Aaaargh. Ridiculous. I had a cold joint on one of the TPs - I measured directly on one 1 ohm resistor. It works fine, now.
Ah, the sound is superb. Thank you, Mr. Pass.
Ah, the sound is superb. Thank you, Mr. Pass.
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Hi All,
My F5 Turbo V2 is silent..... Speaker connected. although when my pre-amp is connected with the F5 it hums loud, there is also a little bit of sharpness in it.
I can not figure out where this hum comes from. The interconnects do not interfere, cables only connected at the power-amp gives no hum. I think it's a Ground-loop triggered by the Pre-amp. today I did tried several things.
My pre-amp is a BA3 FE stage powered by a Powersupply PCBv3 @24V. I made a star ground, and installed a relay volume controle.
BA3 is biased at 1V over R10-R11 and about 20mV DC (meaasusred before CAP en gnd) over R12 there is no DC
The B1 was in and I used this one also to check whether there is a Hum.... And it was..🙁
Since I was testing, I only connected the Main input and output. So try to look trough the Spagetti😉
All suggestions are welcome
Nils
I had the same exact problem on one channel of a different amp.
It turned out that I had soldered rca positive signal input to ground on the pcb.
Check all your wiring.
Hi All,
My F5 Turbo V2 is silent..... Speaker connected. although when my pre-amp is connected with the F5 it hums loud, there is also a little bit of sharpness in it.
I can not figure out where this hum comes from. The interconnects do not interfere, cables only connected at the power-amp gives no hum. I think it's a Ground-loop triggered by the Pre-amp. today I did tried several things.
My pre-amp is a BA3 FE stage powered by a Powersupply PCBv3 @24V. I made a star ground, and installed a relay volume controle.
BA3 is biased at 1V over R10-R11 and about 20mV DC (meaasusred before CAP en gnd) over R12 there is no DC
The B1 was in and I used this one also to check whether there is a Hum.... And it was..🙁
Since I was testing, I only connected the Main input and output. So try to look trough the Spagetti😉
All suggestions are welcome
Nils
yes it is a ground loop. how is the amp grounded? is it stereo or dual mono?
yes it is a ground loop. how is the amp grounded? is it stereo or dual mono?
Amp has a star GND which is connected to the Chassis via a NTC. see pic 1
I did remove the PSU and BA-3 FE and now the noise is reduced to a level that it is barely audible at listening position. But still there is a little noise. Again disconnected Pre the F5T is silent
Nils
Attachments
pictures of amp's gut
Need a special aria taken pictures of?
Attachments
9 wire connections onto that copper Zero Volts plate look very suspicious.
Power zero volts in could be two wires.
Power zero volts out could be two wires.
Safety connection to Chassis is one wire.
What are the other 4 wires?
I hope none of them are AUDIO references !
The audio references MUST NOT go to the PSU zero volts. This plate passes huge charging current pulses.
Those current pulses will contaminate the audio if wrongly connected.
Power zero volts in could be two wires.
Power zero volts out could be two wires.
Safety connection to Chassis is one wire.
What are the other 4 wires?
I hope none of them are AUDIO references !
The audio references MUST NOT go to the PSU zero volts. This plate passes huge charging current pulses.
Those current pulses will contaminate the audio if wrongly connected.
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where do you see 9 wires Andrew? i only see 5. 1 from each speaker Return. 1 from each amp ch. and one going to chassis ground.
there is ofcourse 2 wires comming from the 2 bridges and 2 connections from the bleeder resistors.
there is ofcourse 2 wires comming from the 2 bridges and 2 connections from the bleeder resistors.
the 2 bare leads are the bleeder resistors. 1G/Y is chassis ground. the 2 white close to the transformer is from the bridges. the 2 whites at the center is from the amp boards. the 2 blue are speaker return.
it's all good.
it's all good.
the starground IS the MAG.
but yes, it could be seperated from the PSU. but that is not the noise issue.
but yes, it could be seperated from the PSU. but that is not the noise issue.
locating the MAG on the pulse carrying PSU plate is usually the hum and buzz problem.
Wijgers,
Do you want to confirm what those wires are?
The audio references MUST NOT go to the PSU zero volts. This plate passes huge charging current pulses.
Those current pulses will contaminate the audio if wrongly connected.
Wijgers,
Do you want to confirm what those wires are?
What's up with that grey wire between the transformer and the front plate? Looks like it's forming a loop at first glance.
locating the MAG on the pulse carrying PSU plate is usually the hum and buzz problem.
Wijgers,
Do you want to confirm what those wires are?
if that was the problem, the hum/noise would be present even without a preamp connected.
you're probably right.if that was the problem, the hum/noise would be present even without a preamp connected.
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