How about $20 for 3 power supply PCBs? Plus actual cost to ship.
I could sell the assembled and tested preamp boards for $350 each (minus the op amps). That's roughly the cost of parts! That price would include a bare power supply and IO PCBs. I'd supply the needed OEM RCA IO blocks and rotary selector switch. The rest of the required parts to assemble the Power Supply and IO PCBs can be purchased at Mouser and Digikey. I will email you a documentation package.
Message me if anyone is interested and I will respond.
In closing ...
This has been a fun project. Thanks to Jan Didden and especially Doug Self for their support of my effort. I expect those of you that have built this preamp would agree that it sounds every bit as good (better??) than most commercial products.
Common ground output connectors
Hi !
I'm very happy with this preamp that's been running for months now.
I've had other preamps previously, but this one is my preferate - by far.
There's a little thing that's now disturbing me - the fact that ground is common to right and left output - which is not the best option for my power amplifier (unbalanced).
There is no audible hum or any disturbing noise in my speakers, but as I have a couple of line level isolation devices, I tried them between the DS preamp and the amplifier.
The best result is obtained with a 2 x 1:1 600 ohm transformers device (Behringer HD400 hum destroyer).
The other one has a couple of 10-15K transformers and doesn't sound as good.
Is anybody having an experience of the best option to manage this issue ?
What is the best option to have separate line references for my power amp ?
Thanks for your help
J-M
Hi !
I'm very happy with this preamp that's been running for months now.
I've had other preamps previously, but this one is my preferate - by far.
There's a little thing that's now disturbing me - the fact that ground is common to right and left output - which is not the best option for my power amplifier (unbalanced).
There is no audible hum or any disturbing noise in my speakers, but as I have a couple of line level isolation devices, I tried them between the DS preamp and the amplifier.
The best result is obtained with a 2 x 1:1 600 ohm transformers device (Behringer HD400 hum destroyer).
The other one has a couple of 10-15K transformers and doesn't sound as good.
Is anybody having an experience of the best option to manage this issue ?
What is the best option to have separate line references for my power amp ?
Thanks for your help
J-M
Hi!
Is there a PCB for Self-Preamp left? 🙂
If so, what the Price.
I'm living in Austria | Vienna.
I'm interessted in.
Best regards
Wolfgang
Is there a PCB for Self-Preamp left? 🙂
If so, what the Price.
I'm living in Austria | Vienna.
I'm interessted in.
Best regards
Wolfgang
I believe there is an error in the BOM, regarding 47k resistors. Shouldn't there be three of them, instead of 1?
Yes there are/were some errors. Note, most quantities in the original BOM (I don't know if it's been updated) need to be doubled but there are the correct number of op amps
Not sure if you are saying there's an improvement with the Behringer HD400 over not having it ?
From what you say it sounds like the system is fine without it so I'm not clear what it is you are trying to improve.
From what you say it sounds like the system is fine without it so I'm not clear what it is you are trying to improve.
Any idea where/if I can find an updated BOM? I just found out R4 is in there twice, but no R5, and I'd hate to make errors in such an expensive (for a student at least) project.
I noticed today actually there is an updated BOM in the first post in this thread. That's all I know. The errors that exist are minor
Ah, thanks for the quick reply! I checked it, but it seems to contain the same errors (no R5, but 2 R4s, and a counting error in 47K for R24, R40 and the second DELAY_ON).
Finished Project PICs
Thanks to our good friends at Photobucket my previously posted PICs of the finished builds have disappeared. As result I have posted them again. Both builds are in regular use and a pleasure to listen to.
The build in brushed natural aluminum is a 1U package.
My black brushed aluminum build with meters is a 2U solution
Thanks to our good friends at Photobucket my previously posted PICs of the finished builds have disappeared. As result I have posted them again. Both builds are in regular use and a pleasure to listen to.
The build in brushed natural aluminum is a 1U package.
An externally hosted image should be here but it was not working when we last tested it.
My black brushed aluminum build with meters is a 2U solution
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Still wish someone would correct the BOM for all the poor souls who are being confused by it, and potentially making incorrect purchases
Actually there is a thread of sanity to the BOM madness ...
The BOM (as well as the schematic) describes the passive parts required for a single channel. The preamp is two channels, thus the need to double the passive parts called out in the BOM.
The op amps are active parts and are listed in the BOM as the number required to complete the project. This may sound crazy to some but it is a practice that I established a long time ago when a single quad op amp might service up to four channels and projects might have 'n' channels.
Please write your confusion off to my old habits. Ha, ha ...
If you are truly interested I invite you to adjust the BOM to your satisfaction, forward it to me and I will make it available to all that want it.