Amp bias too hot?

lukedlb

Various pre valve substitutions failed to rid my Kelly (72 built in kings cross) of the light distortion until I remembered that the only work done on this amp was a good set of JJ power tubes taken from the amp's older brother. Is it possible that the jjs are the problem (no problem in the other amp) or did the amp tech (whose reputation as the best in the county has dropped to one who no longer cares about his work) set the bias too hot? I had the impression that the tech favoured the 80s rock side of things so it could explain the problem. 
The amp has two El34 and all I want is clean. I get my drive from pedals hitting the amp. 
I guess changing the bias by myself is out of the question. 

ICBM

If you're getting a slight distortion on a clean sound it's more likely that they're biased too cold, and you're hearing crossover distortion.

Changing the bias yourself isn't too difficult - assuming the amp has an adjustment trimmer, many older amps don't - if you can handle simple tools and are aware of the potential dangers.

ecc83

http://www.vintagehofner.co.uk/selmer/kelly/kel3.html

I found another site (and lost it!) with a user manual that referred biasing to 'qualified personnel' Fair enough. In the link above you can I think make out a bias pre set but I cannot see a cathode I sense resistor?

ICBM is a busy man Luke but if you are prepared to buy a modest test meter and a couple of croc leads, PM me and I will walk you through the procedure. Will need some decent gut shots of amp.

The amps seem to be of Selmer derivation? Perhaps IC could suggest a bias current? I would set for 25-30mA per valve.

Dave.

DJH83004

Is this your amp? if so, this particular Kelly did not have adjustable bias I'm afraid, it is set using resistors, which as IC said was quite common in the day. The one thing I would say is these amps were set for Mullards or Brimars, which in my experience is way too hot for the modern range of EL34s, so suggest its off to a Tech for a resistor change. 

lukedlb

Yes, this is my amp @DJH83004. Photo bucket have just suspended me so I'll have to study imgur to get something posted. I have a good set of gut shots.
I'm not 100% behind this amp. As mentioned, I have the amp's older brother, the Kelly sound master which has the most incredible body. The (black) kelly gets close but not enough. It's volume has more control.
From what I understand, the kelly amps are tidier version of seller treble and bass. mine came from a primary school in North london.
Has anyone had any other experience of the kelly amps, specifically the sound master? I would love to be able to bring it as close as possible to the sound master's tone.

JayKay

lukedlb. Did you get it sorted,?

lukedlb

I took the easy way out and sold it. Thank you to the members offering to help. Life got to busy and then a new life came into my world: a redplate. Hence the sale. The buyer was happy with my opinion of the amp’s flaws, which are more likely pluses for other players.