I arrive here 1 year later...
Have a 47K with the IPS which I got used years ago. I like how it sounds but I'd like to get a bit more out of it.
I have the IPS schematics, which I attach...
I dont' have the 47K circuit diagram, but it's very similar to the Acurus P-10 (same designer). P-10 schematics can be downloaded from their web --> www.acurusav.com - discontinued
The PS supply design it's almost the same on both and the preamp circuit is very similar, a bit more complex on the 47K.
I'm going to change some of the electrolytics but my biggest question it's the output yellow 10uF film caps. Thinking of V-CAp ODAM but I don't know if the expense is worth. With 4,7 or 5,6uF would be more than enough.
The second question is the .22uF Wima mkp10, leave it alone or replace it with a nicer film cap.
So if anyone has modded this phono stage I'd appreciate some hints...
Have a 47K with the IPS which I got used years ago. I like how it sounds but I'd like to get a bit more out of it.
I have the IPS schematics, which I attach...
I dont' have the 47K circuit diagram, but it's very similar to the Acurus P-10 (same designer). P-10 schematics can be downloaded from their web --> www.acurusav.com - discontinued
The PS supply design it's almost the same on both and the preamp circuit is very similar, a bit more complex on the 47K.
I'm going to change some of the electrolytics but my biggest question it's the output yellow 10uF film caps. Thinking of V-CAp ODAM but I don't know if the expense is worth. With 4,7 or 5,6uF would be more than enough.
The second question is the .22uF Wima mkp10, leave it alone or replace it with a nicer film cap.
So if anyone has modded this phono stage I'd appreciate some hints...
Attachments
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The 47k is a great pre. I’m still using it today, although I have boards for a new op amp based one that is exceptionally accurate in RIAA EQ and very wide band with linear gain. The designer is on AK and he designed op amps in a former life... noise and distortion are immeasurably low. It’s really something. Especially considering it uses a switching power supply and the op-amps! Designing optimally has yielded an exceptional outcome. And he just did it to show that properly implemented op-amps can sound as good (or better!) than discrete designs. He knocked it out of the park.
The only tricky bit is the gain setting has to be done on board for best results- ie accuracy of the RIAA and cleanest sound. But it’s really great. And simple. Capacitance is the same, so you are really building the pre for a specific cartridge.
I have my boards now and need to order the parts to complete it.
But back to the posted schematics, I believe the Accurus design is very similar, if not identical, to the Aragon. The cartridge loading jumpers and three gain setting jumpers appear to be the same. I imagine only part quality (including boards themselves) is lower for the Accurus, which was built to a lower price point than Aragon. When I opened up my 47k it was loaded with top tier components, other than the big Mexican caps, on nice boards... I imagine some “tuning” could be done playing with those caps.
If you open the Aragon and trace some leads, you’ll quickly determine if it’s the same or not.
And a hot-rodded power supply is something I had looked into as a commercial item, not unlike our friend in Texas. I did actually chat with him via email since my last posting in this thread, and he is not interested in pursuing it any longer. Cost to make them is a bit high the way I went. It would be retailing around $500 or so for the power supply... but built to mill spec with the best possible components. Then the EE I was working with suggested an instrumentation power supply. They are necessarily very quiet, linear and very low ripple. I plan(ed) to build one with some added capacitance on the output; actually put two into a single 2- rack space box (one analogue one digital for my D2A) but haven’t done that yet.
Those +/- 24v power supplies are under $100 when over rated (about $60 properly rated) and then just add caps to taste (or not), wire and go. I may get one to mess with and see if it’s worth doing. If I do that, I’ll add the info here.
The only tricky bit is the gain setting has to be done on board for best results- ie accuracy of the RIAA and cleanest sound. But it’s really great. And simple. Capacitance is the same, so you are really building the pre for a specific cartridge.
I have my boards now and need to order the parts to complete it.
But back to the posted schematics, I believe the Accurus design is very similar, if not identical, to the Aragon. The cartridge loading jumpers and three gain setting jumpers appear to be the same. I imagine only part quality (including boards themselves) is lower for the Accurus, which was built to a lower price point than Aragon. When I opened up my 47k it was loaded with top tier components, other than the big Mexican caps, on nice boards... I imagine some “tuning” could be done playing with those caps.
If you open the Aragon and trace some leads, you’ll quickly determine if it’s the same or not.
