5751 preamp questions???

[sevycat]

I play a 60's NOS stratocaster thru my boogie mark III green stripe amp. I am wondering if anyone has had any experience with the 5751 preamp tubes. If so, I would like to know if the hype surrounding them is worth it. Also, what type would work best for me, considering my amp. Thanks!

 

[stokes]

If you are looking to reduce the gain a bit,yes they are worth it.I have 17 amps in my collection and every one has a 5751 in the V1 position except one that has a 12AY7,which has even less gain than the 5751.I love them.I would say just about any NOS will do,I have about 15 backups in my box all different brands,and I like them all.The ones with the triple mica are obviously more durable and less prone to microphonics,but to tell the truth I have only found one microphonic 5751,as opposed to the many microphonic 12AX7's I've run across.They tend to smooth out the overdrive in my IIC+,dont have that harsh shrillness you get with most AX7's.I wouldnt recommend the current production 5751's,to me they sound like weak AX7's.

 

[sevycat]

Thanks for that info. I am looking for tripple mica, black plates. Either G.E or the RCA NOS tubes. What I do not understand is, how the different getters come in to play. round, square, and Delta. I am not sure if this is something that I should concern myself with.

I want a lower gain as you stated it will yield, but am hoping for the warmer tone. I currently run tung-sol 12ax7 in all the preamp positions. I got rid of all the GT 12ax7's and the tung-sol were a good starting point. With my mark III, I am playing a stratocaster. I am trying get the right preamp and power tubes in the amp, that will produce the best performance for blues and rock music, think hendrix, srv, stones, etc..

Any suggestions or recomendations would be helpfull!
Thanks, Christopher

 

[carlsoti]

Don't worry so much about the getters, unless you're looking for a particular rare tube. The getter is actually used in the manufacturing process of the tube. It is coated with a substance, then burned off. The process "locks up" any additional oxygen left in the tube after sealing. It doesn't have any direct effect on tube tone.(unless you're a hi-fi geek, then you "may" hear a difference)

 

[stokes]

Okay,I'll agree the getter itself may not be responsible for the tonal differences,but they are helpful in identifying tubes of a certain character.Once again,I would have to defer to Mavguy or Timber Wolf to explain the nuances between the varieties,these guys have done some meticulous listening tests and have given some very good explanations in the past,check their posts out.To me,they all sound good,I am a lot lazier than these two guys are,and dont take it as far as they have.I would suggest you try the 5751 in the V1 and V3 positions in the MKIII,you will hear the biggest changes here.This tube should give you the lower gain,warmer,rounder,browner or however you want to describe it,tone you seek.Another thing you may want to try is to have the adjustable bias mod done and get some good NOS tubes,even the stock Mesa brand tubes will benefit from a little bias tweaking.

 

[Timbre Wolf]

Thanks for that info. I am looking for tripple mica, black plates. Either G.E or the RCA NOS tubes. What I do not understand is, how the different getters come in to play. round, square, and Delta. I am not sure if this is something that I should concern myself with.

Christopher -

As Stokes said, the getter type does not, in itself, indicate tonal character. It is simply a way to identify a particular manufacturer's era of production. :?: Delta getter? Never heard of it!

Triple-mica black-plates? Sounds like the new Baskin Robbins flavor of the month! But I happen to prefer them, myself: black-plate for lively dynamic response, and 3-mica for added stability. In my "taste tests" I have found the RCA to be thicker/darker tonality, and slightly softer feel, whereas the GE is very bright/trebly and a little harder feel. Both exhibit better clarity than the later gray-plate versions.

Has anyone else here tried Tung-Sol long-plate 5751? That's the only long-plate 5751 I know of. All others are short-plate, and, as Stokes said, less prone to microphonics.

8) - Thom

 

[212Mavguy]

I have tried the Tung Sol 5751 long plate. The ones I have are very similar to the Tung Sol 12ax7 longplate. They have a strong, complex midrange, sweet and warm sounding. New ones tend to test very strong, like a 12ax7. I would not be surprised if that's what they actually were, just a different type silkscreened on the bottle, because I do not see any difference in construction at all between the two. Legendary amp builder and luthier Chris Siegmund prefers the vintage TS 5751 over any other preamp tube in the first two positions of his Midnight Blues amps.

My favorite 5751 is the Raytheon blackplate, either triple mica with rectangular getter halo, or the double mica with the windmill getter halo. Hard to find and expensive. The GE 5751's are great sounding also and the grayplate ones won't break your bank. The GE triple mica blackplate 5751 has a bright top end. The Sylvania grayplate 5751's are also nice sounding, and have very strong mids. Unless you are a metal player needing monster amounts of gain any of these mentioned vintage tubes will generally provide superior tone to anything made today, clean or dirty.

 

[dodger916]

If you are looking to reduce the gain a bit,yes they are worth it.I have 17 amps in my collection and every one has a 5751 in the V1 position except one that has a 12AY7,which has even less gain than the 5751.I love them.I would say just about any NOS will do,I have about 15 backups in my box all different brands,and I like them all.The ones with the triple mica are obviously more durable and less prone to microphonics,but to tell the truth I have only found one microphonic 5751,as opposed to the many microphonic 12AX7's I've run across.They tend to smooth out the overdrive in my IIC+,dont have that harsh shrillness you get with most AX7's.I wouldnt recommend the current production 5751's,to me they sound like weak AX7's.

Thanks for the reminder. I just re-installed a GE black plate triple mica in my C+, and the love is back! Oh, how could I ever have strayed!

 

[Timbre Wolf]

I have tried the Tung Sol 5751 long plate. The ones I have are very similar to the Tung Sol 12ax7 longplate. They have a strong, complex midrange, sweet and warm sounding. New ones tend to test very strong, like a 12ax7. I would not be surprised if that's what they actually were, just a different type silkscreened on the bottle, because I do not see any difference in construction at all between the two.

Thanks for your reply, Mav! I tend to agree with every point you make about the Tung-Sol 5751. Except I've found that they are not quite like their 12AX7 counterpart - they are a little less gain. I find they're somewhere between a typical 5751 and 12AX7, in my experience.

- Thom

 

[212Mavguy]

Yep, Thom,

I noticed that the TS 5751 tended to have more gain then most other 5751's, the strongest ones sound like they have more than some of my weaker but still "good" testing 12ax7's do. They can spoil ya tonally. You oughta hear them in an amp with "old school" lower plate voltage for the output tubes running some vintage Tung Sol 5881's...talk about some amazing sweet sounds! (Siegmund Blues Breaker)

 

[Timbre Wolf]

...talk about some amazing sweet sounds! (Siegmund Blues Breaker)

Gonna have to hear that one, some day. :mrgreen:

- T

 

[212Mavguy]

You might be able to hear some sound clips on Chris's site. :wink:

On your next custom amp, Thom, request a lower voltage main tranny so you can run the old glass in the output section. Know you were looking at a particular boutique builder, wasn't it Reinhardt? If he won''t do an amp with lower B+ voltage keep shopping. It's worth it. Saw a pair of NOS Ray 5751's on ebay right now for stupid money. I will steer clear, have a few great lightly used ones already.

Am enjoying 12at7's, they are relatively inexpensive for some brands that sound great, and in a lot of amps there is enough gain in the preamp for at least some dirt. Am waiting on a pair of TS and a pair of Sylvania GB at7's.