Need Tube Recommendation

[Guitar Josh]

I'm looking to retube my VHT UL EQ. Presently, it has the stock Rubys in it, which are a little harsh to my ears.

I'm not really looking to put a ton of money into the amp via vintage tubes, so I'm trying to stay around $20 per.

Here's the manual if it helps:

http://www.sfdamp.com/manuals/G100UL_SFD.pdf (see page 5)

V1 (Gain Stage 1) - Mullard RI

V2 (Gain Stages 2 and 3 for Lead and Rhythm Channels) - Tung Sol RI

V3 (Gain Stage 4 for Lead and Rhythm Channels) - 9th Gen Chinese (simply for gain purposes) but I might also go Tung Sol RI here.

V4 (Gain Stage 2 for Clean and Rhythm Channels) - NOS JAN GE 5751 (I like the lower gain for clean and rhythm channel which I can boost with the amp if I want).

V5 (Phase Inverter) - NEED INPUT

V6 (Power Stage / Buffer Driver) MUST BE A 12AT7 - NEED INPUT

So basically, I really need recommendations for V5 and V6 and I'd appreciate some feedback for the rest of my choices. Sure, I could put a $100 Mullard in V1, but really, I'm looking to stay within a budget for now.

Thanks for the help everyone! :bow

[ur86d]

Talk to this guy. http://www.dougstubes.com/

[Guitar Josh]

No, thanks.

[ur86d]

Heh heh heh ok how about this guy? http://www.kcanostubes.com/

[PlinytheWelder]

NOS Mullard CV4024 (12AT7) in the PI slot. Get 'em while they're still cheap...

[guitarpedaladdict]

Your phase inverter is the only thing you really can't experiment too much with. You will be best served by buying one that I think they call "matched" it has something to do with the internal plates being matched - I'm sure someone here can explain this better.

Personally, I don't see the 12at7 being too critical either - just get something reliable. RCA and GE NOS tubes can be found for $10 a piece, if you are patient, on eBay and should warm things up a bit (in any of your gain stages) over the Ruby tubes.

Really, the two slots you are looking for are not very critical tonally speaking IMO. Even when I have filled an amp with Mullards and Amperex, I will often use a JJ for the phase type slots. I kind of think it's a waste to put a killer NOS in those slots. Just my opinon... oh... you can ALWAYS find new JJ pre amp tubes on ebay for CHEAP.

[Scobro]

For V5 and V6, put a NOS Philips 12AT7WC. Don't waste your money on a "matched" preamp tube. The idea here is that in Class AB, the left side tubes are amplifying one part of your signal and the right side is amplifying the other part. So a "matched" preamp tube will amplify your tone evenly. However, everything I've read implies that it doesn't work that way. And from my own testing, I don't hear the difference. If it were true, it should be equivalent of having slightly unmatched power tubes.

Get rid of that Mullard RI. It doesn't sound anything close to one and it has this annoying high pitch fuzzy buzz that comes out when distorted. If you want a Mullard like tube, get a Gold Lion RI 12AX7. It's expensive as new tubes go but it's pretty close to a real Mullard ECC83, in clean and in distortion.

For V2 and V3, the Tung-Sol RI 12AX7 is an excellent tube, clear, bright, and lots of gain.

As for that GE 5751, I guess that's all that's left as 5751 tubes go. I find the GE and Philips have a too "boing" sound too them. I love 5751's myself and I have a stash of Raytheon 5751 I horded when they were cheap and no one knew how good they sounded in guitar amps.

Scobro

[Guitar Josh]

For V5 and V6, put a NOS Philips 12AT7WC. Don't waste your money on a "matched" preamp tube. The idea here is that in Class AB, the left side tubes are amplifying one part of your signal and the right side is amplifying the other part. So a "matched" preamp tube will amplify your tone evenly. However, everything I've read implies that it doesn't work that way. And from my own testing, I don't hear the difference. If it were true, it should be equivalent of having slightly unmatched power tubes.

Get rid of that Mullard RI. It doesn't sound anything close to one and it has this annoying high pitch fuzzy buzz that comes out when distorted. If you want a Mullard like tube, get a Gold Lion RI 12AX7. It's expensive as new tubes go but it's pretty close to a real Mullard ECC83, in clean and in distortion.

For V2 and V3, the Tung-Sol RI 12AX7 is an excellent tube, clear, bright, and lots of gain.

