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Hi Jim, I seem to remember you talking about your D2A work. We spoke via email a few years back about the power supplies I designed for Aragon components. I haven't dabbled with the D2A. Not that its not a good design for its time, but digital has come so far since the early 90's that its hard...

Yes I am still performing the Acurus & Aragon work. I've taken a break from audio work this summer due to some traveling and house projects that I have going on. I expect to resume audio work either late Sept or early Oct. I have a few people that have been waiting to send me their gear.

Excellent news! Enjoy it...

Unfortunately the L10 board silk screen has errors. There are multiple R24's. Find R23A in the middle of the L channel circuitry it's sitting right next to a mica cap. It should be 36.5k if you're on the right resistor. Now look at the same location in the center of the R channel circuitry and...

Sounds like you're ready to do some testing George... Tell us how it goes!

The L10 & ls11 are numbered differently and laid out a bit differently but its mostly the same circuit. Once you put the two schematics side by side you'll see what I mean. 1) Remove R5 and leave it out, installing a jumper will be a permanent signal mute. 2) Yes replace the 1k with a 100r...

There are a few caveats to the older QA's that I forgot to mention in my last post. The QA400 in addition to the fact its not supported by Win10, and the fact it has no attenuator built in also has a rather limited oscillator output level and will not drive some amps to clipping. For just...

I've used some sound cards along with REW in the past and it works well for distortion measurements. As you've probably already seen, all you need is a simple voltage divider to limit the voltage fed to the soundcard in order to test. You can go quite simple in the dividers design. Early on I...

Sorry I haven't logged in for quite a while so just reading this now. The L10 is mostly the same as the LS11. The L10 uses Noble volume & balance pots and the L10 also uses the J72/K147 Jfet pairs in the outputs versus the later k389/j109 paralleled Jfet pairs. My preference if I'm going without...

Okay if the pots and the rear panel Direct/Cap Coupled switch were all deleted then a loss of signal is prob not your problem. Its worth measuring of course just for verification but not a likely problem.

Did you happen to measure the input signal level at the board? This will verify that something is not screwed up with the volume pot's thats causing a loss of input signal on the right channel. I'd leave the amp off and feed it a 1V rms signal and measure that signal level at the control board...

Well the back side of the board looks pretty good. The fact that you've cleaned it up and it's shiny helps. Due to the type of issue you're seeing I'd still reflow all of the solder joints on this board. It'll take all of 10 min to do so but should give you peace of mind that the joints are all...

To add to what Joe said earlier. There's a lot of evidence of insufficient heat when soldering. Zoom in and look at all of the rough B+/B-/ground connections along the edge of the backplane board. Also zoom in and look at the Q7L/Q8L pin solder joints. Even the joints at the copper ground strap...

Don't be hating on the jumper wifes. All good electronics techs need a jumper wife or two.

Joe, I thought I'd point out that your Acurus pre has a 10 ohm resistor bypassed with a film cap isolating the DC and Chassis Mains ground. So resistance between RCA ground and the IEC ground pin should show 10ohms. Mondial did this in all of their pre's including the Aragon's.

Well the Coherence is a helluva pre so the fact the modded Acurus is in the same ballpark as it is a good thing to hear. I'm really partial to the Acurus pre's for the price the build quality and design are hard to beat. 125 - 129dB RANGE!!! WTH man you are close to breaking windows. :)

By the way, thanks for the kind words on the quality of my work. Its always nice to hear good things from other DIY'ers as they're a critical crowd. Its a lot easier to please those folks that aren't as knowledgeable in this hobby.

Yes, about 60wpc, but 200W dissipated per channel.

I've got Lee's LS11 in my system now. Going to listen to a few discs today if the heat from the Alephs doesn't run me out of the room. They are great amps for the winter time.

Geegz, The 28k is a nice preamp. I had one for several years that I upgraded to use a custom external power supply that I housed in an original Aragon IPS chassis (the triangular one). I used separate transformers for the remote circuitry and analog circuitry and split the ground planes inside...