6550 issue

  • Thread starter Thread starter Buckeyedog
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Buckeyedog

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Got mine today, but I can't them to bias any lower than 51 and 55!! Too darn hot man. What should I do? I requested a "medium range" tube, but I'm not sure if that means anything for bias level. :confused: I put them in my Seminar Head and the lowest I could get was 103! :aww:

Do I have any recourse? Maybe I'll e-mail BIOaudio..........

Sorry guys, just had to vent a little.....was so psyched to try them.
 
Buckeyedog":naocw35x said:
Got mine today, but I can't them to bias any lower than 51 and 55!! Too darn hot man. What should I do? I requested a "medium range" tube, but I'm not sure if that means anything for bias level. :confused: I put them in my Seminar Head and the lowest I could get was 103! :aww:

Do I have any recourse? Maybe I'll e-mail BIOaudio..........

Sorry guys, just had to vent a little.....was so psyched to try them.
Click to expand...
WOW man,I would call them up and see.I played the shit out of the set I just received from them and they smoke!!No problems and within 2.5 MVs
 
Buckeyedog":32mcvaax said:
Got mine today, but I can't them to bias any lower than 51 and 55!! Too darn hot man. What should I do? I requested a "medium range" tube, but I'm not sure if that means anything for bias level. :confused: I put them in my Seminar Head and the lowest I could get was 103! :aww:

Do I have any recourse? Maybe I'll e-mail BIOaudio..........

Sorry guys, just had to vent a little.....was so psyched to try them.
Click to expand...

On my Mod50 combo (an older one...from the serial number) I had to set my bias to the bottom, which put the tubes right at the high level of the bias curve. I think mine ended up being like 45.5mv or 46. 1-2 mv's isn't gonna matter, but 51-55, yeah that's not cool. Ask Jeff which resistor is the one feeding voltage to the bias pot, and have a tech change it so it lowers the voltage going into the bias pot. That's pretty much all my tech had to do to allow a VHT 2502 to accept 6550s. Change the resistor feeding the bias pot.

Eric
 
Buckeyedog":1o8c5uvg said:
What do yours bias out at??
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I've got them set at about 46/48 being high but I can go as low as 18 or so
 
Well, got my "new" 6550's that BIO Audio exchanged for me........although a bit cooler.
Anyway, haven't really got to crank them yet, but at first impressions, they sound great. Nice and balanced and crunchy. Good amount of headroom. I've got them around 41 or so for now. I may boost them up a bit, but am going to play with them a while at this setting. Just playing the LP through the Bassman and SL2 and both modules sound terrific. Can't wait to crank 'em up though! I also want to try them in my seminar head if I can get them to bias ok.
 
Wow, I was hoping you wouldn't run into problems like I did, but damn.

I don't think they're actually matching any of the tubes there.
 
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