Welcome, Guest. Please Login or Register
Decware Audio Forums
06/24/24 at 19:37:33 




Most recent 50 posts

Pages: 1
Send Topic Print
12AT7 in place of 12AX7 (Read 4950 times)
Geno
Seasoned Member
****


Without music, life
would be a mistake.

Posts: 2080
12AT7 in place of 12AX7
03/27/19 at 02:28:20
 
I read that the 12AT7 has lower gain than a 12AX7, but that this can result in possibly better sound quality. I’d like to try one, but can I use it in the first position on the ZP3?
Back to top
 
 

(2)SE84UFO(Balanced Monoblocs) OR Sansui AU-222/Zbit
Cambridge Audio CXN(ModWright)
Crown XLS-1002 Sub Amp
SL-1210MK5(KAB Mods) Soundsmith Aida MKll cart • Darlington Labs MP-8b
Otari MX5050-Bll2 R2R
ZLC Power Cond.
Lii Audio PT-10/W-15 in Open Baffles
  IP Logged
Lon
Seasoned Member
****


"Love without
guts is
worthless!"
Philip K. Dick

Posts: 23962
Re: 12AT7 in place of 12AX7
Reply #1 - 03/27/19 at 02:36:19
 
No, I don't think you can. I believe I tried this and it was a no go. You need to use a 12AU7 type.
Back to top
 
 

HR-1,ZBIT,ZROCK2,SEWE300B,CSP3-25mod; Rega RP3 all GrooveTracer mods;PSAudio:PST+DSD, DAC Mk II, P15,NPC,PowerBases,AC-12 pwr cbls, Reference spkrcbls; Mapleshade SamsonV3; VooDoo:Cremona+Amati interconnects, IsoPods; headphones: Sennheiser HD800S,ZMF Ori,Oppo PM1
  IP Logged
Geno
Seasoned Member
****


Without music, life
would be a mistake.

Posts: 2080
Re: 12AT7 in place of 12AX7
Reply #2 - 03/27/19 at 02:40:27
 
Lon,

I am using a 12AU7 where it belongs. I’m talking about in place of the first 12AX7.
Back to top
 
 

(2)SE84UFO(Balanced Monoblocs) OR Sansui AU-222/Zbit
Cambridge Audio CXN(ModWright)
Crown XLS-1002 Sub Amp
SL-1210MK5(KAB Mods) Soundsmith Aida MKll cart • Darlington Labs MP-8b
Otari MX5050-Bll2 R2R
ZLC Power Cond.
Lii Audio PT-10/W-15 in Open Baffles
  IP Logged
Lon
Seasoned Member
****


"Love without
guts is
worthless!"
Philip K. Dick

Posts: 23962
Re: 12AT7 in place of 12AX7
Reply #3 - 03/27/19 at 03:27:57
 
Sorry, I had that backwards. But I don't think a 12AT7 can be subbed in the ZP3.
Back to top
 
 

HR-1,ZBIT,ZROCK2,SEWE300B,CSP3-25mod; Rega RP3 all GrooveTracer mods;PSAudio:PST+DSD, DAC Mk II, P15,NPC,PowerBases,AC-12 pwr cbls, Reference spkrcbls; Mapleshade SamsonV3; VooDoo:Cremona+Amati interconnects, IsoPods; headphones: Sennheiser HD800S,ZMF Ori,Oppo PM1
  IP Logged
Ace-Tone
Seasoned Member
****


8+ years with
Decware gear and
Loving it!!!

Posts: 775
Re: 12AT7 in place of 12AX7
Reply #4 - 03/28/19 at 01:35:05
 
I tried a 12AT7 in the 12AU7 position....
It took the volume level down and the fidelity as well....so much so that it was immediately removed.
Back to top
 
 

SE84UFO25, ZP3, Zstage, ZR2, ZSB, DM947, HERESY iii
VPI-Traveler2 +SS Zephyr MKIIIes.
Cambridge CXC. Schiit Bimby DAC
IC's Audio Envy, Decware, RAC-PC's, Mapleshade Dbl Helix+Spkr wires & jumpers
Blue Circle PLC FX2X0e, Herbies, GIK, PI Audio DIY treatment
  IP Logged
pursuitofnow
Seasoned Member
****




Posts: 449
Re: 12AT7 in place of 12AX7
Reply #5 - 03/28/19 at 05:38:37
 
Replacing a 12ax7 with 12at7 seems like it may be too much of a drop in gain.

