I was curious as to who here has built a Dumblelator, and their experiences with them. I have the following schematic which Normster kindly posted a while back. Is this the correct circuit? If anyone has any experience with this one or another version please let me know. Since I've got an extra tube socket, I thought I'd fill it with a buffered effects loop.
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As far as being the correct circuit only "The Great One" knows for sure. There are at least a three different versions of this circuit and this is one of them. I will say that I built this one into a buddies amp and it definately works as advertised.
I am finishing up an external version as I type.
Gary
Located in the St Croix River Valley- Afton, MN
About 5 miles south of I-94
aka K0GWA, K0 Glas Werks Amplification www.glaswerks.com
Hi Gary,
I have been curious how your Dumbleator-Reverb loop was coming along. I hope you will consider sharing some details with the group so those of us with compromised electronics knowledge can build stand alone units too. Any opinion about which of the three versions of the circuit is better?
Robert wrote:Hi Gary,
I have been curious how your Dumbleator-Reverb loop was coming along. I hope you will consider sharing some details with the group so those of us with compromised electronics knowledge can build stand alone units too. Any opinion about which of the three versions of the circuit is better?
The Rev-A-Loop is almost done. I was finished the wiring on Sunday and had a small error that "SMOKED" my reverb transformer. I will have the replacement today. The loop is working fine. The other problem that I solved this morning was a 50khz oscillation in the reverb recovery section. The first recovery amp would break into an oscillation when the tone control was maxed out. Lead dress was the cause and adding a 100pf cap across the first stage plate resistor also helped!
An oscilloscope is not only a helpful tool but almost mandatory when working on this kind of stuff. Had I pumped that 50 Khz into my amp the power amp would have been history!
I will probably have to tweak a few values here and there in the reverb to balance it out. As soon as it is complete I will post pics and the schematic.
As far as circuits, the one posted is probably the standard. There is also the D-lator II which (I think) has two signal returns. And the third is that some of the units had a choke in the power supply. I think it was Mr. Ayan who said RF's D-lator used a choke in the power supply.
Gary
Located in the St Croix River Valley- Afton, MN
About 5 miles south of I-94
aka K0GWA, K0 Glas Werks Amplification www.glaswerks.com
I think he means 3 versions of the Dumbleator, there is the Regular Dumbleator and there is the DumbleatorII which is like having 2 in one box, dual in's and out's. I am unaware of the 3rd version.
There are 2 types of Dlators. I think Gary was referring to the fact that some have chokes and some don't.... That may or may not effect the tone. Guess someone needs to try both ways!!
I haven't seen the other Dumbleator schematics. Can you post these?
David Hicks
Hi David,
Funk is correct The DI and DII are the ones I have seen pictures of over the course of time. Somewhere, sometime, someone told that Robben Fords d-lator had a choke. That is about all I remember.
The only schematic I have ever seen is the LOOP.PDF file that circulates around the net.
I've never seen one, but I'd guess a 12AX7. The circuit is an effect loop with variable tone select switches. I've also read that HAD modified one to use as a recording preamp on one of Robben Ford's albums. Like all things Dumble, some people swear this is the greatest, while others think it is "also ran". But it's not much more complicated than several other EL circuits available on the Web and this site is about making Dumble clones.
Sorry to be a numbnuts..............what's a Dumbleator? Is it a standalone effects loop? Is there a post that explains what each of the Dumble products are?
