Tubes Asylum

Questions about tubes and gear that glows. FAQ

Return to Tubes Asylum


Message Sort: Post Order or Asylum Reverse Threaded

The Dynaco looked better with the dust

24.59.229.201

Posted on May 26, 2022 at 07:15:28
Byrd69
Audiophile

Posts: 2633
Location: East Syracuse, New York
Joined: August 23, 2004
Looks like this is a might be a good candidate for a restoration.

It hasn't been powered it up yet. I'll take a peek underneath today to see if there's anything not looking right before I do that. Unfortunately, I don't have any shitty El34s or 5AR4 I can install.

I do have a variac for the task.








Your interest may vary but the results will be same. (Byrd 2020)

I can't compete with the dead. (Buck W. 2010)

Cowards can't be heroes. (Byrd 2017)

Why don't catfish have kittens? (Moe Howard 1937)

 

Hide full thread outline!
    ...
Bringing it up with a 5AR4 wont get you there., posted on May 26, 2022 at 09:06:16
viridian
Audiophile

Posts: 8044
Location: Portland, Oregon
Joined: May 26, 2005
Contributor
  Since:
February 1, 2012
A tube rectifier is not linear in the way it conducts. So at low voltages from your variac, it is not on at all, then, at some point, it comes on.

If you are trying to find out if the amp is bad, or reform the caps, buy one of the cheap, socketed, solid state rectifiers off of the internet, or break open a worn octal tube and solder in a couple of diodes, or even tack solder them to the back side of the 5AR4 socket. You can then bring up the amp in a linear fashion.

 

RE: The Dynaco looked better with the dust, posted on May 26, 2022 at 09:09:49
LtMandella
Audiophile

Posts: 2091
Location: CA
Joined: May 27, 2019
I say just get a can of black spray paint!





Don't wrestle with pigs. You both get dirty and the pig likes it.
Mark Twain

 

Exactly right!, posted on May 26, 2022 at 09:11:22
Triode_Kingdom
Audiophile

Posts: 9483
Location: Central Texas
Joined: September 24, 2006
I have a tube base with a couple 1KV rectifier diodes wired for 5AR4/5R4 testing. Don't risk that nice Mullard 5AR4 in an unknown circuit. As you raise the Variac, the 5AR4 will conduct suddenly and without much warning. If there's a bad cap or other component, the tube can be damaged before you have a chance to remove voltage.


 

Your advice is appreciated and accepted. No power for the Dyna., posted on May 26, 2022 at 09:37:19
Byrd69
Audiophile

Posts: 2633
Location: East Syracuse, New York
Joined: August 23, 2004
I bought the amp only for the tubes. I have no interest in having it restored for my own use. I have had a couple 70s over the years and did not care for them. Sold them both. A friend wants this one to restore. I'll sell it assuming it doesn't work. I'm not going to risk killing a tube. Doing the diode thing is beyond me. It's not that important for me to know if the amp works.

I'm happy the preamp is running. I'm sure some updating might benefit it, but I don't need it so I'll pop in some USA 12ax7 and send it on it's way.


Thank you for the tips, inmates.





Your interest may vary but the results will be same. (Byrd 2020)

I can't compete with the dead. (Buck W. 2010)

Cowards can't be heroes. (Byrd 2017)

Why don't catfish have kittens? (Moe Howard 1937)

 

Before you took the dust off there was hope. :-( nt, posted on May 26, 2022 at 14:54:38
Tre'
Industry Professional

Posts: 16168
Location: So. Cal.
Joined: February 9, 2002
,
Have Fun and Enjoy the Music
"Still Working the Problem"

 

Oh yes it will, posted on May 28, 2022 at 06:08:13
Byrd69
Audiophile

Posts: 2633
Location: East Syracuse, New York
Joined: August 23, 2004
Popped in a borrowed quad of shitty china EL34s and a low testing russian GZ34. That's how you do it. lol

Powers up!

It's sold....cheap.


Your interest may vary but the results will be same. (Byrd 2020)

I can't compete with the dead. (Buck W. 2010)

Cowards can't be heroes. (Byrd 2017)

Why don't catfish have kittens? (Moe Howard 1937)

 

Roll of the dice, glad it worked out. nt, posted on May 28, 2022 at 10:33:14
viridian
Audiophile

Posts: 8044
Location: Portland, Oregon
Joined: May 26, 2005
Contributor
  Since:
February 1, 2012
Nt

 

Dynaco looked better with the dust, posted on May 30, 2022 at 09:16:26
Cleantimestream
Audiophile

Posts: 7421
Location: Kentucky
Joined: June 30, 2005



The Dynaco pictured, promptly replaced the LAMM mono blocs. To be fair, the Dynaco has been modified but is still essentially a stripped down Williamson circuit... {what a Dynaco IS}.
The Mind has No Firewall~ U.S. Army War College.

 

RE: Dynaco looked better with the dust, posted on June 1, 2022 at 08:02:29
Triode_Kingdom
Audiophile

Posts: 9483
Location: Central Texas
Joined: September 24, 2006
Interesting front panel on the Dynaco. Is that a commercial offering?


 

RE: Bringing it up with a 5AR4 wont get you there., posted on June 3, 2022 at 08:49:45
PakProtector
Audiophile

Posts: 12295
Joined: May 14, 2002
The slightly easier way is to just plug in something else. a 5Y3 for instance, and some 6V6's or perhaps cheap 6L6's. Goal is not to get full performance, but reach 75% of B+ and deliver some idle current load.

All in all, for a flipper amp, bring it to the point where you can guarantee the transformers is a useful thing.

And heating up an amp with a GZ34 is not too difficult with a variac and volt meter. Recognize the non-linear behaviour and account for it with the variac's knob.
cheers,
Douglas

Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

 

RE: Dynaco looked better with the dust, posted on June 5, 2022 at 10:04:48
Cleantimestream
Audiophile

Posts: 7421
Location: Kentucky
Joined: June 30, 2005
Yes, it is TK.
The Mind has No Firewall~ U.S. Army War College.

 

Page processed in 0.031 seconds.