ampage Tube Amps / Music Electronics	For current discussions, please visit Music Electronics Forum.

ampage archive

Vintage threads from the first ten years

update: finished DR 'brew...

:

5/14/2005 7:57 PM

update: finished DR 'brew...

I've finished my Recto homebrew, it's far too late to test it out (2:50am), even with the MV fully off.

The voltages all seem within +/- 5% of those listed on the schematic. It'll be interesting to see what it actually sounds like tomorrow when I can at least play it at reasonable volumes.

I've got it plugged in with the gain right up, just turning up the MV (without playing) I can tell that the hum level is very low. I'd just like to thank everyone that replied earlier in this thread for the advice they gave and also Randall Aiken for his article on star grounding which was a big help.

Cheers... Ian

5/14/2005 8:51 PM
Greg Simon	That must have been a PITA to build....theres so much in that circuit. Greg

5/15/2005 4:52 AM
Ian Anderson	Greg, It was just the modern high gain channel I built, not the whole amp (that would be a crazy homebrew, yikes!) I used those old 'RS' Vox-Style tag boards and it was still a tight squeeze. Gonna have a blast 'at volume' in half an hour or so - don't be surprised if you see a post asking for help to tune the tone in soon (heh heh) ... Ian

5/15/2005 6:20 AM
Greg Simon	I was thinking about building the high gain (red channel) into something with a different channel for clean like a Fender or something, but the schematic was so complicated I couldn't pick out what was for the red channel and what was for the orange channel and gave up! So kudos to you. Hope it fires up well! Greg

5/15/2005 7:24 AM

Greg,

Drop me an email and I'll send you the schematic with 'just' the modern high gain channel drawn.

The new DR with the improved clean channel is just a typical BF Fender preamp - there was an unused 1/2 of an ECC83 in the DR and the cleans previously sucked. Doesn't take a genius to figure out that a bog standard Fender clean channel was the way to go with that unused ECC83 triode.

btw, my amp sounds pretty good at bedroom levels with an old Goodmans alnico speaker that's in bad need of a recone. Should sound alot better at a decent volume at rehersals this afternoon with my Marshall 4x12 loaded with G12H-30s

I put a 0.01uF cap to ground right at the input - might as well kill any RF trying to get in there for the sake of 'wasting' a Ł0.30 cap.

... Ian

5/15/2005 5:29 PM

DR update2 (back from jam session) - TONE HELP WANTED...

Just had the DR 'brew cranked up - good overall tone but a bit mushy on the low E string. Tried my mate's LP with EMGs and pushed it with a SD-1 for more gain, MUCH better. I'm fairly surprised that it doesn't have gobs of gain, not as much I expected.

I think the looser/fuzzier low E could be because I'm not using any choke - the OT runs UL. Would putting a choke in there and running another filter cap node for the screens tighten up the low end?

Also thinking of getting an OEI 100w plexi OT to go in there but only as a last resort as I'm trying to keep the budget down and the iron in this old Simms Watts seems pretty good.

... Ian

5/16/2005 7:32 AM

I like UL but I think it needs more uF on the main filter cap to deliver as tight a bass as it is capable of.
I don't know the DR well, do you have NFB?

Also I would think you should taste test a smaller input cap. 0.01uF seems like overkill, when I need one at all it is usually only 100 to 150pf silver mica.
Which is not much more than you expect from cable capacitance so not often actually needed.
The RFI horror stories are more due to imperfect grounds, shields, & connections than lack of input shunting.

Mike

Page 2 of 7