The Humble Pig Project - some photos

[Normster]

I buttoned up the Pignose last week with its new Dumble clone mainboard. Lots of OD and distortion, but no where close to the Carlton/Ford tone I was hoping for. (I'll post clips a little later today.)

Anyway, here's a little pictorial essay of the project:
The Humble Pig project

Next steps are to tweak the tone, clean up the wiring, and add reverb. Maybe I'll be done by Christmas.

 

[trisonic]

V. Interesting, thanks for sharing.

Pete

 

[RussB]

That's a cool write-up you did.

Thanks!

 

[scottl]

Norm,

That layout is the wrong one. It is for the Hot Rubber Monkey Dumbles. You wanted the other one.

Please list all your preamp coupling cap values and bypasses for me.

Better yet, call me. 856-489-3434

 

[TheAmpNerd]

Can you post the correct layout?

I've tried to find it buy can't.

Thanks.

 

[guitarpkr76]

Scott, I'm thinking of building a dumble from the layout that is similiar to Normsters, but without the extra bass, treble, and mid trimmers. Do you happen to know where I can find the schematic for that layout. The layout itself does not have the power supply layout and I wanted to get the correct values. Any help would be appreciated. Thanks.

 

[Normster]

Here's the layout for the '77 Hybrid (the one Scott said is the right one):

'77 Hybrid layout

If the link doesn't work, go to blueguitar.org and click on ftp site map. From there, click on schem/blue_gtr/dclone then select layoutrb.jpg.

While you're there, you may as well download hybrid_a.pdf (the schematic).

 

[guitarpkr76]

I going to go with l3920400. Seeing as how I don't know how to do the relay stuff. I just can't find the schematic. It also uses EL34s.

 

[Normster]

Here's a five-part clip with some of the tonal range of the amp.

1. Blues Deluxe CLEAN (just for reference)
2. Pignose Clean, Jazz, no Boost,
3. Drive, Jazz, no Boost,
4. Drive, Rock, no Boost,
5. Drive, Rock, Boost.

Pig Sample

 

[scottl]

Norm,

Did you add the snubbers on these clips?? How about the post OD stack?? Did you remove it yet?

Thanks for the clips!

 

[Normster]

Originally posted by scottl
Norm,

Did you add the snubbers on these clips?? How about the post OD stack?? Did you remove it yet?

Thanks for the clips!

I added 330pF ceramic snubbers and it's a little smoother, but I think I'm going to replace them with 360pF micas instead. (I know you said 350pF, but I can't find them anywhere.) I also swapped out the cathode bypass caps so that the 1.0uF is on V1B instead of V2B and put the 2k2 and 3k3 resistors where you suggested. That really helped with clean headroom. I added the internal feedback loop, but really don't hear much change as a result. Lastly, I double checked the values of my PI plate resistors and brout the first resistor up to 91K.

I'm going to pull out the OD tone stack this weekend. I'm still waiting on my Mouser order to replace the coupling caps (.047uF). I sure wish they sold this stuff at RadioShack.

 

[memphisrain]

I'm thinking I'm going to build one of these. I just can't seem to scrape together the green for a Fuchs mod. (poor college kid, ya know!)

Any tips/tricks would be appreciated!

Couple questions:

I've seen/read about coax cable being used in these amps. Where is it being used at?

Also, what are snubbers?

 

[glasman]

Originally posted by memphisrain
I'm thinking I'm going to build one of these. I just can't seem to scrape together the green for a Fuchs mod. (poor college kid, ya know!)

Any tips/tricks would be appreciated!

Couple questions:

I've seen/read about coax cable being used in these amps. Where is it being used at?

Also, what are snubbers?

The snubbers are disc ceramic or silver mica caps that are installed from the Plate to Cathodes of the overdrive stages. They normally range from 250pf to 500pf and they smooth the top end of the amp and get rid of the harshness. These are normally not used when the post overdrive stack is installed.

Coax between input to first stage, volume control (first) to second stage, Overdrive stage one to Drive control and Overdrive stage output and return. Use a good grade of cable (low capacitance) or you will suck the highs out of the amp (IMHO).


YMMV,

Gary

 

[memphisrain]

Hey Glasman, I just e-mailed you with that question!! Thanks for the responce on both accounts!



mR

 

[Normster]

Gary, I just wanted to say thanks for the info on your site. After looking at the layout of your boards, I've decided to try another one and include reverb this time. The G60VR had a tube driven reverb so I have the extra tube, transformer, and tank. I just wasn't quite sure how to integrate it into the circuit.

Thanks,
Norm

 

[Ayan]

Originally posted by Normster
I buttoned up the Pignose last week with its new Dumble clone mainboard. Lots of OD and distortion, but no where close to the Carlton/Ford tone I was hoping for. (I'll post clips a little later today.)

Anyway, here's a little pictorial essay of the project:
The Humble Pig project

Next steps are to tweak the tone, clean up the wiring, and add reverb. Maybe I'll be done by Christmas.

I am not sure whether Scott used the term "layout" in error, when he should have said "schematic," or whether he is mistaken himself. However, although you probably have the right schematic for the amp you want to build, both layouts shown (the one before and the one after Scott's post) are not right for the amp you probably want to have -- which I infer is either something that sounds like LC's or else like RF's.

Not to say that you can't get an amp with a different layout to sound perhaps just as good, but the circuit you implemented goes hand in hand with the layout that Dumble himself used for the amp. Furthermore, I have it on good authority that after he had wired up an amp, Dumble would play with the length of certain critical wires to get the sound he wanted out of the amp.

I recently had a chance to put one of my amps side by side with another one, built by someone else but "just like it." The layout is different, however, and although you can obvioulsy tell the amps have similarities, the other one sounds like it's sunk in a bathtub in comparison.

Cheers,

Gil

 

[glasman]

Originally posted by Normster
Gary, I just wanted to say thanks for the info on your site. After looking at the layout of your boards, I've decided to try another one and include reverb this time. The G60VR had a tube driven reverb so I have the extra tube, transformer, and tank. I just wasn't quite sure how to integrate it into the circuit.

Thanks,
Norm

Hi Norm thanks for the comments. The reverb schematic on my site is the same one that I use in my amps. It is very simple and works pretty well, especially with a long delay tank. Just place it right before the Send / Return jacks in the circuit. It has virtually no impact on amp tone.

Gary

 

[Normster]

Originally posted by Ayan although you can obvioulsy tell the amps have similarities, the other one sounds like it's sunk in a bathtub in comparison.

I'd settle for similarities.

I've been studying as many Dumble chassis pics as I can get my hands on and my next board will be much closer to the correct layout. I think you make a good point, however...no matter how much people try to copy the original, it's still going to sound like a copy. I'm sure Mr. Dumble has a deep understanding of what makes his amps sing and I obviously don't have that depth. Still, I keep hoping I'll get lucky and learn enough to get some decent tone.

 

[memphisrain]

Normster,


I'd appreciate it if you could may be post any info you find around the net. I think I'm going to go ahead and give it a whirl and see if I can build one. I've been al ot of places, but you may turn up something I didn't find, and vice versa.


The places I've been so far have pretty much been posted here already, the dumble chassis pics on the one site, the blueguitar page and glasman's page. If I find anything else, I'll let you know.


Thanks,
mR