Dumbleator for #124. Made a layout and schematic. Please C&a

[David Root]

Yeah, I got confused. That .47uF cap is on the CF cathode, not the recovery cathode.

The difference between the 4.7uF recovery cathode and a 47uF there is roughly 22Hz to 2Hz I think. Does that make an audible difference? I guess Normster thought not.

[martin manning]

The difference between the 4.7uF recovery cathode and a 47uF there is roughly 22Hz to 2Hz I think. Does that make an audible difference? I guess Normster thought not.

The difference at 30Hz is ~3dB. My only other thought is that some effects might create some content down there.

[Joost]

Ok, here is the new layout and schematic based on all the feedback. Please let me know what you think!

The thing that I keep wondering about this layout is that all these parts are around the tube and the heater wires. Will this not create more noise than my original layout?

HERE IS THE NEW PROJECTION:
[img2073]http://www.familieassink.com/documents/ ... ionALT.jpg[/img]


HERE'S THE NEW LAYOUT:
[img2883]http://www.familieassink.com/documents/ ... ostALT.jpg[/img]


LOOKING FORWARD TO YOUR RESPONSES AND FEEDBACK


HERE'S THE NEW SCHEMATIC:
[img:439:543]http://www.familieassink.com/documents/ ... ostALT.gif[/img]

[Structo]

There should be no noise as long as you keep the components low and the leads short.

I would still try to eliminate that circuit board with the additional parts on it.

[Joost]

There should be no noise as long as you keep the components low and the leads short.

I would still try to eliminate that circuit board with the additional parts on it.

Thanks for the reply. There really is no room for more. I need that circuit board. If I use coax for the lead to the grid on the send side and for the lead from return pot to phase inverter, I should be fine right?

BTW, CAN ANYONE MARK WHERE I SHOULD PUT THE OUTER FOIL SIDES OF THE CAPS?

[Structo]

Well for instance, the 1K8/ 47uF cathode bypass could go on pin 8.
Then ground the other end of it to the terminal strip lug that goes to ground.
The .047uF cap can go from pin 2 to the terminal strip then a wire from that to the Master volume.

Attached is the foil direction of the caps.
You will have to translate from the original build.

[Joost]

Well for instance, the 1K8/ 47uF cathode bypass could go on pin 8.
Then ground the other end of it to the terminal strip lug that goes to ground.
The .047uF cap can go from pin 2 to the terminal strip then a wire from that to the Master volume.

Attached is the foil direction of the caps.
You will have to translate from the original build.

Thanks for that. Does moving the 1k8/47uF reduce the chances of noise? Because I am really fine with the idea of the extra board. It's not in the way or on top of anything. Plus, even though I might be able to move over some more parts, no way am I getting all of them off the board. Reduced noise would be the only reason to move anything off the board.

[Joost]

Thanks again for all your help Structo. I checked that image to the dumbleator layout in the Dumble Files and came up with this:
btw, I noticed in that layout that every wire that is not B+ wire is coaxial. Should I do the same?

[img2162]http://www.familieassink.com/documents/ ... LTFOIL.jpg[/img]

Well for instance, the 1K8/ 47uF cathode bypass could go on pin 8.
Then ground the other end of it to the terminal strip lug that goes to ground.
The .047uF cap can go from pin 2 to the terminal strip then a wire from that to the Master volume.

Attached is the foil direction of the caps.
You will have to translate from the original build.

[/img]

[Joost]

btw, I want to go for maximum transparancy and lowest noise, so I was thinking of using all metal film and Xicon MPP caps. What do you think?

[David Root]

PRP (Precision Resistive Products) metal films are very quiet. PR9372 type are audio grade. I have used them since for several years. They have higher voltage ratings than most. www.prp.com . May be hard to get in Europe, they are made in USA, but www.partsconnexion.com in Canada has them and they ship anywhere.

Xicon MPPs. I'm not a big fan of Xicon anything but I think Mark Foster likes them. Mark?

[martin manning]

I'm not a big fan of Xicon anything but I think Mark Foster likes them. Mark?

What's your experience with the Xicon stuff? I havent noticed anything bad as of yet. My D'lator has all MF resistors; some Xicon and some KOA Speer, and of course a Dale RN-65 for the recover stage plate load. I had to look for a quiet tube to keep the noise down, and IMO that is far more significant than anything the resistors are contributing.

[ToneMerc]

btw, I want to go for maximum transparancy and lowest noise, so I was thinking of using all metal film and Xicon MPP caps. What do you think?

I'm going to go the other direction here; the Dumblelator by nature isn't really transparent and in many cases is used as a sort of tone control. Before I built one I thought that a built in unit would be such a great idea. However, my experience has been that it's not necessarily the same results with all circuits/amps. Therefore, I prefer to keep them separate.

Has anyone else drawn the same conclusion?

I will say this, my #183 is a different amp using the Lator and the RG400 cables.

TM

[Joost]

Here are some pics of the board inside my Too Rock as well as a close up of the tube used for the dumbleator with all the parts around it on terminal strips.

[img667]http://www.familieassink.com/documents/toorock8.jpg[/img]
[img667]http://www.familieassink.com/documents/toorock9.jpg[/img]
[img667]http://www.familieassink.com/documents/toorock10.jpg[/img]

[Joost]

BTW, I also moved the 1k8/47uF cathode resistor and bypass cap to terminal strips around the tube as per Structo's suggestion, so I used the space that got freed up on the board for the glaswerks mod for the preamp boost