Agree, Birgir 100%.  This phase splitter measured like shit on the scope.  But there are situations that I need SE.  Like for testing, it's a pita to haul my Yggy out , so a SE CD player would have to do.  Will switch the power to the splitter off when using XLR when all tests are done.

But you just install a switch which grounds the - input for SE.  Hell, just make two XLR plugs with pins 1 and 3 tied internally. 

Edited June 29, 20169 yr by spritzer

I use two of these: http://www.neutrik.com/en/accessories/circular-adapters/na2mpmf

Can confirm. The Neutrik RCA to XLR plugs work really well. 

That phase splitter sounds like an over-engineered underachiever......  

Needs a judicious application of Occam's razor......   

I changed the LT1021-5 for LT1021-10. Now, psu it´s fine. 

HV: 402,5 volt. / -401,5 volt

Bias, 578 volt.

LV: 15,4 volt/ -15,1 volt.

Thanks

 

 

 

On 6/28/2016 at 1:15 PM, mwl168 said:

I am fairly certain I've measured similar effect of my Carbon which I have been listening to on and off for months without issue.

I do disconnect my headphone before power on and off.

Was listening to my Carbon/009 tonight and before I shut it down I measured the offset. I have the opto servo engaged and the offset was hovering under 1 VDC while the amp is on. Upon shutting down the power, within a second or two, the offset shot up to just under 200 VDC and gradually declined from there. 

I plan to disable the opto servo and when I do that I will measure the offset again and report back.

I though Birgir said it doesn't matter as long as it is positive and the stax amps do it too? But certainly interesting to hear if the servo has an influence. 

Nothing to do with the servo being enabled or not.
They all swing towards B+ at power up/down.

5 hours ago, mwl168 said:

I plan to disable the opto servo and when I do that I will measure the offset again and report back.

While experimenting - shut down HV with LV remaining and see what happens.

6 hours ago, JoaMat said:

While experimenting - shut down HV with LV remaining and see what happens.

Will do. 

It may be a while before I get around to it - have been working on resolving a noisy I2S connection problem for the past month.

Ok, I´m ready to check it.

 

First start. I'm not lucky

I have all VRs adjusted to mid point

I turn on R channel; both leds shine. A second later, led arround PZTA56, don´t shine (+rail). Turn off the amp and the this led shine again!!! (until the capacitor discharges). The Led arround PZTA06 shine all time. Check Volt on + rail: 1,5 volt. Volt on - rail: -15 volt. No smoke or blown.

L channel, it´s similar to R; the same led is shining and then stop.

 

 

56 minutes ago, jose said:

First start. I'm not lucky

I have all VRs adjusted to mid point

I turn on R channel; both leds shine. A second later, led arround PZTA56, don´t shine (+rail). Turn off the amp and the this led shine again!!! (until the capacitor discharges). The Led arround PZTA06 shine all time. Check Volt on + rail: 1,5 volt. Volt on - rail: -15 volt. No smoke or blown.

L channel, it´s similar to R; the same led is shining and then stop.

 

 

you might check your low voltage ... have the CT been connected correctly?

the 7815 Fairchild that I use have thermal overload protection, so if anything is shorted (or massively wrong) that would explain the voltage drop.

Does it get HOT?

Edited July 8, 20169 yr by congo5

Thanks guys. Yesterday I was until 2 AM checked the amps. All components is OK, correct solders, all conections OK. Finally, I moved the trafo wires and I saw something, when I moved it the led shine sometimes. I saw that the PSU socket was rare: I desoldered this piece and a pin on the socket base was broken.

I don´t remember too tightly. I had had chinese sockets with this problem but not a Phoenix.

So I turned on and all was OK. Leds shine, volt ok. I adjusted the current to 1 volt (20 mA) and then I went to sleep.

Tonight I´m working with the balance and off set.

Thanks for your patience.

Edited July 8, 20169 yr by jose

8 minutes ago, jose said:

Thanks guys. Yesterday I was until 2 AM checked the amps. All components is OK, correct solders, all conections OK. Finally, I moved the trafo wires and I saw something, when I moved it the led shine sometimes. I saw that the PSU socket was rare: I desoldered this piece and a pin on the socket base was broken.

I don´t remember too tightly. I had had chinese sockets with this problem but not an IC&C.

So I turned on and all was OK. Leds shine, volt ok. I adjusted the current to 1 volt (20 mA) and then I went to sleep.

Tonight I´m working with the balance and off set.

Thanks for your patience.

which pin?

1 minute ago, sorenb said:

which pin?

CT pin.

I feel like a stupid . Spend two hours to review all and spend your time too

 

 

Just now, jose said:

CT pin.

I feel like a stupid . Spend two hours to review all and spend your time too

 

 

Nothing stupid about that at all and you didn't spend my time.
I saw something similar a while ago, and spend some time tracking that down as well.
Components "allmost working" can be rather time consuming and cause chasing a lot of red herrings

always check the power supply first. Into a set of resistors if possible.

Thanks all

Dr. Gilmore, What value recommended for HV?

for the high voltage 16 kohm 20 watt, you need a pair of them.

for the low voltage 500 ohm  2 watt

 

On 7/3/2016 at 0:35 AM, mwl168 said:

Was listening to my Carbon/009 tonight and before I shut it down I measured the offset. I have the opto servo engaged and the offset was hovering under 1 VDC while the amp is on. Upon shutting down the power, within a second or two, the offset shot up to just under 200 VDC and gradually declined from there. 

I plan to disable the opto servo and when I do that I will measure the offset again and report back.

Tried again tonight without the servo engaged. Similar result - offset shot up to about 170 VDC a couple of seconds after power off. 

Will try leaving the LV supply on and see what happens as JoaMat suggested next - need to rig something up to separate the HV and LV power switches.

Edited July 9, 20169 yr by mwl168

On 09.09.2015 at 8:46 PM, mwl168 said:

kgsshvcarbonv5.zip (amp board)

kgsshvpssicfetdual2new.zip (GoldenReference HV power supply, all-in-one version)

kgsshvpssicfetsinglenewrightfat.zip (GoldenReference HV power supply, B+ and bias) 

kgsshvpssicfetsinglenewleftfat.zip ( GoldenReference HV power supply, B- and 7815/7915 based +/-15V regulator)

goldenreference4.zip (GoldenReference LV bipolar power supply)

goldenreference4plus.zip (GoldenReference LV V+ power supply   

goldenreference4minus.zip (GoldenReference LV V- power supply)

bias.zip (stand alone regulated Pro and Normal bias supply) 

Why links are inactive? Should buy it? Where then and how much?

You should read some threads on the DIY forum here, starting with this one: http://www.head-case.org/forums/topic/11779-stax-mafia-circuit-boards/

You will only be able to buy these boards if someone makes them available for sale, or if you order a manufacturing run for yourself. Some posts here contain discussions about where and how to do this.