there significant difference in sound and quality between these different tubes, even though they are all listed as 12BZ7's?

MartyStrat54 · 03-15-2009, 04:33 PM

Yeah, a lot of people do that. That is why I tell beginners to make a chart showing which tube came out of which socket. I do see a lot of posting where someone will tell another person with tube problems to just swap a new tube in all of the sockets (in an attempt to cure the problem). Preamp tubes can have problems that will not show up at certain times, so this method of trouble shooting is like hand grenades in a pond. Hopefully, something will float to the top. Just make sure V4 has a nice matched tube in it. An unmatched tube will not hurt the amp, but the phase inverting will be electronically lop-sided.

I would be a liar if I told you all 12BZ7's sounded alike. On the other hand, I would be the God of Tubes, if I could tell you which one would sound the best in your amp. Let me go to Ebay on my other computer and take a look at what is being offered and I will make my suggestions.

JUMP ALL OVER THE BLACK PLATE RAYTHEON!!! Zero bid, a hour and a half to go and starting bid of $7.99

The RAYTHEON Black Plate-BIN for $14.00 (plus $6 to ship.)

The Hytron or GE-BIN for $14.95

Try to get the first one for $7.99!

Let me know how you do.

Marty

MartyStrat54 · 03-15-2009, 07:04 PM

How are your plants? Is that where you've been, watering your plants. Well, being that I am a savvy Ebay buyer, I won the Black Plate Raytheon. I got it for $16.50 including the shipping. I should get it by Wednesday or Thursday. What a sweet deal! Oh I forgot, you were looking for a tube like this. Well, when I get it, I will test it on my sweet B and K 707 tube tester and see how she scores. The seller stated NOS, so it should read at least 90/90. Once I get done testing it, it will be ready for you if you want it. If you don't want it, no problem, I'll just add it to my inventory.

Marty

joshuaaewallen · 03-15-2009, 09:37 PM

Yup. Well watered plants. Hydration is very important.

I sent you an email in response to your excellent eBay resourcefulness... Have a look and let me know. Thanks again Marty!

Ciao!

joshuaaewallen · 03-18-2009, 11:13 PM

Hey Marty,

I am very exited to try out the pre-amp tubes that are heading this way. I will try to contain my inner child and not just go changing tubes willy-nilly

. I'm gonna try my bestest to run through it in an organized scientific (not using the grenade method) sort of way.

I'll post my results here. Thanks again Mate!

joshuaaewallen · 03-21-2009, 08:13 PM

They're Here...

Hi Marty, I got the tubes today. Holy cow you rock man! I haven't put any in yet, but since I am a total geek I have started the preliminary steps of my pre-amp tube experiments.

Right now, here's what is in the amp before making any new changes:

V1 & V2 Both have a Westinghouse 12AX7A:

V3 Has a Groove Tubes GT12AX7R:

And in V4, there's a JJ ECC83S/12AX7:

Far out, eh? Any thoughts?

I think first I think I'll leave all as is, except I will put the Raytheon Black Plate 12BZ7 in V1 and see how that goes...

Let the fun commence!

01-29-2009, 10:07 PM	#1 (permalink)
joshuaaewallen Senior Member Join Date: Jan 2009 Location: The Dark Side Of The Moon Posts: 1,346	Preamp Tubes? - Who, What, When, Where, Why, and How? 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! j2112c likes this. __________________ Josh -2004 PRS Custom 24 10 Top (Sustainiac System w/ Duncan Alnico II bridge PickUp) -1999 Marshall JCM 2000 TSL (Wilder Amplification mods) -Martimus Maximus Preamp Tone Pack (Rollin' With Da Homie's) -ElectroHarmonix .44 Magnum -PRS Dallas 120 2x12 Vintage 30's -Digitech RP1000

01-30-2009, 12:37 AM	#2 (permalink)
Patill Member Join Date: Jan 2009 Posts: 38	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? preamp tubes last A LOT longer than power amp tubes because they don´t get that hot. A broken Preamp tube is mostly a production mistake. Tubes in microphones for example stay there their whole life usually, there is no socket to change them. I don´t know how they will affect your sound, but that´s very hard to tell anyway.

