High-plate Skyline build

[bepone]

very nice!

[Stephen1966]

A little more progress

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Beautiful solder work on the back of the volume pot. Perhaps you could explain for us, how you do that? Mine always looks crap.

[ijedouglas]

Beautiful solder work on the back of the volume pot. Perhaps you could explain for us, how you do that? Mine always looks crap.

Thanks Stephen. I use 2 tips, my regular and then a larger (with 1/4 inch flat surface).
- Prep the pot surface by lightly sanding the area for the joint.
- Prep the coax by stripping the outer shield and then tinning about 3/4 inch of the braid. Once set, cut back the braid to the solder line.
- Measure the location of the end of the inner insulation by placing on pot and marking the pot solder lug and strip the inner insulation.
- Twist the inner core and tin just the tip so it stays together but is still flexible.
- Prep the joint with the smaller tip (important as you don't want the solder to flow too freely) and add enough solder for the joint. It should have the shape of the joint.
- Tie in the inner core to the solder lug and solder, the tinned 3/4 inch braid should lie directly over the solder blob on the back of the pot.
- Switch to the larger tip and heat the solder blob on back of pot while firmly pulling on the coax. As it starts to flow it will melt the solder on the braid. As soon as it flows together and looks good, remove the tip and keep the coax firm.

[ijedouglas]

Getting closer. Had a hiccup with the front panel. Krylon and isopropyl alcohol don't like each other so I ended up having to re-paint the front panel. The good news, this chassis makes it pretty easy to service the amp by removing the front panel. You just need to desolder the lamp and the panel can be removed. I wonder if HAD had this in mind when designing it? I even contemplated building the whole amp and then finishing the front panel last so as to avoid scratches and possible IPA fails.

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[bepone]

i see by component values that this one is little bit different? on V2 there are compensation capacitors over grid stopper? experiment or.. found in some HAD iteration?

[ijedouglas]

i see by component values that this one is little bit different? on V2 there are compensation capacitors over grid stopper? experiment or.. found in some HAD iteration?

Hey Josip, good eye. This is from an actual Dumble I have on the bench. V1b/V2a/V2b all have 220K with a 500pf snubber (I used 240K as that's the only value I have in shiny thin-lead NTE)). I am pretty much doing a part for part clone of this amp (or as near as possible) except a 100W version. V1 plates are 220K/150K with 3K3 and 2K2 cathodes and V2 has 180K/120K with 2K7/1K8 cathodes. OD series resistors are 100K/180K with OD Level and Volume both 250K audio.

[bepone]

thx interesting

[ijedouglas]

Almost there. Heaters, busbar and FET bias to go...

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and the busbar done...

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[alnight]

Nice work! I aspire to someday build an amp that looks that nice inside.

[dbharris]

Incredible work Ian! I bet this amp is going to sound fantastic.

-Dan

[ijedouglas]

Finished and fired up. First time I got everything correct for first start up

Amp sounds great, very close to the cleans of the Dumble. The OD sounds a little thin but I haven't really been able to crank it up yet. I'll let it burn in a bit and then play around with tubes and trimmers. The bourns OD trimmer is a little finicky and sometimes causes the OD to cut out, may need to replace it but I'll work with it for now.

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[bepone]

congratulations!
you can start for OD without treble peakers on grid stoppers so whole balance should be better..if needed with time when the amp mellows out you can put them back in

[ijedouglas]

congratulations!
you can start for OD without treble peakers on grid stoppers so whole balance should be better..if needed with time when the amp mellows out you can put them back in

Thanks Josip. Actually the OD is sounding really good now that I had a chance to turn it up a bit. Both OD and clean are tonally pretty balanced. I'll leave it like this for a while until it breaks in and then see what shakes out

[ijedouglas]

Since I built the chassis from scratch...why not build the cab?

If I knew now how many trips to the hardware store and the frustration in not knowing what I was doing, I probably would have had one built for me. That being said, I ended up learning some new skills and getting a semi-decent cab.

I used baltic birch ply for the box with half-blind dovetail joints and red oak for the cleats. I couldn't find the "correct" grill cloth so I have a generic black one in there temporarily. I did locate the correct stuff and will be updating the front panel as soon as it arrives.

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[dbharris]

Looks great Ian, a proper brother amp! How similar is the sound/feel between them?