The Amp Garage

Remember my failed attempts to repair a DV Mark Little 40 ? I'm looking for a solution to replace the whole circuit with something that can be mounted similarly in the non-traditional chassis. I want to find a PCB for a pair of octal power tubes and three noval preamp tubes, all with tubes-up, PCB-m...

Photos of main PCB, just FYI.

If the imbalance follows the tube, we know the tubes are mismatched, right?

Is this a vintage 1965 amp or a reissue? If it's really 1965, I'd be concerned the 0.1u coupling caps are leaky.

I replaced the pair of post-PI 0.047u coupling caps. Still getting the same bacon frying and pops.

Magnatron wrote: ↑Wed Feb 21, 2024 4:43 pmturn the unit on, the fuse blows. It's happened now 5 times.

When does the fuse blow, immediately when you throw the power switch, or 10-20 seconds later, after tubes heat up? Do you have a standby switch, and does it relate to the problem? What fuses are you using, amerpage, quick or slow?

WhopperPlate wrote: ↑Wed Feb 21, 2024 6:27 pmbut it doesn’t pay to disbelief the person with perfect pitch because you can’t find a tuner.

Difference being, perfect pitch can be easily and repeatably tested and demonstrated.

I removed the main PCB, disconnected the microcontroller daughterboard, resoldered many points, painted all connections with DeOxIt, reassembled. No change in noise!

maxkracht wrote: ↑Wed Feb 21, 2024 3:16 pm Is r36 supposed to be green?

Yes. I replaced it last night anyway (one of the PI's plate resistors).

Is the Presence pot wired backwards or has reverse taper?... No, the Presence control effects the guitar tone exactly as you'd expect...but it affects the noise in the opposite! My voltage scaler control on my Carr Telstar is scratchy every time I turn it. Could there be an issue with the power sca...

The bug showed up. Bacon frying with occasional pops. Noise is post MV, and strangely, turning the Presence all the way UP causes the noise to become DARKER, like rolling the treble off. Weird. Not an FX loop issue. Same bad noises with different set of tubes. Noise is not sensitive to knocks or cho...

Well. That was a long walk off a short pier...

I bought another "project" amp on a whim. This is some modern, whiz bang engineering. 40 watts, only 17.5 pounds. Seller's warning was, "This amp makes intermittent popping and cracking noises." I played it for an hour with no problems exhibited. This is a little concerning, because I won't feel con...

Have you tried it vertical? I've tried vertical 2x12s in the past. Maybe fine on stage, but in my room, I sit near the cab when I play, and I always hear comb filtering when I sit near a vertical 2x12. This cabinet is already sitting on a 2" base of walnut hardwood, and the top surface makes a grea...

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