Friedman - SS100 Bias Question

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zzwish

zzwish

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Quick question about biasing a Friedman SS100. I've biased other amps in the past, but never a Friedman. Could anyone post up a quick walkthrough of biasing this amp? What mA range should the amp be? I just picked it up and unfortunately one of the ARS EL34 tubes rated at "50" was smashed when I opened the box. I have a set of JJ EL34's that say "40" on the box. Just want to make sure I have the amp setup correctly.

Also, is it ok to pop one replacement tube in the broken one's spot? Should it be an ARS valued at 50? Thanks very much! I've owned this amp in the past and it is absolutely killer.
 
The bias pot (if it's similar to a BE100) is located on the main board almost lined up with the last power tube and it's a blue color (if I remember correctly). It takes a small flathead screwdriver with INSULATED handle to adjust. If you have a bias prob, which I highly suggest you pay the $20-60 for one. I got the AmhHead Dual Bias Tester with two probes for the power tubes. I measure the two outside power tubes with amp already out of chassis and balanced upside down with two big boxes. Pet the amp warm up real good, maybe even jam on it for awhile, get it HOT, and then I take my bias probes and let the tubes cool enough to plug them into the sockets and tubes.

Let the amp warm up again for a bit and make sure your multimeter is on and in the VA or MA in Volts. Dave said the bias should be around 29-32ma. I'm guessing that's the same for the SS100, JJ100, or BE100. I have mine set around 31-33ma and love it. Tubes get pretty hot after half and hour of play but mines just a tad of the hotter sit. The bias pot is really sensitive so make sure you turn it down first, and then slowly bring it up to 29-32ma.
Hope this helps a little.
 
32mA at input of 120.0vac, so ideally would be on a variac.
 
Thanks for the info. Successfully biased the amp. It was at 40mA with the new tubes. Brought it back down to 32mA.
 
halomojo":2vsnoe36 said:
Thanks for the info. Successfully biased the amp. It was at 40mA with the new tubes. Brought it back down to 32mA.
Click to expand...

Mine was also bias'd up there near 40ma when I first got it. Brought it down to 32ma and the BE100 seems a little more open with more top end bit. Some may like it higher or lower, but 32ma is the sweet spot I hear with mine also.
 
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