01-30-2009, 12:38 AM	#3 (permalink)
steelhorse Senior Member Join Date: May 2008 Posts: 3,974	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? yep, yep and yep! Have fun with it and explore the different tonal palettes available, you never know what you might stumble across! Depending on the manufacturer, the type of tube (standard, high gain, high gain/balanced, gold pin etc.) and the position, pre amp tubes can make a big difference in tone. HoneyDo likes this. __________________ www.ricojronline.com 760-956-6619 Garmopat Pedal Mods "I wouldn't mind hearing your head smash through a glass door. That would be cool..." luekmeyer

02-13-2009, 05:46 PM	#8 (permalink)
The Mick Member Join Date: Feb 2009 Location: North Carolina Posts: 44	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? One of the best things you can do for your amp and yourself is search the thrift stores for old cabinet stereos from the 50's they were very popular. I have found many with the original Telefunken 12ax7's in them. Dealing with the big cabinet is a pain but for the Telefunken's at the price of the stereo it's worth all the hassle.

02-18-2009, 02:51 PM	#10 (permalink)
joshuaaewallen Senior Member Join Date: Jan 2009 Location: The Dark Side Of The Moon Posts: 1,346	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Hello All... Can anyone tell me on a TSL122 which preamp tube effects which part of the signal chain in the preamp? __________________ Josh -2004 PRS Custom 24 10 Top (Sustainiac System w/ Duncan Alnico II bridge PickUp) -1999 Marshall JCM 2000 TSL (Wilder Amplification mods) -Martimus Maximus Preamp Tone Pack (Rollin' With Da Homie's) -ElectroHarmonix .44 Magnum -PRS Dallas 120 2x12 Vintage 30's -Digitech RP1000

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03-13-2009, 12:33 PM	#11 (permalink)
joshuaaewallen Senior Member Join Date: Jan 2009 Location: The Dark Side Of The Moon Posts: 1,346	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Anyone? __________________ Josh -2004 PRS Custom 24 10 Top (Sustainiac System w/ Duncan Alnico II bridge PickUp) -1999 Marshall JCM 2000 TSL (Wilder Amplification mods) -Martimus Maximus Preamp Tone Pack (Rollin' With Da Homie's) -ElectroHarmonix .44 Magnum -PRS Dallas 120 2x12 Vintage 30's -Digitech RP1000

03-13-2009, 06:17 PM	#12 (permalink)
spikei Senior Member Join Date: May 2008 Posts: 337	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? its quite a complicated one, i can tell you the v4 is phase inverter, i have seen a thread some were. do a search you will find it.

03-13-2009, 06:53 PM	#13 (permalink)
big dooley Senior Member Join Date: Sep 2008 Location: zealand, netherlands Posts: 5,537	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? V1 and V2 are the gain stages V3 tone stack / cathode follower V4 PI

03-13-2009, 07:05 PM	#14 (permalink)
joshuaaewallen Senior Member Join Date: Jan 2009 Location: The Dark Side Of The Moon Posts: 1,346	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? So... Since the four pre-amp tubes "cascade" gain and tone qualities from one tube to the next... Starting with V1 going up to V4... Am I better off going w/ a lower gain more harmonically rich style 12AX7 then increasing the gain in my tube type as I work up to V4 or am I better off to start w/ a high gain 12AX& and move from there into lower gain 12AX7's? The intent being to not lose my overall high gain, but to also create a more harmonically rich tone, not just high gain w/out any soul. Know what ah mean, Vern? __________________ Josh -2004 PRS Custom 24 10 Top (Sustainiac System w/ Duncan Alnico II bridge PickUp) -1999 Marshall JCM 2000 TSL (Wilder Amplification mods) -Martimus Maximus Preamp Tone Pack (Rollin' With Da Homie's) -ElectroHarmonix .44 Magnum -PRS Dallas 120 2x12 Vintage 30's -Digitech RP1000 Last edited by joshuaaewallen; 03-13-2009 at 07:06 PM. Reason: spelling corrections...

