Danelectro DS100 schematic?

[acorkos]

I am working on a Danelectro DS100....4x6L6, dual output transformers, 6x10" speakers. Reverb is not working....there are a couple of loose wires off the reverb pot. This amp is supposed to be similar in design to a Silvertone model 1485 http://schematicheaven.com/bargainbin/silvertone1485.pdf but there are enough differences that the 1485 schematic is not helping solve the Dano reverb problem. Anyone out there with a DS100 schematic? Thanks for your help!

[acorkos]

anyone? puleeeeze!

[Enzo]

Did you look through the Danelectro files there for similarities?

What are you trying to fix, just the reverb? If so which end is the problem, the drive or the return? Two wires off the reverb control? Well most reverb controls have one end grounded, so if one of those wires goes to ground, it goes to the bottom leg of the control. If neither is ground, then one goes to the control and the other returns from it.

SOme of these have the control on the drive side, and others have it where it belongs on the return side, but either way, a signal comes from a source - the reverb unit itself, a previous tube plate, something - and returns to some sort of input, usually the grid of some tube. SO follow those wires and see what sort of thing they each lead to. Most times the signal source feeds the top of the control, and the wiper sends the signal onward to the next stage.

Troubleshooting skill will get you through a lack of schematic a lot better than a schematic will get you through a lack of troubleshooting skill. Practice that magic art.

[acorkos]

thanks enzo

the reverb is the only problem on this amp right now. it works barely....no reverb effect from 7 up to 8 o'clock....i get a little doinky reverb at that point. any higher on the dial and it starts to howl and screach.

please take a look at the 1485 schematic. this amp's reverb circuit is similar around the 6CG7 tube. but this amp has no 12ax7 in the reverb circuit. the pot is on the drive side of the circuit.

my questions....the dashed line from the reverb tank to the reverb pot....is that supposed to be a wire connecting the tank to the wiper of the reverb pot?

this amp has the reverb pot wiper connecting to a 2.2M resistor connecting to pin2 of a 12ax7....the same pin that both volume pot wipers connect to via 330k resistors. Any idea where the input to the reverb pot should come from? that is the one missing connection i am dealing with.

[Enzo]

But the dashed line does not go to the reverb tank, the dashed line goes to the reverb SWITCH. Over by the reverb pan is a switch to turn it on and off. That switch is part of the reverb control. Turn the control all the way down and the switch clicks off. That is what the dotted line means - the switch is part of the control mechanically.

Disconnect the pot and measure it. End to end, and also from the wiper to either end. And check the wiper while rotating the pot as well.

[acorkos]

the reverb pot measures 1M from end to end and sweeps from 0 to 1M like it should.

ok.....i understand about the dashed line. anways, this amp has no switch like in the 1485.

So, now I have 2 connections I'm not sure about:
input to the reverb pot....
reverb tank connection (similar to that which runs through the switch on the 1485)

Here's a schematic from another Dano amp with a single 6CG7 in the reverb circuit. Different circuit than this DS100, but maybe something else to consider? The wiper on my reverb pot connects to a 2.2M resistor which connects to the junction of a pair of 330K resistors coming off the volume pots, the 330K's arranged like in this schematic...

[Enzo]

Does this have a REAL reverb pan, or does it have one of those awful little home made things with one large spring through the center and a couple little slices of piezo crystal stuck within the coils? The awful thing is about 25mmx25mm and maybe 100-150mm long.

Arranged like in this schematic? I see a couple 330k resistors, but they don't go to the reverb or any volume controls, they are plate loads and go to B+.

If you have a 330k resistor from each volume control of a two channel amp, then they are there as mixers, most likely, and the wiper is the return to the signal path.

Doesn't the signal to the top of the pot come from the reverb pan itself?

If this is one of those horrible piezo things, than my first thought is that the reverb iteslef is broken. I have made new piezos for those things, and believe me it is a pain in the ass.

[acorkos]

no real pan....it's one like you described with a rectangular metal cover taped on, covering a long caterpillar spring with the piezos.

thanks for your help. i'm going to call it done and live with the limited reverb range.

[Enzo]

One or both of your piezo crystals are probably shot.