Preamp Tubes? - Who, What, When, Where, Why, and How? - Page 9

solarburnDSL50 · 05-04-2009, 08:36 AM

Quote:

Originally Posted by joshuaaewallen

Hey Marty, How's it goin'? You guys have been BUSY on the forum. Wow! Question... Do you recall which thread has this video you mentioned? I'd really like to see that.

I threw that GE 12BZ7 (I think it's a '52 vintage) into my amp with a couple of tube dampers on it... Boy... I forgot how great that tube sound in V2! Sustain and harmonics for days. I jut need to play a wee bit less sloppy

.

With the dampers and normal playing I'll see how that tube holds up. If it becomes a rattler then I guess we'll know for sure that it just can't survive life it a high gain combo.

Anyhoo... I have a box of tubes headed your way, and as soon as I have a few extra $$$, I'd like to buy a few tubes off you that are in the ICBM type category, and locate a few current production tubes of different makes and do some comparisons.

Great posts! Take care guys, talk at ya later!

Try this Josh:

Dailymotion - Fabrication d'une lampe triode - a Hi-Tech et Science video

solarburnDSL50 · 05-04-2009, 08:43 AM

Check this article out guys. Its a pretty quick read:

NBC: In Russia, a battle for rock's soul - Europe- msnbc.com

joshuaaewallen · 05-04-2009, 09:16 AM

Quote:

Originally Posted by solarburnDSL50

Try this Josh:

Dailymotion - Fabrication d'une lampe triode - a Hi-Tech et Science video

Quote:

Originally Posted by solarburnDSL50

Check this article out guys. Its a pretty quick read:

NBC: In Russia, a battle for rock's soul - Europe- msnbc.com

Quote:

Originally Posted by solarburnDSL50

Try this Josh:

Dailymotion - Fabrication d'une lampe triode - a Hi-Tech et Science video

Quote:

Originally Posted by joshuaaewallen

... Electro-Harmonix Wins Legal Battle To Keep Russian Factory | Fretbase: Guitars, Tabs, Chords and More - The video is from 2006, but the story is pretty recent, February 2009.
... I would have to logically conclude that even though most (I am being generous here by not saying all, even though that wording is more likely true) modern production tubes are inferior to the tubes of yesteryear, there is undoubtedly many differences in design, materials, workmanship, and thus durability & tone, from one tube to the next...

Thanks Solarburn! I've seen that second (Mike Mathews) video before, but that first one... I haven't seen that one before. That's pretty cool. I'm sure that processes was slowed down a bit for the benefit of filming, and that a skilled individual could likely make tube and tube components at a rather impressive rate, however even that can't keep up with today's mass production. And that is a sad fact. It means one factory can crank out tons of tubes of dubious quality. I guess I was yet again born at the wrong time...

solarburnDSL50 · 05-04-2009, 09:34 AM

Quote:

Originally Posted by joshuaaewallen

Thanks Solarburn! I've seen that second (Mike Mathews) video before, but that first one... I haven't seen that one before. That's pretty cool. I'm sure that processes was slowed down a bit for the benefit of filming, and that a skilled individual could likely make tube and tube components at a rather impressive rate, however even that can't keep up with today's mass production. And that is a sad fact. It means one factory can crank out tons of tubes of dubious quality. I guess I was yet again born at the wrong time...

We just have to make the best of what we got now as far as what's left of the NOS and be glad guys like Marty help us noob's out(speaking of myself).

I've been roll'n tubes between 2 amps the last couple of days I need a break today. So does the family he he. Hav'n fun but its work too. I'm gonna be mailing some new production pres to Marty. Can't wait to hear his reactions on them.

joshuaaewallen · 05-04-2009, 11:13 AM

Quote:

Originally Posted by solarburnDSL50

We just have to make the best of what we got now as far as what's left of the NOS and be glad guys like Marty help us noob's out(speaking of myself)...

Count me in on both counts there mate! Marty has been a great source of info, and tubes, for this noobie (me)!

... Additionally, let me say again... All of you guys posting here are awesome!

