If you find you have a hum you could try to partition your preamp.
I was thinking of putting one VRDN/transformer on the left side and the other VRDN/transformer on the right. The BA2018, volume pot, input selector and signal wiring would be in the middle section. Then I would use some steel angle iron to 'wall off' the PSU/transformers from the preamp section.
BAF 2018
Hey Boys she ain't Purty but this Gal sure sounds Great.
My music source is a Raspberry Pi with an Allo Boss DAC,playing FLAC files. I have had to use the Software Volume control. This is somewhat lossy at a lower volume than 100%, not anymore.
Turn the software volume to 100% Hooked the BAF 2018 to the DIY Store F5 and Holy Catfish Batman. I had forgotten how good "Kansas" sounds. Ella Fitzgerald, Sheryl Crow, Nina Simone, Robert Cray,Little Feat, Los Lobos, and don't forget ACDC.
Have to Give a Big Ole Redneck Chest Bump the all the Folks that made this possible.
Mark Johnson for the VRDN power supply, Rick Ray for the VRDN pcb, pfarrell for some pointers,
and who can forget my fellow Pro Pilot 6L6 for all that help.
Thanks Folks
Now for Proof:
Mine Goes To 11 Man.....!
Hey Boys she ain't Purty but this Gal sure sounds Great.
My music source is a Raspberry Pi with an Allo Boss DAC,playing FLAC files. I have had to use the Software Volume control. This is somewhat lossy at a lower volume than 100%, not anymore.
Turn the software volume to 100% Hooked the BAF 2018 to the DIY Store F5 and Holy Catfish Batman. I had forgotten how good "Kansas" sounds. Ella Fitzgerald, Sheryl Crow, Nina Simone, Robert Cray,Little Feat, Los Lobos, and don't forget ACDC.
Have to Give a Big Ole Redneck Chest Bump the all the Folks that made this possible.
Mark Johnson for the VRDN power supply, Rick Ray for the VRDN pcb, pfarrell for some pointers,
and who can forget my fellow Pro Pilot 6L6 for all that help.
Thanks Folks
Now for Proof:
Mine Goes To 11 Man.....!
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A very nice project, for a very good price. $64 for pcb and parts is a very good investment.
In my case I'd prefer using a Jung Superregulator to power it, but the VRDN is a very good one too. Is there a VRDN kit available anywhere?
Also would like to listen to someone that used an eBay 317/337 kit, added a Denoiser or Dienoiser, and listened to the results.
Will probably simulate the Wayne's with LTSpice, even if it's quite likely that someone already did.
What about these asc files and better yet: actual measurements?
What program have you used on the Raspberry + Allo Boss DAC? What pot on the Wayne's: brand and value?
In my case I hooked a Topping D50 DAC at the Raspberry 3B USB output, used the Rasp just for the Ethernet network, and fed the DAC directly into the power amp, no preamp, just a volume pot in between.
I do not like DACs that you plug into Raspberry, as then the analog audio power supply is the Rasp's, which is very poor.
You could consider:
- a different PSU for the Rasp + DAC / HAT.
- a DAC / HAT that allows for a separate PSU for the HAT. I use two dedicated PSUs for one of mine. I'm not sure if it affects the sound, but the design allowed for it, so I did it. Some (not me) have used what I'd consider expensive stand-alone linear PSUs and rave about them.
There may be other options.
If that you mean the external PSU you feed into the Rasp, that doesn't change a thing. The question is to replace the internal Raps's DC-DC supplies for linear ones. Impossible to do in that small space.
Other Raspberry alternatives allow you to do so.
IMHO the power supplies for low level signals should be linear. One thing I intend to change on my Topping D-50 is the power supply feeding the analog output stage, which is not linear as that feeding the DACs.
What pot did you use between the DAC and the Wayne's? Was it necessary? Couldn't you just control the level digitally?
I am building this preamp with a pair of VRDNs. I'd like to include a power LED on the chassis faceplate. The easiest option would seem to be to remove the LED from the preamp PCB and extend flying leads to an LED mounted to the panel. But I probably wouldn't want to use this LED -- I'd probably try and find a 2 or 3mm flat topped cylindrical LED to flush mount.
The schematic shows the LED(s) between two transistors which makes me think it has a more critical role than just power indication. And since I haven't found the BA2018 BOM (I bought the parts kit), I don't know the specs.
Could someone confirm it's best not to modify this LED? What is a better way to power a single LED here? Straight from a VRDN with an appropriate resistor?
The schematic shows the LED(s) between two transistors which makes me think it has a more critical role than just power indication. And since I haven't found the BA2018 BOM (I bought the parts kit), I don't know the specs.
Could someone confirm it's best not to modify this LED? What is a better way to power a single LED here? Straight from a VRDN with an appropriate resistor?
Ooh! Post #508! I think I probably gave up at exactly #500.
I thought maybe the BOM was a secret to encourage parts kit sales!
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Good point. I've already landed on 2 LEDs for the F5 faceplate, although I could do many more! Amp board (2), universal PSU (2), speaker protection (2), soft start (1?). I could make it look like a sci fi prop with all those lights.
make it look like a sci fi prop with all those lights.
Self Illuminating Rainbow Jellyfish : Flashing lights! - YouTube
You achieve pretty good results by using the Allo Boss in conjunction with their isolator board. The isolator sits between the Pi and the DAC, allowing you to have complete galvanic isolation. You'll need separate supplies, obviously. I built one of these a few years ago and powered the DAC from LiPo batteries. It is completely free from Pi "noise". The player runs piCorePlayer software.
See this post in the Logitech Squeezebox forum for the example I built: pi based systems - Page 6
There are other builds in that thread too.
I am building the LCDuino display/volume control from AMB Labs. It controls the companion stepped attenuator and input/output selector (which I am also starting to construct). The input/output selector is very flexible, allowing for up to 8 input or output "ports" or any mix up to 8 total.
I have the display unit running on the bench and it is very cool. It has a motorized ALPS pot, but the pot is NOT used for audio signals. It is only used to allow for manual control of the stepped attenuator. The display unit has an IR remote sensor which allows for remote control. As you use the remote for volume, the pot rotates simultaneously with the display, which is calibrated in dbs.
These are very DIY-ish projects, since he does not sell complete kits, just PCBs, but the parts lists and instructions are very clear.
He also has boards for other projects, including a complete preamp. Interesting stuff.
Take a look at his website: AMB Laboratories
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