new build

[kwijabo]

inspired by others on this forum (once again), i recently completed a new build for myself. (inspiration: https://tubeamparchive.com/viewtopic.ph ... a497c03858). two channel amp using two of the Dr.'s circuits.

couple things different:
1. little bit different layout.
2. only 2 x EL84.
3. diode, not tube rec'd. would change this if i did it again.
4. PPIMV.
5. Bright switches.

it's maybe too stiff as is. and using the 0.047uF couplers on both sides of the phase-inverter made the EF86 channel way too bassy (the schematic i found only called for 0.01uF, but the12AX7 channel called for 0.047Uf). so changed the cathode cap on the EF86 to 10uF. sounds fine, but might move it down to even 5uF.

the EF86 has some fantastic cleans. it has been recommended on this forum before, but allow me to add my recommendation, too. if you want a clean amp that doesn't really break up, this is a great circuit.

but for me, what really works is setting the EF86 channel to 5/10, then turning the 12AX7 channel to about 2/10 with the bright switch on. this amp has been through two bar shows at those settings and for what we play its worked out quite nicely.

i hate recording - mostly because i'm no good at it. with that said, in the one recording, you will first hear the clean channel followed by the same lick but a mix of the two channels as i described. then the dirty recording is just the 12AX7 channel pumpin' mids and gain like it do. i'm sure this sound has its place but i don't need it.

[kwijabo]

pics or it didn't happen, i suppose. now attached!

[xtian]

Haw haw! I was going to import this GIF from TGP:

[img:392:46]http://my2wheels.com/forum/images/smili ... thless.gif[/img]

Thanks, looks nice!

[Colossal]

Looks great! Cool layout. Say, are the leads on your Cut control soldered or was the photo taken prior?

[kwijabo]

doooooooooooooooooooooooooooooood.

you know, some time ago i asked the question on this forum about how do you attach your wires. i took the advice and started j-hooking the leads around and make it so its a good mechanical connection first, then solder it. thankfully i learned that because i just got away missing a solder connection and playability was unaffected!

thanks for the eagle eye!

also, a tip of the hat to this forum. this is twice now i've posted gut shots without asking anyone to look/critique and someone's come back with a something i missed.

[Colossal]

thanks for the eagle eye!

also, a tip of the hat to this forum. this is twice now i've posted gut shots without asking anyone to look/critique and someone's come back with a something i missed.

Right on right on!

What kind of music are you using this amp for? There's been a bit of buzz here around EF86s in the front and middle of late, both in ACxx and D-style topologies.

When you said if you could do over, you'd use a tube rectifier...is that for tone and feel or did you want to dump a bit more voltage or both? What tube would you use? For the wiring runs, I like how you left a straight shot from the PPIMV up to the power tubes. Very discreet.

[M Fowler]

Sounds like some Dwight Yokum playing. Good looking build.

[kwijabo]

Sounds like some Dwight Yokum playing. Good looking build.

Ayup! i always thought dwight songs were better than they ever recorded them.

What kind of music are you using this amp for?

the band i'm in is pretty full: fiddle, accordion or keys depending on song, acoustic, bass, drums, and me on guitar or tenor banjo. the fact that there are so many voices in the band means the need for an out-front lead guitar isn't necessary; you're just as likely to hear a fiddle or keys lead/fill as guitar. so i'm mostly playing between rhythm and lead. a lot of licks, but not a lot of solos.

When you said if you could do over, you'd use a tube rectifier...is that for tone and feel or did you want to dump a bit more voltage or both? What tube would you use?

for feel. on the ACxx when i hit it hard theres a really nice response. best example i can use to explain what i mean is when he hits the end chord at about 1:10 in this video:

http://www.youtube.com/watch?v=9McodoUTNeQ

my AC30TB can give that style of response with a heavy chord dig, but this one doesn't. i was worried about not a tight enough response if i used a tube recto. true, the ray and GT use tubes, but i thought since i was combining them it might be too much. in hindsight i don't think it would be too much for a 5AR4 to handle since this is only 2xEL84 instead of the 4xEL84 they do.

[Reeltarded]

Dood! I love that! It would make the best baritone guitar amp ever!!!

Congrats!

[Colossal]

for feel. on the ACxx when i hit it hard theres a really nice response. best example i can use to explain what i mean is when he hits the end chord at about 1:10 in this video:

http://www.youtube.com/watch?v=9McodoUTNeQ

my AC30TB can give that style of response with a heavy chord dig, but this one doesn't. i was worried about not a tight enough response if i used a tube recto. true, the ray and GT use tubes, but i thought since i was combining them it might be too much. in hindsight i don't think it would be too much for a 5AR4 to handle since this is only 2xEL84 instead of the 4xEL84 they do.

I know what you mean. I've built/played Rockets and Acs and I have a high gain amp believe it or not with a GZ34 and 4xEL84 power section that has the perfect balance of sag and compression. Just feels like effortless sustain under the fingers. I think a 2xEL84 amp with a GZ34 would be great. They work very well feel wise in a Princeton with 6L6s.

[Structo]

What size is your first filter cap?

You can try to go lower with that to relieve some of the stiffness.

If no choke was used you could try a smaller filter cap and choke which might work better.

[kwijabo]

What size is your first filter cap?

80uF and there is a choke in. will try lowering it. i've put that off because i just don't like the process of unsoldering the B+1 or B+2 lugs since there's about 5 connections to each one. takes sooooo much heat.

They work very well feel wise

HAHA. first time i've ever heard a tube referred to as "wise." i like it and i'll be using this frequently.

i'll also add one more thing about the amp. once the 12AX7 side gets the volume at and above 3/10, you really can't hear any difference from adjusting the EF86 side. The 12AX7 side is just that much more loud.