Changing Preamp and Power Amp Vavles?

[Pob]

I have a Marshall TSL 100 100w valve head and I am thinking of changin the valves from the stock ecc83 and EL34 Svetlana tubes to Groove Tubes (GT- ecc83s and E34-LS).

I have had the head for a while so I think it's time to change the power amp valves . However I want to get a better much more transparent sound by changing the preamp valves.

Am I right in thinking I need to have the amp re-biased?

Also do you know if the change in preamp valves will produce a significant difference in clarity?

Cheers for any help.

[mrlizard]

Originally Posted by Pob

I have a Marshall TSL 100 100w valve head and I am thinking of changin the valves from the stock ecc83 and EL34 Svetlana tubes to Groove Tubes (GT- ecc83s and E34-LS).

I have had the head for a while so I think it's time to change the power amp valves . However I want to get a better much more transparent sound by changing the preamp valves.

Am I right in thinking I need to have the amp re-biased?

Also do you know if the change in preamp valves will produce a significant difference in clarity?

Cheers for any help.

you don't need to re-bias for the preamp tube, you can pick pretty much any tube with the same pin configuration until youget the sound you prefer.

Power amp tubes are a different beast, they need to be matched and biased. i would leave that to somebody that knows what they are doing, unless you wanna end up dead or with fucked output transformer.

I think if you have a lack of clarity it probably has more to do with the output tubes than the preamp, although changing the pre tubes to something else may well might get you closer to your desired sound.

PM me and i'll put you in touch with a guy that can do it for you.

[paul engage]

get JJ EL34s btw..

[captain ahab]

Everything Mrlizard said is true. Believe! I would recommend against groove tubes though man, its just a name and they aren't all they are cracked up to be, claiming they are precisely matched and actually being quite far out. Buy a matched set of power tubes from a amplifier technician, not a shop. They often don't have a clue! And Paul is right too...JJ EL34's are sweet as are their ECC83's, but buy a few different preamp tubes and experiment...if you can find mullard NOS for a good price then get em...the best ECC83's ever.

I have just had my 1959 retubed with Electro harmonix EL34's and JJ ECC83's with and it sounds REALLY good

oh yeah...if you are lacking clarity that was there before, it could be failing filter caps. Man...i love them, but valve amps are pretty confusing...

[Pob]

Cheers for the help. I'll look into JJ EL34's.

Do you change all four of the preamp valves when experimenting?

I don't have a clue about this valve stuff.

[I_got_a_mohawk]

JJ's are great, thats what i have in my SVT II, well, the pre section, wish i had stuck them in the power section too, but that'll happen in due time

www.eurotubes.com

Bob is really easy to deal with, tell him what you want, and what kind of sound your looking for (as you said, more transparent) and he'll set you up with a good set of pre tubes (cant really change types of power tube, well, not easily anyway)

As MrLizard said, power tubes are possibly the reason for it running too hot, if you can, maybe try a 12AU7 (ECC82) instead of a 12AX7 (ECC83S) in the driver section, you'll lower the gain going to the power section so it'll stay cleaning sounding, but a bit quieter (im sure thats right anyways? )

[paul engage]

You can order JJs from Music Ground on Denmark Street in London. Might be easier than ordering from Eurotubes.. dunno..

[I_got_a_mohawk]

Originally Posted by paul engage

You can order JJs from Music Ground on Denmark Street in London. Might be easier than ordering from Eurotubes.. dunno..

Ah right, didnt know, from eurotubes (even with postage and import tax) was cheaper than anywhere i looked, shall check from them next time i need some, cheers

[paul engage]

Ha.. only found that out when I had to hunt for tubes for Ninjafest.. great shop too.
Check out the vintage amps.. $20,000!!!

www.musicground.com

[I_got_a_mohawk]

holy . . . fricking . . . shit

No vintage SVT's for you to play with there tho (even tho they would have been a shit lot cheaper!)

But, erm, wow, and i thought the phil jones 650 watt tube head was expensive . . .


Can't find the valve prices there, might be missing it tho

[paul engage]

I went into the shop for the valves - I don't think they're on the website. Probably have to call them..

[I_got_a_mohawk]

Dont have to worry about that for quite a while i hope, but have saved that address, cheers

[captain ahab]

Originally Posted by I_got_a_mohawk

JJ's are great, thats what i have in my SVT II, well, the pre section, wish i had stuck them in the power section too, but that'll happen in due time

www.eurotubes.com

Bob is really easy to deal with, tell him what you want, and what kind of sound your looking for (as you said, more transparent) and he'll set you up with a good set of pre tubes (cant really change types of power tube, well, not easily anyway)

As MrLizard said, power tubes are possibly the reason for it running too hot, if you can, maybe try a 12AU7 (ECC82) instead of a 12AX7 (ECC83S) in the driver section, you'll lower the gain going to the power section so it'll stay cleaning sounding, but a bit quieter (im sure thats right anyways? )

yeah man, 12au7's i think are about 10% lower gain than 12ax7's. But you know... I ordered a set of JJ's from Bob, and the power tubes weren't the best matched....passable but not the best. HOWEVER, the ECC83 that was balanced for the phase splitter was absolutely perfect...hmmm funny that

Oh yeah, Damage. The V1 position is the place you want to be experimenting with. It is the preamp tube closest to the power tubes and will affect the sound the most. I'm pretty sure I'm right, anyone know any different?

[I_got_a_mohawk]

Originally Posted by captain ahab

yeah man, 12au7's i think are about 10% lower gain than 12ax7's. But you know... I ordered a set of JJ's from Bob, and the power tubes weren't the best matched....passable but not the best. HOWEVER, the ECC83 that was balanced for the phase splitter was absolutely perfect...hmmm funny that

Oh yeah, Damage. The V1 position is the place you want to be experimenting with. It is the preamp tube closest to the power tubes and will affect the sound the most. I'm pretty sure I'm right, anyone know any different?

The tubes i got from bob were ace, only pre tubes tho

If i remember correctly, 12AX7 = 100% gain, 12AU7 = ~70%

The V1 tube is the one closest to the input, and furthest from the power tubes in the signal chain, the driver tubes are closest to the power tubes and have least bearing on the sound i think?