Welcome, Guest. Please Login or Register
Decware Audio Forums
04/24/19 at 22:56:41 


       



Pages: 1 ... 12 13 14 
Send Topic Print
Anyone Tube Roll with the ZMA yet? (Read 137172 times)
NormD
Seasoned Member
****




Posts: 180
Re: Anyone Tube Roll with the ZMA yet?
Reply #650 - 04/14/19 at 23:55:50
 
I'm running 7027a's from TAD and I'm not thinking go rolling anything else at this point. Too much to do and too little time. And I retire in two weeks!
Back to top
 
 

OPPO Sonica DAC
Technics SL-1200M3D Turntable
SoundSmith The Voice cartridge
JRMedia Center running on a MacMini
Oppo 103D for video
Marantz AV8802a Pre
ZTPre & ZMA for Stereo
Rotel RMB-1585 amp
Focal Electra 1038Be speakers (93 db)
2Hsu Research ULS-15 M
  IP Logged
Archie
Seasoned Member
****




Posts: 1328
Re: Anyone Tube Roll with the ZMA yet?
Reply #651 - 04/15/19 at 00:37:12
 
Norm, have you tried a 7581A?
Back to top
 
 

Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
HR1s (Upgrd - top & bass drivers & X-ovr)
Silver Cabling
DIY Isolation platforms under everything.
  IP Logged
NormD
Seasoned Member
****




Posts: 180
Re: Anyone Tube Roll with the ZMA yet?
Reply #652 - 04/15/19 at 03:02:15
 
I have tried the 7081a's and I like the 7027 better - they seem to have a more balanced range, whatever that means.
Back to top
 
 

OPPO Sonica DAC
Technics SL-1200M3D Turntable
SoundSmith The Voice cartridge
JRMedia Center running on a MacMini
Oppo 103D for video
Marantz AV8802a Pre
ZTPre & ZMA for Stereo
Rotel RMB-1585 amp
Focal Electra 1038Be speakers (93 db)
2Hsu Research ULS-15 M
  IP Logged
Lon
Seasoned Member
****


"Love without
guts is
worthless!"
Philip K. D*ck

Posts: 15620
Re: Anyone Tube Roll with the ZMA yet?
Reply #653 - 04/15/19 at 03:36:45
 
NormD wrote on 04/14/19 at 23:55:50:
IAnd I retire in two weeks!

Congrats on the retirement! You're going to love it! Like me you may miss making a bit more money, but you won[t miss the necessary grind.
Back to top
 
 

HR-1,ZTPRE,ZBIT,ZROCK2,SE84UFO3-25th, CSP3-25th.Taboo Mk IV+MK III;Rega P3 w/modPS Audio:DMP+DSD,P10,NPC,PowerBases,AC-12 pcs; Mapleshade:SamsonV2+V3,double helix Plus spark cbl;Oppo UDP205;VooDoo:Cremona+Amati,Iso-Pods;MD90-T SE tuner; headphones: PM1,HD800S,LCD-
  IP Logged
Archie
Seasoned Member
****




Posts: 1328
Re: Anyone Tube Roll with the ZMA yet?
Reply #654 - 04/15/19 at 17:07:05
 
Thanks Norm.  I guess a quad of 7027As is in my future!  I'm also looking at some NOS Tungsram for my ZMA and CSP3 based on your recommendation -- assuming you still like them.
Back to top
 
 

Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
HR1s (Upgrd - top & bass drivers & X-ovr)
Silver Cabling
DIY Isolation platforms under everything.
  IP Logged
Archie
Seasoned Member
****




Posts: 1328
Re: Anyone Tube Roll with the ZMA yet?
Reply #655 - 04/15/19 at 19:16:12
 
Well, I'm sort of side-stepping into more expensive NOS tubes.  I just bought 8 Tungsram PCC88 NOS tubes for $17/ea, delivered.  They will cover my ZMA and CSP3 with one spare.  I could have had matched quads but for a lot more $.  I've had good luck with other tubes by the each so hopefully I will with these as well.
Back to top
 
 

Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
HR1s (Upgrd - top & bass drivers & X-ovr)
Silver Cabling
DIY Isolation platforms under everything.
  IP Logged
NormD
Seasoned Member
****




