It's the "they can't hurt" part that I was concerned about. Without knowing if it was part of the original Stasis design, combined with not finding it in the other amp, is why I questioned it.
I was just trying to figure out if it was there to make the amp as stable as possible across the widest possible audience at perhaps a slight degradation of the sound vs running it a little more "risky" to get that extra margin of performance.
I would assume that Nak would have tended to lean on the ultra conservative side as they likely wanted the most reliable product possible.
As I mentioned, I don't have the design knowledge, so I didn't know how to interpret its purpose but was looking to eek out the best performance possible. Hence why I asked.
Thanks to all for the help.
Best regards,
Steve
Hello colleagues,
I will refresh a very old thread, I replaced all small capacitors in my pa7 and I noticed that what we put in place of the C105/C205 has a significant impact on the sound. The no longer produced Elna ROA RED that was there was sounds great, modern capacitors do not give such effects anymore. I tried the auricap XO which gave amazing space and detail but the sound seems a bit harsh. How your research with this system has ended? Thanks!
Hello olmaster,
I recently recapped the two VAS shunts and used 10uf/35v Elna Silmic II capacitors. Sound was improved, as the cerafine caps previously used were out of spec. This seemed to improve sound, I also set dc balance and idle current. It was running at around 150mv when I got it vs the 40mv.
I used this for over a week before getting brave and using two of the 470uf/25v bipolar Nichicon muse and two 4700pf/63v 1% wima film/foil caps in parallel to replace each of the large 10uF/200v mylar feedback capacitors. It would be quite easy to design a board for this. I also made sure to put the new electrolytic capacitors away from the output transistors
Next, I intend to buy a stock of NOS output transistors and redo transistor matching with a jig. Once this is done, I intend to bias it much higher into class A.
I still have yet to replace the small protection capacitors, but should do that at the same time as the output rematching.
I recently recapped the two VAS shunts and used 10uf/35v Elna Silmic II capacitors. Sound was improved, as the cerafine caps previously used were out of spec. This seemed to improve sound, I also set dc balance and idle current. It was running at around 150mv when I got it vs the 40mv.
I used this for over a week before getting brave and using two of the 470uf/25v bipolar Nichicon muse and two 4700pf/63v 1% wima film/foil caps in parallel to replace each of the large 10uF/200v mylar feedback capacitors. It would be quite easy to design a board for this. I also made sure to put the new electrolytic capacitors away from the output transistors
Next, I intend to buy a stock of NOS output transistors and redo transistor matching with a jig. Once this is done, I intend to bias it much higher into class A.
I still have yet to replace the small protection capacitors, but should do that at the same time as the output rematching.
To continue my efforts, I replaced the entire protection circuit. The 47uf bipolar cap was replaced with a bipolar muse. The 10uF/100v bipolar was swapped to a Panasonic film (I noticed simular amps used a film cap here).
I installed new ohmite audio grade non-inductive 1% emitter resistors as well. This seems to have a positive effect on stability and sound.
I also added 4.7uF bypass caps to the main filters. These were already around and I had extra.
Overall, I'm very pleased with the results.
Amp is now around 50mv or so of idle current keeping perfectly stable.
I installed new ohmite audio grade non-inductive 1% emitter resistors as well. This seems to have a positive effect on stability and sound.
I also added 4.7uF bypass caps to the main filters. These were already around and I had extra.
Overall, I'm very pleased with the results.
Amp is now around 50mv or so of idle current keeping perfectly stable.