Tube for Preamp

[David Vega]

Hi all!
What brand a model of a good tube for the SVP-BSP. I want high gain, warm tube sound. This preamo wll hold only one tube. The one installed is a Electro Harmonix, 12ax7

Any thoughts

 

[John D Harris]

The EH that's already in it is pretty good for Rock (there may be some variation in the quality of the tube itself, though).

Telefunken ECC83 are usually higher than average gain and (from all reports) very good tone.

I like the balanced sound of Jan Philips 12AX7WA.

 

[fremenblue]

Any other tube choices/preferences? I'm in the same boat with the same preamp.

 

[A9X]

Tube sonic signatures are massively overrrated, so don't waste your money or time.

Any tube, eg a 12AX7 that provides more gain, is no longer a 12AX7. Mu should be close to 100, and it's damnably hard to get a tighter grid spacing to make it higher, so I don't believe the new TFK gain claims until I see it on the bench.

 

[Crabby]

I have a new EHX 12AX7 in my SWR Bass 350 and it is a nice sounding tue. There was a brand X tube in the amp when I got it and it hummed a bit, The new tube took care of the hum and the tone seemed more open and somehow cleaner with the new tube.

 

[fremenblue]

I've got two tubes on order. One is a Tung Sol 12ax7. The other is a Sovtek 5751 SRV Tube, I believe it is the same as a 12au7, suppose to help tame an overly "gainy" amp. If it doesn't work well in my BSP preamp I'll try it in my Mesa/Boogie 400+.

 

[Tim1]

Hi Fremenblue - put the 12AU7 in the driver position of your 400+ and you will never look back. It is a revelation.

 

[fremenblue]

Hi Fremenblue - put the 12AU7 in the driver position of your 400+ and you will never look back. It is a revelation.

Looking at the back of the amp, which would be the driver position? I'd love to retube the whole dang thing and have a bias pot put in. I've just never been happy with the amp, not for what it cost me. It may yet find itself replaced with an SWR Super Redhead.

 

[amos]

Tube sonic signatures are massively overrrated, so don't waste your money or time.

Any tube, eg a 12AX7 that provides more gain, is no longer a 12AX7. Mu should be close to 100, and it's damnably hard to get a tighter grid spacing to make it higher, so I don't believe the new TFK gain claims until I see it on the bench.

+1

 

[A9X]

The other is a Sovtek 5751 SRV Tube, I believe it is the same as a 12au7,

A 12AU7 is not the same as a 5751. A 5751 may be substituted for a 12AX7 for decreased gain with no modification to the circuit. Mu (intrinsic gain of tube) is 100 for a 12AX7 and 70 for a 5751. Actual gain in circuit will be lower.

 

[fremenblue]

A 12AU7 is not the same as a 5751. A 5751 may be substituted for a 12AX7 for decreased gain with no modification to the circuit. Mu (intrinsic gain of tube) is 100 for a 12AX7 and 70 for a 5751. Actual gain in circuit will be lower.

Thanks for straightening me out!

 

[A9X]

Thanks for straightening me out!

A pleasure sir.

 

[mrpackerguy]

The EH's have not let me down with my Kern.

 

[svp]

A Ruby will warm it up, but I don't know as far as increased gain. Last time I checked there were only like 3 companies in the world that made the tubes that all the other companies stick their decals on.

 

[mark roberts]

Hi all!
What brand a model of a good tube for the SVP-BSP. I want high gain, warm tube sound. This preamo wll hold only one tube. The one installed is a Electro Harmonix, 12ax7

Any thoughts

GT ECC83/7025

 

[musicelectronix]

my 2 cents, EH is an OK tube, average quality with very good price, 3 of the 10 I got had noise issues. They are made by Sovtek, Russia. Jan Phillips and regular made in Holland Phillips are really good, but they are a bit pricy and you need to find NOS tubes for both. Older Tesla tubes are the best, but they go around $80.

I just ordered a couple of new Teslas - also known as JJ - and Mullard reissues, I can report back in 2-3 days I guess. Their price is around $8-10 for JJ and $15-20 for Mullard Reissue.

For the technical perspective, I say go with 12ax7/ecc83. 12ua7 will have more headroom, hence lesser gain.

 

[A9X]

For the technical perspective, I say go with 12ax7/ecc83. 12ua7 will have more headroom, hence lesser gain.

The 12AU7 will have less gain because it has less gain: mu=20. It will usually not bias up correctly/well in a cct designed for a 12AX7.

 

[musicelectronix]

The 12AU7 will have less gain because it has less gain: mu=20. It will usually not bias up correctly/well in a cct designed for a 12AX7.

be that as it may

 

[Zooberwerx]

Tube sonic signatures are massively overrrated, so don't waste your money or time.

Any tube, eg a 12AX7 that provides more gain, is no longer a 12AX7. Mu should be close to 100, and it's damnably hard to get a tighter grid spacing to make it higher, so I don't believe the new TFK gain claims until I see it on the bench.

+1...almost. Replaced the stock EH 12AX7 with a NOS Brimar (made in England). It warmed the Demeter up a bit but, in the larger scheme of things, the overall change was not profound. Not a complete waste of time / $$$ as I've learned from the experience.

Riis

 

[fremenblue]

I've put a Tung Sol 12ax7 in my SVP-BSP just today and am very pleased with the results. The clean side is sweet as Texas Tea and the drive side is much more manageable now. I plan to use the same tubes in my 400+.