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Re: Palpigrade Build Thread

Posted: Fri Jul 23, 2021 9:36 am
by Joe Malone
Gersef wrote:
Fri Jul 23, 2021 7:13 am
Hi Joe,

Wanted to share the finished Summing Amp with you.
This unit is absolutely dead quiet, no noise floor, amazing.
The difference in output voltage between the 16 channels is within +/-0,0015V.
The sound is really nice and it works beautifully.

The only not so nice looking parts are the ribbon cables as they are right now, but doesn‘t affect sound so who cares…

All of that could not have been achieved without your Palpigrade kits.
So a really cool little kit that is really fantastic quality.
Good thing I found that in your shop when I decided to build a summing unit.

And luckily it came with a sticker I put on the top of the box (above the input modules).

I am looking forward to the countless hours of fun I will have with this summing box.
Wow, very nice build :D Great to hear you got it all working perfectly. Thanks for posting the photos. 8) :D

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Re: Palpigrade Build Thread

Posted: Mon Feb 07, 2022 8:25 am
by waveterm
Hi Guys !

I am looking forward to building both the Palpi and the Tardi.

Does anyone have a BOM from Mouser, RS etc...?

Best,

Lars

Re: Palpigrade Build Thread

Posted: Mon Mar 07, 2022 2:40 am
by waveterm
Hi again !

I´ve now built both a Tardigrade and a Palpigrade and will need to look into the PSU. I was planning on using a SMPS with +/-15V output.

Do I need to add the Zener diodes ?

Or could I just connect the PSU directly ?

Best,

Lars

Re: Palpigrade Build Thread

Posted: Mon Mar 07, 2022 8:19 am
by Joe Malone
waveterm wrote:
Mon Mar 07, 2022 2:40 am
Hi again !

I´ve now built both a Tardigrade and a Palpigrade and will need to look into the PSU. I was planning on using a SMPS with +/-15V output.

Do I need to add the Zener diodes ?

Or could I just connect the PSU directly ?

Best,

Lars
If you have dual power rails -15v 0v +15v then no zener diodes are needed.

Zeners are only used to change single 24v to 36v into +/-12v to +/-18v

Re: Palpigrade Build Thread

Posted: Wed Jul 27, 2022 2:51 pm
by Bullfish
Hey guys, I’m building something almost exactly like the unit above with Capi ACA Bo and 2 of the Palpigrades, which I just ordered.

I have a question about power.

I found the power board in the project above on a German site and no way to order it… was too lazy to have it translated… 🤷‍♂️ I’m wondering what power delivery combo available from JLM would do the same job as the unit above? And do I need to use the toroidal Trafo?

Thanks again for your time!

Re: Palpigrade Build Thread

Posted: Sat Jul 30, 2022 5:07 pm
by Joe Malone
Bullfish wrote:
Wed Jul 27, 2022 2:51 pm
Hey guys, I’m building something almost exactly like the unit above with Capi ACA Bo and 2 of the Palpigrades, which I just ordered.

I have a question about power.

I found the power board in the project above on a German site and no way to order it… was too lazy to have it translated… 🤷‍♂️ I’m wondering what power delivery combo available from JLM would do the same job as the unit above? And do I need to use the toroidal Trafo?

Thanks again for your time!
This setup would be fine with +/-16v @ 500mA so our AC/DC EM kit with 2 x 18vac 30VA transformer would work fine.

Re: Palpigrade Build Thread

Posted: Sat Sep 30, 2023 4:32 am
by dan1b
“Joe” wrote: C2 & C3 are 39pF not 47pF. 39pF gives 200kHz flat bandwidth.
Extra 39pF can be added under pcb to improve CMRR over whole audio bandwidth.
Joe Malone wrote:
Mon Nov 23, 2020 10:28 am

Palpigrade kit parts list

8 x 10k 4pin SIL
2 x 10R
8 x 100uF 10v Non Polar caps
24 x 39pF ceramic caps
Hi Joe,

I’ve ordered 1x Tardigrade kit + Tardigrade PCB + Palpigrade PCB to the UK.

Questions:
  • 10k 4pin SIL - Only 2% tolerance available over here for 4-pin SIL, is this suitable or should I substitute a matched pair of 10k 1% resistors?
    2x 10R - I assume these are 1W rated?
    24 x 39pF - Can I substitute 39pF for 47pF on the Tardigrade (as per Palpigrade errata?) The 47pF are on backorder and considerably more expensive than 39pF. m
    8 x 100uF 10v Non Polar caps - are these the caps that can be substituted for the 10uF MKT on Tardigrade if lower input impedance is needed?
I’m going to be using the LM49720 on ±15V.

Thanks,

Dan

Re: Palpigrade Build Thread

Posted: Sat Sep 30, 2023 9:24 am
by Joe Malone
dan1b wrote:
Sat Sep 30, 2023 4:32 am
“Joe” wrote: C2 & C3 are 39pF not 47pF. 39pF gives 200kHz flat bandwidth.
Extra 39pF can be added under pcb to improve CMRR over whole audio bandwidth.
Joe Malone wrote:
Mon Nov 23, 2020 10:28 am

Palpigrade kit parts list

8 x 10k 4pin SIL
2 x 10R
8 x 100uF 10v Non Polar caps
24 x 39pF ceramic caps
Hi Joe,

I’ve ordered 1x Tardigrade kit + Tardigrade PCB + Palpigrade PCB to the UK.

Questions:
  • 10k 4pin SIL - Only 2% tolerance available over here for 4-pin SIL, is this suitable or should I substitute a matched pair of 10k 1% resistors?
    2x 10R - I assume these are 1W rated?
    24 x 39pF - Can I substitute 39pF for 47pF on the Tardigrade (as per Palpigrade errata?) The 47pF are on backorder and considerably more expensive than 39pF. m
    8 x 100uF 10v Non Polar caps - are these the caps that can be substituted for the 10uF MKT on Tardigrade if lower input impedance is needed?
I’m going to be using the LM49720 on ±15V.

Thanks,

Dan
2% sil or 1% metal film resistor will both work fine and fit. 10R are just normal 1/4w carbon. All 39pF should work fine. The Tardigrade has 1uF mkt. If you change to 10uF np the input impedance resistor can be changed from 100k to 10k