MartyStrat54 · 05-04-2009, 02:53 PM

God, it took me a long time to find that video. I didn't respond to the thread so I manually looked through page after page before doing a search and that still took three attempts before I found it. In case the hyper link does not work, it is called:

How Valves/Tubes are made. By Mystic Fred

mullard tubes : Mullard Tubes : MullardTubes.com

Marty

MartyStrat54 · 05-04-2009, 02:55 PM

I had to manually edit the hyper link to work. At the bottom portion of the page you will see a link that states, "Watch the exciting video of the Blackburn plant, etc."

Marty

MartyStrat54 · 05-04-2009, 03:16 PM

Josh, I sent you an email about the Ruskie EL84's. Please respond.

Marty

joshuaaewallen · 05-04-2009, 03:40 PM

Quote:

Originally Posted by MartyStrat54

God, it took me a long time to find that video. I didn't respond to the thread so I manually looked through page after page before doing a search and that still took three attempts before I found it. In case the hyper link does not work, it is called:

How Valves/Tubes are made. By Mystic Fred

mullard tubes : Mullard Tubes : MullardTubes.com

Marty

Quote:

Originally Posted by MartyStrat54

I had to manually edit the hyper link to work. At the bottom portion of the page you will see a link that states, "Watch the exciting video of the Blackburn plant, etc."

Marty

That's cool. A real taste of history. I liked that. Thanks Marty.... In fact I watched it twice with my wife making fun of me the entire time for how much of a nerd I am for watching w/ such fascination...

Quote:

Originally Posted by MartyStrat54

Josh, I sent you an email about the Ruskie EL84's. Please respond.

Marty

Thanks for the heads up Marty. I'll have a look!

solarburnDSL50 · 05-07-2009, 03:23 AM

Well I finally got to wind up the NT all the way on 15 watts. Pretty damn loud 15 watter I must say. After using 12AX7 new production and NOS I think I have a combo I like best.

I've settled on, for now, a CV4024 AT7 along side a JAN Philips 12AX7WA. Both are NOS tubes. This is with the Sovtec EL84's. All this may change when I buy some NOS EL84's from Marty in a few days.

With these I'm getting the Vox chime and some nice overtones on mildly overdriven tones. I notice just a slight gain loss using the AT7 but better articulation when soloing I think. This is a plus on the Thick setting. There is an overdose of gain on it anyways(IMO). I'm liking the touch/feel that's there and the tone seems a bit better than with 2 12AX7's.

Even though there is a slight loss of gain, my clean boost puts that back in when I want it. So really with a click of a pedal any gap in gain per tube is filled in and more if needed.

Eventually I want to pair it up with a Greenback speaker so I may be rolling again when that happens. At any rate I'm going to start dig'n in and playing on it cause the NT does not hide anything.

Still have the NOS in the Marshall. Its gonna stay that way for awhile. It is a beast compared to the NT. So much bigger and open sounding with those 50 watts. Frigg'n love that amp! In a couple of months I'm going to try some SED winged C's in it. Haven't tried them yet and I hear such good things about them in a DSL. Gotta do it.

MartyStrat54 · 05-07-2009, 06:21 PM

Yeah, I put a pair of the Winged -C-'s in one of my 602's and I think they are better than most current EL34's. Maybe the E34L is right there with it, but nonetheless, the Winged -C- is a super 34 replacement.

You know, I'm thinking that I should have sent you a 5751. You could have subbed the AT7 with it. I'll bet it would be a perfect match for you. Too bad the one you have is garbage. You'd get just a little more gain without it being a super gain with an AX7.

As I said, that seems to be your style. A good 5751 cranked in V1 going into a high gain 12AX7? Well if you go back about five pages you will see I already did such a test and my conclusion was that a super high gain will make up for any gain loss in the 5751. It does however allow you to shape your tones, most notably the clean (cause that is what a 5751 does so well) channel with a different window of tones over an AX7. But when you need to wail, the ICBM in V2 will handle the matter and you have your total Marshall tone wailing away.

You ought to get yourself a 5751. They usually go for a lot less $$$ than a 12AX7. Look for one that tests stout.

Marty

solarburnDSL50 · 05-07-2009, 08:05 PM

Quote:

Originally Posted by MartyStrat54

Yeah, I put a pair of the Winged -C-'s in one of my 602's and I think they are better than most current EL34's. Maybe the E34L is right there with it, but nonetheless, the Winged -C- is a super 34 replacement.

