Suggest me (2) 12ax7 tubes for my 70's Ampeg V4B

ajunea3 · #1 11-22-2011, 04:54 PM

I just re-tubed the power section of my V4B. Now I'm looking to try out some different preamp tubes.

I want channel 1 to be more hi-fi, and channel 2 to be the warm channel.

What tubes do you suggest for both?

chaosMK · #2 11-22-2011, 05:52 PM

I don't think it's exactly a science... too many variables. The differences I've noticed are very subtle... I keep meaning to record and spend time A/Bing these tones. This is my experience rolling various tubes in various slots and quantities on my Bass 400:

JJ's- slightly mid oriented
EH (current production)- glassier highs, spacious lows
Sovtek (slighly old) - balanced, very likeable grit
Mesa (stock circa 1987) - balanced, clean, detailed
Fender (ancient looking)- similar to Sovtek but less
Jan 12at7 (vintage)- overly clean, hard

The EH has the most recognizeable personality with the highs emphasized and kind of loose lows, but it's probably more suited for guitar frequencies (breaks up early too).

chillerthanmost · #3 11-22-2011, 06:04 PM

My V4 really likes GE tubes. I have a 12AX7 in channel 1 and a 5751 in channel 2 (which I never use). I also rock a nos black plate 12BH7 in the PI slot and it sounds phenomenal. Each of those will run around $25. I've tried a lot of different tubes and those seem to sound great so far. RCA's also sounded good but cost more. I'd go nos GE before the prices keep going up.

grendle · #4 11-22-2011, 06:07 PM

For the hi fi channel a GE or sylvania 5751 would be my choice. There are other even more hi fi 5751's as well which I haven't tried ($$$) but those 2 are reasonable and sound amazing.

For the other Chanel try a EH, mullard, telefunken, or sylvania 12ax7 . Their not as hi fi sounding as the 5751 but are much better sounding 12ax7's. They go from reasonable to $$$

Imo, stay away from the JJ, ruby, sovtek 12ax7' s. They don't bring much to the table and don't really sound any different if at all from one another.

One trick, I believe its tube world (not affiliated) has several tubes of different grades listed (and good audiophile descriptions). Most of the tubes that show wear go for deep discounts. Pick up the less expensive ones and try those to see what you like before you put down bigger cash on a like new or cryogenic treated one. Preamp tubes last a long time and you can sell the ones you rolled to other tube guys looking to try them out.

96tbird · #5 11-22-2011, 06:19 PM

I recently picked up some Baldwin branded RCA's nos 60's for around $14 a piece delivered on ebay. The Baldwin are nice because they are specially selected for low noise use in organs. Also they go cheaper because of the label. Sounds great in my v-4b.

While you're at it stock up on 6k11's they are nearly extinct. Shop around for some deals, around $16 each. I rolled an Nos RCA in and it really tightened it up. Probably the most noticible roll I have done yet. That and the blackburn Mullard '58 12au7 slot.

But if yours is like mine, it still had the original Amperex ax7's in there and they can't be beat. I didn't need new pre's I just got a collection together to try rolling.

grendle · #6 11-22-2011, 08:36 PM

What are 6k11's ?

ajunea3 · #7 11-22-2011, 08:40 PM

Quote:

Originally Posted by grendle

What are 6k11's ?

From what I can gather online, this tube is used in the V4B to control the mid-frequency selector.

ajunea3 · #8 11-22-2011, 09:59 PM

Thanks for the replies guys. I think I will stick a 5751 in V1 and a 12ax7 in V2. Not yet sure which brands though.

chillerthanmost · #9 11-22-2011, 10:15 PM

Quote:

Originally Posted by ajunea3

Thanks for the replies guys. I think I will stick a 5751 in V1 and a 12ax7 in V2. Not yet sure which brands though.

If you can put out for RCA's than do it. But you can't beat GE for the price. They will sound great in there.

And yeah, the 6K11 controls the mids. I have an RCA in there and it sounds good. I haven't put my nos GE yet.

96tbird · #10 11-22-2011, 11:23 PM

Oh, sounds like you have a reissue v4bH, Grendle, you left the H off. The original '70s v4b's had a 6k11 in them. The chances of 6k11 reissues are slim to none.

coreyfyfe · #11 11-23-2011, 05:26 AM

Quote:

Originally Posted by chillerthanmost

I also rock a nos black plate 12BH7 in the PI slot and it sounds phenomenal.

Interesting choice. Any particular reason?

grendle · #12 11-23-2011, 07:36 AM

Quote:

Originally Posted by ajunea3

From what I can gather online, this tube is used in the V4B to control the mid-frequency selector.

oh, cool.

grendle · #13 11-23-2011, 07:45 AM

Quote:

Originally Posted by ajunea3

Thanks for the replies guys. I think I will stick a 5751 in V1 and a 12ax7 in V2. Not yet sure which brands though.

Just stay away from the JJ, sovtek,ruby,GT, 5751's Their not what a 5751 is about and you will be disappointed. I honestly think they just mark the 12ax7's that fail for gain as 5751's. Switching to a 5751 was some of the best $ I ever spent. If it sounds anything like a 12ax7 it's bad. lol.

I'm thinking about changing my svtIIp to all 5751's actually. GE's me thinks.

mrpackerguy · #14 11-23-2011, 07:48 AM

I always like the Electro Harmonix tubes and they are pretty reasonable.

chillerthanmost · #15 11-23-2011, 10:11 AM

Quote:

Originally Posted by coreyfyfe

Interesting choice. Any particular reason?

I heard about someone doing it and really "opening up" their tone. Making it very textured and 3D sounding.

I was fed up with my V4. The two years I had it, I never thought it sounded as good as it could. It was muddy, dark and it would eat up the Ruby and JJ reissue 7027's within a year each. I decided to get some NOS tubes before selling it to find out of it made a difference. I used Sylvania 6L6GC's for the power section, mostly GE in the preamp and that black plate 12BH7 in the PI.

Well.... Im not sure which made the biggest difference but it sounded AMAZING after that. The only way I could describe it is that it sounded earthy. It gave it a 3D feel, cleaned up any muddyness it had and kept it cleaner when pushed harder. The tone was just very earthy; warm and thick with a round rotating feel to it.

I don't know, that was just my experience but unfortunately for most of you, this was an experience on guitar as I hate my v4 for bass

Sorry to get off topic. I still, very strongly, recommend GE or any good USA made nos tubes for these heads. They love to chew up and spit out the cheap stuff.

**pacojas** · #16 11-23-2011, 12:34 PM

the Shuguang 12AX7-C9!!!

hard to find, but I recently purchased the latest version, the 12AX7-B(china). the existing tube(12AX7-EH) was nice, but the -C9 clone is flat-out way better to my ears. obvious improvement across the bass spectrum. the -C9 is supposed to be the highest gain of this genre. in comparison,.. the -EH sounds muddy next to the 12AX7-B!

quick review:
-huge bloom & swell
-clear, distinct harmonics
-very hi-fi with great presence/mid-range
-tolerable noise ceiling