The best pics I have are on page 39 of this thread.
Link: http://www.diyaudio.com/forums/solid-state/69591-marantz-pm66-ki-tweeks-39.html
My amp is in bits right now. The only part you can't see is the soldering, but just follow the traces from the ribbon connectors to the pot and switch and solder directly to the pins. You want to do L,R,LG and RG. Use good, well insulated wire like Kimber and twist the signal and ground wires together.
Link: http://www.diyaudio.com/forums/solid-state/69591-marantz-pm66-ki-tweeks-39.html
My amp is in bits right now. The only part you can't see is the soldering, but just follow the traces from the ribbon connectors to the pot and switch and solder directly to the pins. You want to do L,R,LG and RG. Use good, well insulated wire like Kimber and twist the signal and ground wires together.
Hey Brent, I copied you and used 16v 100uF Black Gate N for the feedback caps in my amp. I'm going to be rebuilding it soon but I actually have a possible alternative home for those caps (i.e. DOS). How ideal do you think those caps are for that position, and how significant are they? Do they benefit much from being non-polar or would FK work? Would something like a 470uF N with a 0.1uF Wima bypass be suitable?
Hey Brent, ignore that last post, I know what I am doing now after chatting with Ray.
I read through most of this thread this evening and I saw that lots of people have come and gone who had exciting mods on the go. It would be great to hear from some of you guys if you're still listening.
My amp was sounding amazing, but then I blew it up. I think it was just a PCB flex followed by some over-tired PSU rewiring. I've got all the parts lined up to do a rebuild in the next week or two. Thanks to Brent of course, the main highlights of my previous mods were:
- Dual KI transformer
- 100% Black Gate electrolytic recap - mostly FK, including 80v 10,000uF FK smoothers
- 1% silver micas on main board
- LM4562HA op-amp in phono stage
- Source direct bypass with Kimber TCSS
- Mundorf M-Resist Supreme output resistors
- Furutech IEC socket with decent power cord
The additional changes I've got planned in the rebuild are as follows:
- Schottky bridge
- 18 turn orecision trim-pots for bias circuit
- 150w transistors w/ beefed up heatsinks (somehow - not sure yet)
- 1% silver micas for phono stage
- Integrated "Lightspeed" LDR attenuator at main board input to replace original 50k volume pot
- 2.7uF Mundorf Silver/Oil coupling caps (in place of BG 10uF 50v AC)
I read through most of this thread this evening and I saw that lots of people have come and gone who had exciting mods on the go. It would be great to hear from some of you guys if you're still listening.
My amp was sounding amazing, but then I blew it up. I think it was just a PCB flex followed by some over-tired PSU rewiring. I've got all the parts lined up to do a rebuild in the next week or two. Thanks to Brent of course, the main highlights of my previous mods were:
- Dual KI transformer
- 100% Black Gate electrolytic recap - mostly FK, including 80v 10,000uF FK smoothers
- 1% silver micas on main board
- LM4562HA op-amp in phono stage
- Source direct bypass with Kimber TCSS
- Mundorf M-Resist Supreme output resistors
- Furutech IEC socket with decent power cord
The additional changes I've got planned in the rebuild are as follows:
- Schottky bridge
- 18 turn orecision trim-pots for bias circuit
- 150w transistors w/ beefed up heatsinks (somehow - not sure yet)
- 1% silver micas for phono stage
- Integrated "Lightspeed" LDR attenuator at main board input to replace original 50k volume pot
- 2.7uF Mundorf Silver/Oil coupling caps (in place of BG 10uF 50v AC)
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Hello Ben,
Im following this thread, sorry abt your amp.
Once i had the PM62MKII, I added a discrete regulated PSU for the both chanells, and also discrete regulated PSU for the AN7062, the chanell separations improved a lot, also in general the sound was much cleaner and sound stage deeper. I suggest you to try these mods in the future.
regards
Goran
Im following this thread, sorry abt your amp.
Once i had the PM62MKII, I added a discrete regulated PSU for the both chanells, and also discrete regulated PSU for the AN7062, the chanell separations improved a lot, also in general the sound was much cleaner and sound stage deeper. I suggest you to try these mods in the future.
regards
Goran
Hi Goran,
Nice to hear from you. I did wonder if I could split the channels, since I'm running two identical transformers. I'd like to know how you achieved that exactly, although I guess you don't still have the amp to hand. I can definitely look at a dedicated PSU for the pre-amp, as well as the phono stage.
