Preamp Tube Substitutions With Steve Carr
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- เผยแพร่เมื่อ 18 พ.ย. 2010
- Steve Carr of Carr Amplifiers describes the characteristics of different preamp tube types and suggests some useful substitutions. A Carr Rambler amp is used for demonstration.
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Terrific explanation - really helps me understand tubes and options. Thanks!
In such videos i rarely see people explaining which tubes goes where and why. It is very well explained here, as is EH vs Sovtek ECC83 which makes a lot of sense. I hope people will understand why ECC81/82 aren't suited for V1 position because they are drivers. Mr. Carr explained it very well.
i'm glad u mentioned the current and power characteristics. resistor biasing is also important. and those voltage amplification factors are theoretical folks.
cool amps!
Great job. A very good 'no bs' explanation.
Correction on the 12ay7-it has a gain factor of 44. A 5751 has a gain factor of 70.
Extremely helpful! Thank you very much.
Great explanation of 12A tubes, I am currently trading to get a Carr Mercury and cant wait Ill let you know what I think of her. I can tell Ill already love it. Thanks for getting evolved with your fans and customers to help them get the sound they desire!
Steve, thanks so much for your informative video. Today I installed a 12AT7 in the first position in my 5 watt combo that had a loose bottom end. I had tried swapping out the speaker at one time, due to my lack of knowledge. Now the amp has a much firmer, tighter bottom end. I have two combos at this time, one each from other makers in North Carolina. My next amp will be one of yours. The Mercury seems like it will be a great fit for me. Thanks again, and best wishes.
about time someone knowledgeable adressed this - THANKS, Steve !
love my Rambler, too ...
Great informative video.
I've been using 12au7's as a tube driver and a TAD 12ax7 in V1 and 12ax7 JJ's in the other slots. Now my Fender Red Knob twin used 12AT7 for the Reverb and I assumed it was just a fender thing. But I recently swaped out the Fender for a Carvin MTS 3200 and I'm going to put the tube voodoo on it. It has reverb on the V4 I'm going to drop a 12at7 in there because 1)with the knob up, it has a slight hum, 2)it's produces high frequency reverb tones that are a little shrikish with the existing 12AX7. So one thing I got out of your video was about Reverb control! I have some Laney's too, But I've already did the voodoo to them. I liked the Red Knob, but it was heavy and I'm 64 and was going to chop the cabinet until a buddy offered a trade. Thanks Steve!
SRV used a 5751 to lower the gain and push the power tubes and it was cleaner sounding so chords worked well !
Thank you for the awesome explanation.
loves your videos, hope to see more of them. :)
I have a peavey windsor that broke up WAY too early for my taste... I replaced v2 with a 12AU7 and it made so much of a differance... The tone with the preamp all the way up is PERFECT, creamy, overdrive.. still plenty of power going to the power tubes as well... Sounds bomb :D
You may be right about that!
Thanks for checking up on this.
Thanks for your help Mr Carr! My Randall was not making the distortion its supposed to be making(Hardly any with gain maxed). it was also noisey with tons of loud shhhhhhhhhhhhhhh"
I kept swapping the pre tubes around till I hit paydirt! WOW! what a day and night difference!
Absolutely no noise now! Plenty of warmth and Bottom.Distortion is Equal to about an JCM 800 (amount).I put in a matched pair of EL34"s in place of the 6L6"s just to see...and really warms this baby up"!.A bit softer.
Thanks for your video, Steve. Your printed page that you show, and the term tighter sound gives me the info I need. I have a 5 watt combo with a 12 inch speaker that has a loose sounding bottom that I do not like. I shall give the 12AT7 a go in place of the 12AX7, to tighten things up. Best wishes for you.
telecasterbear I’m thinking of doing the same thing. How did it go for you?
I have a very short list of heroes. Steve is on the list.
Hi Steve, I like your amps!
Just sharing for the hell of it. My most coveted 12AX7 type is the Gold Lion (British) B759 went for about $500 in the '90's. Very fat, thick sounding 12AX7.
I put the 12AU7"s(2) in the middle.I will try some 12AT7"s when I order some.
