A Little Engineering That I Appreciated

[Phostenix]

I recently needed to replace a reverb pan for a friend's amp, so I bought one of the MOD brand pans.

I really like how they configure their input & output jacks. I purchased the 4EB2C1B pan because it was the closest I could get to the original, but the original had the input jack tied to the pan & the output jack was isolated. This pan is the reverse, but the clever way they use to "ground" or isolate the jack from the pan allows you to convert it to whatever configuration you need. If you look closely at the pics, you'll see that the PCB trace has 2 breaks in it that you can solder bridge to complete the circuit to ground the jack or leave it open to isolate the jack. They even put 2 breaks in the trace so that you don't have to solder under the wire once it is in place.

[Mick Bailey]

It looks nicely made - how are the coils connected? They look better than the Accutronics that go open where the windings are soldered to the connector pins. The wire looks better, too. And the little clip - how many Accutronics fail with a broken wire at the RCA socket?

Seems to be better though out.

[JoeM]

Somebody was thinking

[guitician]

Maybe pretty girls in controlled environmental conditions...

[pontiacpete]

Now if they can get them to sound as good as the old acoutronics ... that would be nice.

[Chuck H]

Indeed! I just used one in a build (And I DID use the board trace options to alter the grounding! Very nice). It sounds acceptable. That's not bad because IMHO the Belton and new Accutronics tanks sound worse. Some of the mojo of the old Accutronics tanks is in the materials the transducers were made from. At least one of which will never be available to any manufacturers again. Incidentally, it's precisely that material that ages and makes the old tanks go microphonic. As much as I like the aesthetic of vintage reverb circuits I think the day is fast approaching when digital reverbs will actually sound better than the available physical/analog parts. It's just a new paradigm that we'll need to adapt to.

[Phostenix]

It looks nicely made - how are the coils connected? They look better than the Accutronics that go open where the windings are soldered to the connector pins. The wire looks better, too. And the little clip - how many Accutronics fail with a broken wire at the RCA socket?

Seems to be better though out.

No connectors. Wires go from the transducer coils to the jacks. I didn't take any pics of the rest of the internals & I didn't spend a lot of time studying it. I did notice the springs, though. They look to be epoxy'd where they hook on at the transducer ends (glossy black) and there is no coupler where the 2 springs join together in the middle. The 2 springs are hooked to each other & it appears they are spot welded together.

The pan is much springier sounding than the original Peavey pan (Accutronics). I'm hoping it will relax over time.

[Phostenix]

Some of the mojo of the old Accutronics tanks is in the materials the transducers were made from. At least one of which will never be available to any manufacturers again. Incidentally, it's precisely that material that ages and makes the old tanks go microphonic.

Tell me more.

Is there an easy way to rewind the transducer coils when the wire breaks right at the coil?

[Chuck H]

Tell me more.

Is there an easy way to rewind the transducer coils when the wire breaks right at the coil?

I read it here in fact. I'm not searching for the original thread, but the gist was that the original rubber damping rings in the spring charge tubes used by Accutronics became unavailable. Trying to redesign for different materials apparently wasn't working out very well and may have been a part of the original companies demise. This mystery damping material in the original units dries out and hardens with age. No damping=microphonic reverb.

As to refurbing original transducers... Rewinding the little electromagnetic element doesn't seem too tough. The design looks like the plastic coil bobbin could be slid off for easier rewinding. Rebuilding the original spring charge tubes is probably impossible. The truth is that I've never tried to disassemble one of these so I don't know what sort of "this was never intended to come apart" engineering might block your efforts. I have a couple of old pans here. I'll look at them and report back later.