03-14-2009, 02:47 PM	#18 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Now in Muskogee, by Tulsa Posts: 18,271	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? I posted the following on a different thread that had expanded into tube usage. I thought I would go ahead and post it here since it contains info on preamp tubes. Marty ************************************************ ******** The gain stages are V1 and V2. One thing a 401 shares with its big brothers are four preamp tubes. What these four tubes do has been posted on other threads, so I won't go into detail about them all. However, keep in mind that an ECC83/12AX7 is a high-mu twin triode. It contains two gain stages per tube and that means your amp has four gain stages and that's a lot. In theory, a 12AX7 has a gain factor of 100, but when it is placed in the amp, it looses some of its gain due to the resistance of the circuit. A tube that will give you more gain is a 12BZ7. It is a direct replacement for a 12AX7 and has a gain of 100 as well. However, it has half the plate resistance so it maintains more gain when placed into a circuit, such as V1. I know several players who did this and they love the way it sounds. Note: I would only use a 12BZ7 in V1. Adding more could make the amp feedback and squeal at moderate volume levels. Some people want less gain. This allows the volume controls to be cranked more and therefore you get more power tube distortion (the 12BZ7 will give you more preamp gain and preamp distortion). The tubes of choice are a 12AT7 with a gain factor of 70, a 12AU7 with a gain factor of only 17 and a 5751 (which is a low noise, lower gain 12AX7) with a gain factor of 70. Other 12xx7 tubes with a 9A pin layout are: 12AX7A, 12AD7, 12DF7, 12DT7, 7025 (Ultra quiet, high gain 12AX7), and 12DM7. There are many more and some of these other tubes might work. I'm only listing what are known to be direct replacements for an ECC83/12AX7 tube. Note: If you want a super clean channel, I would recommend a 5751 or a 7025. This is what I use in V1. However the 5751 can be bought for less money than a 7025. The 7025 is very quiet, but has a gain factor of 100 like a 12AX7. I you want to try a 12BZ7, the only place you can find them are on Ebay. I haven't seen any tube dealers that sell them (or they were out of stock). These tubes are usually new old stock (NOS) tubes and are in great condition.

03-14-2009, 03:59 PM	#19 (permalink)
joshuaaewallen Senior Member Join Date: Jan 2009 Location: The Dark Side Of The Moon Posts: 1,346	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? V4 is the one in the metal shield / tube, correct? __________________ Josh -2004 PRS Custom 24 10 Top (Sustainiac System w/ Duncan Alnico II bridge PickUp) -1999 Marshall JCM 2000 TSL (Wilder Amplification mods) -Martimus Maximus Preamp Tone Pack (Rollin' With Da Homie's) -ElectroHarmonix .44 Magnum -PRS Dallas 120 2x12 Vintage 30's -Digitech RP1000

03-14-2009, 06:43 PM	#21 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Now in Muskogee, by Tulsa Posts: 18,271	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? V1 is the shielded tube with the metal cover on it. It is the first tube in the preamplification chain and it is imperative that it does not pick up any RF or other radiation or else it will send it down the line and V2 will amplify any unwanted noise from V1. That is why my first choice for V1 is a RCA 7025. You may want to try a 12BZ7 in your rig. It won't hurt anything and you may like it. If you run two 12BZ7's you would probably get into a situation where the tubes would squeal (not in control, but out of control). I haven't ever heard of anyone using two, just one in the V1 position. V3 and V4 are part of the amp circuit and V1 and V2 are in the gain stages. It is V4's job to perfectly "flip" the AC signal prior to going to the power tubes. That's why you want a closely matched tube to perform this. V3 is in the cathode follower circuit/tone stack. Again, part of a circuit in the amp. Now this is to see if you are reading or not. I posted pictures of my amps. Did you see them? Well it is under a thread called, "About Time I Posted My Gear...Some Of It Anyway." in Marshall Amps. I want to post more pictures of my gear, but I do not know how to paste a picture directly to the thread. How the hell do you do it? I had to use TinyPics.com to host my pictures and you have to click on a link. I want my pictures to be right there on the page without any clicking. Please respond here, or you can email me at meospeak@aol.com. Thanks, Marty 61rocker likes this.