And a hot-rodded power supply is something I had looked into as a commercial item, not unlike our friend in Texas. I did actually chat with him via email since my last posting in this thread, and he is not interested in pursuing it any longer. Cost to make them is a bit high the way I went. It would be retailing around $500 or so for the power supply... but built to mill spec with the best possible components. Then the EE I was working with suggested an instrumentation power supply. They are necessarily very quiet, linear and very low ripple. I plan(ed) to build one with some added capacitance on the output; actually put two into a single 2- rack space box (one analogue one digital for my D2A) but haven’t done that yet.
Those +/- 24v power supplies are under $100 when over rated (about $60 properly rated) and then just add caps to taste (or not), wire and go. I may get one to mess with and see if it’s worth doing. If I do that, I’ll add the info here.
Jim, the yellow output caps on mine are from Electronic Concepts, ECI TMPO 10uF 100V. There are people out there who like these caps a lot. Your "mexican" ones are exactly similar to mines in shape and color, so maybe in the end they are ECI's but just manufactured in Mexico.
The bipolar yellow ones at the back of the picture are ECI as well.
So, since mines seem to be in good shape I think I'm going to leave them and just bypass them with 0,1uF nice ones.
The bipolar yellow ones at the back of the picture are ECI as well.
So, since mines seem to be in good shape I think I'm going to leave them and just bypass them with 0,1uF nice ones.
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Finally I replaced all the electrolytics in both IPS and preamp with Nichicons. Also 2 signal caps replaced with silver micas. Some resistors changed as well, for instance 100ohm loading with a z-foil (for my sota turntable with a denon dl-s1 0,18mv cart) and made room for a 100k ohm resistor to load an empire 4000 d/3 on other tt).
Being honest have to say I didn't hear big differences after these changes, mainly because that dark sound was still there, a sound that somehow I like but I think it acts as a veil.
Some weeks later I replaced the yellow Eci 10uF output caps with Jantzen Alumen 5,6uF. The fit is very tight but it worked. And now yes, the changes are quite evident and have to say this thing sounds much better than before. I've only tried it with the empire MM cart at the moment. I couldn't be more happy.
Some pics:
Being honest have to say I didn't hear big differences after these changes, mainly because that dark sound was still there, a sound that somehow I like but I think it acts as a veil.
Some weeks later I replaced the yellow Eci 10uF output caps with Jantzen Alumen 5,6uF. The fit is very tight but it worked. And now yes, the changes are quite evident and have to say this thing sounds much better than before. I've only tried it with the empire MM cart at the moment. I couldn't be more happy.
Some pics:
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Well, i would have gone with 10uF, just to keep manufacturer specs, in case they fit and my budget was unlimited. My amplifier input impedance is 220K so I could have gone -theoretically- with much lower capacitance, 1uF for instance, but didn't want to go that low. Thought about 4,7uF, but the 5,6 ones were priced the same so jumped for them.
I'm convinced the differences in sound are because these capacitors are much better than the stock ones.
I'm convinced the differences in sound are because these capacitors are much better than the stock ones.
Once again resurrecting my old thread...
So, I'm considering MIT 10uf caps to replace the yellow ones, since that made the largest impact to you (and makes sense).
But I had a question about your earlier comment about a small (.01uf) bypass cap in parallel: did you ever do that, and was that in place with the original caps, as you had planned, prior to your upgrade, and if not, did you install them along with your upgrade caps?
Thanks!
So, I'm considering MIT 10uf caps to replace the yellow ones, since that made the largest impact to you (and makes sense).
But I had a question about your earlier comment about a small (.01uf) bypass cap in parallel: did you ever do that, and was that in place with the original caps, as you had planned, prior to your upgrade, and if not, did you install them along with your upgrade caps?
Thanks!
I'm leaning toward V-cap ODAMs now. Their size is more friendly and I've not found a negative review of them yet.
I'm just not sure if I should add the small .01 bypass caps as well (which adds another $100 or so). Obviously I can try without them first, but I'd have to buy them just to try them, whenever I do...
V-Cap ODAM Oil Damped Advanced Metalized Audio capacitors
I'm just not sure if I should add the small .01 bypass caps as well (which adds another $100 or so). Obviously I can try without them first, but I'd have to buy them just to try them, whenever I do...
V-Cap ODAM Oil Damped Advanced Metalized Audio capacitors
Continued thread with schematic posted here: https://www.diyaudio.com/community/...uit-aragon-47k-acurus-p10-phono-stage.389228/
![IMG_5256[1].jpg](/community/data/attachments/1136/1136888-6291a15c0987490055acfa6a6c64e53d.jpg)
