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6c33c warm up time

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Posted on February 5, 2017 at 06:11:08
Eric Chan
Audiophile

Posts: 84
Joined: October 31, 2001
I have an BAT using 6c33c. I have found the warm up time for the amp is very long, something like 1.5 hour up to start sounding normally, before reaching such.warm up the amp sound awfully harsh , bright and unnatural

What is your experience with 6c33c, does it take ling time to warm up ?

 

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RE: 6c33c warm up time, posted on February 5, 2017 at 08:13:01
Chip647
Audiophile

Posts: 1629
Location: The South
Joined: December 24, 2012
I don't think that is a characteristic of the tube. I have built with them. With an amp, it is easy to look at the big output tubes and assume they are controlling everything. Truth is, there are dozens of parts in your amp that could have the aforementioned impact on your sound. Could be capacitors.

There is an odd chance that you have some instability (Oscillation) in the amp that goes away when all the parts get fully warmed.

What you are describing does not seem normal.

 

RE: 6c33c warm up time, posted on February 5, 2017 at 08:18:21
Eric Chan
Audiophile

Posts: 84
Joined: October 31, 2001
>> Could be capacitors.

There is an odd chance that you have some instability (Oscillation) in the amp that goes away when all the parts get fully warmed

What capacitor you are referring to, I have replaced their original oil cap with more reliable REL CAP RT,betyer, but it still need

 

RE: 6c33c warm up time, posted on February 5, 2017 at 08:27:52
Eric Chan
Audiophile

Posts: 84
Joined: October 31, 2001
What cap could that be? Eletrolytic cap? I have replaced the coupling cap,better but not fixing the issue

In case of OSC during start up and OSC gone after warm up, how do I troubleshoot it easily, I have signal generator and an osciliscope

 

RE: 6c33c warm up time, posted on February 5, 2017 at 09:26:12
Chip647
Audiophile

Posts: 1629
Location: The South
Joined: December 24, 2012
There is a lot going on inside a BAT amp. I don't know which one you have but it just may be the nature of the beast. You could ask Victor Khomenko (he and Steve Bednarski founded BAT). He posts frequently on the Asylum and seems like a very knowledgeable and helpful guy.




 

RE: 6c33c warm up time, posted on February 5, 2017 at 13:03:12
Lew
Audiophile

Posts: 8723
Location: Bethesda, Maryland
Joined: December 11, 2000
I have used the 6C33C in my Atma-sphere OTL monoblocks. I rigged them so that I could turn on output tube filaments well in advance of applying plate voltage. I used to let the 6C33Cs get beyond "warm" to hot to the touch, before applying plate voltage. That seemed to take 5-10 minutes. After applying plate voltage, I would not say that the amplifiers sounded as good as they did get after maybe 30 minutes, and I attributed that to time required for the plate voltage to equilibrate. After 30 min or so, there was usually an apocalyptic moment when the amps really started to sing, but I never felt short-changed up to that time. (The Atma-sphere circuit is pretty near exactly like your BAT, except that BAT puts an output transformer between the output tubes and the speakers.)

About 1-2 years ago, I changed over from 6C33Cs to 7241s. I was thus able to cut back from six output tubes per channel to four, with no loss in power. It's a tough call, but I would say that the 7241s sound a bit better than the 6C33Cs, and the difference between "cold" and warmed up operation is not as pronounced, although I can still hear that happening.

 

Not that long..., posted on February 6, 2017 at 14:10:42
Ralph
Manufacturer

Posts: 3164
Location: Minnesota
Joined: April 24, 2002
Contributor
  Since:
April 1, 2002
We were the first company in the US to use that tube (one of the founders of BAT was a customer of ours before BAT got started).

It does not seem to take that long. After about 45 minutes to an hour the amps we've made with them seem to have gotten to where they were going. I would not describe that tube as sounding harsh even in the first 15 minutes. Its something else in your amp.

 

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