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Re: Regurgitator kit Build Thread

Posted: Sun Aug 26, 2018 2:48 pm
by tlhpsound
OK. Thanks. I ordered another kit to pair them as stereo. To connect two boards side by side, do I need to connect all pins 1 to 5 of J1 header on one board with the corresponding pins 5 to 1 on J2 on the second?

Can I use OP275? With OP275, what voltage is optimum?

Re: Regurgitator kit Build Thread

Posted: Sun Aug 26, 2018 4:26 pm
by Joe Malone
tlhpsound wrote:OK. Thanks. I ordered another kit to pair them as stereo. To connect two boards side by side, do I need to connect all pins 1 to 5 of J1 header on one board with the corresponding pins 5 to 1 on J2 on the second?

Can I use OP275? With OP275, what voltage is optimum?
You only need J1 to J2 pins 1 to 3 or 3 to 5 but all 5 will work fine.

OP275 is work well up to +/-18vdc

Re: Regurgitator kit Build Thread

Posted: Sat Sep 08, 2018 4:03 pm
by tlhpsound
OK. Thanks. I have another question. I ordered these kits as a make up gain for a stereo volume pot which I want to place after the DAC module. The application is a DIY car stereo using a Linux chip-on-the-board PC. I do not know the output impedance of the DAC. What would be the optimal impedance of the pot? I am looking at a 50k pot. Would this kind of configuration work?

Re: Regurgitator kit Build Thread

Posted: Mon Sep 10, 2018 12:25 pm
by Joe Malone
tlhpsound wrote:OK. Thanks. I have another question. I ordered these kits as a make up gain for a stereo volume pot which I want to place after the DAC module. The application is a DIY car stereo using a Linux chip-on-the-board PC. I do not know the output impedance of the DAC. What would be the optimal impedance of the pot? I am looking at a 50k pot. Would this kind of configuration work?
A DAC will usually run 2k loads so a 5k to 10k log volume pot between the dac output and regurg +in should work perfectly with the regurg giving you makeup gain and balanced output.

Re: Regurgitator kit Build Thread

Posted: Thu Sep 13, 2018 11:51 am
by tlhpsound
OK. Thank you. One more question, please. What level of max. attenuation do you recommend on the pot? 50 dB is good? The spec of the DAC I am going to use is in the link below.

https://dl.khadas.com/Hardware/ToneBoar ... _Specs.pdf

Re: Regurgitator kit Build Thread

Posted: Thu Sep 13, 2018 1:28 pm
by Joe Malone
tlhpsound wrote:OK. Thank you. One more question, please. What level of max. attenuation do you recommend on the pot? 50 dB is good? The spec of the DAC I am going to use is in the link below.

https://dl.khadas.com/Hardware/ToneBoar ... _Specs.pdf
If you want the pot to work as volume then wire the bottom of the pot to 0v ground and it will work as a normal full off to full on volume which is usually roughty -90 to 0. If you want to limit the off range you will need a extra resistor under the pot to 0v to stop it going fully off.

Re: Regurgitator kit Build Thread

Posted: Sun Sep 16, 2018 2:32 pm
by tlhpsound
Hi. I received the second kit. I compared it with the first one and noticed a minor difference. The second one has no beige component parts on Z01 and Z02. The first one does have parts in place. Is it intentional? Or it's an error?

Re: Regurgitator kit Build Thread

Posted: Sun Sep 16, 2018 3:36 pm
by Joe Malone
tlhpsound wrote:Hi. I received the second kit. I compared it with the first one and noticed a minor difference. The second one has no beige component parts on Z01 and Z02. The first one does have parts in place. Is it intentional? Or it's an error?
When the ZD1 & 2 are not fitted sometimes the guys here fit extra mono caps there but either way will work fine.

Re: Regurgitator kit Build Thread

Posted: Sun Sep 16, 2018 9:19 pm
by tlhpsound
What is the purpose of adding mono caps there? As a stereo pair, is not it better that both have caps (or both don't)?

Re: Regurgitator kit Build Thread

Posted: Sun Sep 16, 2018 9:32 pm
by Joe Malone
tlhpsound wrote:What is the purpose of adding mono caps there? As a stereo pair, is not it better that both have caps (or both don't)?
If you are powering them together from one power supply they share the caps anyway as they are just extra smoothing to the +/- rails. Feel free to cut the 1uF caps off or add 1uF to the other module either way it will not make any difference with NE5532A they are not needed at all.

When we used OPA2604AP which is no longer available we would add these caps as stabilize that very unstable that opamp.

Re: Regurgitator kit Build Thread

Posted: Sun Dec 02, 2018 12:53 pm
by tlhpsound
If I wire a pair of 600 ohm/600 ohm transformers to the outputs of DAC, can I use a log volume pot of 50k or higher? Or I should still use a 5K to 10K pot? I like the effect of the transformer.
Joe Malone wrote:
tlhpsound wrote:OK. Thanks. I have another question. I ordered these kits as a make up gain for a stereo volume pot which I want to place after the DAC module. The application is a DIY car stereo using a Linux chip-on-the-board PC. I do not know the output impedance of the DAC. What would be the optimal impedance of the pot? I am looking at a 50k pot. Would this kind of configuration work?
A DAC will usually run 2k loads so a 5k to 10k log volume pot between the dac output and regurg +in should work perfectly with the regurg giving you makeup gain and balanced output.

Re: Regurgitator kit Build Thread

Posted: Sun Dec 02, 2018 1:16 pm
by Joe Malone
tlhpsound wrote:If I wire a pair of 600 ohm/600 ohm transformers to the outputs of DAC, can I use a log volume pot of 50k or higher? Or I should still use a 5K to 10K pot? I like the effect of the transformer.
Joe Malone wrote:
tlhpsound wrote:OK. Thanks. I have another question. I ordered these kits as a make up gain for a stereo volume pot which I want to place after the DAC module. The application is a DIY car stereo using a Linux chip-on-the-board PC. I do not know the output impedance of the DAC. What would be the optimal impedance of the pot? I am looking at a 50k pot. Would this kind of configuration work?
A DAC will usually run 2k loads so a 5k to 10k log volume pot between the dac output and regurg +in should work perfectly with the regurg giving you makeup gain and balanced output.
Balanced input is twice the impedance so pot value can double but 50k log pot is a bit high and will change the log curve a lot. Keeping the pot low like 5k or 20k is better for the correct curve and lower noise.

Re: Regurgitator kit Build Thread

Posted: Sun Jan 12, 2020 6:43 am
by JGale
Hello All.

Is it possible build a Regurgitator as BAL-in to BAL-out with Gain?

Will this then serve to increase the apparent loudness of the 60 Watt AMPkit without overloading anything?

Thanks in advance.

- A tube amp tinkerer and Solid State Novice.

Re: Regurgitator kit Build Thread

Posted: Sun Jan 12, 2020 10:07 am
by Joe Malone
Yes regurg kit is made to do bal in to bal out with up to 18dB gain.

If using our 60w amp kit you can get more gain from the amp by making the 1k resistor small value. Also if not using the volume control on the amp kit use the volume+/- as the audio input instead to get a few dB more gain from the amp.

Re: Regurgitator kit Build Thread

Posted: Sun Mar 08, 2020 1:05 am
by earthsled
I am working on a html sheetsheet using a formula Rob sent me so this can be more easily calculated by anyone.
Hi Joe - just wondering if this html sheet ever was finished/posted? I'm interested in calculating fixed resistances in place of the trim pot for various levels of gain on the Regurgitator. Perhaps you could share the formula? Thanks for your help!