Sjöström Audio DIY forum

Desolderd Transformers and Rectifiers:

Rectifiers measure fine. Transformers give about 20.5 V AC out with 226 V in.

Where to look now?

Hi,

the things start to get worse :(

At the first start with 230 V I tried to check the Voltage at the rectifier out (around 21V) then had a short "spark" at the right channel rectifier +_terminal. But everything seemed to be OK?

Meassuerd Voltage at the output terminals (few mV). After a while the transformers started to got hot (72 °C) and voltage all around changed a lot?

Now when I check Voltage at the transformers fron below side I get 230 V in but only 6 V out (still soldered to board)?

Seems like I perforated the solder mask with my tiny meter probe and made a short (see picture below)

What to do next? desolder the transformers and rectifiers?

Thank you

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Tonight have build the Amp :)

Now would like to check it:

"Check the finished amp

Apply voltage again and check the output voltage. Measure the DC voltage at the output. It should be the specified offset voltage (see datasheet) and times the gain, 4 in this case. I got 78 uV(!) for AD8610 and 2 and 10 mV for the TPA6120 at the amp outputs. 10 mV is OK and won't harm the headphones."

Where and how do I measure the DC Offset for AD8610 and TPA6120?

Without anything connected I measure at the output Terminals  -1.83 V and +2.26 V

Thank you!

PS: The Transformers (Myra 44159) get quite Hot?

heaveno,

got an Alps 27 10 K stereo Pot.

Branko
(The Text Box changes the word " H E L L O" to "heaveno" when I click Post?)

Try to find a dual 10 kohm pot logarithmic of a good quality. Try to find something and I can say yes or no to your choice.

heaveno,
just bought the PCB and planning to assemble it.
Do you have any recommendation for the Volume control?
And how would it be implemented?Thank you.

Branko

Quote from: espirit on December 06, 2024, 04:03:40 PMT2 replaced on PCB 1, points on K2 continue to bounce.


D1,D2,D3,D4,and DZ1,all changed, K2 points continue to bounce.

Not Shure what to try next?.

Will please measure the voltages around T1 and T2 when you have 24 VDC connected across DZ1.

Try to measure the coil resistance of the K2 to rule out any shorts.

T2 is suspect since you can't have more than 1 V across base-emitter.

Esprit wrote:

heaveno, I have two of the SST01 rev.1, one each in mono Pass F5t.
Following application of 24v across DZ1, the following results were obtained.


PCB No1
T3, B/E= 0v.    C/E= 22v
T2, B/E= 23v.   C/E= 23.1v
T1, B/E= 143mv. C/E= 40mv


PCB No2
T3, B/E= .94v.  C/E= 60mv
T2, B/E= .4v.   C/E= 22.2v
T1, B/E=.623v.  C/E= 1mv

December 02, 2024, 09:09:24 AM
No worries. Take your time.