You know, I'm thinking that I should have sent you a 5751. You could have subbed the AT7 with it. I'll bet it would be a perfect match for you. Too bad the one you have is garbage. You'd get just a little more gain without it being a super gain with an AX7.

As I said, that seems to be your style. A good 5751 cranked in V1 going into a high gain 12AX7? Well if you go back about five pages you will see I already did such a test and my conclusion was that a super high gain will make up for any gain loss in the 5751. It does however allow you to shape your tones, most notably the clean (cause that is what a 5751 does so well) channel with a different window of tones over an AX7. But when you need to wail, the ICBM in V2 will handle the matter and you have your total Marshall tone wailing away.

You ought to get yourself a 5751. They usually go for a lot less $$$ than a 12AX7. Look for one that tests stout.

Marty

I tried my Jan GE 5751 in it today in place of the AT7 and it didn't appeal to me. I think what I don't like about the 5751 is it seems less dynamic than the AT7. I don't like the texture/tone its adding in other words. Clean or overdriven. I did sub another Mullard 12AX7 in place of the AT7 and I almost settled on it. I liked it. It was pretty even as far as which 1 I wanted to use.

Next time I send you some tubes I will send the 5751 and you can test it to see if it is where it should be. I wish I had remembered I would have sent it with the batch that's on its way. Your reasoning for using the 5751 is exactly why I use the AT7 with just a hair less gain on tap. My clean boost puts a push on it too when I want. The CV4024 really is a nice AT7 I must say. That being said its bigger bro almost got the spot.

MartyStrat54 · 05-07-2009, 10:40 PM

Yeah, don't judge the sound and performance of all 5751's with the one you have. It's a dog I'm sad to say. I have two Tung-Sol 5751's and they both tear up the tester. These are 1958 tubes (not for sale) that I bought on Ebay about two years ago. I used the stoutest one when I conducted my tube tests. It gave the amp a different window of tones, but it still had some fire in its belly. With a stout 12AX7 in V2 and the amp in the crunch channel, it was crunch away. It didn't miss a beat. I can honestly say that I could live with that 5751 in V1 with a high gainer in V2. It wouldn't be a problem. A lot of people (like you) tend to like a 5751, because it is a quieter tube than an AX7. That quiet translates into a chiming clean channel. Again, it allows different tones to be shaped because of its design.

Personally, I don't think that I would want to go as low as an AT7. I tested with a real good one and I wasn't pleased with it. It was okay, but the punch seemed to be missing.

Marty

solarburnDSL50 · 05-07-2009, 11:41 PM

Quote:

Originally Posted by MartyStrat54

Yeah, don't judge the sound and performance of all 5751's with the one you have. It's a dog I'm sad to say. I have two Tung-Sol 5751's and they both tear up the tester. These are 1958 tubes (not for sale) that I bought on Ebay about two years ago. I used the stoutest one when I conducted my tube tests. It gave the amp a different window of tones, but it still had some fire in its belly. With a stout 12AX7 in V2 and the amp in the crunch channel, it was crunch away. It didn't miss a beat. I can honestly say that I could live with that 5751 in V1 with a high gainer in V2. It wouldn't be a problem. A lot of people (like you) tend to like a 5751, because it is a quieter tube than an AX7. That quiet translates into a chiming clean channel. Again, it allows different tones to be shaped because of its design.

Personally, I don't think that I would want to go as low as an AT7. I tested with a real good one and I wasn't pleased with it. It was okay, but the punch seemed to be missing.

Marty

Prolly right about my 5751. I'll send it to you one of these days soon and for curiosity sake lets see where it tests at. What the heck its not like I'm getting any use out of it. Sounds like I need to get a good 5751 cause I do like the mix of a lower gain tube with a 12AX7.

The NT is kind of different as far as having much punch. Even with 2 12AX7's there isn't really punch. There's presence but not really punch. Of course I'm use to a 50 watter that has awesome punch. I think 15 watts has alot to do with that as well as the EL84's that are in it. That's why I say I don't hear or feel like the AT7 is robbing the amp of much impact when overdriven.

I will pay close attention to that and see if there is a lessening of any impact. I've been pop'n them tubes in and out like crazy to gage the differences. I'll take a little break and see if I notice more when I come back fresh.

