Grainger Firebird 100H guitar amp, 2007

Epiphone would seem to be the origin, this one

the red one , with change of name-plate on the front. anyone know the Epiphone model number of that one ?

got there in the end, Epiphone Triggerman 100H

"Nutcase Kook "

A polished turd would still smell as foul, by any other name ...

( apologies to Willy Boy )

.... Phil

Grainger were amps that the now defunt Sound Contol had made in China. They apparently came off the same production line that previously had badged them Epiphone. I was given a few shop stock ones that were dead out of the box - design and manufactuing quality was absolutely shocking

If you wanted, you could probably fly to the same chinese factory tomorrow, and have them make you a range of "Cook" badged amps, and it would be identical to the Epiphone/Grainger and whoever else had the same idea.

Gareth.

the

scratched

logo.

They

them

and

tomorrow,

I wonder what the internal build quality of the relays are , maker's names Good Sky and Hui Ke. So far 3 problems in the PREA found plus one made by me in the process of removing a crimp spade (more solder on the contact side, than the solder side , bled through from the wiring side) and of course I will have to demount the PA for pre-amptive dealing with the "usual suspects" solderings there.

Does yours have a digital reverb PCB? I seem to remember some of the ones I saw had them and they generated a ton of hash. The manufacturers had done a few local bodges to try and get rid of it, but presumably it was a basic design fault that fed it through the power supplies/earths.

Another one had a weird fault I can't fully remember now - I eventually concluded it must be a layout or PCB problem (remember the Marshall PCB), and thus unfixable. So I didn't waste any more time trying to fix it.

I wasn't best impressed with these amps at all.

Gareth.

ton

but

The digital effects includes reverb/delay . Not just that faux SMD Philips but some other SMD chip with pins bent-fomed under, to solder into the available space - how are those supposed to be soldered properly - will have to remove this sub-board to see how bad it could/will be. I see a pressure pad on that IC coming intp play as a pre-emptive, if its as bad as it looks skew-on

Crackley master vol pot seems to be due to DC getting on the wiper, not from either end of the pot track but coming out of a 4580 dual opamp input , when varying the pot . It is directly connected to the wiper so perhaps a few hundred ohm should go in line as well as a new IC. The pot track was bad so perhaps with some DC getting through a blocking cap was enough to disrupt the IC input

Horrendous DC bangs have gone , replacing that 4580 with TL072. Maybe both op-amps set as unity-gain followers is something to do with the failure. Also replaced the 47uF, 63V electro and wire link to MV wiper with 200R. Have to replace both treble pots before I'm in a position to comparitive check the f-resp with 200R and shorted but seems ok just monitoring the output audibly. So of course Epiphone Triggerman 100H would likely be susceptible to the same failure, whatever precisely caused it.

No observable (to 0.2% measurement) difference, 200R or 0R, 60 Hz to 10KHz. If the opamp failure was due to excess dV/dt then I doubt it would stop it recurring with a bad pot /cap in the future