As for that GE 5751, I guess that's all that's left as 5751 tubes go. I find the GE and Philips have a too "boing" sound too them. I love 5751's myself and I have a stash of Raytheon 5751 I horded when they were cheap and no one knew how good they sounded in guitar amps.

Scobro

This is exactly the type of information I was hoping for, THANK YOU SO MUCH!! My gut feeling was to shy away from the Mullard as well, but I've read nice things, so I was thinking about it.

No surprise it comes from a Rivera fan either :). Great amps.

[harryjmic]

PI -go with a Sovtek LPS, awesome tube here.

Buffer - mullard 12at7 or one of the Phillips with the blue label.

[guitarpedaladdict]

"For V5 and V6, put a NOS Philips 12AT7WC. Don't waste your money on a "matched" preamp tube. The idea here is that in Class AB, the left side tubes are amplifying one part of your signal and the right side is amplifying the other part. So a "matched" preamp tube will amplify your tone evenly. However, everything I've read implies that it doesn't work that way. And from my own testing, I don't hear the difference. If it were true, it should be equivalent of having slightly unmatched power tubes."

I agree with most of what Scobro has recommended and he has a very well done reference site. The "matched" preamp tubes really only run you about an extra $1-2 over the exact same "unmatched" and like Scobro, I am skeptical that there is much difference between the two, but you might want to do some more research. Your original post said something about a $20 budget and to my ears Phase inverter slots make virtually no difference to your tone - this is why I'm recommending JJ - they are pretty consistent, reliable, and cheap and I wouldn't waste an NOS tube in that slot.

The Mullard reissue tubes are usually made in China and have nothing in common with the originals except for an effort to make them look the same. I read that they bought some of the original Mullard tooling - but that doesn't mean they are using the same materials and care in construction. I've been down the NOS road for a long time and used virtually every brand of 12ax7/ecc83 (except for the elusive and WAAAAY too expensive tele 803) that has ever been made and it's a really individual "taste" thing. In the end, my favorites tend to be the amperex, but that's me.

With your budget in mind, I was recommending the RCA or GE. I think most who have tried them will agree that they should sound A LOT better than the Chinese or Russian tubes.

Digressing a bit, the biggest "one shot" tone change for an amp can be often found with swapping speakers.

Good luck and great work on your site Scobro!

[scottl]

Disagree.....

Get a matched PI. Todays tunes can vary 10+% per triode. That is up to 20% imbalance. If you happen to randomly get one where you have the excess gain on the inverting side of the PI, then the amp will not so sound or feel as good as when the tube is more evenly balanced. Most amps use different size plate loads for the two PI halves to compensate for the natural imbalance. Using a balanced tube will guarantee pleasant results. Maybe not ideal, but close. Maybe a random unbalanced will be better, but that is a crapshoot. Plus, since the dealers are selling balanced tubes, not getting balanced guarantees a big mismatch.

Best bet is to try a bunch of unbalanced and choose the one that sounds best. Then measure it so you know what is best for your amp.

[guitarpedaladdict]

Thanks Scottl, I figured someone would chime in on this -

When I said "no differenct in tone" from the PI - would this be accurate from brand to brand as long as they are balanced (that was my intention)?

[Blue Strat]

Thanks Scottl, I figured someone would chime in on this -

When I said "no differenct in tone" from the PI - would this be accurate from brand to brand as long as they are balanced (that was my intention)?

Many disagree. 1000s of my customers have found the Mullard CV4024/12AT7 to be a worthy upgrade (they're not very expensive for NOS tubes that may last 10 years or more) over mediocre 12AT7s.

[guitarpedaladdict]

Mike, I take your word for it, you run a good business. I've definitely noticed a difference with 12at7 in driver slots for reverb, etc. I guess by the time it gets to the pi slot, a great deal of the refinement available from better tubes has been done, but there's always more tweaking that can be done.

If the pi is affecting current it's gonna make a difference to the amps tone so what you are saying makes sense. I know a lot of guys debate the rectifiers role in tone and all you have to do is swap out a mullard gz34 for a ruby and it's pretty hard to debate that there is not any change.

Interesting thread.

[PlinytheWelder]

Another good tube to look out for is an NOS Tungsram 12AX7. It's a really good low noise high gain tube. I have an Express type amp and these are really picky for V1. The Tungsrams shine in these.