Well Salas, I explaint you:
Before connected:
-Mains earth external PSU to chassis Itch box not the same where is connected the signal GND
-Tonearm GND only connected to other chassis GND and not connected to signal GND
-Itch signal GND connected to chassis trought a ground loop breaker (see Rod Elliot attached schematic) but not connected to the mains earth PSU.
Now:
-Mains earth external PSU to chassis Itch box sharing the same point as signal GND
-Tonearm GND connected to signal GND input RCA of Itch
-Signal GND connected to chassis trought ground loop breaker at the same point like mains earth PSU
Scope don't show any trace of ripple or any other strange, now time to listening if the buzz is gone
Before connected:
-Mains earth external PSU to chassis Itch box not the same where is connected the signal GND
-Tonearm GND only connected to other chassis GND and not connected to signal GND
-Itch signal GND connected to chassis trought a ground loop breaker (see Rod Elliot attached schematic) but not connected to the mains earth PSU.
Now:
-Mains earth external PSU to chassis Itch box sharing the same point as signal GND
-Tonearm GND connected to signal GND input RCA of Itch
-Signal GND connected to chassis trought ground loop breaker at the same point like mains earth PSU
Scope don't show any trace of ripple or any other strange, now time to listening if the buzz is gone
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Headphones listening is the most sensitive to buzz. Means its not coming from the Itch source anymore. If buzz will appear on loudspeakers then it will be interconnection ground loop or internal problem to be looked for in the other units. Best chance is there should be no more buzz.
Hi Salas,
as announced in the njfet thread i´m about to go with the ValveItch.
Todays job was to search for all those parts in my boxes - nearly every-
thing is there exept for the IR-Diodes (will be ordered) and the 6sn7 tubes.
Are there alternative tubes for those? Maybe with noval socket?
Greetings
as announced in the njfet thread i´m about to go with the ValveItch.
Todays job was to search for all those parts in my boxes - nearly every-
thing is there exept for the IR-Diodes (will be ordered) and the 6sn7 tubes.
Are there alternative tubes for those? Maybe with noval socket?
Greetings
Unfortunately that's a system interfacing buzz problem that I can not positively guess from afar. Keep on trying different grounding policy until it will interface well (?) Also check the output capacitors in case they developed DC leak (?) because there is some pot scratch I also heard
Salas one DC heater is chassis grounded & the other is floating where the B+ is floating, can be the source of noise?
No, it should not be on B+, in the original psu design there is a heater lift divider across B+ to tap for that purpose (B+470k:220k//47uFground)
V1 V2 valves (as named in V1.2 schematic) have their heaters connected directly to ground.
V3 V4 have them connected at the lifter between its two resistors. There's no hum by heater lifting. Its there not to allow higher than the tube's max spec for cathode to heater potential which would otherwise happen in the μ follower's top tubes if their heater was directly grounded.
V3 V4 have them connected at the lifter between its two resistors. There's no hum by heater lifting. Its there not to allow higher than the tube's max spec for cathode to heater potential which would otherwise happen in the μ follower's top tubes if their heater was directly grounded.
Heaters GND valves V1 V2 aren't connected to signal ground were connected to chassis GND trought SLB so now corrected to:
1-Connected DC heaters valves V1 & V2 to signal GND trought Bus signal GND
2-Bus signal ground connected to chassis trought SLB at the output sockets RCA signal GND only one wire
3-Separate neutral AC mains earth
4-TT GND wire connected to chassis GND in other single point chassis and connected to input sockets RCA signal GND
Waiting to solve the issue
No buzz in headphones, waiting tomorrow to connect the loudspeakers.
1-Connected DC heaters valves V1 & V2 to signal GND trought Bus signal GND
2-Bus signal ground connected to chassis trought SLB at the output sockets RCA signal GND only one wire
3-Separate neutral AC mains earth
4-TT GND wire connected to chassis GND in other single point chassis and connected to input sockets RCA signal GND
Waiting to solve the issue
No buzz in headphones, waiting tomorrow to connect the loudspeakers.
What happened with buzz when connected to pre+power amp on speakers?
Salas was pin 1 problem of balanced Erno Borbely mono amps, mine friend Angel forgot to connect input signal RCA to chassis.
NOW ZERO NOISE!!!!
I'm ultra happy
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