Building a Douglas Self design preamp

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Elektor Preamplifier 2012

In Elektor magazine web site, if you go to (might have to log-in to view, i.e. create user etc.): -
https://www.elektormagazine.com/lab...ine-intonevolume-board-110650#/comments/11662
This link will show all comments from everyone.
It's very important to read all those comments on this project as it originally came out in 2012 and therefore some components used have changed spec. & supply voltages need to be checked.
The project ran in three issues, April, May and June 2012, all can be downloaded for a small fee from Elektor Magazine we site.
 
... How has your build evolved?

The design as presented is quite mature and competes well with the best of commercial products.

However I do continue to evolve the design. I am making the design more modular. That way the project can be build with varying levels of capabilities and features. My current effort adds a 4.3 inch color LCD touchscreen with BeagleBone computer that selects the input, adds a nice AKM USB DAC and music server in a snappy commercial grade enclosure.
 
... BeagleBone computer that selects the input, adds a nice AKM USB DAC and music server in a snappy commercial grade enclosure.

I will be interested to see this.

I have a twisted pear audio buffalo 3 dac that i have been using as a digital preamp and a dedicated pc as media server.

The new preamp will be the new master control unit of the system and and I will implement some communication protocol for connected units.

Im guessing that you either have or will achieve digital volume control? Using motorized or digital pot?
 
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I will be interested to see this.

I have a twisted pear audio buffalo 3 dac that i have been using as a digital preamp and a dedicated pc as media server.

The new preamp will be the new master control unit of the system and and I will implement some communication protocol for connected units.

Im guessing that you either have or will achieve digital volume control? Using motorized or digital pot?

#1) In my current implementation the DAC that I am using simply plugs into the IO board. I brought a DAC into the preamplifier chassis for convenience.

#2) I've put Doug's slick tone control on to a PCB of it's own.

#3) I am using a MUSES 7230 chip for volume control under BeagleBone control.

#4) The IO board now stands alone and uses THAT chips for multiple balanced IN/OUTs as well as the traditional RCA phono I/O switched by the BeagleBone.

However all of this is subject to change. I am fickled that way!
 
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Hello Carl,

Hey did you receive back the shipment finally ?

I just received all the parts from Mouser one week ago and I' beginning to populate the kit. I bought as well several caps for the main powersupply to benchmark the sound in relation to the rest of my hifi for the best marriage ! And also went for a little sfernice Vishay P11 to test the two type of pot (with the one you provided) for the volume control ! I will post the conclusion when it will be test !

First : have to populate with the BOM and listen and keep time for caps burning in...

Well done for the Muse chip volume control :)

best regards

Eldam
 
The Pope will have a Douglas Self pre...:D ! First time I see such a thing with a shipment ! I will ask your local post for the money back in your shoes !

Yes of course I will go back on the thread, as I bought the exact BOM (I had to wait for one month to have all the parts from Mousers because of that: wanted to have all the Yageos resistor and the 4 KP caps which were out of stock ! )

with the main genuine BOM cap of the powersupply, I will test also some brand new TDK, Panasonic, IC, BC, Nichicon, etc ... all from the same value in uF & voltage...

I will say what I prefer knowing all being subjective about cap and personal hifi ! But as I have a very clear and good resolution with both DAC/amp and speakers combos, and a more classic Yamaha Pre, it could be interressant indeed !
 
Cool!

Did you compare with anyother chips? How do you find the distortion levels your setup?

The distortion levels are very low. The noise and artifacts are well below what I can hear thru my Sennheiser HD 650 headphones. My aging AP Portable One struggles to find it. Once I have a design that is closer to final I'll probably make a visit to a friend of mine that has a test bench equipped with the latest AP test sets and see what shows then.

This is the first time that I've used the MUSES part. In the past I have used TI PGA23xx chips extensively. I find that they work best when preceded with a simple FET buffer. The times that I have done that the PGAs become transparent. I've never used the Cirrus Logic part. It's not that I have a bias or prejudice against it, I simply have never used it.
 
This is the first time that I've used the MUSES part. In the past I have used TI PGA23xx chips extensively. I find that they work best when preceded with a simple FET buffer

Thank you! Exactly the input I was hoping for:)

When putting digital volume control into you design, did you simply slip it in where the manual pot used to be or did you place it after the preamp-board?
 
Thank you! Exactly the input I was hoping for:)

When putting digital volume control into you design, did you simply slip it in where the manual pot used to be or did you place it after the preamp-board?

The MUSE volume control is currently wired previous to the tone control board. That guarantees no chance of level overload when applying EQ gain.
 
Ive started on this Preamplifier too and would like some suggestions.
All components ar mounted, so now its a question of putting it all together.
Case to use?
How did you go about fitting the boards for the front and rear?
Cabling and connections?
help would be most appreciated
 
Ive started on this Preamplifier too and would like some suggestions.
All components ar mounted, so now its a question of putting it all together.

Well done! Would love to see some pictures:)

How did you solve eg C1 on the power supply board? It is supposed to be lead spacing 7,5 mm farnell number 1200728 but the suggested alternative 9750983 has 5 mm lead spacing. Where you able to fit the alternative or did you source the original from somewhere else?
 
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