Doug Self Preamp from Linear Audio #5

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#2,223
Carl_Huff said:
Just a quick point of clarification for those who have recently joined this thread or haven't really been paying attention.

This thread is NOT about Doug Self's 2012 preamp published in Elektor magazine, rather this thread is all about the Doug Self circuit fragments published in Linear Audio #5 in 2013. A couple of years later I strung together Doug's ideas into the project that this thread is about.

Once again I want to thank both Jan Didden and Doug Self for all of their help and support during the long run of this thread.
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Hi Carl

reading again this thread, I have questions for someone like me wanted to build this preamplifier (the doug not the elektor). Is there any summary of schematic used I can get ? Where I can get the gerber files ? If price not to much I can pay .

Your feedback will be appreciated,Please let me know.

Georges
 
#2,225
madeleeuw said:
Hello All,

Just thought I would share some photos of my now (finally!) completed preamp. In a 1U Hifi2000 chassis with engraved front and rear panels by Schaeffler. Super quality. It took some time to get it all together, and along the way I did make a few changes:

Some adjustments were made to the fpd file I downloaded. The XLR input layout was not quite right, and I went back and measured actuals on the center spacing. I have an updated file which works very well if anyone is interested. And yes - be patient and seat the connectors in the rear panel prior to full soldering makes life much easier. I learned the hard way.

For the front I wanted a 10mm panel so I had to counterbore for the pot bushings. I used the counterbores to recess the knobs. Biggest issue there was managing tolerances but it all worked out. I also swapped the In/Out switch for one with a longer barrel and tweaked the leads a bit to get body of the switch right up to the back of the panel. This avoided a countersink on the front and makes for a cleaner look IMO. I need to go back and put a bit of black paint inside the cbores to cut the sliver of glare.

Anyway a very interesting project and thanks for all the support from the forum, Carl, and Doug Self!

Best,
Mike

View attachment 1026520View attachment 1026521
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HI
Amazing look ! I love it. Please can you give the caracteristics of the case you used ? What brand and size please.

Thanks a lot

Georges
 
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#2,229
madeleeuw said:
Hello All,

Just thought I would share some photos of my now (finally!) completed preamp. In a 1U Hifi2000 chassis with engraved front and rear panels by Schaeffler. Super quality. It took some time to get it all together, and along the way I did make a few changes:

Some adjustments were made to the fpd file I downloaded. The XLR input layout was not quite right, and I went back and measured actuals on the center spacing. I have an updated file which works very well if anyone is interested. And yes - be patient and seat the connectors in the rear panel prior to full soldering makes life much easier. I learned the hard way.

For the front I wanted a 10mm panel so I had to counterbore for the pot bushings. I used the counterbores to recess the knobs. Biggest issue there was managing tolerances but it all worked out. I also swapped the In/Out switch for one with a longer barrel and tweaked the leads a bit to get body of the switch right up to the back of the panel. This avoided a countersink on the front and makes for a cleaner look IMO. I need to go back and put a bit of black paint inside the cbores to cut the sliver of glare.

Anyway a very interesting project and thanks for all the support from the forum, Carl, and Doug Self!

Best,
Mike

View attachment 1026520View attachment 1026521
Click to expand...
HiMike,
very amazing look,
Can you also share photos of the inside?
What riaa preamp is?
 
#2,230
Hello DIYers,

Probably unnecessary, but is there any recommendation for a direct substitute to the RCA inputs, with gold plating on the signal contacts as well as the shield?

Carl might be the person to answer this - can I alter the time of the relay timer by changing the 47k resistor to 100k? Calculating the charge time, I believe the constant is currently 2.2s and I'd like to move it to 4.5-5s.

Thank you kindly
 
#2,235
Ha, ha ...

Don't take it as a personal slight Doug. What I meant was it was not presented as a 'finished' preamplifier. For example unlike your 2012 Elector article there was no output section presented. I took the article's intent was to tutor readers on the findings of your current research on tone controls and your version of the Baxandall active volume control.

Incidentally, it was a great article! No slight intended.
 
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#2,236
I have this built up and running finally but I'd like to lowee the gain by swapping out or paralleling over R42 and R45.

Could someone tell me generally where they are ?! With the populated board I can't really see the silkscreen . I've trawled the thread for a picture of a bare board but not clear enough to make it out.

Any help appreciated.

Thanks
 
#2,238
It is with a heavy heart that I feel the need to inform the other builders in this thread that, the generous soul who designed the PCB layout for this preamp project, Carl Huff, has passed away in recent weeks. Condolences can be made in the thread dedicated to him:

C

Thread 'Carl Huff'

My beloved husband of 21 year, Carleton Howard Huff, has passed away on October 30, 2024. He was the kindest, smartest, most loving human being I ever known.He often talked about how much he enjoyed this forum, interacting with people from all over the world and learning new things. Thank you for sharing your life with me. I will always love you and cherish all of the wonderful memories we have together. This is not a goodbye. It is until I see you again.
Your loving wife as ever, Elena Huff
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