Checked all resistor values, and transistor orientation. I then started pulling transistors to verify. With the ZTX558, I got the following reading for one transistor
and the other
Strange, I am thinking I got a bad batch of the transistors as both boards (L & R) behaves the same in circuit. I have not pulled out the pair on the other board however.
Abe
and the other
Strange, I am thinking I got a bad batch of the transistors as both boards (L & R) behaves the same in circuit. I have not pulled out the pair on the other board however.
Abe
Yes, that is the testing device I had in mind.....I have a similar and it actual works so I think you have bad transistors. Strange.....so even brand new never used.....they measure bad?
The natural explanation would be that transistors was damaged "in-circuit" caused by some kind of error......
That interested me, and I had to look it up ... 🙂
Actually, it is possible that the ZTX558 are manufactured in Germany ...
Diodes Incorporated, which has bought Zetex, has a manufacturing plant in Neuhaus am Rennweg, Thuringia.
Company Profile
The company states that while the wafers are made in the UK and in Shanghai, they say that they have assembly and test facilities in China, Germany and Taiwan ... 🙂
Regards, Claas
Actually, it is possible that the ZTX558 are manufactured in Germany ...
Diodes Incorporated, which has bought Zetex, has a manufacturing plant in Neuhaus am Rennweg, Thuringia.
Company Profile
The company states that while the wafers are made in the UK and in Shanghai, they say that they have assembly and test facilities in China, Germany and Taiwan ... 🙂
Regards, Claas
Ok.....then maybe I have German made transistors in my M2X right now!
It is like Telefunken in the old days......ECC803S....it was a good one.
It is like Telefunken in the old days......ECC803S....it was a good one.
Thank you for the input guys! I already ordered the “ECC 803S” transistor version and will receive it tomorrow (ordered a dozen) and will test prior to soldering to the board.
Bringing "Silicon" from China to Silicon Valley?
It is like bringing sand to Sahara?
The German ZTX558 sounds very good in IPS6.
There is very good "attack" on transients in the music.
Maybe try this one on Tidal where it can be streamed in "hi-res":
Benjamin Grosvenor | Homages
Also very good recording. Decca usually makes fine recordings.
First no. is good to check how IPS6 handles a Grand Piano.....it does very good.
It is like bringing sand to Sahara?
The German ZTX558 sounds very good in IPS6.
There is very good "attack" on transients in the music.
Maybe try this one on Tidal where it can be streamed in "hi-res":
Benjamin Grosvenor | Homages
Also very good recording. Decca usually makes fine recordings.
First no. is good to check how IPS6 handles a Grand Piano.....it does very good.
I replaced Toshiba jfets for my stock. They have Idss 9.6mA. The previous ones were V grade idss 11.1 and 11.5 idss. Before the capacitor C1, I measure 6mV. Can I remove C1? Will be a problem for edcor? If I'll mount RV1 may I compensate to 0 mV before edcore ?
The RV1 main purpose is to adjust amount of 2nd harmonic.
Now the DC you measure is when board is up in temp. You can have more DC during warm-up of the input boards. Also during switch-off there can be a DC-spike.
Removing the cap will not cure the "hum-issue". It is there to protect Edcor from DC. Some may think they can hear a difference without cap.....but it is probably only an imagination.....
Now the DC you measure is when board is up in temp. You can have more DC during warm-up of the input boards. Also during switch-off there can be a DC-spike.
Removing the cap will not cure the "hum-issue". It is there to protect Edcor from DC. Some may think they can hear a difference without cap.....but it is probably only an imagination.....
I meant edcore because I was not sure what is better - small DC or output capacitor. The measurement, of course, was on a hot amplifier.
In conclusion - the noise on Ishikawa is acceptable to my ears so the music is already playing 🙂 When the ordered mumetal arrives, I will take further steps to listen to Mountain View. Thanks to everyone for help and for everyone I wish Merry Christmas 🙂
In conclusion - the noise on Ishikawa is acceptable to my ears so the music is already playing 🙂 When the ordered mumetal arrives, I will take further steps to listen to Mountain View. Thanks to everyone for help and for everyone I wish Merry Christmas 🙂
I see the gerber files for the daughter boards and was wondering if there are gerber files for the amp itself? Thanks.
what about give a bit of gain to the Norwood IPS by lowering the NFB?
and then maybe remove the edcor....
Yes i know it is no more anM2x, but it is worth experimenting?
and then maybe remove the edcor....
Yes i know it is no more anM2x, but it is worth experimenting?
If preamp has some gain then first try could be to just bypass Edcor using a wire the right place? ......and check how it sounds?
It should give lower noise and distortion.
Looking at schematic it looks easy just to try it out.
It has been suggested before but no reports I know about......
It should give lower noise and distortion.
Looking at schematic it looks easy just to try it out.
It has been suggested before but no reports I know about......