Variac on zero, power switch off- connect power cord. 2). Connect either output to load box (load A). 3). Resistance loads open (switch in. Gallien Krueger rb Schematic Diagram. Uploaded by esquisof. Gallien Krueger rb Schematic Diagram. Copyright: © All Rights Reserved. Download as. Hello, Service Manual of the Gallien Krueger rb this is a amp for bass, there are layout, pcs, schematics for preamp and poweramp.

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If your wondering about the NTE parts use their online cross reference http: I can’t remember if GK has a few of those chips, but you might want to contact them to see if they still have some “reserve” kruegeer, just for this purpose.

Also, it’s generally not as loud as it should be. The bias voltage is dominated by Q4 Q5 current, which increases with temp, instead of a multiple of Q9 voltage, which decreases with temperature. This makes me wonder if one of the other parts is still sick. Opening it up R50 had burnt up. Started by skipwave The Lab. Scheatic would like a pdf copy of the schematic if possible.

Per the tech note on the schematic measured across Q13E and Q14E, adjusting R49 galpien very little, 9mv is about the highest it will go, 7mv the lowest. Let me know what else I can do to help you guys help me. The resistance divider current must be “much” higher. If you don’t use a footswitch to boost, than this is not only acceptable, but no different than having the I.


I’ve attached a screen shot of the schematic problem area. Q4 Q5 flow about 4mA 0. Education is what you’re left with after you have forgotten what you have learned. I know their obsolete. If this does not happen, the amp gets hot, idles at higher temp, gets hotter yet, and goes into “run-away”.

When the going gets weird However if connected wrong, the amp will burn-up at turn-on.

Can’t see what you done from miles away. The output transistors are double-stacked so each gets less voltage.

When things went wrong, the voltage would fall very ga,lien, the resistors get hot instead of the transistors. I’ll probably just remove the chip and jump the pins.

What can I use?? If it actually takes most of 4mA, the base current is less than 2uA.

Gallien-Krueger 400RB Service Manual

Good morning, for sentimental reasons I picked up a Gallien Krueger B, it’s an earlier version of the popular RB but it’s all discreet along the lines of an old Sunn or Acoustic. The bases of the outer devices are nominally half the supply voltage, noted as Ass-uming that the output two triple-Darlingtons needs six times 0.

Ass-uming that Q9 is exactly 1. Can someone check me? I’m turning some of them back on. Each transistor base-emitter drop should be near 0. Votes for the wrong politicians? Fixed that up, things are pretty good now, but it still won’t bias right. November 20, Different transistors have different areas and doping so the exact voltage needed will vary.


Not sure, but that TL chip may be out.

I don’t have much faith in the work that was done to it before Schsmatic got it. Here’s what I’ve done so far For a fairly constant idle current in Q13 Q14, we need a bias that DEcreases when the amp gets hot. I’d want to do it different.

I’ll keep replacing resistors but if anyone could help me figure out a way to keep it powered on long enough to measure some voltages that’d be a big help. When things go wrong, it gets VERY expensive fast.

Help repairing Gallien Krueger B

If they don’t, then you can remove the I. When the IC became history, they made up a small board with long pins, you install it in the same pc board holes and galluen does the function.

Krugeer, thanks for the tip on the NTE stuff, I had no idea that existed. I’d put these in series with the power rails. Maybe one of these hypex class D modules. But will be a little rough-throat sounding around the 1W level. A ohm resistor would be “right”, except it has an all-wrong temperature coefficient.

I would appreciate the schematic for the B or service manual – THX.