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What tubes now?

B

BruenoB

Well-Known Member
Well when I first purchased my JWN amp from a fellow AKer I was using it for full range. Because of this and the fact I like bass, I tried to equip it with tubes that would give good bass and I feel I've done well with that.

However, now with the addition of my Hawthorne Audio Duets (open baffle), I have gone to a bi-amp setup with my JWN amp pushing the coaxials for mids and highs and a solid state plate amp pushing the bass drivers for the low end.

Therefore, I think I need to do some rolling to increase the upper end. (mids and highs)

My current tube setup :

Rectifiers : big bottle GE / Ken Rad JAN-CKR-5R4GY (x2)
12AU7 : RCA clear tops (x2)
6SN7 : Ken Rad black glass (x1)
Power Quad : Electro Harmonix EL34 (x4)

Jim told me I should keep the rectifiers as 5R4.

Any good suggestions on other tubes (possibly the 6SN7 & 12AU7 first?) that would give me better highs and mids? I love detail and smoothness. I can't stand harshness. Music tastes are very eclectic. I'd prefer not to break the bank with purchases. LoL

Keep in mind also that the speakers are open baffles.
 
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I like the Sylvania 6SN7GTA chrome dome "tall" bottles. Nice clean sound from top to bottom; should be more neutral and less "sweet" but also less dark and bloated than the Ken-Rad. Also -- the GTA/GTB series tend to be less microphonic than the earlier GT type, they should last longer as they're rather for higher plate voltage, and they're reasonably priced. I've never been super-impressed by the GT or VT231 types (too expensive to justify the sound), except for the amazing Tung-Sol round plate, which is incredibly expensive and hard to find. If you need a decidedly bright tube that still sounds decent (when said brightness is necessary), the Raytheon 6SN7GTB is that.

With 12AU7, I don't have too much experience; clear tops are I think a nice choice for your stated goals. Perhaps try a GE 5814. Try a Tung-Sol 12BH7 if you can spare the extra 0.3A (per tube) of heater current! Maybe even a Sylvania (these have powerful punch bass, though). The RCA 12BH7 are lovely, but most are decidedly warm sounding.

For your power quad, the EH 6CA7 fat bottle has cleaner upper-range, and also has more energy up there than the EH EL34 (I liked both sets of tubes when I had them in an Eico HF-87). It will also give you more punchy, tighter bass. And very reasonably priced -- sounds like an easy choice there!
 
Thank you for the suggestions. Im definately going to get a quad of the EH 6CA7 now. I really need to get that 6SN7 rolled too since the only other one I have is a Sylvania green letter which is a very warm tube with lots of bass (almost as much as the ken rad but not quite).

I "think" the clear tops I have might be ok to keep. Any other suggestions for the 6SN7 or the 12AU7 for clarity and detail?
 
I believe the 6SN7 is the input tube, and the 12AU7s are the phase inverters. That's how my JWN amp is set up. If yours is, too, then the biggest change will come from swapping the 6SN7. I'm running a Ken-Rad in mine, so can't really help re: suggestions for you to try.
 
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