Dumb and Dumbler

[dreric]

I've been frustrated with the wealth of information here especially since tony did all the cool layouts. I decided to build two clones side by side so I could really learn the differences between then. To keep track I'm calling them Dumb and Dumbler.

Dumb is a 102 / Ford build:
CE Chassis
Magnetic Components PT and choke
NOS Fender "super twin" OT
Home made boards
Mil spec resistors (metal and carbon film), NOS Bevschlag on the main board, new dales
NOS 80's 6PS orange drops


Dumbler is a Bluesmaster, HRM EL34 build:
CE Chassis
Magnetic Components PT and choke
NOS Dagnall (marshall 800) OT
Home made main board, all other boards from Jason
Mil spec resistors (metal and carbon film), NOS Bevschlag on the main board
NOS 70's 418 orange drops

So far I've learned:

The difference between the voltage double and bridge rectified relay PS. (waiting for the 6V transformer)
That making your own boards, provided you have the tools, is very cool and remarkably toxic.
That Jason provides a quality board.

Here's some photos, I always like it when guys take you on a tour of their building process and I thought I'd return the favor.

Lastly............ if you see me making any mistakes please speak up!

Eric

[dreric]

Dumb's PS

[erwin_ve]

What? You totally wrecked my nomenclature. I thought this was a dumb:

[guitardude57]

Very cool.

Looking forward to hearing your report of differences on these.......as well as some clips.

Good job!

[Structo]

Looking good!

Do your transformers have any surface rust on them?

Are you going to install the FET board?

[67plexi]

Eric, Looks great. The best resistor complement I have seen to date.
The preamp boards looks killer. The super twin output transformer is huge.
Top notch job on the HRM to preamp board.

Steve.

[Structo]

I was looking at those resistors.

Can you describe what each different looking resistor is?

For instance the large red with color bands?

[dreric]

Looking good!

Do your transformers have any surface rust on them?

Are you going to install the FET board?

Dumb's OT (Fender super twin) has some rust nothing I'm worried about. There are certain levels of obsession that I try and steer clear from. Hearing rust is one of them. Also, It's the one part I'm leary of as it's been kicking about my shop for ten years now, I figured I try it and see if I like it, I can always swap it out.

I still have to make Dumb's FET board and waiting on parts for both.

Thanks for looking!

Eric

[Structo]

Oh, I wasn't saying it was bad.
I was just curious if yours had some rust.
I thought it odd to receive new transformers and have some rust on the bells.
They probably have all the bells in a large container that is open to the air so a little surface rust is OK I guess, just weird to sell them like that.

[dreric]

Eric, Looks great. The best resistor complement I have seen to date.
The preamp boards looks killer. The super twin output transformer is huge.
Top notch job on the HRM to preamp board.

Steve.

Thanks Steve

I have to give you credit as inspiration for the resistors. You always use cool parts in your builds. And Dumb's huge caps should look familiar to you! If you look for them, there are lots of the mil spec resistors kicking around. Beyschlag's, I got lucky at the local store. The Marshall guys are all over those. I really curious to see how it all sounds.

The hard part with the HRM board was the mounts. Took me three tries to get everything on there without shorting an eyelet to the mounts screws. There are only so many places where the mounts fit on the main board.

Thanks for your compliments.

Eric

[dreric]

I was looking at those resistors.

Can you describe what each different looking resistor is?

For instance the large red with color bands?

For you Tom ......... Absolutely!

From the picture below:

Left: Beyschlag 1 and 2 watts, they are big boys, carbon film and they don't seem to have that much drift in them. Also sold as Piher. Vishay bought up Beyschlag years ago. Being from Germany you see them in Marshall, Hi watt etc. They were also used pretty much exclusively in old Fischer tube stereo equipment. I think they sound warmer than current stuff. HAD used them in early amps as they were plentiful back when there was a surplus market.

Middle: RN70, RN65 1% metal film 1 watts from various manufactures. There are also a few RN20s on the boards. We'll see what these sound like.

Right: RN65 1% Carbon films. This one is a 1/2 watt 1 watt are just a little bigger, from my research they are way over speced.

I'm no authority on these old parts and I'm sure others will have info to share.

Personally I find NOS, surplus parts fascinating. There's a life for these things are the aren't making them anymore and I must admit to getting into the search and collect addiction.

Tom a website you referenced in a earlier post has been very educational. The owners name is Mark, I got some stuff from him, he has a lot more than is listed if you ask. EXCELLENT service.

http://www.33audio.com/

[Structo]

Thanks a lot Eric!

Looking forward to seeing the end product!

Tom

[dreric]

Oh, I wasn't saying it was bad.
I was just curious if yours had some rust.
I thought it odd to receive new transformers and have some rust on the bells.
They probably have all the bells in a large container that is open to the air so a little surface rust is OK I guess, just weird to sell them like that.

I see what you mean. The lighting in my shop makes photos look very yellow / red. The new new trannies are rust free, the color is just from the photo.

Eric

[David Root]

That website has some paper/polyester caps from the '70s, EM-Arco, which he says

"They are very similar to the later solid-impregnant Sprague Black Beauty (later Di-Film version) and the Sprague type-PS Orange Drop that were also paper/polyester until the late 1970s. The EM-Arco and the Sprague Orange Drop appear to be identical inside. Perhaps Sprague made them all. Sprague had a trademark for their proprietary impregnant. EM-Arco did not state that they had their own impregnant."

Note especially the reference to PS orange drops that were also paper/polyester until the late '70s.

First, is it likely that HAD would have used these early orange drops? I recall Tony saying a while back that he did not think Black Beauty caps had any place in a Dumble circuit. When did HAD start using orange drops?

Secondly, does that statement have any credibility to those like Tony who have some experience with real Dumbles?

[Structo]

I am curious about the picture of the Dumbler.

The way you oriented the filter cap board, is that how you are going to run it?

Usually the row of eyelets are towards the back of the chassis.

That's cool to build two versions of this amp side by side.