Does putting a good tube in V1 improve the tone?

[kiteman]

I'm thinking about buying an NOS tube to put in V1 of my Alchemist. Would that be worth it?

I have an RCA 5751 so that would be worth a try?

I'm also thinking about a balanced tube for the inverter. Since I mixed the tubes I don't know which was the balanced tube (if it had one) but it was a chinese tube.

This is how the tube are used:

V1 - 1st stage chan 1 & 2 - 2nd stage chan 1 (EH 12AX7)
V2 - crunch stage chan 1 - 2nd stage chan 2 (EH 12AX7)
V3 - 3rd stage chan 2 - 4th stage chan 2 (Ruby high gain 12AX7)
V4 - external effect loop - internal FX (Chinese 12AX7B)
V5 - power amp phase inverter (Chinese 12AX7B)
V6 & V7 - power amp tubes (GT 6L6 CHP)

What tube(s) would be worth a try? Thanks.

[TradAmpGuy]

Most recommend putting your best sounding, lowest noise, tube in the earliest stages of your preamp section. The tone generated there is amplified by the later stages. As far as the PI is concerned, some like the sound of a balanced tube in that position, others like the thickening of a slightly off balance tube there. Food for thought... even if you put a balanced tube in the PI, there are other components in the PI section that are not going to be perfectly balanced (plate and load resistors for example) leading to an asymmetrical PI stage anyway. In that vein, some builders blueprint the components in the PI to assure symmetry. It becomes a matter of taste. Tone is what sounds good to you.

[deeaa]

A bad or cold 1st preamp tube can totally ruin your sound in an amp where the guitar signal really first sees that tube not ic's. In a more complex/modern amp it doesn't really matter that much.

BUT think about it, if the amp is a true simple toob amp, that tube is virtually _everything_ in transcribing the guitar signal into amplified sound. So yeah, it's absolutely vital to have a suitable tube there.

My p-t-p all tube Ceriatone is a good example; the sound changes drastically according to the type of tube in V1 and also if I put too many FX in front of it. True bypass and few pedals make for great sounds.

So go for it; easy enough to try a couple of toobs there!

[deeaa]

BTW the 5751 is a nice tube for some applications, but in many cases it can sound cold in the V1 position, due to 30% less amplification than AX7. Might just sound cleaner and still warm, but can indeed lack warmth too. You have to try it to see how it works...no amp is the same in this respect I'm sure.

[Radioboy950]

V1 tube changes always made a significant difference in my 2 channel Rivera combo (6L6GC output).

The Telefunken ECC83 (12AX7) turned out to be the best vintage tube in my amp. Prices for NOS are absured, so I took a chance on a used one that tested fine.

That tube was just right...big, open sound, with power and clarity...not thin nor fizzy when dialing in some gain.

I bet you'd like it.

[kiteman]

You're right, the prices for some NOS are absurd. I can get a used USA made tube but they select the brand so I won't know what I'll get. I get all my tubes from Tube Depot. When I ordered the 5751 they gave me the RCA and later sent me an email asking how it was. I told them terrific, I bought it for the VJr then along with JJ EL84.

I experimented with the tubes in my box on the Kustom Defender 5H head and the best combo was the JAN 12AT7 and Mullard RI EL84. The RCA 5751 sounded good on it but I have to tame the beast, this thing is LOUD (through my BH 1x12 cab).

I did the same with the Handsome Devil head and now it has Tung-Sol NP 12AX7s and Sovtek EL84Ms.

Now the Alchemist still have the original set in the preamp, gonna have to do something about it. :D

[sumitomo]

BTW the 5751 is a nice tube for some applications, but in many cases it can sound cold in the V1 position, due to 30% less amplification than AX7. Might just sound cleaner and still warm, but can indeed lack warmth too. You have to try it to see how it works...no amp is the same in this respect I'm sure.

Good point deeaa,I tried the 5751 in my Pignose,no bueno,now in my Fender's it gives me what I want,you just have to try different one's you wont hurt anything(except your ear's)I say try different tubes and play with each one for a day or more(changing settings ect.)don't pop 'em in and say I don't like that and hurry and try another,cause I've gone and retried one's I didn't like and just played with settings and WOW I missed what I was looking for.Sumi:D

[Commodore 64]

And if you have a SS amp with socketed IC chips, you can play around with them too. There's all sorts of 8 Pin OP AMPs to try!

[kiteman]

Hmm... I tried the RCA 5751 and it was no better than the Mullard RI in V1, both sounded shrill or too bright. I have a Fender tube which was a rebranded Sovtek 12AX7WC and that sounded good but louder. I figured what tubes came with the amp did well enough. I don't know if I can improve it.

I think I'm gonna grab some winged Cs and replace the GTs. :)

[deeaa]

Hmm... I tried the RCA 5751 and it was no better than the Mullard RI in V1, both sounded shrill or too bright. I have a Fender tube which was a rebranded Sovtek 12AX7WC and that sounded good but louder. I figured what tubes came with the amp did well enough. I don't know if I can improve it.

I think I'm gonna grab some winged Cs and replace the GTs. :)

Both probably are too low amp, and the amp wants hotter tubes in V1 then.

There doesn't seem much consistency in what tube sounds good in what amp, but I've found JJ 12Ax7S's to sound a little darker and more saturated than most, and mil-spec (M) labeled Sovteks etc. usually sound 'harder'...other that that it seems it's each case is different.