Another 124 build

[BobW]

Here's a few pics of my 124 (+/-) build. thanks to Funk for the great looking chassis.

I don't like the results of the cloth wire w/no wax (pic 4) so, I may change over to teflon.

[Fischerman]

What do you not like about that cloth wire?

BTW...I'm probably not seeing things right but I don't see how that first preamp socket could be wired correctly (there's only two things soldered to it...but both should be at the grids i.e. pins 2 and 7 and I can't see a way that those two pins soldered to could be #2 and #7).

EDIT: Forgot to say it looks good though! What/where did you get that white shielded cable? I'm about out of RG174 and I want something that can take more heat...that inner insulation around the center core is pretty sensitive to heat in the RG174 (or 178 or whatever I have).

[v00d00blues79]

It definitely looks like the input grid resistor is soldered to the cathode pin.


Andy

[larsmuller]

It´s the sockets V1 V2 V3 that are turned around....the "gap" between pin 1 and 9 should be pointing towards the mainboard...this makes the wiring easier and it´s the Dr. D way...

[larsmuller]

double post...sorry

[BobW]

Man, I must be dyslexic, thanks for catching that major error!

The unwaxed cloth wire tends to fray, other than that no issues with it.

[Structo]

Lookin' good Bob.
I've heard you can put some super glue on the cloth end to prevent fraying.
But, I really like the way teflon works other than stripping the darn stuff.

[BobW]

Forgot to mention, that I used a SPDT on the bright switch for use with either a humbucker or single coil. It seemed to work well on a fender amp.

An exacto knife works well for making a clean strip on teflon wire. You can 'feel' when you've cut to the wire, and wire nicks are minimized.

I'll give the super glue trick a try, thanks.

[Structo]

Yes a sharp knife is what I resorted to on teflon.

As a noob to teflon wire I had bought an expensive automatic stripper in preparation for my first build.
Hehehheh, the darned insulation is so slippery that the grippers can't even grab it.....
So much for a $40 pair of strippers.

The super glue might be the ticket.
What I have done when using it inside a guitar was put a drop of the thin kind on the insulation before I scored around it.
Kept it nice and tight.

[Fischerman]

Bob, You may already do this but when you cut the cloth wire it's better to use a cutter that's more like scissors than regular wire cutters...you get a much cleaner cut on the cloth that way. Then after you cut it...take your fingers and kind of flatten the end of the cloth, then turn it 90 degrees and flatten it again...repeat until it's nice and snug to the wire...even after I pull the cloth back I then kind of try to pull it back towards the freshly cut end but hold the cloth near it's end such that it can't pull back toward the end (hard to describe) and keep flattening it snug to the wire each time. This really helps the fraying. I like using the stuff because it's just so easy. With Teflon my fingertips were raw by the time I finished an amp.

[BobW]

Good tip, thanks. Yeah the old cloth wire was so easy, just cut and pull back the insulation.

[BobW]

Another pic... filter board.

Since I've already built an HRM and a Non-HRM in the past, this one will be built using the #124 as a baseline. 100K/1k5 plate and cathodes, 1/2 power switch etc. To add more versatility the bright switch has two settings. More pics to follow.

The Teflon cable was bought from a local electronics shop that is going out of business. Everthing, what's left, is 1/2 price No part number on the cable but it has a 20 ga. conductor and a hefty amount of teflon dielectric. My guess is it's a MIL-C-17 cable.

[Funkalicousgroove]

It´s the sockets V1 V2 V3 that are turned around....the "gap" between pin 1 and 9 should be pointing towards the mainboard...this makes the wiring easier and it´s the Dr. D way...

I think you are mistaken, on the 4 that I've been inside, and 90% of the pictures I've seen, pin 9 points toward the back of the amp.

Here is a pic of #124 for example-

[glasman]

There are examples of Dumbles with the keyway towards the main board and away from the main board. Old ones were toward the board (Santa Cruz) and later ones toward the back of the amp.

But according to Mullard, for best noise performance in cascaded gain stages the second section should be used asa the first stage opins 6,7 and 8.

YMMV

Gary

[Funkalicousgroove]

Personally I've tried both ways, and notice absolutely NO difference.