Remember that pedal page? Dumbleator added, clip

[groovtubin]

I've been wanting to try this for a long time. I've built several dumble inspired preamps with fets, with pretty good results.

So, does your's sound like the overdrive channel of a dumble?

Jake

It does, when it's plugged into the clean channel of a Dumble. Into a Fender it's a bit scooped in the mids and a tad bright.

Also, I think if I can lower the output impedance a little it'll match better. Any suggestions?

[Bob-I]

If you can add ONE stage, run the last stage into the FIRST stage of a Dumbleator, I`ve built several preamps for ext picky guitar players, and it works VERY WELL. If you need proof, e-mail me, i`ll fwd a customer e-mail[/quote]

Great idea. No I don't need any proof, I believe you.

[groovtubin]

Great idea. No I don't need any proof, I believe you.

[Bob-I]

Is this the idea?

[img647]http://www.patmedia.net/bob-ingram/JPEG ... reamp2.jpg[/img]

I added the first stage of the Dumbleizer right after the master volume. Maybe I don't need the master anymore and can just use the dumbelizer output control.

That .47 is huge, I'll have to look around for one as all I have that large is electrolytics.

[groovtubin]

Is this the idea?

[img647]http://www.patmedia.net/bob-ingram/JPEG ... reamp2.jpg[/img]

I added the first stage of the Dumbleizer right after the master volume. Maybe I don't need the master anymore and can just use the dumbelizer output control.

That .47 is huge, I'll have to look around for one as all I have that large is electrolytics.

you could use a RESISTOR as FIXED pot at end of OD. The master at out of last buffer stage is what i do as well! The circuit was diff, but that WILL work fine.. Simply voice the last coupling cap by ear.

[Bob-I]

you could use a RESISTOR as FIXED pot at end of OD. The master at out of last buffer stage is what i do as well! The circuit was diff, but that WILL work fine.. Simply voice the last coupling cap by ear.

That ckt is taken directly from the Dumbelator posted on schematicheaven.com.

Thx, I'll let you know how it goes.

[tictac]

Did you notice your mid pot is in the wrong place, or did you wire it that way on purpose?

TT

[Bob-I]

Did you notice your mid pot is in the wrong place, or did you wire it that way on purpose?

TT

LOL... no, that's a mistake but I didn't wire it that way, I just drew it wrong.

Here's the corrected schematic plus another clip with the CF (1/2 of the Dumbelator) in place.

[img647]http://www.patmedia.net/bob-ingram/JPEG ... amp_CF.jpg[/img]

http://www.patmedia.net/bob-ingram/Music/test_CF.mp3

[Pete]

HI
I'd like to see that whole schem. (is there more to it, on the right side?)
is it posted somewhere?
can't find it on that site mentioned.
thanks

[Bob-I]

HI
I'd like to see that whole schem. (is there more to it, on the right side?)
is it posted somewhere?
can't find it on that site mentioned.
thanks

That's the entire schematic. It's just a preamp.

[HiGain]

That sounds great!

What guitar and amp did you use? How did you resolve the excessive high end issue?

Oh, and did you actually get the PT from Hoffman?

Thanks,
Jake

[Bob-I]

That sounds great!

What guitar and amp did you use?

I'm using an Edwards LP copy with Seymour Duncan PU's. Excellent guitar. I just bought it in Japan last week. The amp is my 3 channel build using the Fender channel on very low volume, tones on 5.

How did you resolve the excessive high end issue?

I used Groovetubin's suggestion of the 1/2 of the Dumbelator as an output stage. Really sweetened up the top end.

Oh, and did you actually get the PT from Hoffman?

Thanks,
Jake

Yes, I got the PT and the Toroid both from Hoffman. I'm getting a solid 12VDC for theaters using a 12V regulator and about 220VDC for the B+. It's quiet as a mouse and stable, almost 0 fluxuation on the B+.

[oldmacman]

Wow! That's a great tone! Good playing as well!

[pedro]

Thats really great Bob,

I notice you've now got a 0.0022uF coupling after OD1 stage and 1uF on OD2 cathode. Is that something thats got you closer to the RF tones - I still have 0.01uF on OD1 coupling and 4.7uF on OD2 cathode.

Let me know what you think - Have you implemented that in your amp as well ?

regards
Pete C

[Bob-I]

Thats really great Bob,

I notice you've now got a 0.0022uF coupling after OD1 stage and 1uF on OD2 cathode. Is that something thats got you closer to the RF tones - I still have 0.01uF on OD1 coupling and 4.7uF on OD2 cathode.

Let me know what you think - Have you implemented that in your amp as well ?

regards
Pete C

oops.... That's actually a .01uF not a .0022uF, my mistake.