Posts: 180
Re: Anyone Tube Roll with the ZMA yet?
Reply #656 - 04/15/19 at 20:08:48
 
I’m still running the Tungstam PCC88’s in my ZMA. I also have them in my ZTPRE and haven’t decided between these and my Amperex.
Back to top
 
 

OPPO Sonica DAC
Technics SL-1200M3D Turntable
SoundSmith The Voice cartridge
JRMedia Center running on a MacMini
Oppo 103D for video
Marantz AV8802a Pre
ZTPre & ZMA for Stereo
Rotel RMB-1585 amp
Focal Electra 1038Be speakers (93 db)
2Hsu Research ULS-15 M
  IP Logged
Lon
Seasoned Member
****


"Love without
guts is
worthless!"
Philip K. D*ck

Posts: 15620
Re: Anyone Tube Roll with the ZMA yet?
Reply #657 - 04/15/19 at 21:09:10
 
I just put a six pack of 6N6P in my ZTPRE in place of the Amperex 7308. Enjoying the change, a less focused, more relaxed sound.
Back to top
 
 

HR-1,ZTPRE,ZBIT,ZROCK2,SE84UFO3-25th, CSP3-25th.Taboo Mk IV+MK III;Rega P3 w/modPS Audio:DMP+DSD,P10,NPC,PowerBases,AC-12 pcs; Mapleshade:SamsonV2+V3,double helix Plus spark cbl;Oppo UDP205;VooDoo:Cremona+Amati,Iso-Pods;MD90-T SE tuner; headphones: PM1,HD800S,LCD-
  IP Logged
Archie
Seasoned Member
****




Posts: 1328
Re: Anyone Tube Roll with the ZMA yet?
Reply #658 - 04/15/19 at 21:23:08
 
Going further in, I just bought a used quad of RCA 7027As.  Seller claims 95% of new and matched.  From the late 1960s.  Should be fun!
Back to top
 
 

Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
HR1s (Upgrd - top & bass drivers & X-ovr)
Silver Cabling
DIY Isolation platforms under everything.
  IP Logged
Lon
Seasoned Member
****


"Love without
guts is
worthless!"
Philip K. D*ck

Posts: 15620
Re: Anyone Tube Roll with the ZMA yet?
Reply #659 - 04/15/19 at 23:16:16
 
Lon wrote on 04/15/19 at 21:09:10:
I just put a six pack of 6N6P in my ZTPRE in place of the Amperex 7308. Enjoying the change, a less focused, more relaxed sound.

And just as quickly they are out. . . too diffuse and indistinct. I put the Sixpack of red-tipped 6N5P I got from Steve, these are sounding excellent right now.
Back to top
 
 

HR-1,ZTPRE,ZBIT,ZROCK2,SE84UFO3-25th, CSP3-25th.Taboo Mk IV+MK III;Rega P3 w/modPS Audio:DMP+DSD,P10,NPC,PowerBases,AC-12 pcs; Mapleshade:SamsonV2+V3,double helix Plus spark cbl;Oppo UDP205;VooDoo:Cremona+Amati,Iso-Pods;MD90-T SE tuner; headphones: PM1,HD800S,LCD-
  IP Logged
Archie
Seasoned Member
****




Posts: 1328
Re: Anyone Tube Roll with the ZMA yet?
Reply #660 - 04/15/19 at 23:23:39
 
Lon, that's interesting.  What was the difference between the two six packs?  Not in sound but in tube.  Was it just that Steve hand picked great tubes?
Back to top
 
 

Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
HR1s (Upgrd - top & bass drivers & X-ovr)
Silver Cabling
DIY Isolation platforms under everything.
  IP Logged
Lon
Seasoned Member
****


"Love without
guts is
worthless!"
Philip K. D*ck

Posts: 15620
Re: Anyone Tube Roll with the ZMA yet?
Reply #661 - 04/15/19 at 23:29:07
 
Steve thoroughly tests and matches tubes, and tests for factors many other testers DON'T. The 6N6P were just a batch I bought from eBay, not tested and matched. The 6N5P were little jewels from Steve. I've determined if he carries a tube type and brand you want or use, the best examples are from him.

