DACgy Posted July 5, 2018 Share Posted July 5, 2018 Hello, Need to consult, first time user on this forum and received two stepped attenuators yesterday from Chicago Electronics. I purchased two of them but one is defective I believe. One works well while the other has a problem with the left channel with no output. System connection: RPI with DigiOne -->RCA-->DAC-->Right channel -->Stepped attenuator IN (R) Stepped attenuator O (R) --> amp input R -->GND-->GND (R) -->Left channel -->Stepped attenuator IN (L) Stepped attenuator O (L) --> amp input L -->GND-->GND (L) Tried swapping the working right channel input to the left channel of the stepped atteunuator, but still no output on left. Measured stepped attenuator Left IN to gnd, ok @ 10K ohms on all positions while output to gnd corresponds to various Resistance value at each step. Right channel measures identically for practical purposes. There is one suspicious measurement - GND (R) to GND (L) measures 10K ohm in any switch positions. Shouldn't this be at infinite? There shouldn't be any connection to each GND? The other good attenuator measures infinite. DACgy Link to comment
4est Posted July 5, 2018 Share Posted July 5, 2018 Likely the opposite of infinite- zero. Wired backwards perhaps if using 10K pots? A picture is worth the effort. Debugging verbally is/can be awful. Forrest: Win10 i9 9900KS/GTX1060 HQPlayer4>Win10 NAA DSD>Pavel's DSC2.6>Bent Audio TAP> Parasound JC1>"Naked" Quad ESL63/Tannoy PS350B subs<100Hz Link to comment
DACgy Posted July 5, 2018 Author Share Posted July 5, 2018 That is very interesting, that makes logical sense. Thanks for the quick reply. Yes, that is a 10K version. So if this is the case, it may be the only wiring in there (green & black) may be soldered incorrectly at the wrong points. It's a bit difficult to inspect since all parts are soldered tightly. I will try an get a return authorization from Chicago Electronics but fine prints says I will have to consult Allo engineers here at the forum and try to resolve issues first. But I don't think I want to desolder a defective unit to correct it's fault since it was new and unused from factory. Link to comment
4est Posted July 5, 2018 Share Posted July 5, 2018 Good luck! Forrest: Win10 i9 9900KS/GTX1060 HQPlayer4>Win10 NAA DSD>Pavel's DSC2.6>Bent Audio TAP> Parasound JC1>"Naked" Quad ESL63/Tannoy PS350B subs<100Hz Link to comment
ALLOsupport Posted July 6, 2018 Share Posted July 6, 2018 15 hours ago, DACgy said: Hello, Need to consult, first time user on this forum and received two stepped attenuators yesterday from Chicago Electronics. I purchased two of them but one is defective I believe. One works well while the other has a problem with the left channel with no output. System connection: RPI with DigiOne -->RCA-->DAC-->Right channel -->Stepped attenuator IN (R) Stepped attenuator O (R) --> amp input R -->GND-->GND (R) -->Left channel -->Stepped attenuator IN (L) Stepped attenuator O (L) --> amp input L -->GND-->GND (L) Tried swapping the working right channel input to the left channel of the stepped atteunuator, but still no output on left. Measured stepped attenuator Left IN to gnd, ok @ 10K ohms on all positions while output to gnd corresponds to various Resistance value at each step. Right channel measures identically for practical purposes. There is one suspicious measurement - GND (R) to GND (L) measures 10K ohm in any switch positions. Shouldn't this be at infinite? There shouldn't be any connection to each GND? The other good attenuator measures infinite. DACgy Resistance measurement , stepped attenuator GND(L) and GND(R) no connection on Stepped Attenuator unit. The GND is connecting common at Amplifier side / Dac side. 1) All wires disconnected case GND(L) & GND(R) infinitive - from your explanation this not meeting . clarify. 2) Resistance you can measure in between L (IN) and L(O) or L(GND) and L (O) , it will vary from 0 to 10k , L(IN) & L(GND) always 10k or near to 10k value. Allo.com Tech. Support Link to comment
DACgy Posted July 6, 2018 Author Share Posted July 6, 2018 Hello Allo, The unit has miswiring: Right portion is not isolated to Left portion. Here are the measurements: Left Right Measurements (Ohms) GND GND 10K Any position GND IN 20K Any position GND OUT at Min = 10K at Max = 20K IN GND 20K Any position IN IN 10K " IN OUT @ Min = 2 ohms, @ Max = 10K OUT GND @ Min = 10k, In between = various, @ Max = 2 ohms OUT IN @ Min = 20K, In between = 12K to 19K, @ Max = 10K OUT OUT 10K Any position Here are the photos attached. Link to comment
4est Posted July 6, 2018 Share Posted July 6, 2018 1 hour ago, DACgy said: Hello Allo, The unit has miswiring: Right portion is not isolated to Left portion. Here are the measurements: Left Right Measurements (Ohms) GND GND 10K Any position GND IN 20K Any position GND OUT at Min = 10K at Max = 20K IN GND 20K Any position IN IN 10K " IN OUT @ Min = 2 ohms, @ Max = 10K OUT GND @ Min = 10k, In between = various, @ Max = 2 ohms OUT IN @ Min = 20K, In between = 12K to 19K, @ Max = 10K OUT OUT 10K Any position Here are the photos attached. Interesting device there. Is that some sort of rolled ribbon with resisters soldered on? I'd love to see a close up of it. Oh, I see it now. Little PCB. Neat! Forrest: Win10 i9 9900KS/GTX1060 HQPlayer4>Win10 NAA DSD>Pavel's DSC2.6>Bent Audio TAP> Parasound JC1>"Naked" Quad ESL63/Tannoy PS350B subs<100Hz Link to comment
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