Saturday, 24 January 2015

FIXED - Carlsbro PA 60

So, that Carlsbro PA 60 I took on from Mr. Foxen all that time ago is finally all fixed.

I got a big new resistor to replace the one that was smoking, wired everything up, put the valves in and tested it with the nearest convenient cab, which was a Peavey Deuce VT combo.

It crackled like Rice Krispies while Snap and Pop are on their hols. That was a shit metaphor but I'm keeping it, okay?

Anyway, fast forward past the eating lunch and doing the weekly shop and I lug the chassis upstairs to test it with my Orange OBC 115. And it appears that the thing actually works. Pots are a bit scratchy, but that's no biggie. It has a nice, warm clean sound and does not appear to drive the preamp by itself so that would need a booster. I ran my Retrovibe RVT-40 into it via my Nine of Swords Burial at Sea and it sounds pretty good running fuzz. I think with the right booster and right fuzz this amp could doom pretty hard.

Once it's been all cleaned up it will be put up for sale.

Tuesday, 2 September 2014

I Ate'nt Dead

I'm still around! Got a bit demoralised with the whole amp tinkering thing after taking on a mid-90s Marshall to fix and I just totally couldn't. (note to self: no mid-90s Marshalls ever.) But here I am! My pile of guitar builds has got a bit closer to being guitars again as I've heat stripped some bodies and intend on refinning as soon as I can. I've also just picked up a Peavey Deuce VT combo as a fixer project. 120w for £50. Sweet. AND I'm waiting to hear from a dude I know who wants one of his amps looked at and possibly repaired. Hurrah!

Sunday, 27 April 2014

What a Difference a Valve Makes

Got a Mullard ECC83 off Mr. Foxen to try in the Blackstar HT-DistX he traded me. It doesn't "completely open up the EQ" as I've seen claimed on the interwebz about replacing the valves in the HT pedals (a pox on over exaggeration), but it does make the gain sound nicer which is a big plus.

Now follows some gutshots and notes.

Fuck your warranties.

The immediately obvious thing when taking the boards out of the HT-DistX is that they're generic. Theoretically this means the pedal is very, very moddable. In practice it appears no bugger has even bothered and schematics are pretty much hen's teeth, so that's something to ponder for another time.

As on the other board there is a lot of space other components, including two more switches. Shown is the stock Sovtek valve

I had wanted to get the pot values as they would be the most immediately useful mod I could potentially make, but there are no values visible. I doubt these are particularly great pots, which makes it even more of a pain. L-R: Gain, Bass, Mid, Treble, 'Infinite* Shaping Feature**', Level.

*Not actually infinite.
**Possibly as in 'it's not a bug, it's a...' as I haven't found the point where it does anything awesome.

Tuesday, 4 March 2014

Retrovibe RVT-40

Well, it works perfectly! The sound is so much clearer and definitely a bit more Rick-like when I have the settings right.

Can't wait to test it at band volume.

I may do a recording at some point.

Saturday, 1 March 2014

Carlsbro PA60 Blues and Retrovibe RVT-40

The Carlsbro amp still isn't working. Having sorted the filter caps and the HT fuse (which it turns out needed to be slow-blow) the choke resistor (basically a great big resistor that sits between the power transformer and the rest of the circuit) is duff, smoking when the power's on and reading about twice as much as it is supposed to. Sigh.

I've also rewired my Retrovibe RV-4 to roughly approximate the wiring of a Peavey T-40 bass. Thus, Retrovibe RVT-40. I got all excited when I finished it and forgot to get a picture of the wiring, but here's the outside of the bass with classy-looking new knobs and a wee switch that does phasey stuff to the bridge pickup (in theory) and the T-40 wiring diagram.

Retrovibe RVT-40

I can't test that it works until tomorrow, on accout of it being quarter to eleven at night... but once it is tested I'll report back either in celebration or lamentation.

Sunday, 16 February 2014

Carlsbro PA60 - Power Up Test

New resisistor and HT fuse in, powe cord into amp, plugged into circuit breaker (safety first).

Power on! Light! Wheeee!

Check HT fuse, just to be sure, and it's blown with no valves in the amp.
New HT fuse = blown

Dodgy capacitor is the most likely culprit according to Foxen and sure enough there's a bit of white fluff by the vent on one of the filter caps, which means it's probably dead, and this is further borne out by a quick voltage test across the caps. Best thing at this stage is to do a 'brute force' recap, so that's more money to spend.

Bah. But learning is good.

Sunday, 2 February 2014

Plumbing the Depths

Retrovive RV-4 in C# standard -> Nine of Swords Burial at Sea -> Blackstar HT-DistX -> Peavey Firebass power amp -> Orange OBC 115

Sub. Ter. Ran. Ean

That is all.