Thanks Again!
My 1970 fender Princeton amp has a 7025 listed on the lable in the cabinet, as the first tube. I was wondering where that tube would fall on your list. Thanks Steve.
i have a blues junior and swapped the first stock pre amp tube for a 12at7 and now i can crank the amp without it getting so messy sounding. i can use the fat button now without the amp sounding too loud. the 12at7 also gives a little warmer smoother tone.
Hello DJ Sal
I am more of a guitar guy but what would you like in a bass pre ? - I was kicking around the thought of a tube bass pre -- what type of power amp would you use it with - and details we help me. I am afraid I do not have a feel for the choices out there.
Question...: I have a Zoom G7.1ut with a 15vac tube preamp in it...changed out the chinese tube for an old rca I had...fixed the fluffy lows and muddy low mids..still is a little to grindy and a little to much hi hi harmonics...can only tolerate 20% gain before upper harmonics get to crispy...and output level around 20% before it begins to compress and overdrive my digital section...
looking for lower output... so not to sound compressed..
but with a big breathy kind of headroom and a fat shimmering tone?
any thoughts..
Got a hot rod deluxe and it’s just to loud, will try this 👍
Steve, have you tried any pentodes for V1 (Like EF 86)?
...and would a 12AY7 or 12AU7 give a more harmonically complex tone in
exchange for a bit less gain?
Thanx in advance and... cheers
I have a Blackstar club40, and I never turn the OD channel gain past 20% and I get the exact kind of OD I want... Full and roaring. Am I correct in assuming a 12au7 replacement would be sufficient to still get the same kind of overdrive? Since it's 20% the gain of a 12ax7? Or is there something else to consider?
I'm also considering replacing the pair of EL34 with a pair of KT77 for a tighter, brighter, less compressed sound. Any advice?
Hi Steve, I have a Bugera Veyron bass amp with tubes, 12ax7c and 2 12ax7a 3 tubes in total, I'm hearing that the Tung Sol 12ax7 would be an upgrade replacement would it be ok to use all 3 Tung Sol 12ax7 tubes they don't list a c or a?
Hi Steve, I'm interested in purchasing a 3-4 stage tube preamplifier for bass guitar.
I am doing the research and reading conflicting views. Would you have any recommendations of advice ?
Thank you,
Sal Z.
I have a Precision Electronics S35 and I'd like to convert it to a 2 channel guitar amp. One channel for clean and one for a modern metal distortion with a huge sound. Is this possible without too many changes using the stock tubes? It has 2 6EU7s, a 6C4, and 2 7868 output tubes. Thanks.
Great info! I have to disagree with the amplification factor on the 12AY7 though. It should be around 44. The 5751 is around 70.
Yes, you are correct! I need to read the cue cards more accurately... !
Hi Steve, so if I hear you right, My Carr Mercury in V1 has a 12ax7 and if I put a 12AY7 in it in the V1 it would give me a little more head room before it starts to break up? My Mercury the old model is the best amp I've ever owned, its just amazing with a Humbuckers or single coils, I've thought about also trying a KT-66 Gold Lion with a Celestion Blue Alnico. Any advice would be greatly appreciated. Just love the sounds I can get with it, just need more clean head room on the first gain stage. Thanks John
A little!
I see this is about a guitar preamp. Wondering if the same would apply to tube stereo audiophile pre-amplifiers? Say, if the volume control is too aggressive in a system?
Most likely.
Nice video! I have a used marshall TSL 100, 8 years old, it seem it has the original preamp tubes in it. Do you know how the preamp tube layout looks like on that? I suspect V1-2 are gain stages V3 reverb tank, 4 phase inverter. Could you recommend a great preamp tube for me? I play 80's kinda stuff. Many thanks!
We use a lot of Electro-Harmonix pre amp tubes, and have good success with them.
a question: what is the period of life of the preamp tubes with a regular daily use of the amp????
Nice information...
My interest comes from my Prima Luna Integrated amp.
Are there rules regarding gain types in p1 and p2? for example could you have a 12AU7 in p1 and 12AX7 in p2 in terms of electronics or does p1 always have to have the higher gain valves?
