Excuse me for not being completely clear. I mean the problem also excist when my pre amp is switched off and or completely disconnected from the mains. Only need to connect both of the interconnect cables.
Hi Mark
Try to add 1 uH inductor to each amp's output in series with +SPK wire (outside chassis).
Also try to connect interconnect cables to CD player at stop mode, just to see if the input problem exist with different source, other than preamp.
Try to add 1 uH inductor to each amp's output in series with +SPK wire (outside chassis).
Also try to connect interconnect cables to CD player at stop mode, just to see if the input problem exist with different source, other than preamp.
Thanks Andrej. I probably have some 1.4 mm square air coils around. I could use the wire from them to make 1 uH new coil. Or does it need bigger diameter wire? Any tips for the diameter of the coil as I have no experience with it.
Pumping in system environment
I didn't catch which revision level is proving troublesome here... is this sort of 'system sensitivity' applicable to all revisions, or only 1.2 or 1.3?
Cheers
I didn't catch which revision level is proving troublesome here... is this sort of 'system sensitivity' applicable to all revisions, or only 1.2 or 1.3?
Cheers
To none of them, it's just a quick advice to test a troublesome cabling, ground loop or something else which causing a problem in a Mark's system.
I have connected my Pass B1 buffer between my DAC and FO, this completely solved my problems. I want to investigate further why I can't run my DAC directly to FO. I've used it this way with several other power amps without trouble. My DAC uses exactly the same output stage as the Audio Note M3 and M5 pre amps.
But after some struggling I am happy to be able to listen to music again.
So your DAC uses line transformers on the outputs, their secondaries could be completely floating, no GND reference, just thinking, not knowing the exact sch.
That could be a problem, as both FO channels form a loop from their inputs to outputs, causing infra low frequency oscillation (LC resonant circuit) and that explain why problem arise only after both interconnects applied to the output line transformers, making loop to be formed.
BTW what is your digital source, CD transport, network streamer? What model of loudspeakers are now in the system?
The secondaries are indeed completely floating... What can I do? Just connecting both channel ground together at the RCA output terminals? Or is it needed to connect the ground from the secondaries to the chassis? (via resistor?)
Digital sources:
- MacMini with Amarra via USB to battery powered Audiophilleo AP2 USD/SPDIF converter
- CEC TL2X transport
Loudspeakers:
- Speaker Heaven Edition30 (ScanSpeak alu 25cm woofer, mid and high Accuton ceramic) EXTREMELY good (the best I've ever experienced) value for money.
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Mark, does DAC have balanced XLR or single ended RCA connectors for analog output?
Cold or minus phase from transformer's secondary of each channel should be referenced to GND, similar as XLR to RCA adapter schematics.
Cold or minus phase from transformer's secondary of each channel should be referenced to GND, similar as XLR to RCA adapter schematics.
I have RCA connectors and XLR connectors. My OPT's secondaries have the following connections:
-VE Phase
+VE Phase
Ground
I've wired the ground connection from OPT to ground of RCA and +VE Phase is connected to center connection of RCA. As suggested by AN.
-VE Phase isn't connected to anything.
If I understand correctly, you are suggesting connecting -VE Phase wire coming from OPT to the ground wire coming from OPT, when using RCA outputs. Is this correct?
Thanks!
Mark.
-VE Phase
+VE Phase
Ground
I've wired the ground connection from OPT to ground of RCA and +VE Phase is connected to center connection of RCA. As suggested by AN.
-VE Phase isn't connected to anything.
If I understand correctly, you are suggesting connecting -VE Phase wire coming from OPT to the ground wire coming from OPT, when using RCA outputs. Is this correct?
Thanks!
Mark.
Use your XLR output with a symmetrical shielded wire. Rely ground and -VE in the RCA that goes in the input of your amp.
Unfortunately that didn't work either...
Could it help if I place a resistor (eg. 200k) between +VE and ground?
Other suggestions to try?
That only means GND pin of XLR is not connected to GND reference potential of DAC itself. GND is a reference zero potential of both DAC channels or that's what it should be.
Andrej,
The ground pin of XLR is coming from secondary side of transformer. Center tap = ground for analog output connectors. It's not connected to chassis. Should I connect it to chassis?
Isn't it made floating deliberately to avoid digital noises at the analog output?
Mark.
The ground pin of XLR is coming from secondary side of transformer. Center tap = ground for analog output connectors. It's not connected to chassis. Should I connect it to chassis?
Isn't it made floating deliberately to avoid digital noises at the analog output?
Mark.
you mean the primary ? The secondary in the XLR is supposed to be floating.
Ground at pin 1, signal, 2 & 3.
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In my DAC the secondary side of the Output Transformers are connected to the XLR output connectors like this:
-VE is connected to Pin 3
+VE is connected to Pin 2
Center Tap is connected to Pin 1
The secondary side is floating.
-VE is connected to Pin 3
+VE is connected to Pin 2
Center Tap is connected to Pin 1
The secondary side is floating.
LC,
Will there be balanced inputs for FO modules some day, so we could build a balanced amplifier without wasting double amount of modules and power? I am using a balanced 8 channel DAC with my active 4 way system and want to use FO for 6 channels (110hz-500hz, 500hz-3khz, 3khz and up) and class D for subs. Currently I am shorting minus and ground inputs to use 2 channel FO with my DAC.
Will there be balanced inputs for FO modules some day, so we could build a balanced amplifier without wasting double amount of modules and power? I am using a balanced 8 channel DAC with my active 4 way system and want to use FO for 6 channels (110hz-500hz, 500hz-3khz, 3khz and up) and class D for subs. Currently I am shorting minus and ground inputs to use 2 channel FO with my DAC.