12AX7/12AX7A/7025/ECC83/CV4004
Gain factor: 100

5751
Gain factor: 70

12AT7/ECC81/E81CC/CV4024
Gain factor: 60

12AU7A/5963
Gain factor: 20
Back to top
 
 

VPI Classic Signature | Koetsu Urushi Black | Bob's Sky 20 | ZP3 | Swiss Digital Fuse Box
DirectStream DAC (APS nickel transformers, Vocm mod)
ZTPRE | ZBIT | ZROCK2 | SE84UFO3
Omega Super 3 HO XRS | Deep 8
Zenwave D4 | PCR-11 | PI Audio Uberbuss
---
ZR 3
  IP Logged
Steve Deckert
Administrator
*****


If the 1st watt
sucks why continue?

Posts: 6290
Re: 12AT7 in place of 12AX7
Reply #6 - 03/28/19 at 05:53:44
 

If experimenting with the 12AT7, the tube should replace the first 12AX7 at the front of the ZP3.  Yes, the gain drops, so if you have a lowish output cartridge this change is not likely to do you any favors.  However if you have gain to spare from either a higher output cartridge and or a gain stage after the ZP3, the 12AT7 can in some cases be the magic bullet.  

One of my favorite combinations with the ZP3 is the ZSTAGE on its outputs.  This adds about 6 dB or more of noiseless gain and puts the dynamics of your cartridge on steroids...  If you have gain to spare like this, and you are occasionally hearing the midrange and top end become forward, using a 12AT7 would lay it back and mellow it out by taking the sharpness out without effecting the speed, resolution or frequency balance.

Steve
Back to top
 
 
WWW   IP Logged
Dilbert99
Verified Member
**




Posts: 5
Re: 12AT7 in place of 12AX7
Reply #7 - 05/05/23 at 01:45:28
 
I just swapped out the front 12AX7 with a 12AT7 with very good results.  Running a ZP3 through an all Decware system to Zu Soul Supremes.  

I kept the volume levels consistent before and after swapping the tube, practically no noticeable drop in the level from a Nagaoka MP-110 with 5mV of output, so with a lower output cartridge you mileage may vary.

The tube only has a couple hours on it, so it hasn't reached its full sound potential just yet.

Pretty pleased with the result, especially given the lower price for good NOS 12AT7 as opposed to the 12AX7.

I haven't tried another 12AT7 in place of the middle 12AX7, not sure if that would have any further impact, or if it even advisable.  

I'm curious to know if others have seen the same result as I or if they've had success with the swap in the middle position.
Back to top
 
 
  IP Logged
Rivieraranch
Seasoned Member
****




Posts: 2126
Re: 12AT7 in place of 12AX7
Reply #8 - 05/20/23 at 23:55:29
 
What about a 5751?
Back to top
 
 

MINI TORII & ZROCK2 both anniversaried; 'Lil Audio F-15; TECHNICS SL1200MK2 KAB MODDED TT; ONKYO 6 DISC CD; MARANTZ 2226B; SCHIIT MULTIBIT DAC; SENNHEISER HD-580s
55   IP Logged
surfers5
Verified Member
**




Posts: 10
Re: 12AT7 in place of 12AX7
Reply #9 - 08/09/23 at 19:34:49
 
As Steve said, if you have gain to spare the 12at7 can be the magic bullet for the V1 position in the ZP3.

I just posted my in-depth experience of trying different gain tubes in the V1 and V2 spots of the ZP3 in the - Tube Rolling 12au7, 12ax7 thread.
Back to top
 
 
  IP Logged
Pages: 1
Send Topic Print