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Lots of questions please help


Monte Anderson
Posted on Wednesday, January 12, 2005 - 08:23 pm:   

Ok, I'll make the long story short: Had a music man HD150 many years ago. I didn't know anything about it or anything about tube amps in general but loved the tone. Anyways I now have the SAME head back. It's dirty but appears to be in good shape. Only 2 of the 4 tubes (6l6gc no other markings) are in it. I'm anxious to fire it up. What are the basics of working with tubes? I hear about matching, bias, etc. and have no clue. I want to know what to do before I fire it up. I know new tubes are in order but, out of curiosity, can this 4 tube amp be run with 2 tubes to cut down on power and risk of blowing my celestions? I am semi-capable of working on analog stuff but I know very little about tubes. Please help.
Who Knows?
Posted on Wednesday, January 12, 2005 - 11:58 pm:   

I run 2 tubes in my 4 tube hd130 210...but....you probably have the SS driver and one of the MM experts will guide you the right way for the newer amp you have... my guess is, since you bought it that way it will work...or should
Monte Anderson
Posted on Thursday, January 13, 2005 - 08:22 pm:   

I didn't buy it back. I never sold it in the first place. I had a deal with a friend to store it and some other stuff when I moved. He left town and neglected to tell me that he hadn't paid his bill for about 2 years. (even though I had paid him!!) The storage company sold what they could and put the rest in a barn. It sat there for about 6 years until an old aquaintance of mine saw my name on some of the stuff and contacted me about a month ago. It looks like no one did anything to it except remove 2 of the tubes. I plugged it in tonight and the 2 tubes glowed. gonna experiment with it tomorrow. Anyone know a good place to get tubes for a reasonable price?
Posted on Friday, January 14, 2005 - 11:28 am:   

If its a cathoded Biased amp(one resistor for all 4 tube cathodes) you may see some red glow on the plates using less than 4 tubes... then you would possibly need all 4 tubes installed... also the resistors can be split (4 seperate cathode resistors..)but... it will more than likely need to be done by an expert..(since the vaulue and rating for each tube will need calculated) The Tube Depot is a good place for tubes....
Posted on Friday, January 14, 2005 - 11:37 am:   

One more thing, red plate glow is a good indication for an overheated tube... in the dark is a good place to check it out....if you see no red glow and it sounds ok, then you are probably ok....but the safe bet would be is to replace the tubes and then have a tech BIAS them...It probably has 6L6 tubes, good ones would be the SED Flying "C" 6L6GC because of the vintage design and tone...
Steve Kennedy (admin)
Username: admin

Registered: 03-2002
Posted on Saturday, January 15, 2005 - 09:36 pm:   

My suggestion would be to take the amp to a technician and get it checked out. Then put in new tubes and get it biased. If it sat in a barn for 6 years there may be some problems more serious than just a couple of missing tubes!