What I do get from the mix is great sustain and the notes are present. That hasn't been neutered. I like the tone's texture mixed with a 12AX7. Remember I tried 2 AT7's and it neutered the overdrive. So I know the AT7 can take away. The 3 12AX7's I liked together out of all the combinations were the Mullard and the Jan Philips 12AX7A as well as the RCA 12AX7A. The Mullard mixed with either of these 2 NOS was pretty good. Worth using for sure. I just can't take the RCA's out of the Marshall to run in the NT cause I like them where they are.

I will say I like the new Mullard 12AX7 in both amps and my HT dual. Nice tone frequency range & gain characteristics and has been a solid performer so far.

Joe

RiverRatt · 05-08-2009, 10:11 AM

If I wanted to up the gain on my Blackheart 5 watt head, would I need a 12BZ7? Do these perform well in an amp with only 1 preamp tube?

solarburnDSL50 · 05-08-2009, 10:15 AM

Quote:

Originally Posted by RiverRatt

If I wanted to up the gain on my Blackheart 5 watt head, would I need a 12BZ7? Do these perform well in an amp with only 1 preamp tube?

If it only has 1 preamp tube you will probably need to boost it for more gain. What preamp tube comes in it?

RiverRatt · 05-08-2009, 10:28 AM

It's a 12AX7. It came with a Sovtek, now it has a Tung-Sol.

solarburnDSL50 · 05-08-2009, 10:40 AM

Quote:

Originally Posted by RiverRatt

It's a 12AX7. It came with a Sovtek, now it has a Tung-Sol.

Read this thread:

12BZ7 info? - The Gear Page

solarburnDSL50 · 05-08-2009, 10:47 AM

Quote:

Originally Posted by RiverRatt

It's a 12AX7. It came with a Sovtek, now it has a Tung-Sol.

Sovtec's suck but they are durable thats why you see them in a lot of amps or pedals like my HT Dual. I prefer the new Mullards as far as new production go. Guys like Marty have some real hot NOS 12AX7's but they can be spendy.

If it was me I'd slap a Mullard in it and clean boost it or use a nice transparent over drive pedal in front of it. I can recommend some if you are interested. Others here will chime in about the tube.

joshuaaewallen · 05-08-2009, 04:29 PM

Quote:

Originally Posted by RiverRatt

If I wanted to up the gain on my Blackheart 5 watt head, would I need a 12BZ7? Do these perform well in an amp with only 1 preamp tube?

Hey there RiverRatt,

I've been using a GE 12BZ7 in the V2 of my Marshall for a while. LOVE the sound. To my ear it seems to have a bit more testosterone than many 12AX7's. It definitely articulates better than most 12AX7's... Which will show up more mistakes if your a sloppy player like I am, but this is a good thing because it forces me to play better.

As far as using it in a single tube amp... Dunno... Never tried. I'd say if you have one, throw it in and let your ears be your guide.

Anyhoo... That's my two cents.

RiverRatt · 05-08-2009, 05:10 PM

Thanks. I'm going to check out a nearby antique mall tomorrow. There's a guy there who has a pretty large collection of oddball tubes. Maybe I'll get lucky and find a 12BZ7. If not, I believe TubeDepot in Memphis has a few. So long as there's no chance of damaging the amp, I'll just try it out and see how it does.

MartyStrat54 · 05-08-2009, 06:58 PM

Quote:

Originally Posted by RiverRatt

Thanks. I'm going to check out a nearby antique mall tomorrow. There's a guy there who has a pretty large collection of oddball tubes. Maybe I'll get lucky and find a 12BZ7. If not, I believe TubeDepot in Memphis has a few. So long as there's no chance of damaging the amp, I'll just try it out and see how it does.

It won't damage the amp. However, the amps circuit may or may not like it. If it does, you will be able to overdrive your EL84 like crazy. It will most certainly change the gain of the amp. If you can find a "good one," give it a spin.

Marty

joshuaaewallen · 05-09-2009, 02:00 PM

Quote:

Originally Posted by solarburnDSL50

... I'm gonna be mailing some new production pres to Marty. Can't wait to hear his reactions on them.