And these are two different (compatible) tube types: the 6N6P are larger in size, slightly different electrically.
Back to top
 
 

HR-1,ZTPRE,ZBIT,ZROCK2,SE84UFO3-25th, CSP3-25th.Taboo Mk IV+MK III;Rega P3 w/modPS Audio:DMP+DSD,P10,NPC,PowerBases,AC-12 pcs; Mapleshade:SamsonV2+V3,double helix Plus spark cbl;Oppo UDP205;VooDoo:Cremona+Amati,Iso-Pods;MD90-T SE tuner; headphones: PM1,HD800S,LCD-
  IP Logged
Archie
Seasoned Member
****




Posts: 1328
Re: Anyone Tube Roll with the ZMA yet?
Reply #662 - 04/15/19 at 23:30:41
 
Oh, I didn't catch that they were 6N6Ps. I read them as 6N5P.
Back to top
 
 

Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
HR1s (Upgrd - top & bass drivers & X-ovr)
Silver Cabling
DIY Isolation platforms under everything.
  IP Logged
Archie
Seasoned Member
****




Posts: 1328
Re: Anyone Tube Roll with the ZMA yet?
Reply #663 - 04/17/19 at 16:24:06
 
Tube update:

I found a matched quad of late '60s RCA 7027As for a reasonable price that I should have in a few days.  I'll get to see if they do for me what they are doing for everyone else.   Smiley
Back to top
 
 

Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
HR1s (Upgrd - top & bass drivers & X-ovr)
Silver Cabling
DIY Isolation platforms under everything.
  IP Logged
Archie
Seasoned Member
****




Posts: 1328
Re: Anyone Tube Roll with the ZMA yet?
Reply #664 - Yesterday at 00:24:30
 
I have the RCA 7027As in and while they sound quite nice, one seems to be weak.  I've had to swing the bias adjust all the way right to match two of the tubes.  I'll be contacting the seller and likely be sending the tubes back.  I don't trust that I'll get the life out of them that would justify the price.  The three good tubes are stronger than any tube I've had in with the meters ranging from 70s to an estimated 110mA+.  I've biased toward the low end at 76mA.
Back to top
 
 

Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
HR1s (Upgrd - top & bass drivers & X-ovr)
Silver Cabling
DIY Isolation platforms under everything.
  IP Logged
Jeff of Arabica
Seasoned Member
****


Name the greatest of
all inventors...
Accident.

Posts: 794
Re: Anyone Tube Roll with the ZMA yet?
Reply #665 - Yesterday at 00:57:13
 
Hey Arch,
Sorry to hear that man.  I was really hoping they would work out.  Good thing is you are covered well with purchasing on eBay, even if the seller gives you hassle.  Still, the reason you purchased them in the first place was to get a solid set of 7027A's in your system.  It is worth the journey so keep trying to find that quad that will deliver the goods.

I am also concerned that the lowest they would bias is 76mA.  That seems too high for the minimum.  I generally bias around 64 but can go below 60 if I wanted.  I don't because the strength of that tube type is its ability to handle higher bias settings.  

Send it back and keep looking.
Back to top
 
 

ZMA//Zen Ultra//Rachel//Super Zen//Taboo MKIII//PS Audio DirectStream DAC + Memory Player + P10//Muse Phono Stage//London Decca Reference//Dynavector DV-507 MKII//Zen Head//SonoruS Reel-to-Reel w/ tube playback pre-amp//Omega SAHOs//DM946//Oppo UDP-205
  IP Logged
Archie
Seasoned Member
****




Posts: 1328
Re: Anyone Tube Roll with the ZMA yet?
Reply #666 - Yesterday at 01:13:07
 
I'm a bit confused by what my meters are telling me.  I swapped the weak tube to the other side and I can equalize with a little bit of margin, maybe 2 to 4 mA.  On that side my bias window is from 52 mA to 80 mA while on the other side with the tubes balancing well, my bias window is 68 mA to 96 mA.  Using the controls to "test" tube strength, the weak tube is measuring far below the other three with a much lower high and low reading.  I don't really know how to use the meters as tube testers but clearly one tube has different readings despite being well matched according to the seller's test results.  I'm biasing at 72 mA right now.  These do seem to have a nice clarity.
Back to top
 
 

Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
HR1s (Upgrd - top & bass drivers & X-ovr)
Silver Cabling
DIY Isolation platforms under everything.
  IP Logged
NormD
Seasoned Member
****




