Filter Caps for #124 type build

[blues38pavol]

So, I have been pouring over the photos, drawings and schematics of the #124 ODS. I gotta say, I am totally stoked that this stuff is out here. I moved my Twin power and output trannies to the ODS chassis I have and I am working on the tube sockets this week. I have a couple of eyelet boards that I received from the guy I bought the chassis from. I will be more than pleased if I can get sound out of this whole thing...it's just a complete blast.

Ok, I noticed that filter caps used in the #124 were yellow Sprague Atoms, according to the pictures and drawings, specifically two (2) TVA1628 300uF/500VDC and two(2) TVA1906 20uF/500VDC. I can find blue TVA1906s - chime in here if I should use something else - but for the life of me I can't find anyhting close to the TVA 1628s . Everything I read says just use 100uF/350 VDC or 220uF350VDC caps but being my first build, thought I would post the question here.

My other question would be, how is this affecting the sound? My understanding is that by increasing the capacitance of the filter cap I can increase the low end response of the amp. Am I wrong? Am I thinking of the other caps (20uF)?

[Structo]

I don't think it increases the low end, more like it will tighten up the bottom end.

Hopefully IC-racer will chime in as he built a replica of #124.

Notice on the #124 layout that the 300uf 350v caps have radial leads while the 20uf 500v have axial leads.

[ayan]

So, I have been pouring over the photos, drawings and schematics of the #124 ODS. I gotta say, I am totally stoked that this stuff is out here. I moved my Twin power and output trannies to the ODS chassis I have and I am working on the tube sockets this week. I have a couple of eyelet boards that I received from the guy I bought the chassis from. I will be more than pleased if I can get sound out of this whole thing...it's just a complete blast.

Ok, I noticed that filter caps used in the #124 were yellow Sprague Atoms, according to the pictures and drawings, specifically two (2) TVA1628 300uF/500VDC and two(2) TVA1906 20uF/500VDC. I can find blue TVA1906s - chime in here if I should use something else - but for the life of me I can't find anyhting close to the TVA 1628s . Everything I read says just use 100uF/350 VDC or 220uF350VDC caps but being my first build, thought I would post the question here.

My other question would be, how is this affecting the sound? My understanding is that by increasing the capacitance of the filter cap I can increase the low end response of the amp. Am I wrong? Am I thinking of the other caps (20uF)?

You might get lucky and find some 300uF caps, but I guess it's no wonder no Dumble built in the last 20 years has had any in it... I have always used 220uF and been fine with them, as well as everyone else I know. I am not sure I know how much tightness in the low end one could get going from 220uF to 300uF as in these amps, there is no lack of integrity in the bottom end as per my experience. I even built one or two amps with 100uF caps, and liked that quite a bit as well.

Gil

[ic-racer]

I believe these are the ones I used. Very close in physical and 'electrical' size to what is in #124.

http://www.tedss.com/item.asp?id=2020003615


[img:500:401]http://www.tedss.com/stock/images/1175/1175001678.jpg[/img]

[blues38pavol]

I believe these are the ones I used. Very close in physical and 'electrical' size to what is in #124.

http://www.tedss.com/item.asp?id=2020003615

You guys rock, this is what I was looking for.

[Sven]

Greetings,

Why do you ruin your amp by sqeezing that black goop there. If you must use silicone putty there, use clear stuff.

And you could also use a wet rag or wet finger, to smooth it nicely, like a thin, long and very unobtrusive clear line.

Sven

[rmb550]

Gives it more of an authentic Dumble look

[ic-racer]

Greetings,

Why do you ruin your amp by sqeezing that black goop there. If you must use silicone putty there, use clear stuff.

And you could also use a wet rag or wet finger, to smooth it nicely, like a thin, long and very unobtrusive clear line.

Sven

I have never seen pictures of an ODS with the 300uf caps done like that. I have seen black and silver and it does not look all that pretty.

BTW, those big radial lead capacitors need to be glued to the board, the leads won't keep them in place.