... Any verdict on these tubes?

joshuaaewallen · 05-09-2009, 02:10 PM

Quote:

Originally Posted by solarburnDSL50

If it only has 1 preamp tube you will probably need to boost it for more gain. What preamp tube comes in it?

Here's a quote that I found interesting from the forum over at the gear page that talks about the 12BZ7 vs. the 12AX7 (& other 12A** types):

Quote:

effects of tube swapping...
Ever wonder what happens when you swap preamp tubes? Aside from the "sonic" changes, each different tube also changes the circuit "gain" or voltage amplification (AV), which, in turn, affects when (sooner or later) the tube goes into distortion.

Consider the "normal," cathode-biased, preamp circuit with 12AX7, 100K-ohm plate load resistor (Ra), and 500K-ohm "next-circuit" load (Raa):

12AX7: rp = 62.5K-ohm; mu = 100

Ra' = (Ra||Raa)
AV = (mu*Ra')/(Ra' + rp)

Ra' = (100K||500K) = 83.3K
AV = (100*83.3K)/(83.2K+62.5K) = 57.1

...thus, while the tube gain is mu =100, the "combined" load (100K||500K) reduces the total "circuit" gain to less than 60!

Now, replace the 12AX7 with a 12BZ7 tube and see what happens to the total "circuit" gain:

12BZ7: rp = 31.8K-ohm; mu = 100

AV = (100*83.3K)/(83.3K+ 31.8K) = 73.7

...the total "circuit" gain actually goes UP by 30% (+2.22dB)!

What happened? The two tubes have the same gain (mu =100), so why is there at difference? Answer: tube plate resistance!

It is PLATE resistance (rp), NOT tube gain (mu), that has the most affect on circuit gain! Or, stated differently, the tube with the LOWEST plate resistance is LEAST affected by the combination of plate and "next-circuit" loading, and thus LOOSES the LEAST gain because of those circuit loadings!
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Last edited by Old Tele man; 12-25-2004 at 03:19 PM.

solarburnDSL50 · 05-09-2009, 08:52 PM

Quote:

Originally Posted by joshuaaewallen

... Any verdict on these tubes?

Hey Josh! Marty should get the new production tubes on Monday. So expect to hear about it not too long after that he he. I hear you got a torpedo from him. Let us know how it goes man?

MartyStrat54 · 05-09-2009, 08:58 PM

Gee! I've only been telling you that for about three months now.

In fact, I printed out that very same thread. It starts with, "Mike K," on 12-23-2004, 11:56 AM and kept a hard copy for myself. The info on the plate resistance I have brought up many times. I also mentioned the tube in the real world being put in a circuit and it would lose gain because of the resistance value of the circuit. I stated that the BZ7 had half the plate resistance of a 12AX7 and when injected in a circuit would exhibit more gain because of this fact. If you don't remember any of this, then the thread is too long and has served its usefulness.

Of course, what I have yet to say is that they are going by the fact that both tubes are equal with a gain factor of 100. Resistance plays the major role in the gain factor of the circuit, but the sheer gain of the tube plays a role as well. If you have a 12AX7 tube that has a gain of 120 with the same plate resistance you are going to notice an increase in gain. Two 12AX7's with 120 gain factors? Big change in the gain of the amp. In other words, it's just not plate resistance. I mean I could start talking about how hard a vacuum was pulled on a tube, because that in a small way affects the gain factor from an electronics standpoint. And tube getters, you know what they do, right?

Maybe I should quit posting here for a while? One thing I hate is repetition. You put it down in the thread one time and it shouldn't have to be repeated. A lot of that stuff I didn't want to put in this thread, because it's technical in nature and unless you are knowledgeable about electronic components, it is foolish to put it in print.

Maybe I'll be able to go find something interesting to comment on , but that's getting harder to do as well.

Marty

steelhorse · 05-09-2009, 10:42 PM

You seem highly appreciated in here Marty.

joshuaaewallen · 05-10-2009, 09:26 AM

Quote:

Originally Posted by MartyStrat54

Gee! I've only been telling you that for about three months now.

