50 watt non-HRM just finished! (w/ pics!)

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dave g
Posts: 383
Joined: Fri Aug 10, 2007 11:34 pm
Location: Cambridge, MA

50 watt non-HRM just finished! (w/ pics!)

Post by dave g »

I just finished this one tonight and fired it up; no explosions, so I'm happy! This is the first D-style amp that I've done that sounded really good straight off the workbench - I think I'll still probably end up doing a whole lot of tweaking before heading back to college next week :lol:

[img:2816:2112]http://img174.imageshack.us/img174/217/imgp2958vd8.jpg[/img]
[img:2816:2112]http://img520.imageshack.us/img520/1456/imgp2966ad3.jpg[/img]
[img:2816:2112]http://img520.imageshack.us/img520/5701/imgp2968xx2.jpg[/img]
[img:2816:2112]http://img520.imageshack.us/img520/8387/imgp2970te7.jpg[/img]
[img:2112:2816]http://img520.imageshack.us/img520/3999/imgp2957ab6.jpg[/img]
Homemade U-chassis with .080 T6 aluminum plate top and .125" extrusions for the sides. Heyboer Bassman OT, Hammond Twin PT, Mercury Plexi choke, Winged C 6L6GCs and Tung-Sol 12AX7s (EH PI). The front panel is CNC engraved black anodized aluminum. I've got about half a dozen old Telefunken and GE 12AX7s that I took from an old Fisher stereo and some no-name 60's guitar amp that I want to try in it tomorrow. I also picked up a really nice board of flamed maple that I'm going to be using for a cabinet. I'll probably start work on that tomorrow as well, along with a 1x12" cab for it. I picked up a board of mahogany for that, along with a G12-65 to throw in it.

I used push pull pots for the bass, mid, and treble pots, and wired them up as the deep, mid boost, and bright switches respectively. I also made my own little PCBs for the relays (PAB and OD are footswitchable) so I could do both manual and remote switching. The PAB and OD controls on the front panel are 3 way on/off/on switches, so in the up position it's a manual override for "on", in the middle position it's a manual override for "off", and in the bottom position they're in footswitch mode. The LEDs above each control are on when their respective control is on, and they work both when you're on footswitch and manual modes.

It's basically got the full skyliner stack, but I wired the PAB so that it throws a 500pF across the treble cap when engaged and it also uses 4.7M resistors for the lift (a la yeahyeah). Also, I put a "cut" control on the front panel. It's basically Gil's HFT, but with a 1M pot wired as a variable resistor with a .001 to ground. I might replace it with a 500k push pull pot tomorrow when my Mouser order comes in. In that case, pulling the pot out would remove the taper from the circuit.

220/150/220/150 plates, 5uF bypass caps, but I might go to 10uF on CL1 and CL2 tomorrow and fiddle around some more with the OD entrance.



It's been a long day so I think I'll hit the sack! :lol:
Last edited by dave g on Thu Jan 03, 2008 11:13 pm, edited 9 times in total.
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skyboltone
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Re: 50 watt non-HRM just finished! (w/ pics!)

Post by skyboltone »

The pics don't boot. Is it the S in https://? Nope. They open, they just don't auto open. Weird.
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User avatar
dave g
Posts: 383
Joined: Fri Aug 10, 2007 11:34 pm
Location: Cambridge, MA

Re: 50 watt non-HRM just finished! (w/ pics!)

Post by dave g »

I think I fixed it - they should work now.
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