Check solder joints. All of them, also @ the pot. No need to solder up a new board at this point.
Need a few ideas. I built a Wayne's Linestage 2018. It's been terrific paired with an Aleph J. I wanted to try the WLS with my ACA mini. Connected it and got nothing unless turned up a lot and then it was very faint and distorted. Conected it back to the Aleph J --same result. I checked the power supply-- a Pete Millett 18-24 volt build. It seems fine. I rechecked all my soldering and it looked good except for those teeny tiny Q1-Q4 where the solder looks a little globby without a great flow. But, hey, it was working. Maybe that's it? I've included voltage drop measurements which seem to be requested a lot when others were asking for trouble shooting as well as a picture. LEDs are lit on pre-amp and PSU boards All of these are DC volts. Offset set very close to .000 volts. Picture included. would different measurements be more useful? Do these look like what they should be?
Channel 1 Channel 2
R1 .038 R27 .038
R2 .039 R28 .038
R7 2.613 R38 2.604
R11 .295 R32 .392
R13 2.604 R31 2.602
R12 .396 R33 .392
Rails
V+ 21.50 V+ 21.53
V- 22.67 V- 22.65
Channel 1 Channel 2
R1 .038 R27 .038
R2 .039 R28 .038
R7 2.613 R38 2.604
R11 .295 R32 .392
R13 2.604 R31 2.602
R12 .396 R33 .392
Rails
V+ 21.50 V+ 21.53
V- 22.67 V- 22.65
I’ve completed the third and final (Ha! As if!) iteration of my preamp. I'm starting to feel like Marge Simpson with her Chanel suit but I've had three or four other pretty good preamps in the system and I'm yet to hear one I like more.
The biggest change is that, after years of anxiously futzing about with balanced connections, cables and converters, I've allowed myself to become completely unbalanced (lol) and feel 100% better for it.
To some of you this box probably looks like an hilarious Rube Goldberg machine of redundant complications. I'm ok with that. This is just how I could do the things I wanted to do without four years of trade school and/or forty years of field experience. I've tried to use what I do know to have a bit of fun without causing any sonic degradation and, as far as I can hear, I've been successful in that.
Here's where I've ended up:
- A Schurter filtered AC inlet
- a 50VA triad magnetics medical-grade (to utterly misquote Mr Pass, if it's good enough for dialysis it's good enough for music) toroidal transformer
- a Glassware bipolar lv-reg PSU
- An EIZZ 4-way input selector
- a DACT-style smd 21-stepped attenuator
- Duelund 26GA tinned solid copper wire in cotton and oil for audio signals
- Multicomp gold-plated, pure copper rca sockets
- half of a Rod Elliot P05 PSU with a discrete 10VA transformer, which drives:
- an LED input indicator
- LM3914-based LED volume-level indicators
- an AliExpress VU meter driver-board and VU meters, the signal wires of which are galvanically-isolated from the audio circuit with the redundant bal-SE converter transformers
- A slightly-modified/butchered 320mm aluminium enclosure from AliExpress
I was worried about potential interference from the VUs and LEDs (I worry a lot about interference. Can you tell?) so I put in a defeat switch for the P05, just in case any of it was audible. I don’t think it is, at least in my current system configuration. I still have an earth leak or some grounding issue somewhere. It's not bothering me enough to chase down at the moment but I'll need to address it at some point.
That brown thing is an organic, dielectronic, cryometrically-isolated quantum-state resonator and definitely not a bit of decking off-cut I jammed in there because my sticky came unstuck. No siree. Nope.
So, I've ended up pretty much where I wanted to - insofar as the operation and "features" go - and it certainly sounds superb (which I can’t really take credit for. But I didn’t F it up, which is something). It's not as elegant as I imagined, either in an aesthetic or tactile sense but it's not bad for a (mostly) first go. The LEDs are a bit bright but I’ll fix that when I get around to it.
thanks again to any and all who answered my stupid questions and helped me fix my noob mistakes. I’m going to tackle an M2X next but I’ve enrolled in an electrotechnology basics night-school course for this semester so I’m going to wait to start the amp until I’m slightly less of an idiot.
only in very rare cases does it make sense to put the pot before the output. In most cases input and output impedances make before the input the best position. For an example of a pass design that favours it before the output, see some of the zen pre’s on passdiy.com. Move it like 6L6 sez and enjoy an even better WLS.
I really do appreciate your help-- all of you. I want to emphasize that. This EE stuff is not just obscure to a lot of us it's nearly opaque. It's clear that this is a genuine passion for you though. For me, I know enough about electricity to reliably not die. I like building things and solving problems but in the stereo world my interest is primarily ending up with high value, extremely amazing sound. This community has made that possible. DIYAudio and the people who hang out here are real gems as well as electronic geniuses. Nelson Pass's contributions are stellar and he is giving them away! Hanging in there with us mere electronic mortals and helping our projects move along is a real gift. Again, thank you.