In fact, I printed out that very same thread. It starts with, "Mike K," on 12-23-2004, 11:56 AM and kept a hard copy for myself. The info on the plate resistance I have brought up many times. I also mentioned the tube in the real world being put in a circuit and it would lose gain because of the resistance value of the circuit. I stated that the BZ7 had half the plate resistance of a 12AX7 and when injected in a circuit would exhibit more gain because of this fact. If you don't remember any of this, then the thread is too long and has served its usefulness.

... Maybe I should quit posting here for a while? One thing I hate is repetition. You put it down in the thread one time and it shouldn't have to be repeated. A lot of that stuff I didn't want to put in this thread, because it's technical in nature and unless you are knowledgeable about electronic components, it is foolish to put it in print....

Sorry mate. Didn't mean to offend... I just posted that because RiverRatt had expressed interest in BZ7's and that info just reinforced what you had said earlier regarding the BZ7's...

I would have to disagree that this thread has totally served it's usefulness. As you have pointed out, there are numerous other facets of tubes that can be discussed. My intent when this thread was started was to discuss and learn "all things tube".

There's an old saying, "Repetition Is The Mother Of Retention". Personally I believe that's true. That's how I learn just about everything, including playing guitar. I read it, write it, hear it, think it, practice it, and... I do it all over again. Hopefully with as little annoyance to others as possible.

Quote:

Originally Posted by MartyStrat54

.... it's just not plate resistance. I mean I could start talking about how hard a vacuum was pulled on a tube, because that in a small way affects the gain factor from an electronics standpoint. And tube getters, you know what they do, right?

Actually, I have only a vague concept of the point of a getter, and I really would like to learn more. And as far as how hard a vacuum was pulled on a tube... Not a clue. My point mate, is that I actually am interested in these subjects and learn best by lively discussion, and repetition.

Quote:

Originally Posted by steelhorse

You seem highly appreciated in here Marty.

Steelhorse... I would like to reiterate your statement here with one small adjustment... "You are highly appreciated in here Marty".

Now that I have put my foot in my mouth... And attempted to remove it... I'm gonna shut up and go away now. Thanks guys, you rock!

steelhorse · 05-10-2009, 04:17 PM

I totally agree joshua!

Now what was it we were talking about it again?

All this tube talk has my head spinning!

RiverRatt · 05-11-2009, 11:26 AM

Well, I struck out in my 12BZ7 quest. I did find a few 12BY7s but I wasn't sure if they were a legitimate substitute or not. Any ideas?

05-04-2009, 02:53 PM	#246 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,391	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? God, it took me a long time to find that video. I didn't respond to the thread so I manually looked through page after page before doing a search and that still took three attempts before I found it. In case the hyper link does not work, it is called: How Valves/Tubes are made. By Mystic Fred mullard tubes : Mullard Tubes : MullardTubes.com Marty

05-04-2009, 02:55 PM	#247 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,391	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? I had to manually edit the hyper link to work. At the bottom portion of the page you will see a link that states, "Watch the exciting video of the Blackburn plant, etc." Marty

05-04-2009, 03:16 PM	#248 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,391	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Josh, I sent you an email about the Ruskie EL84's. Please respond. Marty

05-07-2009, 06:21 PM	#251 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,391	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Yeah, I put a pair of the Winged -C-'s in one of my 602's and I think they are better than most current EL34's. Maybe the E34L is right there with it, but nonetheless, the Winged -C- is a super 34 replacement. You know, I'm thinking that I should have sent you a 5751. You could have subbed the AT7 with it. I'll bet it would be a perfect match for you. Too bad the one you have is garbage. You'd get just a little more gain without it being a super gain with an AX7. As I said, that seems to be your style. A good 5751 cranked in V1 going into a high gain 12AX7? Well if you go back about five pages you will see I already did such a test and my conclusion was that a super high gain will make up for any gain loss in the 5751. It does however allow you to shape your tones, most notably the clean (cause that is what a 5751 does so well) channel with a different window of tones over an AX7. But when you need to wail, the ICBM in V2 will handle the matter and you have your total Marshall tone wailing away. You ought to get yourself a 5751. They usually go for a lot less $$$ than a 12AX7. Look for one that tests stout. Marty

