"It would show the residual filtered DC component you have in your mains."
I suggest the use of a large value resistor feeding an integrator cap.
I suggest the use of a large value resistor feeding an integrator cap.
I thought my different words were saying the same thing.
It's the difference in current one way cf the current in the other direction that creates the unbalance. That unbalance saturates the core, particularly if the core is already running at high flux.
OK So it is.
If you feeding an unbalanced current to a transformer, the transformer feels
it like a DC component and is saturating the core by the DC, not the total flux and makes mechanical noise!!
Johan
At the risk of abusing your expertise;
I am finally throwing together a test set-up of a DC Blocker, I am out in the sticks, so quick access to parts is limited to my electronics 'grave yard'.
Can I use a large 30 amp bridge ( MDA990-2) ? It only has a Reverse Voltage rating of 100 V. Given the type of connection, my thinking is this bridge will never 'see' more than just under 2 Volts.
I am finally throwing together a test set-up of a DC Blocker, I am out in the sticks, so quick access to parts is limited to my electronics 'grave yard'.
Can I use a large 30 amp bridge ( MDA990-2) ? It only has a Reverse Voltage rating of 100 V. Given the type of connection, my thinking is this bridge will never 'see' more than just under 2 Volts.
Erm Why Not just relocate the Contraption.. so It's goofy noises are well out of Earshot.
Nawww.. Too easy a 'fix'.
Nawww.. Too easy a 'fix'.
OK, after 66 posts, I have built a 'DC Blocker'. The bridge (above) with + connected to -. Two 20,000 uF , 40 V caps, reverse paralleled. This circuit had no effect on the noise level from the Toroid.
I had the circuit set up so it could be rapidly bypassed for comparison. (no difference)
I installed my Fluke DVM across the blocker and measured 1 mV or less with the meter set to DC, and about 90 mV AC, with the amp idling. I did see a spike in DC voltage when the Micro wave was started, but the DC Voltage returned to an almost immeasurable level within a fraction of a second, but the noise remained.
I had the circuit set up so it could be rapidly bypassed for comparison. (no difference)
I installed my Fluke DVM across the blocker and measured 1 mV or less with the meter set to DC, and about 90 mV AC, with the amp idling. I did see a spike in DC voltage when the Micro wave was started, but the DC Voltage returned to an almost immeasurable level within a fraction of a second, but the noise remained.
Attachments
Oh my God! 2.7VDC (230V/50Hz)
Weekend, Sunday, 11:45am
AC: 234.5V
DC
Scale 20V
DC: 2.7V !!!!!!!!!!!!!!!!!!!!!!!!!
Scale 2V
DC: -1 => I need scale 20V
Weekend, Sunday, 11:45am
AC: 234.5V
DC
Scale 20V
DC: 2.7V !!!!!!!!!!!!!!!!!!!!!!!!!
Scale 2V
DC: -1 => I need scale 20V
By the way, VDC ranges or varies continuously and very fast from + / - 2.7VDC (max) !
It should not be a fixed value, with little swing?
It should not be a fixed value, with little swing?
Hi Bare;
If my wife yells at me for talking to that blonde, and I just walk away, I have not really won the argument. I would like to make the amp quieter and keep it in the rack.
Andrew;
Parden the appearance of my thrown together setup, but electrically, it is the same as the Bryston 4B circuit. I still want to investigate the noise or DC situation on the line voltage, but has anyone ever treated the windings of a toroid trans, post manufacture?
Thanks all, for your patience. We may be coming full circle, but I usually don't give up until everyone is ticked off!
If my wife yells at me for talking to that blonde, and I just walk away, I have not really won the argument. I would like to make the amp quieter and keep it in the rack.
Andrew;
Parden the appearance of my thrown together setup, but electrically, it is the same as the Bryston 4B circuit. I still want to investigate the noise or DC situation on the line voltage, but has anyone ever treated the windings of a toroid trans, post manufacture?
Thanks all, for your patience. We may be coming full circle, but I usually don't give up until everyone is ticked off!
Yes there were a couple of reports on trying to impregnate windings of transformers.
Ordinary varnish will not work well.
The big problem is getting the transformer impregating resin inside the insulation to fill all the air spaces. Vac/Vac impregnation is good at sucking the air out to be replaced with resin.
Then you have to cook it till the resin sets.
Probably need to repeat to fully satuarte the outer windings.
Almost no hope od saturating the inner windings due to too many layers of tightly wound Prim to Secondary insulation. Absolutely no hope of impregating the toroid core.
Ordinary varnish will not work well.
The big problem is getting the transformer impregating resin inside the insulation to fill all the air spaces. Vac/Vac impregnation is good at sucking the air out to be replaced with resin.
Then you have to cook it till the resin sets.
Probably need to repeat to fully satuarte the outer windings.
Almost no hope od saturating the inner windings due to too many layers of tightly wound Prim to Secondary insulation. Absolutely no hope of impregating the toroid core.
Sunday 20:00 pm
AC: 236.5V
DC: +/- 2.1V
The transformer is more cold that this morning and... the sound is better!
More cold => COLD
AC: 236.5V
DC: +/- 2.1V
The transformer is more cold that this morning and... the sound is better!
More cold => COLD
Last edited:
Thanks Andrew and maty;
Do you have any more clues on how I could find those articles regarding the impregnating of the windings?
Thanks again, Peter
Do you have any more clues on how I could find those articles regarding the impregnating of the windings?
Thanks again, Peter
Hi Simon,
I will check voltage tonight, transformer is quiet during 'soft start' then hums (buzzes) when the speaker relays pull in.
As mentioned noise increases when a microwave on different breaker is used, but no DC could be measured across my Blocker circuit.
I will check voltage tonight, transformer is quiet during 'soft start' then hums (buzzes) when the speaker relays pull in.
As mentioned noise increases when a microwave on different breaker is used, but no DC could be measured across my Blocker circuit.
i haven't found it yet, but i seem to remember a little tidbit in passing from Nelson about a little resistance like that from a CL60 in the primary to do a "soft start" may help quiet some trannys.
mlloyd1
mlloyd1
My line voltage is 124 VAC at the moment. A little on the high side, My Phase Linears with E+I trannies and the Yamaha P2200 with a Toroid are dead quiet. I am tempted to put my scope with a 10 to 1 probe, on the line, don't know if there is any point to that.
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