Small footprint dumbleator

[BobW]

After a bit of effort squeezing it into a 5 x 10 x 3 enclosure, it's complete except for tweaking the bright switch values. It doesn't look pretty but the sound definitely makes up for it. Thanks for all the dumbleator comments and suggestions here on this forum. I could not have built this without. I am amazed how well the dumbleator brings out the tone of a #124 build, even when using molded patch cables. Now all I need are some decent cables. The layout is typical except I used Structo's Fender Reverb power section, and also added the bypass switch.

All jacks are isolated. The only issue I had was having to re-route the PT secondary wires (twisted red), away from the tube to remove the 60 Hz. buzz. This wouldn't have been an issue had I used a larger enclosure.

[Bob-I]

Looks great. I've oftne thought about trying this myself. Glad to see it worked out.

Don't worry too much about the patch cables. I've actually found that it sometimes sounded better with cheep cables.

[Structo]

Nice!

Curious, did you include the 220K/250pf network on the loop jacks in the amp?

[BobW]

Yes the 220K/250pf network is in the amp, but haven't pulled the chassis (in quite a while) to verify it's wired correctly. I'll check it this weekend.

[Structo]

I'm thinking of removing it in my amp.
It only is in circuit when the loop is not being used.
I feel it really brightened the amp too much when the loop is not plugged in.

[talbany]

For me the 220k network works fine on some amps and not so on others..It's kind of a taste thing.. FWIW Dumble didn't use them on all his ODS as well..Congrats on the build Bob..Very nice. Icing on an already sweet cake..

Tony

[BobW]

Thanks to all. Tony, that's a nice pic of Gregor's amp.

[Structo]

I didn't know that amp had been photographed.

Got anymore?

I forget, what was the serial # on that one?

[talbany]

I didn't know that amp had been photographed.

Got anymore? :D

I forget, what was the serial # on that one?

Yeah he posted posted a couple shots when he had it on E-Bay a while back these are what I have.. Serial #123

Tony

[gilgalad101]

Tony, isn't it #94, not #123?

[BobW]

I pulled the chassis and the 220K/250pf network is installed and wired correctly. However, I much prefer it with the dumbleator connected than without. This build was definitely worth the minor effort.

Settings that work best for my rig are:
Drive at 3 o' clock
Return at 3 o'clock
Recover at 1 o'clock

I've considered adding series resistors to the Drive and Return pots to normalize my settings closer to the 12 0'clock setting, and allow for additional (reserve) gain if ever needed.

Orange Drops were not used or tested but am happy with the Xicons.

[talbany]

Tony, isn't it #94, not #123?

Yeah!! Could be.. When the pics surfaced here someone (Sorry can't remember who) made a Schemo.. (Posted above) so I assumed it was 123.. It does look older.. Fonts.. Please correct if am wrong.. Thanks.. T

[gilgalad101]

Found the thread where it is discussed:

https://tubeamparchive.com/viewtopic.php?t=5874&start=0

[Structo]

I pulled the chassis and the 220K/250pf network is installed and wired correctly. However, I much prefer it with the dumbleator connected than without. This build was definitely worth the minor effort.

Settings that work best for my rig are:
Drive at 3 o' clock
Return at 3 o'clock
Recover at 1 o'clock

I've considered adding series resistors to the Drive and Return pots to normalize my settings closer to the 12 0'clock setting, and allow for additional (reserve) gain if ever needed.

Orange Drops were not used or tested but am happy with the Xicons.

Bob, I noticed the same thing with the 220K/250pf network on the jack.
It isn't in the path unless the plugs are in the jacks, right?
But I noticed my amp seems a lot brighter with no plugs in the jacks than it was before.
Unless I did something else that caused it.
I mean, it's almost brittle with no loop plugged in.

I tried jumping across the network with a test lead one time and didn't hear any difference then.
But boy, when you go without anything in the jacks, very bright.
I suppose it could be the bright cap on the master doing it. I don't think I had that there before the D'lator.
I believe I have a 47pf on that.

Is this the way you wired it Bob?

[BobW]

Tom, mine is wired per the #124 schematic provided by Ic-Racer in the Files section.

The 220k/250pF is only engaged when using the loop. I do hear a slight increase in the upper end when simply using a cable in the loop, but the amp as is, w/o a cable or dumbleator is not brittle. Check your wiring.