05-07-2009, 10:40 PM	#253 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,391	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Yeah, don't judge the sound and performance of all 5751's with the one you have. It's a dog I'm sad to say. I have two Tung-Sol 5751's and they both tear up the tester. These are 1958 tubes (not for sale) that I bought on Ebay about two years ago. I used the stoutest one when I conducted my tube tests. It gave the amp a different window of tones, but it still had some fire in its belly. With a stout 12AX7 in V2 and the amp in the crunch channel, it was crunch away. It didn't miss a beat. I can honestly say that I could live with that 5751 in V1 with a high gainer in V2. It wouldn't be a problem. A lot of people (like you) tend to like a 5751, because it is a quieter tube than an AX7. That quiet translates into a chiming clean channel. Again, it allows different tones to be shaped because of its design. Personally, I don't think that I would want to go as low as an AT7. I tested with a real good one and I wasn't pleased with it. It was okay, but the punch seemed to be missing. Marty

05-08-2009, 10:11 AM	#255 (permalink)
RiverRatt Senior Member Join Date: May 2008 Location: Between Memphis and Nashville Posts: 470	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? If I wanted to up the gain on my Blackheart 5 watt head, would I need a 12BZ7? Do these perform well in an amp with only 1 preamp tube?

05-08-2009, 10:28 AM	#257 (permalink)
RiverRatt Senior Member Join Date: May 2008 Location: Between Memphis and Nashville Posts: 470	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? It's a 12AX7. It came with a Sovtek, now it has a Tung-Sol.

05-08-2009, 05:10 PM	#261 (permalink)
RiverRatt Senior Member Join Date: May 2008 Location: Between Memphis and Nashville Posts: 470	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Thanks. I'm going to check out a nearby antique mall tomorrow. There's a guy there who has a pretty large collection of oddball tubes. Maybe I'll get lucky and find a 12BZ7. If not, I believe TubeDepot in Memphis has a few. So long as there's no chance of damaging the amp, I'll just try it out and see how it does.

05-09-2009, 08:58 PM	#266 (permalink)
MartyStrat54 Senior Member Join Date: Feb 2009 Location: Formerly Phoenix, now north of KC Posts: 2,391	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Gee! I've only been telling you that for about three months now. In fact, I printed out that very same thread. It starts with, "Mike K," on 12-23-2004, 11:56 AM and kept a hard copy for myself. The info on the plate resistance I have brought up many times. I also mentioned the tube in the real world being put in a circuit and it would lose gain because of the resistance value of the circuit. I stated that the BZ7 had half the plate resistance of a 12AX7 and when injected in a circuit would exhibit more gain because of this fact. If you don't remember any of this, then the thread is too long and has served its usefulness. Of course, what I have yet to say is that they are going by the fact that both tubes are equal with a gain factor of 100. Resistance plays the major role in the gain factor of the circuit, but the sheer gain of the tube plays a role as well. If you have a 12AX7 tube that has a gain of 120 with the same plate resistance you are going to notice an increase in gain. Two 12AX7's with 120 gain factors? Big change in the gain of the amp. In other words, it's just not plate resistance. I mean I could start talking about how hard a vacuum was pulled on a tube, because that in a small way affects the gain factor from an electronics standpoint. And tube getters, you know what they do, right? Maybe I should quit posting here for a while? One thing I hate is repetition. You put it down in the thread one time and it shouldn't have to be repeated. A lot of that stuff I didn't want to put in this thread, because it's technical in nature and unless you are knowledgeable about electronic components, it is foolish to put it in print. Maybe I'll be able to go find something interesting to comment on , but that's getting harder to do as well. Marty

05-09-2009, 10:42 PM	#267 (permalink)
steelhorse Senior Member Join Date: May 2008 Posts: 3,852	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? You seem highly appreciated in here Marty. __________________ 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

05-10-2009, 04:17 PM	#269 (permalink)
steelhorse Senior Member Join Date: May 2008 Posts: 3,852	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? I totally agree joshua! Now what was it we were talking about it again? All this tube talk has my head spinning! __________________ 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

05-11-2009, 11:26 AM	#270 (permalink)
RiverRatt Senior Member Join Date: May 2008 Location: Between Memphis and Nashville Posts: 470	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Well, I struck out in my 12BZ7 quest. I did find a few 12BY7s but I wasn't sure if they were a legitimate substitute or not. Any ideas?

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