Today I soldered the remaining connections to get the second channel up and running. The result is impressive. The AVC project is now finished. And I’m a happy bunny.
The sound is stunning. As good as I was expecting to be. Very detailed and no loss at bass or treble. The combination of 4P1L driving the AVC and the 814 input step-up transformer seems to work much better this way. The 4P1L preamp has no challenges in driving the AVC, however the full signal swing from the 4P1L step-down via by the AVC seems to sound extremely well.
Thanks to Dave Slagle for such a wonderful AVC. I measured the AVC and matching with a FR sweep and the scope. I was pleased to see the matching between channels and also the nice response 10Hz up to 30-40kHz.
Hard work to wire but it’s worth every penny, trust me…
I have also tried a new set of interconnect cables I made using PTFE shielded RF coaxial. Very simple to build and with nice performance.
The AVC is placed very closed to the power supplies (as you can see on the picture below). The AVC is still very quiet and there is no hum picked up due to the system layout. Lucky me.
Hi Ale,
Looks awesome. Waiting to hear your listening impressions.
Best,
Radu
Very nice Ale. I’m glad that you like sound with Slagle TVC.
Your PTFE coax for IC is with copper or silver-plated copper wire?
Best diying
Hi Rajko. It’s silver-plated one, very easy to work with, and ICs are built in 30 min or less. They sound superb. I bought the coax from China,..
Ale
+A shame that beautiful layout is hidden in a box. All I can think is WOW!
Tnx Ale.
I needed that info. My friend has an IC, PTFE coax with bare copper wire (Belden 89259 .. or so). Simple and sounds really good.
Ping me an email and I will send you what I used
Yup , 200$ AVC is bargain 😉
See mine here : http://tinyurl.com/qbs59wv
Sowter and reed switches.
Hi Ale,
I take that you are using the Slagle/Intact Audio $400 AVC which requires a 28 or more position two deck switch with one channel per deck. You seem to like repetitive tasks, eh? Thus it is a stereo control with no option for balance trim. I’m on a similar track…I have a Shallcross 28 position, two deck, make-before-break rotary switch that I found on ebay thinking along similar lines to yours…I’ll attach a photo if I can.
It looks like you are using enameled “magnet wire”. What gauge? Copper or Ag?
To date, my preamp, a 5687 WOT has been volume controlled with a two deck, 12 position make-before-break resistive ladder attenuator which gives 3dB per step, a stereo control, and since I am mostly listening in the next room, no problem…placed at input to the 5687.
You seem to have taken heroic steps with shielding the interior of your AVC box…could you please explain a bit about that…the reasons and the method?
Very Best Regards,
Robert 1111111
`Hi Again Ale, Time passes, and inflation has its effects…Slagle’s $400 AVC is now $500. I re-evaluated my position on which Slagle AVC to buy and came down on the now $400 modules that have two rotary switches per channel, twelve 3.75 dB major steps on one, and three +0- 1.25 dB steps on the other, which effectively gives 1.25 dB steps over the the range of the control. And, big plus…three wire connexion, thus much reduced soldering and some balance adjustment possibility. I’ve been thinking about using your 01a DHT Preamp Version 6 (Low Gain 6dB) Dec 2020 to guide my build. I have the Gyrator boards per that schematic, and also have your source follower boards to populate. AVC goes just beyond the 510K to ground? Have you tried your Slagle AVC in other applications? Any other suggestions?
Thank You for your efforts and generosity, Best, Robert
Hi Robert, Correct, the AVC goes after the coupling cap and 510K resistor to ground. I haven’t tried the AVC in other applications so can’t comment further.
This is the setup I’m using and very happy with it. Good luck!
cheers, Ale