D-763 amp

[tubenit]

This amp borrows ideas from the Dumblish camp & also from the AB763 topology (not component values).  Hence the D-763 name.  Actually using 6L6's in mine but being cathode biased you can easily swap for 6V6's.

Relay switching on a 3 button foot switch.  It has a very nice clean tone and can be easily pushed to hang on the edge of break up. 

I've never really gotten along well with the dumblish PAB feature as it's been too trebly, too harsh and too much of a volume jump for me.  I've done the PAB thing numerous times and almost never use the feature. 

However, with this amp and this tone stack ………….. the way I have PAB set up now is like just "more" and a boost retaining close to the same tone but with a little push and a little more sustain. VERY useable feature for me.

It's very quiet at idle.  I used some TDK 2 watt metal film resistors as plate resistors.  And I used some 2 watt carbon film Kiwame resistors here and there in the signal path.  And I used Orange Drop PS caps & ceramic caps for the small values.  I using a Warehouse ET65 12" speaker which seems to be a good match.  I think an Emminence Texas Heat would be another good match for this amp.

Might be an amp design for someone looking for something a little different.

CHECK for ERRORS!  IF there is a discrepancy, then go with the schematic.

** UPDATE:  Both versions sound great to me.  This was a "rebuild" in a 18.5" x 6" x2" chassis. ALOT going on in that small
                   chassis.  The "v.3" was reasonably quiet at the levels that I normally play it, but had more floor noise then I
                   wanted when cranked. I am confident this was due to the chassis being cramped especially with the relay
                   switching.   So, I tried the 1-7-2020 version which is it's current state.  Not much difference in tone but the amp is
                   quieter (floor noise) when cranked. I think the 1-7-2020 version may have a slightly cleaner sounding reverb
                   with the reverb insertion point changed.

This is a very sweet musical sounding amp. Even with the reverb completely turned off, the amp has a rich full tone to it.

With respect, Tubenit

[tubenit]

Consider this an unproven DRAFT idea.  This incorporates Sluckey's Vactrol tremolo that uses one triode & returns the amp back to a "one tube reverb" state.  I'd like to build this amp at some point, but currently have no plans to do so.

IF you pursue this, consider that you will have to experiment to get the tremolo like you want and perhaps also the reverb.   CHECK for ERRORS!  (presume there may be some)   IF there is a discrepancy between the schematic and layout, then go with the schematic. 

With respect, Tubenit

[jordan86]

Hey

Tubenit

Do you have these 4 attachments in a PDF? For the life of me, I can not find a program to view the .sch files on my mac.

[shooter]

and you won't, .sch only works on windows based SW (I believe)

[sluckey]

This single pdf covers all 4 of those sch files (I think).

[DummyLoad]

Hey

Tubenit

Do you have these 4 attachments in a PDF? For the life of me, I can not find a program to view the .sch files on my mac.

http://jschem.bplaced.net/

newer versions of MacOS may require a Java RE work-around.


--pete

[tubenit]

I plan to rebuild one of my amps into this D-763 with an active FX loop. Will start on this in about 2 weeks from now.


CHECK for ERRORS!   If there is a discrepancy, go with the schematic instead of the layout.



With respect, Tubenit