Category Archives: Amp repair

Ashdown MAG300 Bass Amp Repair

I’ve had quite a few Ashdown bass amps in the workshop for repair. Here’s the inside of a MAG300 I had in a recently. The amp was not powering up, and on inspection the mains fuse has blown. On energizing the unit employing a current limiter (a 60W light bulb in series with the amp), […]

Also posted in Bass Amps, JPF Amps | Comments closed

Vintage 70’s Ampeg SVT 300W Bass Amplifier Repair

Here’s a rare example of a 70s Ampeg SVT that I had in the workshop. Introduced in 1969, the SVT has, rightly, gained the reputation as one of the greatest bass amp ever made. Indeed, even today the SVT is the industry standard bass amp for live work. However, working on these amps is not […]

Also posted in Bass Amps, JPF Amps, London | Comments closed

Fender Blackface Deluxe Reverb Repaired By JPF Amplification

We’ve repaired hundreds of vintage Fender amps, and it’s always a pleasure to get these classic amps back in tip-top working order. It’s a testimony to Leo Fender that so many Fender amps from the 1960’s are in use today. Here’s a picture of the inside of a vintage 1960’s Fender Blackface Deluxe Reverb we […]

Also posted in London, Vintage amps | Comments closed

Two Marshall JCM900 Amps Repaired At JPF Amps

Here are a couple of Marshall JCM900s guitar amplifiers we’ve had in our workshop for repair in the last few weeks.     The one on the bottom simply need new output jack. Unfortunately the one on the top needed a new mains transformer and power valves, a significantly more expensive repair. These are original early 90’s amps, […]

Also posted in Guitar Amps, Vintage amps | Comments closed

Orange Crush 15R & 30R Guitar Amp Repair

Here’s some photos from a pair of Orange Crush guitar amps I’ve had in for repair: a 15R and a 30R. Both had a very loud hum when the amp was at idle. In a solid state amp this is almost always due to poor power supply filtering. and further inspection showed that this was caused […]

Also posted in Guitar Amps, JPF Amps, London | Comments closed

Peavey ValveKing 100 Guitar Amp Repair

Peavey have earned a reputation for making well-engineered amps at reasonable prices, so I was not expecting any major issues when I took in a ValveKing 100 for repair. The symptoms where that the amp was not powering up: neither the indicator light, nor the valve heaters where illuminated. This fault is usually due to […]

Also posted in Guitar Amps, JPF Amps | Comments closed

Fender Hot Rod Deluxe Guitar Amp Repair: New Filter Caps.

Here’s Fender Hot Rod Deluxe that came into our workshop in need of new filter caps. Whilst you would expect the filter caps in, say, a 40 year old Fender Twin Reverb to need changing, it’s surprising that the caps in a 10 year-old Hot Rod Deluxe should have expired; however from my own experiences, […]

Also posted in Guitar Amps, London | Comments closed

Fender Blues Junior Guitar Amp Repair

I see quite a few Fender Blues Juniors in the workshop for repair; not that they are unusually unreliable, it’s just there are a lot of them out there! However you do see many of the same faults occurring, so here’s some photos highlighting these from a recent repair. Firstly, like many amps that use […]

Also posted in Guitar Amps | Comments closed

Aguilar AG500 Bass Amp Repair: Man vs SMD Round 1

Here’s a repair I conducted on a more modern amp, a Aguilar AG500 bass guitar amplifier, where we were dealing with the dreaded SMDs. This amp is quite an interesting design as it has a class D output stage, however unlike most class D amps it’s not ultra light. It employs a linear power supply […]

Also posted in Bass Amps, Guitar Amps | Comments closed

VOX Night Train Guitar Amplifier Repair

Here’s some photo’s from a recent repair of a VOX Night Train amplifier. The amplifier was producing no sound. Curiously the HT voltage on the first pre-amp valve was only 95 VDC, way below spec. I removed the valves and the HT on the first valve stage was still only 95 VDC. On further investigation […]

Also posted in Guitar Amps | Comments closed