03-14-2009, 08:14 PM	#22 (permalink)
joshuaaewallen Senior Member Join Date: Jan 2009 Location: The Dark Side Of The Moon Posts: 1,346	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? HI Marty, Another great post, as usual. Apparently I had the order of V1-4 mixed up, but gradually, thanks to all these great posts, I am starting to comprehend how things work w/ regard to my amp. Thank you! Pictures. Easy peezy. Obviously you will be logged into the forum to start with, so... 1st: I like to upload my gear pics right to my Marshall forum profile (you can create an album)(I think it's simpler this way). You can see mine at Marshall Amp Forum - joshuaaewallen's Albums. When you do this, each picture in your album has it's own URL (web address). 2nd: Create a post or thread. 3rd: Write what you want in your post. Wherever you would like a picture to appear in your post click on the symbol above the text window that looks like a post card. This pops up a window asking for a URL for the picture you want to paste. Now simply paste the URL from the picture you want to post onto the box and click 'ok'. 4th: Enjoy your expert quality post. Ok... So this post isn't 'expert' by any means, but... Hopefully it helps. Lemme know if you need more help. Do you use instant messenger? That may speed up the process... __________________ Josh -2004 PRS Custom 24 10 Top (Sustainiac System w/ Duncan Alnico II bridge PickUp) -1999 Marshall JCM 2000 TSL (Wilder Amplification mods) -Martimus Maximus Preamp Tone Pack (Rollin' With Da Homie's) -ElectroHarmonix .44 Magnum -PRS Dallas 120 2x12 Vintage 30's -Digitech RP1000

03-14-2009, 11:58 PM	#23 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Now in Muskogee, by Tulsa Posts: 18,271	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Holy cow! You went the full Monte didn't you. My God, you even copied the Windows page for me. Well, I found out how to do this. I don't know why the other web hosting company didn't work. I went from TinyPics.com to PhotoBucket.com and it worked with PhotoBucket. It is nice to know that I can store my pics in "My Album." That's what I'll do from now on. Thanks for your help. Marty

03-15-2009, 08:23 AM	#24 (permalink)
joshuaaewallen Senior Member Join Date: Jan 2009 Location: The Dark Side Of The Moon Posts: 1,346	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? A picture is worth a thousand words... So I always try to go that route in the hopes that it will clarify anything that my own inept directions may be lacking... __________________ Josh -2004 PRS Custom 24 10 Top (Sustainiac System w/ Duncan Alnico II bridge PickUp) -1999 Marshall JCM 2000 TSL (Wilder Amplification mods) -Martimus Maximus Preamp Tone Pack (Rollin' With Da Homie's) -ElectroHarmonix .44 Magnum -PRS Dallas 120 2x12 Vintage 30's -Digitech RP1000

03-15-2009, 04:33 PM	#26 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Now in Muskogee, by Tulsa Posts: 18,271	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Yeah, a lot of people do that. That is why I tell beginners to make a chart showing which tube came out of which socket. I do see a lot of posting where someone will tell another person with tube problems to just swap a new tube in all of the sockets (in an attempt to cure the problem). Preamp tubes can have problems that will not show up at certain times, so this method of trouble shooting is like hand grenades in a pond. Hopefully, something will float to the top. Just make sure V4 has a nice matched tube in it. An unmatched tube will not hurt the amp, but the phase inverting will be electronically lop-sided. I would be a liar if I told you all 12BZ7's sounded alike. On the other hand, I would be the God of Tubes, if I could tell you which one would sound the best in your amp. Let me go to Ebay on my other computer and take a look at what is being offered and I will make my suggestions. JUMP ALL OVER THE BLACK PLATE RAYTHEON!!! Zero bid, a hour and a half to go and starting bid of $7.99 The RAYTHEON Black Plate-BIN for $14.00 (plus $6 to ship.) The Hytron or GE-BIN for $14.95 Try to get the first one for $7.99! Let me know how you do. Marty