Thanks in advance for any advice. generally at the moment I am considering my next p2(Rectifier) valve choice.
Steve, could changing any of the preamp tubes cause a need to rebias an amp?
any good result if i put at v1,v2,v3 high grade tubes???
or just waste of money???
Where is V1 on a Peavey 6505 MH20? Can't see the tube sockets, a circuit board covers them.
can you swap out a EL803s tube into a 12AX7 jack?
my amp has ecc83 preamps it distorts way to quickly should i go with the at7
Maxwell Carpenter What amp do you have ?
Ok so the 12 at is the reverb input and v3 doubles as post reverb and a gain stage.
?
Mr. Carr, I obtain a MonoPrice 15 Watt Tube Amp. yes cheap? but would like to know, what tubes in what position of the front end would you recommend? OLD FAT STARTING OVER
what is the main diference if you have 2-3 preamp tubes vs having 5 or 6 ??
+Konan Panagiotopoulos Mostly cascading gain stages unless your amp has other effects. Do you have a Drive control or boost? they usually drive an extra gain tube. Some amps that have 2 or more channels may have tubes for those channels. check with your manufacturer or owners manual for tube function.
Have u ever tried 6X8's as preamp tubes? They are killer. I have an external bias adjustment on the front of my amp on my preamp 6X8's, and also bias on my 6AQ5 powered input stage. Although 6AQ5's are mini power tubes they have tons of clean headroom for an input. The ability to externally bias adjust preamps is the most amazing feature. EL34's in the power stage. With the bias u can dial the amp from a growling bastard to a screaming demon.
I had a jap 12aw7 hifi nos in my jcm900 as compliment to a silvertone ehx and a sylvania and found the magic of no harsh clip or hiss. But thieves got my whole rig.
I did have the loudest 50w bassman in town they stole it too
In what way does an increase in power handling, current capacity or "muscle" (what he says increases as we go down the list) influences tone?
cheer up Steve
12AX7: gain 100
5751: gain 70
12AT7: gain 60 (ECC81, 6201, 6679)
12AY7: gain 45 (6072)
12AV7: gain 41 (5965)
12AU7: gain 19 (ECC82, 5963, 5814, 6189)
how can I tell if my amp has a "long tail" circuit?
What amp do you have ?
Carr Amplifiers
well I'm looking at getting a Peavey 6534+, and having never tested one because I can't, I'm hoping the option to put a 12at7 in the P.I. and/or a 5751 in the V1 if the tone is to cold/dry/gainy will give me the confidence to buy it anyway.
I'm not familiar with that amp, you should try writing to Peavey directly.
Carr Amplifiers
ok thanks, I will. I was trying to research the hell out of stuff so I wouldn't have to bother them with a million questions because I'm very specific and picky, but I think I got it all figured out except that last bit of info.
You could always ask the folks on The Gear Page.
I need more reverb even at 10 its way back
I can slap the amp and hear the springs almost as loud as a twin but playing with reverb on 10 can barely hear it.
I need smooth tight for my high gain
Whats got the highest frequency response?
He forgot the 5751 tube as it is 70% the gain of 12ax7 and bias and plate volts are the same as 12ax7 as the others are slightly different designs of the plates and grids !
those ax7's sound too harsh in a preamp. I got great results using au7's. the tone is warmer and no distortion
You shouldn't replace preamp tubes unless the manufacturer says it's OK for your amp. Some designs rely on specific tubes and although you CAN interchange them, it may damage the amp over the time. I know at least one brand with this problem, and that's Fryette. Even the Memphis, my personal amp, which has a front panel design that allows easy to access to four preamp tubes, does not recommend anything other than the stock types.
Does anyone currently make a 12AU7?
Tonetwisters Tube Amp Doctor
dude buddy BRØ☝🏼 rock and roll brother man🤘 thank you for making this video🎵🎶🎙️ what a perfect explanation of what preamp tubes do💯 finally I completely get it and it's because of you 🅾️ shit I appreciate the shit out of you rock on ❕❗Rock off❗❕🤘✊👍🖤🎶🖕😁🤘