Category Archives: Bass Amps

Gallien Krueger MB 150 Mains Transformer Replacement

By Frank | Published: June 30, 2021

The Gallien Krueger MB 150 is a popular bass amp, especially with double bass players. We recently had an MB150 in for repair with a blown mains transformer, GK part No. TTO-10879-02 (equivalent to TTO-10879-01). Unfortunatley, sourcing a replacement was tiresome. The UK distributor quoted 6 months lead time! I couldn’t find an off-the-shelf mains […]

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MESA M-Pulse 360 Bass Amp Repair

By Frank | Published: May 31, 2021

We recently had a MESA Pulse 360 bass amp in our new workshop for repair, with a fault description that it was powering up but not passing any signal. I’d repaired an M-Pulse 360 last year with a identical fault condition, so we wondered whether the fault in both amps was being caused by the […]

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MESA Carbine M9 Bass Amp Repair

By Frank | Published: June 15, 2015

Here’s some photos from an emergency repair I did for the band Swans. I got phone call from their tech saying that one of their amps. a MESA Carbine M9, had died with smoke emanating from the innards. Swans needed the amp turned around quickly as they were on tour. I said that this didn’t look […]

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Ashdown MAG300 Bass Amp Repair

By Frank | Published: February 8, 2015

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), […]

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Vintage 70’s Ampeg SVT 300W Bass Amplifier Repair

By Frank | Published: February 2, 2015

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 […]

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JPF Prototype Nimrod 100W Bass / Guitar Amplifier

By Frank | Published: November 11, 2013

Here are some photos of the 1st prototype of a 100W bass / guitar amp. The amp was initially designed as a bass amp (mainly for my use!), but there was some interest in the design from a couple of guitar players, so we will develop a guitar version of this amp too. The amp […]

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Aguilar AG500 Bass Amp Repair: Man vs SMD Round 1

By Frank | Published: July 31, 2013

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 […]

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Brighton Guitar Workshop website now active

By Frank | Published: March 21, 2013

I’ve posted previously that a friend of mine, Nathan, is building and repairing guitars in Brighton. Nathan’s now got his web-site, Brighton Guitar Workshop,  up and running so you can check out his work.    

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JPF Amps now doing guitar amp and effects repairs in Brighton

By Frank | Published: October 6, 2012

If you’ve been following our blog, you may have noticed that I have advertized that a good friend of mine, and excellent guitar repairer and builder, Nathan, has got his workshop up and running in Brighton. Nathan has been getting requests from his customers for amplifier repairs, so has asked me if I would be […]

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Christmas Holiday

By Frank | Published: December 18, 2009

Just to let you know that we will be shutting for business on Monday 21st December and will be re-opening in the New Year on January 4th. In the New Year we will be adding a Tech Info section, which we hope will present some information not found elsewhere. We will of course continue to […]

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