Pop/click free HW-based relay attenuator V3

[Neutrality]

2 : For those who have ordered both RA V3 and EXP V1 PCBs, I have just received shipping information for the EXP V1 PCBs and they should hopefully arrive this week.
With luck I can ship them out this coming Friday.

EXP V1 PCBs have arrived. But since I have to leave for work soon and tomorrow is a holiday I wont ship until Friday.

 

[adrianbaugh]

Thanks for the update. Is there anything we should know about the courier you use (will they be wanting someone to be in to provide a signature, do they provide tracking information?)

 

[Neutrality]

Thanks for the update. Is there anything we should know about the courier you use (will they be wanting someone to be in to provide a signature, do they provide tracking information?)

I will be using regular mail service. PCBs will be shipped in a small padded envelope, so they should be delivered directly to your mailbox.

 

[adrianbaugh]

Perfect. Thanks!

 

[Neutrality]

I just got home from the post office.

All remaining orders have been sent today.

 

[adrianbaugh]

My boards arrived today! Many thanks, I hadn't expected them so quickly! I'll post back with a build report once I'm done.

 

[diyralf]

I am waiting impatiently for the report.

 

[Neutrality]

I am waiting impatiently for the report.

Me too.

I hope those who build it are as happy about the design it as I am.

 

[Joerg D]

My boards arrived yesterday! Still waiting for the last electronic parts, then the modification of me preamplifier can start.
Many thanks for your good job!

Best regards
Jörg

 

[steefdebruijn]

Boards arrived today in good condition. thx.

 

[adrianbaugh]

Well I've built it, it powers up and the relays appear to click at about the right rate as I turn the pot. So far so good! That was the most nerve-racking build I've ever done, lots of cleaning up of solder bridges and straining over my magnifier! But I don't seem to have ruined any of the components, which I have to admit surprised me a little. But I did learn a lot along the way and it's a lovely and compact design. Really looking forward to testing some audio through it now.

 

[adrianbaugh]

And here's a photo

Just finished, on the workbench and complete with expansion board. Now to install it into my Modulus-86 amp

 

[Neutrality]

Good job. Looks great.

Look forward to hear what you think of it in use.

 

[adrianbaugh]

I've had a chance to listen to it for a while now. A photo of my setup is attached. The relay attenuator is controlled by an Alps linear 100k pot attached to a no-name Chinese remote control board, and the signal gets fed from XLR inputs via the relay attenuator (plus extender board) to 2 of Tom Christiansen's Modulus-86 boards, with output through 2 speakon connectors.

It's exactly what a relay attenuator should be: totally transparent, I can't make out any noise added to the signal, and the 0.1% matched resistors make for a very well preserved stereo field. I haven't heard a pop yet!

 

[Neutrality]

I am glad you liked it.

And that is a very nice amplifier.

If I were not exclusive listening to music through headphones, I would have considered building something like the Modulus 686 for my audio system.

 

[Neutrality]

Just a little update.

Been using V3 almost daily for the last 3 months and no issues has been found with it, it just works.

I needed 3 tries to get it 100% right, but in the end it worked out very well.

Another thins is that I am down to having only 10 x RAB V3 and 6 x EXP V1, when those boards are gone they most likely wont be available again.

 

[454Casull]

Would you be able to provide the BOMs for the main board and expander board in xls format? I cannot easily parse the PDF versions provided and would like to avoid manually entering every item in DigiKey/Mouser.

 

[454Casull]

Would you be able to provide the BOMs for the main board and expander board in xls format? I cannot easily parse the PDF versions provided and would like to avoid manually entering every item in DigiKey/Mouser.

Never mind... I forgot about the text files.

 

[Neutrality]

Never mind... I forgot about the text files.

That is why I made the .txt files, it makes ordering easy.

 

[philsu]

Hi Neutrality,
Thanks once again for the design and pcb's.
Just wanted to share a couple of pics showing your design saving my cherished Sony TA-F333ESL with a dodgy volume pot.