Hans,
The need for so many channels is as a home theater preamp. I was not satisfied with the performance of many Pre/Pro products costing upwards of 4k and wanted a very high quality DAC along with a very high quality Volume control.
Sure I could look at the Denon Receiver but I wanted Dirac room correction and monoblocs for amps.
I am using JRiver Media Center to playback bluray's and using a focusrite PCIeR to multiple Burl BDA4M cards via Dante. Going to come out balanced out of the burl to the BPBP with your volume board and Tibi's controller.
I'm figuring out the power supply for each board now but the idea is to use choke input supply to reduce ripple as much as possible and the in one chassis with the Tibi's Controller having its own 9V transformer.
with the sjostrom SSR03 for each BPBP ... wondering if maybe the SLB power supply is a better choice than a choke supply ... to power the SSR03 and subsequent BPBP's and your volume switching board.
Comments / thoughts welcome of what I might do better. I was asking about a potential replacement for the LM part as some have said it sounds clinical. Its a great spec'd part and I will likely just stick with it. However thought I'd ask before I start soldering.
The need for so many channels is as a home theater preamp. I was not satisfied with the performance of many Pre/Pro products costing upwards of 4k and wanted a very high quality DAC along with a very high quality Volume control.
Sure I could look at the Denon Receiver but I wanted Dirac room correction and monoblocs for amps.
I am using JRiver Media Center to playback bluray's and using a focusrite PCIeR to multiple Burl BDA4M cards via Dante. Going to come out balanced out of the burl to the BPBP with your volume board and Tibi's controller.
I'm figuring out the power supply for each board now but the idea is to use choke input supply to reduce ripple as much as possible and the in one chassis with the Tibi's Controller having its own 9V transformer.
with the sjostrom SSR03 for each BPBP ... wondering if maybe the SLB power supply is a better choice than a choke supply ... to power the SSR03 and subsequent BPBP's and your volume switching board.
Comments / thoughts welcome of what I might do better. I was asking about a potential replacement for the LM part as some have said it sounds clinical. Its a great spec'd part and I will likely just stick with it. However thought I'd ask before I start soldering.
Hi all,
I've just be going through my electronics "things" and noticed a PCB for this preamp that was originally provided with Linear Audio. However, I likely will not be using it so if someone here would like to have it you are welcome. Just send me a PM (will cost the shipping).
Cheers,
Jesper
I've just be going through my electronics "things" and noticed a PCB for this preamp that was originally provided with Linear Audio. However, I likely will not be using it so if someone here would like to have it you are welcome. Just send me a PM (will cost the shipping).
Cheers,
Jesper
I too have been looking for an answer to this issue.
As a latecomer to this build Ive missed out on the relay board
I have decided to go ahead using a potentiometer, a Vishay P9A2R100FISX1103MA. It was mentioned in an earlier thread . It is 10K Linear and has a conductive plastic track. A Cermet track is listed in Vishays data but I cant find one in the UK .
Its identified as P9S
I run Ncore amps which do shut down fast if a transient overload occurs!
My pre is up and running with a 10k linear pot and exhibiting all the issues with excessive gain. My Ncore amps auto shut down if the pot is over rotated with no input signal.
I need a 16 bit attenuator board and construction details.
Is there any chance anyone has one or can advise where I might get one ?
The audio quality is superb so I must resolve this issue
I need a 16 bit attenuator board and construction details.
Is there any chance anyone has one or can advise where I might get one ?
The audio quality is superb so I must resolve this issue
I suppose you don't need 16 bits of attenuation 
7 bits (64 steps) with 1dB each (0 to -63dB) will probably be plenty.
You can have a look at a tested schematic/layout here (will require you to install kicad):
VolCtrlDR - Balanced Stepped Volume Control
This of course will require you to remove everything you don't need out to rebuild it entirely on the complete PCB.
I know there are specific relay attenuator boards out there, maybe someone else will chime in...
7 bits (64 steps) with 1dB each (0 to -63dB) will probably be plenty.
You can have a look at a tested schematic/layout here (will require you to install kicad):
VolCtrlDR - Balanced Stepped Volume Control
This of course will require you to remove everything you don't need out to rebuild it entirely on the complete PCB.
I know there are specific relay attenuator boards out there, maybe someone else will chime in...
I have Hans' gerbers for the 64 step attenuator if you are interested (I'm using it, working on a Arduino controller to control it as well as Hans' input selector board.
That looks great!
Can you explain something basic to me for better understanding? Hypex and Purifi always talk about adding a buffer with gain (-> 9.6 VRMS) to achieve maximum power. Is this really necessary or useful in practice? If so, what is the most elegant way to integrate adjustable gain into this "preamplifier"?
I'm not sure that the schematic of #1015 would work at all - I've never seen such an instrumentation amplifier.
As regards gain, the volume control stage in the original preamp schematic can provide gain at will. My experience with Bruno's preamp and a Hypex UcD180 (since 2013) is that I need attenuation of some 20 to 30 dB for comfortable listening with 85dB/W loudspeakers in my room.
My attenuator came from Jos van Eindhoven:
RelaiXedPassive -- Documentation
but I had to modify the PCB somewhat (scalpel and soldering) in order to adapt it for use in the preamp.
Regards,
Braca
As regards gain, the volume control stage in the original preamp schematic can provide gain at will. My experience with Bruno's preamp and a Hypex UcD180 (since 2013) is that I need attenuation of some 20 to 30 dB for comfortable listening with 85dB/W loudspeakers in my room.
My attenuator came from Jos van Eindhoven:
RelaiXedPassive -- Documentation
but I had to modify the PCB somewhat (scalpel and soldering) in order to adapt it for use in the preamp.
Regards,
Braca