Cheers,
Ben
Nice to hear from you. I did wonder if I could split the channels, since I'm running two identical transformers. I'd like to know how you achieved that exactly, although I guess you don't still have the amp to hand. I can definitely look at a dedicated PSU for the pre-amp, as well as the phono stage.
Cheers,
Ben
I used one transformer 50V -0- 50V on the secundar. That gaves me abt 70V per rail after rectifier and caps. The PM62 used 42V per rail as I remember well.
I used a discrete regulated PSU to achieve 42V for each rail, it means 4, one per output transistor. You will need a bigger heatsinks for this.
In my case i leaved the drivers like they were on the same PSU with AN7062 (PM62MKII has darlingtons on the output, so the "drivers" were small transistors). Just output transistors were on a regulated PSU. Later I add the separate PSU and trafo just for the drivers and for the rest of the board.
You can achieve excellent results implementing these mods.
Also, the separate trafo-PSU for the phono stage would be a big step forward.
I used a discrete regulated PSU to achieve 42V for each rail, it means 4, one per output transistor. You will need a bigger heatsinks for this.
In my case i leaved the drivers like they were on the same PSU with AN7062 (PM62MKII has darlingtons on the output, so the "drivers" were small transistors). Just output transistors were on a regulated PSU. Later I add the separate PSU and trafo just for the drivers and for the rest of the board.
You can achieve excellent results implementing these mods.
Also, the separate trafo-PSU for the phono stage would be a big step forward.
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Goran, that sounds very impressive. I feel like that might be a bit ambitious for me to take on at this stage, although I'll probably be considering a separate phono stage PSU before too long.
Hi Jon, I guess I could. I didn't know whether the required value was likely to change over time as I do more mods. Does the trim-pot have an effect on sound quality then?
Hi Jon, I guess I could. I didn't know whether the required value was likely to change over time as I do more mods. Does the trim-pot have an effect on sound quality then?
Hello,
this is my 6010 with little mods....Thanks to the mod list I find here.. The 6010 now sound very well !
this is my 6010 with little mods....Thanks to the mod list I find here.. The 6010 now sound very well !
An externally hosted image should be here but it was not working when we last tested it.
Wow, looks impressive - what are the details of this, suryday?
I notice you've not done the source direct bypass yet. Unless you use all that extra circuitry like balance, tape loops, then you should consider trying that as it makes a big improvement.
Also, wow, a floppy disk - I've not seen one of those in a while.
Hey guys, can you sanity check this plan for me? I've been looking into DC blocking caps. I currently have back-to-back BG 220uF FK blocking DC from leaving my CD player, then I have the input wired directly to the main board through the pot, where I have 10uF BG AC. The phono stage has 10uF on the input and 2.2uF on the output.
In the interests of having the signal travel through as few caps as possible, I'm thinking of removing the caps from the outputs of both sources, and the ones from the input to the main board, and inserting a single pair of Mundorf Silver/Oils on the *input* to the volume control.
Does that sound OK?
I notice you've not done the source direct bypass yet. Unless you use all that extra circuitry like balance, tape loops, then you should consider trying that as it makes a big improvement.
Also, wow, a floppy disk - I've not seen one of those in a while.
Hey guys, can you sanity check this plan for me? I've been looking into DC blocking caps. I currently have back-to-back BG 220uF FK blocking DC from leaving my CD player, then I have the input wired directly to the main board through the pot, where I have 10uF BG AC. The phono stage has 10uF on the input and 2.2uF on the output.
In the interests of having the signal travel through as few caps as possible, I'm thinking of removing the caps from the outputs of both sources, and the ones from the input to the main board, and inserting a single pair of Mundorf Silver/Oils on the *input* to the volume control.
Does that sound OK?
I would remove the caps from the cd output and use just one nice polypropilen in the input of the amp.
Why 3.3uF? whats the value of the input caps on your amp, 22uF? At the moment i have 22uF/400V Ero on the input, no caps on the output of the CD player.
I currently have 10uF Black Gate AC, but the phono stage has 2.2uF after the op-amps and I haven't noticed much bass roll-off. I wanted to upgrade to Mundorf Silver Oils because I read such great things about them on the forums and in various capacitor shoot-outs. I have two-way speakers, and I figured the -3dB point for 3.3uF should be lower than they can go. Plus, the price of the Mundorfs goes up exponentially from about there.
I see, but how you know that there is no roll-off? (maybe you did some scope measuring) Replaceing the input caps with smaller values ones, can result with "better- tight and clean bass" because of roll-off. Also the changeing of the value of the input capacitor have influence on the input impedance. In many cases decreasing the value of an input capacitor can result with higher THD on the output.
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