Welcome, Guest. Please Login or Register
Decware Audio Forums
03/28/24 at 17:52:07 




Pages: 1
Send Topic Print
OA3 replacement? (Read 7180 times)
Hipfan
Senior Member
***




Posts: 65
OA3 replacement?
09/04/12 at 01:45:43
 
I was losing power in my left channel and noticed that the left channel OA3 regulator tube was flickering, so I shut the amp down. Upon re-power up, it seems OK. Not sure if it is bad or not. If so, what is a recommended replacement? The stock tube in the Sylvania OA3.
Back to top
 
 

Torii MK3, Icon Audio PS2, Rega P5, azur 640C V2, Klipsch Forte II (Crites), PS Audio Duet, MAC cabling
  IP Logged
Lon
Seasoned Member
****


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

Posts: 23305
Re: OA3 replacement?
Reply #1 - 09/04/12 at 04:12:24
 
I've had good luck with RCA OA3, so I would recommend trying one of those.
Back to top
 
 

HR-1,ZTPRE,ZBIT,ZROCK2,SEWE300B,CSP3-25mod,Taboo MkIV;Rega RP3 all GrooveTracer mods;PSAudio:PST+DSD,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
will
Seasoned Member
****




Posts: 2914
Re: OA3 replacement?
Reply #2 - 09/04/12 at 04:43:47
 
I have tried a number of OA3s and like them all for different sound, some brighter and more open, some warmer, some punchier, some more or less balanced, but my fav now is a short straight sided bottle labeled Ameperex. The 50s RCA ST coke bottle shape that came with my amp is a least favorite for me, but a perfectly good sounding tube.

Tubeworld usually has a good selection if you can't find what you want on Ebay or wherever. Some OB3s are really good too, especially Raytheon or Tungsol.

Have you checked the tube pin connections... cleaned the pins and slid the tube in and out of the socket a bit with deoxit on the pins?
Back to top
 
 

All Modified: Balanced Transformer-DIY Strip/Shunyata Defender-RevolutionMacMini/Amarra-KTE Singxer/Gustardx20pro-ZBIT-CSP3-OldChen 300B/845, Torii IV, Simple Wave 300B-HR1/SVS Micro3000sub-Pi PCs-DIY PCs, ICs, USB, I2S, Speaker-SR and aluminum w ball bearing feet
  IP Logged
Hipfan
Senior Member
***




Posts: 65
Re: OA3 replacement?
Reply #3 - 03/11/13 at 22:28:30
 
Regarding the Sylvania OA3. I noticed there are a few variations of these tubes. I've seen the coke bottle type in 3 different sizes and also a non-bottle tubular version. Do these all sound the similar?
Back to top
 
 

Torii MK3, Icon Audio PS2, Rega P5, azur 640C V2, Klipsch Forte II (Crites), PS Audio Duet, MAC cabling
  IP Logged
will
Seasoned Member
****




Posts: 2914
Re: OA3 replacement?
Reply #4 - 03/12/13 at 01:58:37
 
I am not sure. The only Sylvania OA3 I have is early 80s, ST (coke bottle) shape and they have a really good, complete sound that is quite open and transparent. The 50s STs I have are warmish. Also the OB3 ST and OC3Ws I have from the fifties are warmish...the Raytheon/Tungsols are nice tubes and warm, and the Sylvania OB3 ST I have are a little less warm, but still on the warm side.

A Russian tall/straight bottle I have is very open....tending to hard/edgy unless balanced with pretty warm tubes. I have some sylvania short straight OC3s (70s) that are quite open and sound good. Some Raytheon, RCA and Amperex, short/straight, all warmish and probably earlier vintage.

So go figure! I wonder if the early stuff is more warm and the later...more open...no solid information here though.
Back to top
 
 

All Modified: Balanced Transformer-DIY Strip/Shunyata Defender-RevolutionMacMini/Amarra-KTE Singxer/Gustardx20pro-ZBIT-CSP3-OldChen 300B/845, Torii IV, Simple Wave 300B-HR1/SVS Micro3000sub-Pi PCs-DIY PCs, ICs, USB, I2S, Speaker-SR and aluminum w ball bearing feet
  IP Logged
Pages: 1
Send Topic Print