Our audio shop has closed due to retirement and I would like to share our mod for the GFP-750. I hope that this will help some of you who would like a little better sound quality but the mod will improve clarity first and foremost. It is already a terrific performer designed by Nelson Pass and is similar to the Pass Aleph P.
Thank you for this list of parts and locations. This is what I've been looking for!
In the list, you say to install a common mode choke in L17. Is there a specific choke to put there? I've done a bit of reading on it and before I go down this rabbit hole, if there is a part number you can provide, it would make my life a bit easier
I may have more questions in a few days,
Thanks,
Eddie
In the list, you say to install a common mode choke in L17. Is there a specific choke to put there? I've done a bit of reading on it and before I go down this rabbit hole, if there is a part number you can provide, it would make my life a bit easier
I may have more questions in a few days,
Thanks,
Eddie
Ok. I have 2 more questions.
I can't find LKG2A222MESAAK for C23 anywhere (out of stock) and it looks like you're doubling the size of the original cap. Is there an alternative you can recommend that's available?
Also, after the section of cap replacements it says "Install .1uF/250V WIMA MKP4F031003C00KSSD polyproplyene film across C23. Sorry, another newbie questions. I don't understand what you mean by "across". Is this just in parallel like on the bottom of the board?
There is another mention to install another across D19~D22.
Thanks again in advance for providing this and helping iron out my newbie questions
I can't find LKG2A222MESAAK for C23 anywhere (out of stock) and it looks like you're doubling the size of the original cap. Is there an alternative you can recommend that's available?
Also, after the section of cap replacements it says "Install .1uF/250V WIMA MKP4F031003C00KSSD polyproplyene film across C23. Sorry, another newbie questions. I don't understand what you mean by "across". Is this just in parallel like on the bottom of the board?
There is another mention to install another across D19~D22.
Thanks again in advance for providing this and helping iron out my newbie questions
Eddie, I may have enough new parts left in my stock to provide an upgrade kit but not sure if I have the choke. I do have the upsized main power supply cap along with the 2 power rail caps.
The Wima .1uF MKP4 is soldered in parallel across C23 but under the board.
D19~D22 have small Kemet .1uF bypass caps to reduce noise from the rectifiers. They can be mounted under the board easily. I always removed the diodes and mounted the caps on top and resolder diodes back in.
The Wima .1uF MKP4 is soldered in parallel across C23 but under the board.
D19~D22 have small Kemet .1uF bypass caps to reduce noise from the rectifiers. They can be mounted under the board easily. I always removed the diodes and mounted the caps on top and resolder diodes back in.
Thanks for this. I followed (most of) your upgrade advice for my GFP-565’s and am more impressed than going from a 555-II preamp.
Really appreciate your putting this out there.