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Distinction-1541 v2 complete PCB interest list

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Following on from setting up PSUs to feed the Distinction board and, for me, a CEN output stage.

For the CEN I will use Ryan's CapMx and some LM317/TL417 regulation. I will make the attached by hand milling the boards, as per a previous post - so have designed a layout that allows for single sided pcb. The CapMx board will be of course much simplified.

Thought I would post these before I set to making them - part selection according to my own BOM of course, leaving no options for different part sizes.

Looks good Clayton, be interesting to hear your impressions once finished.

The CapMx circuit is not mine - just for the record, I saw it somewhere on the interwebs somewhere.. out there... Then just adapted it a little bit.

How much current are you going to shunt through the pass PNP?

Don't forget that you may need an extra 3V across the 317 CCS, plus about 2V across each capmx. You may not need R3 and R4 in your schematics if using the reg afterwards - I only had them there as a way to drop the voltage.

Do you have any plans to test the shunt reg with and without the pass transistor? As it may or maynot be that important to feed a very low output impedance to a high impedance load. It will be interesting to get your impressions of both ways.

After I finished tweaking the capmx/filter circuit I had a good listen and confirmed through listening to my most familiar music that I had gained an increase in low level detail - sounds I had never heard before in tracks I was very familiar with were a little more audible, unfortunately this was accompanied by a little graininess.

This lead me to revert back to my previous output stage - an SRPP tube configuration, but this time with the B1 buffer afterwards to get the output impedance down form 10k, which was surely a bottle neck that I did not address at the time.

The graininess had gone but a slight edginess to voices remained, so I nulled the DC offset on AOL and AOR form -127mV to around -13mV via two 2k7 resistors from 5V. This improved things considerably. This lead me to a good listening session... very nice sound, very little fatigue, great lively music, some of the best i've heard on my system thus far. I'm keen to try using a plain resistor to replace the CCS in my CEN circuit to see if it will give me a similar improvement. I wonder if the graininess is from the CCS that John Brown pointed out in his thread a week or so ago.
 
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Looks good Clayton, be interesting to hear your impressions once finished.

The CapMx circuit is not mine - just for the record, I saw it somewhere on the interwebs somewhere.. out there... Then just adapted it a little bit.

Sure. "there is nothing new under the sun"

How much current are you going to shunt through the pass PNP?

Not something I had considered because I didn't know I should :) I am a copy-cat not a designer. The regulator section is from the Zen>Sen>Cen thread. I will re-position the pnp to allow a heat sink if needed.

Thinking that I need to breadboard this before I commit everything to solder. But I find breadboards very confusing and difficult to setup.

Don't forget that you may need an extra 3V across the 317 CCS, plus about 2V across each capmx. You may not need R3 and R4 in your schematics if using the reg afterwards - I only had them there as a way to drop the voltage.

Certainly got plenty of headroom for the Cen and I believe I will be ok with for the DAC. I'll nix those resistors from the Cen supply for starters.

I'm starting to feel like this is all getting a bit to fussy and complex for me now - sadly I don't have the time for multiple iterations. I may just end up putting the CEN to one side for now and just use the Pass I/V stage that I have along with the SSR03 that I have sitting there. (The Pass I/V is what started all this business in the first place).

Will sort out the Capmx for the Distinction and put that with the 6N1P output that I am using currently.
 
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Hi Ryan

Having problems getting this to work as it should. What voltage transformer do you use?

I've done the circuit as per the schematic in this post and using a 2x12v (48va) in series to give 24v into full rectifier but cannot then get it to drop to anywhere near 26-27v?

Have I misunderstood and do I need further regulation beyond this CapMx?

I've only got 5r (1w I think?) in R4/5 because that is what I had to hand - I have some higher values I can try in this position - how many watts min should these be?

Perhaps it is simply that I am not putting sufficient load when I am testing as I only have 2x10r 3w in series - and they were starting to smoke :D - briefly with no load I see low 30s. I do have 200r but only 0.25w so was cautious about using it for my test. I've just noticed I've got some 240r 2W so will give one of them a try and report.

[just tried with 220r 1w for the load and got to about 30.5v - that resistor gets hot which makes me nervous. will try increasing R4/5 to drop the volts a little more - to hand I've got 10r 0.4w and 12r 1w - they might be a tad high? will try and see]

Thanks as always


Hi guys,

Attached is a schematic of the cap MX circuit that I ended up with after testing. Also attached a basic ripple rejection graph of the measurements I took.

The previous measuring setup I had (Virtins multi-instrument) seemed to give me differing results each time, so I used my scope instead using a differential measuring technique. Here's a link to one of Dave Jones videos that describes the technique I used: YouTube

Test setup was the same as before but using my scope to analyse the waveform instead.

I had a short listen to my system with this circuit in place and its sounding like i've gained some improvement in sound quality, Ill have a better listen soon.
 
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Hi Clayton,

If using full bridge (your using both sides of the wave form at the same time), you will get a higher output voltage.

Try using only 2 diodes with the 2x24V winding connected with the negative for the center tap.

You can also adjust the voltage drop across the capmx by changing the values of R1 and R3.

If you had the load resistors smoking you might have blown the BJTs. (they may still conduct but just act as a resistor.)


Hi Ryan

Having problems getting this to work as it should. What voltage transformer do you use?

I've done the circuit as per the schematic in this post and using a 2x12v (48va) in series to give 24v into full rectifier but cannot then get it to drop to anywhere near 26-27v?

Have I misunderstood and do I need further regulation beyond this CapMx?

I've only got 5r (1w I think?) in R4/5 because that is what I had to hand - I have some higher values I can try in this position - how many watts min should these be?

Perhaps it is simply that I am not putting sufficient load when I am testing as I only have 2x10r 3w in series - and they were starting to smoke :D - briefly with no load I see low 30s. I do have 200r but only 0.25w so was cautious about using it for my test. I've just noticed I've got some 240r 2W so will give one of them a try and report.

[just tried with 220r 1w for the load and got to about 30.5v - that resistor gets hot which makes me nervous. will try increasing R4/5 to drop the volts a little more - to hand I've got 10r 0.4w and 12r 1w - they might be a tad high? will try and see]

Thanks as always
 
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