[nattonrice]

RK50 

 
Good form!
 
Edit1: Directed at Doug
 
Edit2: My post #888! My Chinese side rejoices in your amp's good fortune! 

 

[Victor Chew]

John, 2 pieces of 2amp each in series. That should reduce the inrush current by quite a bit before it hits the transformer. 
What are your thoughts on it? I believe Kevin did recommend this at the KGSSHV, Balanced Dynahi Rec A and Dynafet board run page 6.
 
I was also thinking of putting a high rated cap in series at the mains to block any potential incoming dc causing saturation to the transformer.
 
HDman, place the thermistor at the live. IEC to thermistor to switch.      

 

[HDMan]

Quote:

 
HDman, place the thermistor at the live. IEC to thermistor to switch.      

 
K, thanks.
 
I was reading that soldering the thermistor can cause failure from repeated heating and cooling of the solder joint, what are your thoughts?
 
What is the best way to mount it?

 

[deadlylover]

Quote:

I was reading that soldering the thermistor can cause failure from repeated heating and cooling of the solder joint, what are your thoughts?
 
What is the best way to mount it?

 
Solder it, that's what the datasheet said.

 

[HDMan]

I used a 4 piece connector, buzzing noise from the transformer is still there. Sounds like a normal issue with the SumR.
 
I got this from google:
 
Where does the constant humming sound come from in transformers?


Answer

Most transformers make some audible sound at the frequency of the current they're operating on, for transformers running on utility power in the US this is 60 Hz. The sound is due mostly to the wire in the transformer coils and the steel in the transformer core vibrating at 60 Hz because of the interaction of the magnetic fields of these components. Some of this sound may also be due to something called magnetostriction in which the steel of the core actually expands and contracts with the fluctuating magnetic field.
 
 
 
Actualy after more than 1 hour operation with the lid on, i can only just hold onto heatsinks for 5 seconds. I am going to get an IR thermometer.

 

[gilency]

Quote:

 
 
HDman, place the thermistor at the live. IEC to thermistor to switch.      

Do you use only one or a total of 2?

 

[HDMan]

Noise in the headphones turned out to be the stax jack, amphenomal metal pins are realy loose, i had to do a realy tight job on soldering and heatshrink to get it tight. I see why everyone is using teflon stax connectors, can't wait to get some from Spritzer.

 

[Victor Chew]

Quote:

Do you use only one or a total of 2?

I would use 2 in series.

 

[Victor Chew]

Quote:

 
K, thanks.
 
I was reading that soldering the thermistor can cause failure from repeated heating and cooling of the solder joint, what are your thoughts?
 
What is the best way to mount it?

Thermistor works by increasing resistance when heat goes up. That way as resistance goes up it will block big rate of flow (ie. current) before it reaches the transformer. If the heat goes too high for the thermistor it will melt - like a fuse. Inshort, it is an "intelligent fuse".
 
As far as I my limited knowledge goes,Torriodal transformer are more susceptable to saturation and buzzing. If you can hear it 3 feet away, that for me is not on. The buzzing is not dangerous to the equipment though, but irritating. However, over prolong periods of friction the coil insulation may be taken out and a short may occur. 

 

[gilency]

​

Victor, let me be sure I understand, you use to thermistors in series in the same wire or one thermistor per wire between the IEC and the transformer ?
And if I have a relay with the e24' is he thermistor really necessary?

 

[Victor Chew]

Quote:

 
Victor, let me be sure I understand, you use to thermistors in series in the same wire or one thermistor per wire between the IEC and the transformer ?
And if I have a relay with the e24' is he thermistor really necessary?

That depends. Amb site posted , "[size=x-small]An optional sensing loop employing thermal breakers can be used with the ε24, so that in the event of device overheat, it will be automatically shut off". If you have that you should not need additional thermistor.[/size]

 

[johnwmclean]

Quote:

That depends. Amb site posted , "[size=x-small]An optional sensing loop employing thermal breakers can be used with the ε24, so that in the event of device overheat, it will be automatically shut off". If you have that you should not need additional thermistor.[/size]

 
The ε24 does not provide any inrush protection, the ε24’s thermal sensing circuitry provides automatic shutdown from overheating i.e. intended for output devices.
 
 
 

 

[Victor Chew]

Thanks John. I stand corrected then.

 

[HDMan]

Replaced the black knob with a silver one, much nicer looking. The letters are to big, have ordered some small font and volume stripes. And a Danger High Voltage sign for the back panel (hole) that was cut out.
 

 

[Forte]

Nice, Where are you ordering  the lettering from?