Posts: 180
Re: Anyone Tube Roll with the ZMA yet?
Reply #667 - Yesterday at 02:29:07
 
I have my TAD 7027a's biased a 50ma.
Back to top
 
 

OPPO Sonica DAC
Technics SL-1200M3D Turntable
SoundSmith The Voice cartridge
JRMedia Center running on a MacMini
Oppo 103D for video
Marantz AV8802a Pre
ZTPre & ZMA for Stereo
Rotel RMB-1585 amp
Focal Electra 1038Be speakers (93 db)
2Hsu Research ULS-15 M
  IP Logged
Archie
Seasoned Member
****




Posts: 1328
Re: Anyone Tube Roll with the ZMA yet?
Reply #668 - Yesterday at 15:53:06
 
Norm, that seems pretty low for that tube.  The 35W plate dissipation lends itself to higher biasing, no?  I realize it's a different tube but I bias my 7581As at 64mA.  Heat is not an issue, especially with the anniversary mods.

Since these RCAs are 99% likely to go back, I'm considering a quad of Tung-sol 7027As.
Back to top
 
 

Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
HR1s (Upgrd - top & bass drivers & X-ovr)
Silver Cabling
DIY Isolation platforms under everything.
  IP Logged
NormD
Seasoned Member
****




Posts: 180
Re: Anyone Tube Roll with the ZMA yet?
Reply #669 - Yesterday at 16:05:29
 
Archie:

I forget how to figure the right biasing, so I may be low. Will you please refresh my memory?

If you want to test drive a set of 7027a’s, PM me - I have a set of JJ’s.
Back to top
 
 

OPPO Sonica DAC
Technics SL-1200M3D Turntable
SoundSmith The Voice cartridge
JRMedia Center running on a MacMini
Oppo 103D for video
Marantz AV8802a Pre
ZTPre & ZMA for Stereo
Rotel RMB-1585 amp
Focal Electra 1038Be speakers (93 db)
2Hsu Research ULS-15 M
  IP Logged
Archie
Seasoned Member
****




Posts: 1328
Re: Anyone Tube Roll with the ZMA yet?
Reply #670 - Yesterday at 16:20:21
 
This link has a calculator.  Jeff posted his ZMA voltage a while back.  I think it was under 400V.  The A and AB are for 90% and 70% capacity.  Even with my faulty memory, 60mA+ is easily handled.

http://www.tedweber.com/webervst/tubes1/calcbias.htm


Edit:  Check out some of Jeff's posts on page 10 of this thread.  His plate voltage was 390V.
Back to top
 
 

Technics 1200G TT w/ Ortofon Jubilee MC cart
ZMC1
ZP3 (25th A Mods)
ZR2 (25th A Mods)
CSP3 (25th A mods)
ZMA (25th A mods)
HR1s (Upgrd - top & bass drivers & X-ovr)
Silver Cabling
DIY Isolation platforms under everything.
  IP Logged
NormD
Seasoned Member
****




Posts: 180
Re: Anyone Tube Roll with the ZMA yet?
Reply #671 - Yesterday at 16:37:53
 
Thanks for the reminder and link. I’ll move my bias up this evening.
Back to top
 
 

OPPO Sonica DAC
Technics SL-1200M3D Turntable
SoundSmith The Voice cartridge
JRMedia Center running on a MacMini
Oppo 103D for video
Marantz AV8802a Pre
ZTPre & ZMA for Stereo
Rotel RMB-1585 amp
Focal Electra 1038Be speakers (93 db)
2Hsu Research ULS-15 M
  IP Logged
NormD
Seasoned Member
****




Posts: 180
Re: Anyone Tube Roll with the ZMA yet?
Reply #672 - Today at 15:24:31
 
VIVA tubes has a sale. Here is a link to 7027a’s.

https://www.vivatubes.com/search.php?search_query=7027a&section=product
Back to top
 
 

OPPO Sonica DAC
Technics SL-1200M3D Turntable
SoundSmith The Voice cartridge
JRMedia Center running on a MacMini
Oppo 103D for video
Marantz AV8802a Pre
ZTPre & ZMA for Stereo
Rotel RMB-1585 amp
Focal Electra 1038Be speakers (93 db)
2Hsu Research ULS-15 M
  IP Logged
Pages: 1 ... 12 13 14 
Send Topic Print