My #102 Build.

jazzyjoepass · Post by **jazzyjoepass** » Sat Nov 03, 2012 12:19 am

Hi fellas,

Been lurking here since many years ago. Build a few Dumbles with PCBs, etc. Here's my RF #102 with Funk's chassis that I bought many moons ago and finally came round to fixing it up.

I've already swopped the 1st dropping resistor from 2.2K to 1K.
The plate voltages come up good at 450V, 290V/280V, 205V/198V, 205V/196V, but this is without the FET board connected.

I've got a quad of Winged C 6L6GC, 2 BEL 12AX7 Mullards, 1 Raytheon (Lowrey) 12AX7.

Once I got the FET connected voltages drop by about 10 to 20V.

I've got Hammond 290FEX 240V power transformer in there.

Structo · Post by **Structo** » Sat Nov 03, 2012 12:21 am

Nice build!
How are you liking it?

Man that is some tight heater wire!

I didn't know those chassis had the "D" word on them.

jazzyjoepass · Post by **jazzyjoepass** » Sat Nov 03, 2012 12:31 am

Hi Structo, you're quick !!!

Haven't had the chance to really crank it up at good volumes but the clean is fantastic!!! But going to OD at low volumes was kind of harsh. I think probably the 68pF I used on the Master. But then again I had the 500pf/220k/500pf on the Preamp Out/Power In that was on some of the layouts. Any advice how I should tweak it?

Yeah the heater wires are real tight ... wound it with a power drill. The heater wires were originally twice as long as the whole stretch.

The chassis with the "D" word was probably a a couple of one-offs from Funk. He had one last chassis that I bought couple of years back.

MIKE.

aflynt · Post by **aflynt** » Sat Nov 03, 2012 12:50 am

Nice job! I recently ditched the 68pF entirely and went with a 250pF/250k/250pF network on the loop, but even now it still sounds much better with the D'Lator patched in and still gets a bit smoother sounding when you crank the master. With the 68pF on the master the tonal character changed a lot when as I turned the amp up. With the 500pF/250k/500pF network it went from slightly harsh / buzzy at low volumes all the way to slightly muffled at higher volumes.

-Aaron

jazzyjoepass · Post by **jazzyjoepass** » Sat Nov 03, 2012 7:14 am

aflynt wrote:Nice job! I recently ditched the 68pF entirely and went with a 250pF/250k/250pF network on the loop, but even now it still sounds much better with the D'Lator patched in and still gets a bit smoother sounding when you crank the master. With the 68pF on the master the tonal character changed a lot when as I turned the amp up. With the 500pF/250k/500pF network it went from slightly harsh / buzzy at low volumes all the way to slightly muffled at higher volumes.

-Aaron

So now when u ditched the 68pF totally and went with 250pF/250k/250pF, it must be muffled at low volumes and probably start opening up at 4 to 5 ???
And if I bypass the 250pF/250k/250pF with a patch cable, it will be truer, I guess.

I remember reading about this somewhere on Ampgarage. Can someone point me to the thread?

CHIP · Post by **CHIP** » Sat Nov 03, 2012 12:52 pm

Nice build.
I did notice something suspicious. Is the eyelet for the coax cable for OD volume soldered. (the 150k and cable junction).

jazzyjoepass · Post by **jazzyjoepass** » Sat Nov 03, 2012 12:55 pm

CHIP wrote:Nice build.
I did notice something suspicious. Is the eyelet for the coax cable for OD volume soldered. (the 150k and cable junction).

Hi Chip, it is soldered ... I used RG59/U cable and was cut a little bit too long and was abit hard to flex it to the eyelet. I was also trying not to use too much solder, just in case I needed to take it out.

cheers.

stelligan · Post by **stelligan** » Sat Nov 03, 2012 1:34 pm

Nice looking build. Those chassis are/were killer......

jazzyjoepass · Post by **jazzyjoepass** » Sat Nov 03, 2012 1:37 pm

stelligan wrote:Nice looking build. Those chassis are/were killer......

Yes, the best run ever made. Super thick 1/8" aluminium. Feels hefty and rugged.

Assume you have one of them with the "D" word there too ???

stelligan · Post by **stelligan** » Sat Nov 03, 2012 1:57 pm

Foolishly let it go.... No "D" logo - but, same chassis. Looking forward to another CE chassis run.

paging odourboy

aflynt · Post by **aflynt** » Sat Nov 03, 2012 2:04 pm

jazzyjoepass wrote:
aflynt wrote:Nice job! I recently ditched the 68pF entirely and went with a 250pF/250k/250pF network on the loop, but even now it still sounds much better with the D'Lator patched in and still gets a bit smoother sounding when you crank the master. With the 68pF on the master the tonal character changed a lot when as I turned the amp up. With the 500pF/250k/500pF network it went from slightly harsh / buzzy at low volumes all the way to slightly muffled at higher volumes.

-Aaron

So now when u ditched the 68pF totally and went with 250pF/250k/250pF, it must be muffled at low volumes and probably start opening up at 4 to 5 ???
And if I bypass the 250pF/250k/250pF with a patch cable, it will be truer, I guess.

I remember reading about this somewhere on Ampgarage. Can someone point me to the thread?

Actually with no master bright and the 250pF/250k/250pF loop network, the amp is just slightly buzzy at lower volumes and then smooths out a bit between 3 and 4 on the master (I've got a PEC in there so where it opens up might be different). By "slightly buzzy" I mean ever-so-slightly. It still sounds decent, just less compressed and not totally congealed. With the 68pF bright cap in place it was very buzzy and harsh at lower volumes. With the loop network bypassed and the bright cap out it's quite a bit brighter all the way through the dial. I'm thinking that a 330pF/250k/330pF loop network might be closest to my particular cable/d'lator/cable setup.

-Aaron

dcribbs1412 · Post by **dcribbs1412** » Sat Nov 03, 2012 3:27 pm

Congrats jazzyjoepass
great looking build...
what speakers are you using?

Darin

Structo · Post by **Structo** » Sat Nov 03, 2012 3:43 pm

I believe I put a 30pf on my Master.

No network on the Send Return since I always use the D'lator.

If you don't like the tone difference between the clean and OD, you can add some things that will balance it out.

First is to set the OD trimmer inside, with the amp on measure the resistance between the output of the trimmer and ground.

Set it around +- 25K. Fine tune to your ears.

If the OD seems brighter and fizzier than the clean tone, you can install a little treble bleed circuit like Ayan made.

The great thing about running a D'lator is that you can run the amp controls up high in the sweet spots and tame the overall volume with the output of the D'lator.

Another mod I really like is the Bright on Clean mod.
What this does is turn on the bright cap on the volume control in clean mode.
Then turns off when you switch to OD.
You can still have it on for both since it is a three position switch.
It just takes the place of the bright switch on the front panel.

But, you will most likely need another relay to do this unless you have half of one not being used.

I have a 120pf bright cap, tailor the value to your likes.

ic-racer · Post by **ic-racer** » Sat Nov 03, 2012 4:44 pm

jazzyjoepass wrote: Funk's chassis that I bought many moons ago and finally came round to fixing it up..

I thought that chassis looked familiar. I just completed my long-term build on a Funk chassis.
You did a good job.

rogb · Post by **rogb** » Sat Nov 03, 2012 8:01 pm

Nice job man! I'm getting into my #102 this month, cab+speaker is complete and all the parts (I hope...) are here from the land of Uncle Sam.

MC iron is here and ready to rock too!

Thanks for the great photos too.

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