03-15-2009, 07:04 PM	#27 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Now in Muskogee, by Tulsa Posts: 18,271	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? How are your plants? Is that where you've been, watering your plants. Well, being that I am a savvy Ebay buyer, I won the Black Plate Raytheon. I got it for $16.50 including the shipping. I should get it by Wednesday or Thursday. What a sweet deal! Oh I forgot, you were looking for a tube like this. Well, when I get it, I will test it on my sweet B and K 707 tube tester and see how she scores. The seller stated NOS, so it should read at least 90/90. Once I get done testing it, it will be ready for you if you want it. If you don't want it, no problem, I'll just add it to my inventory. Marty

03-15-2009, 09:37 PM	#28 (permalink)
joshuaaewallen Senior Member Join Date: Jan 2009 Location: The Dark Side Of The Moon Posts: 1,346	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Yup. Well watered plants. Hydration is very important. I sent you an email in response to your excellent eBay resourcefulness... Have a look and let me know. Thanks again Marty! Ciao! __________________ Josh -2004 PRS Custom 24 10 Top (Sustainiac System w/ Duncan Alnico II bridge PickUp) -1999 Marshall JCM 2000 TSL (Wilder Amplification mods) -Martimus Maximus Preamp Tone Pack (Rollin' With Da Homie's) -ElectroHarmonix .44 Magnum -PRS Dallas 120 2x12 Vintage 30's -Digitech RP1000

03-18-2009, 11:13 PM	#29 (permalink)
joshuaaewallen Senior Member Join Date: Jan 2009 Location: The Dark Side Of The Moon Posts: 1,346	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Hey Marty, I am very exited to try out the pre-amp tubes that are heading this way. I will try to contain my inner child and not just go changing tubes willy-nilly. I'm gonna try my bestest to run through it in an organized scientific (not using the grenade method) sort of way. I'll post my results here. Thanks again Mate! __________________ Josh -2004 PRS Custom 24 10 Top (Sustainiac System w/ Duncan Alnico II bridge PickUp) -1999 Marshall JCM 2000 TSL (Wilder Amplification mods) -Martimus Maximus Preamp Tone Pack (Rollin' With Da Homie's) -ElectroHarmonix .44 Magnum -PRS Dallas 120 2x12 Vintage 30's -Digitech RP1000 Last edited by joshuaaewallen; 03-21-2009 at 08:14 PM.

03-21-2009, 08:13 PM	#30 (permalink)
joshuaaewallen Senior Member Join Date: Jan 2009 Location: The Dark Side Of The Moon Posts: 1,346	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? They're Here... Hi Marty, I got the tubes today. Holy cow you rock man! I haven't put any in yet, but since I am a total geek I have started the preliminary steps of my pre-amp tube experiments. Right now, here's what is in the amp before making any new changes: V1 & V2 Both have a Westinghouse 12AX7A: V3 Has a Groove Tubes GT12AX7R: And in V4, there's a JJ ECC83S/12AX7: Far out, eh? Any thoughts? I think first I think I'll leave all as is, except I will put the Raytheon Black Plate 12BZ7 in V1 and see how that goes... Let the fun commence! __________________ Josh -2004 PRS Custom 24 10 Top (Sustainiac System w/ Duncan Alnico II bridge PickUp) -1999 Marshall JCM 2000 TSL (Wilder Amplification mods) -Martimus Maximus Preamp Tone Pack (Rollin' With Da Homie's) -ElectroHarmonix .44 Magnum -PRS Dallas 120 2x12 Vintage 30's -Digitech RP1000

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