Dlator Values

[angelodp]

I am looking at the schematic and the pics from Funk's build and I do not make out the second 10M resistor at .22uF??

[IMG791]http://i260.photobucket.com/albums/ii9/ ... alues3.jpg[/img]

[IMG563]http://i260.photobucket.com/albums/ii9/ ... atic-1.jpg[/img]

[moj067]

The .22uF Cap is obstructing you from seeing it.
It goes from the right leg of the .22 cap to the two left legs of the 500pF and 220K resistor.

[glasman]

Be wary, the 27K and 1Meg are correct on the board, but the labels are swapped.

Gary

[angelodp]

Ok I think this is good to go know.

Thanks

[IMG659]http://i260.photobucket.com/albums/ii9/ ... 7board.jpg[/img]

[angelodp]

Is the 3w100k a Vishay Dale

How about the 330R are they Metal Oxide ?

The 47uF what voltage please? is it 450v ?


[IMG:400:300]http://i260.photobucket.com/albums/ii9/ ... uesjpg.jpg[/img]

[heisthl]

Is the 3w100k a Vishay Dale

How about the 330R are they Metal Oxide ?

The 47uF what voltage please? is it 450v ?


[IMG:400:300]http://i260.photobucket.com/albums/ii9/ ... uesjpg.jpg[/img]

The 100k can be any type and 1 watt is adequate.
the 330r can be any type and 1/4 watt is adequate. (there is only 1 BTW)
the 47uF at 250v would be adequate.

[angelodp]

I am contemplating putting discharge caps across the 47uf caps. What value would you use.

A

[odourboy]

Ok I think this is good to go know.

Thanks

[IMG791]http://i260.photobucket.com/albums/ii9/ ... alues4.jpg[/img]

I may be mistaken, but isn't the cathode cap on the return triode supposed to be 4.7uF? (At least that's what I've been using in my loops.)

[angelodp]

There are two ( maybe more ) schematics that i have one shows the

1.5k 4.7uF pair the other shows 1.3k 47uF

I sure would like to know which one is the correct way to go. Look at the schematic above is it a typo??

[angelodp]

I am damn close to building this thing. Major learning curve with great help from lots of generous folks here. I do think this is ready to go. But now odourboy raises a question on the cathode cap return triode. Seems like the schematic has a typo ??

[IMG563]http://i260.photobucket.com/albums/ii9/ ... atic-1.jpg[/img]

[IMG654]http://i260.photobucket.com/albums/ii9/ ... e_pins.jpg[/img]

[IMG:974:1024]http://i260.photobucket.com/albums/ii9/ ... phic11.jpg[/img]

[angelodp]

I guess the other shem is incorrect, but thats a guess.

[IMG:567:569]http://i260.photobucket.com/albums/ii9/angelodp1/4.jpg[/img]

[ayan]

There are two ( maybe more ) schematics that i have one shows the

1.5k 4.7uF pair the other shows 1.3k 47uF

I sure would like to know which one is the correct way to go. Look at the schematic above is it a typo??

This is what I can tell you, based on many pictures of different Dumbleators. :

1. All seem to have 47uF at the cathode, I believe the 4.7uF shown on some schematics is in errror.

2. Most have 1.5K//47uF on the recovery stage. Also, these units have 1.5K and 10K at the "tail" of the cathode follower.

3. I know of one Dumbleator, courtesy of Scott L., where the cathode resistor is 1.3K instead of 1.5K. On that unit, the input resistor on the recovery stage (usually a 220K to ground) is a 250K (I think) pot, mounted on the front panel. Also on that unit, the CF tail is 1.8K, 27K. I know Scott and Gary J. like this arrangement a lot. This is definitely a one of as far as the third pot on the front panel goes. However, that might suggest (so please, refrain from jumping all over me if you don't like what I write ) that the signal level coming out the FX unit was pretty hot. And, if it was hot coming out, it probably needed to be hot going in... and to accommodate that Dumble gave that CF more voltage headroom. Just an (un)educated guess on my part. Also, I don't understand the reasoning behind descreasing the input impedance via the pot, while at the same time increasing the gain stage by descreasing the cathode resistor from 1.5K to 1.3K. Hack job? Who knows.

4. I have it on good authority that RF's Dumbleator is as described in #2 above, and uses a choke in addition to everything else. Pictures of the unit opened, showing the choke, are floating around on the internet.

5. For what it's worth, part of the key to getting a good sound is to set the signal levels adequately at the various stages. I have never had a problem inadvertently overdriving the CF described in #2, for example, but I believe Scott and Gary have. That may have to do with how hot they run the signal coming out of the preamp... I like mine as hot as possible just before clipping the CF.

Cheers,

Gil

[odourboy]

Well that clears up that! Thanks Gil. Always an education.

[glasman]

If you want to try the choke idea, one for a fender deluxe works great and really reduces the ripple on the supply.

Ted Webers little cheap ones from china work fine in this application.

Gary

[greiswig]

Not meaning to hijack, but...

Kevin O'C (London Power) has a series/parallel FX loop based on a single 12AX7 that can be put into an existing amp and uses the amps HV and filament supply. My guess is that a lot of people here are familiar with it from the TUT volumes.

How comparable is this loop to a D'Lator?