1st Dumble Amp Build Success

[talbany]

Very clean dress...I am curious to know the why of your cap choices if your game to discuss

It's a Dumble and looks to be a .01

Tony

[jcsifu]

Hi Tony,
I should have been clearer that I was referring to the OP's choice in what I assume are 225P caps in certain locations as my post did come right after your post on the switch. I am familiar with the strat switch as well, though. I've added it to few peoples amps as well as at least 1 of mine and I will use on occasion but I usually come armed with a Les Paul.

JC

[talbany]

Hi Tony,
I should have been clearer that I was referring to the OP's choice in what I assume are 225P caps in certain locations as my post did come right after your post on the switch. I am familiar with the strat switch as well, though. I've added it to few peoples amps as well as at least 1 of mine and I will use on occasion but I usually come armed with a Les Paul.

JC

[amplifiednation]

Great looking build!

[Abe5150]

Very clean dress...I am curious to know the why of your cap choices if your game to discuss

Ya those are Panasonic ECQ 630v polyester film foil. I used them for the .01 and the .1 in the phase inverter. I just wanted to experiment, the lower voltage ones are used a lot in pedals so I wanted to try them in a amp. The little blue ones are murata monolithic ceramic 1kv once again just experimenting no real rhyme or reason. They work and didn’t blow up that’s about all I can report. The Panasonic’s are interesting because identifying the foil was a lot easier. I did it the cheap method into an amp and the foil was strong more so than the cde 6ps.

[Abe5150]

The Red Plate had a switch for humbuckers and single coils, does anyone know how that works???

No I don't have a clue!

Tony

Whoa that’s cool. Am I understanding that switch correctly, when you pull it it replaces the .01 in the circuit with that of a different value like .047 ? Oh wait now that I look again it’s just adding it.

[norburybrook]

Very clean dress...I am curious to know the why of your cap choices if your game to discuss

Ya those are Panasonic ECQ 630v polyester film foil. I used them for the .01 and the .1 in the phase inverter. I just wanted to experiment, the lower voltage ones are used a lot in pedals so I wanted to try them in a amp. The little blue ones are murata monolithic ceramic 1kv once again just experimenting no real rhyme or reason. They work and didn’t blow up that’s about all I can report. The Panasonic’s are interesting because identifying the foil was a lot easier. I did it the cheap method into an amp and the foil was strong more so than the cde 6ps.

The last set of 6PS caps I had I found it very hard to find the outside foil using my tried and tested 'cheap' method like you. The older,larger 6ps it was easy to hear but the new ones are either better made or something's changed as I think you'd need a scope now to reliably tell. That may mean it's not as important, who knows?

M

[donvan]

Whoa that’s cool. Am I understanding that switch correctly, when you pull it it replaces the .01 in the circuit with that of a different value like .047 ? Oh wait now that I look again it’s just adding it.

I interpreted it differently. I may be wrong but the way I see it seems like a good solution. I'm seeing it as a .047uF and .01uf in series which gives you .0082. When you pull out the pot/switch, the .01uf is shorted out and you have .047.

I like this way better than putting another switch on the back or bottom of the amp.

Thanks for the pic Tony. It got me thinking differently. By doing it this way, I don't have to worry about additional shielded wires running to a new switch and I don't have to drill a new hole.

[donvan]

Does anyone have a part number for a 250K push/pull switch like the one shown in Tony's picture?

[jcsifu]

Very clean dress...I am curious to know the why of your cap choices if your game to discuss

Ya those are Panasonic ECQ 630v polyester film foil. I used them for the .01 and the .1 in the phase inverter. I just wanted to experiment, the lower voltage ones are used a lot in pedals so I wanted to try them in a amp. The little blue ones are murata monolithic ceramic 1kv once again just experimenting no real rhyme or reason. They work and didn’t blow up that’s about all I can report. The Panasonic’s are interesting because identifying the foil was a lot easier. I did it the cheap method into an amp and the foil was strong more so than the cde 6ps.

I'm familiar with those caps in the 50v version for just that reason. They were very nice to implement in pedals, which is how I started changing my tone and later building my rigs. I was unaware the ECQ had a 630v version

[Abe5150]

Very clean dress...I am curious to know the why of your cap choices if your game to discuss

Ya those are Panasonic ECQ 630v polyester film foil. I used them for the .01 and the .1 in the phase inverter. I just wanted to experiment, the lower voltage ones are used a lot in pedals so I wanted to try them in a amp. The little blue ones are murata monolithic ceramic 1kv once again just experimenting no real rhyme or reason. They work and didn’t blow up that’s about all I can report. The Panasonic’s are interesting because identifying the foil was a lot easier. I did it the cheap method into an amp and the foil was strong more so than the cde 6ps.

I'm familiar with those caps in the 50v version for just that reason. They were very nice to implement in pedals, which is how I started changing my tone and later building my rigs. I was unaware the ECQ had a 630v version

Ya I am looking at them right now on Mouser. I was surprised too when I saw them. They are pretty much the gold standard for pedals. I wonder how a whole Dumble in those caps would sound.

[talbany]

BTW. For those who are curious here is another pic of the amp. Notice the op-amp driven loop. I hear it was removed at one point from the amp
Caps are dated 82 and uses the same board material as 124

IMG_2640.jpg

Tony

[norburybrook]

Tony, is that big resistor there as part of the dropping string to power the op amp FX loop?


M

[talbany]

Tony, is that big resistor there as part of the dropping string to power the op amp FX loop?


M

I think so, But it looks a bit overkill. I can't see the loop pulling that much current

Tony

[Abe5150]

Does it say MOGY 08 on the effects loop board??