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Old 24th March 2011, 12:50 PM   #361
GoranB is offline GoranB  Poland
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I bought Marantz PM44SE (second hand for 50 Euro). Looking at circuit board of PM66 on pictures posted here i cant notice differences with PM44, probably the only difference is PS voltage, maybe output trans also.
I've changed caps (the small ones of 100uF) with Silmic's, the amp sounds much better. I also increased a bias current to 150mA per transistor, highs are more clear, but there was no improvements in imaging. Maybe separate trafo's and PS per chanell will be worth to try. Also small trafo and regulated PS for AN7062. I did this before on Marantz PM62MKII, great soundstage, deep and wide. Im highly recomending separated power suppllies for power outputs and regulated one for AN7062.

Last edited by GoranB; 24th March 2011 at 12:58 PM.
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Old 24th March 2011, 01:53 PM   #362
triocat is offline triocat  England
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put in the bigger caps and it all gone tong, the fuse is very slow to blow, had a bit of smoke then blow, fitted the smaller caps in and these are over heating.

will get some new 15k or 12k cpas to fit and leave it at that i think,

Tc
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Old 24th March 2011, 03:06 PM   #363
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Hooray! Good catch! Looking forward to pics.
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Old 25th March 2011, 11:23 PM   #364
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Quote:
Originally Posted by Ben Hanke View Post
Hooray! Good catch! Looking forward to pics.
@TC: Oh no, sorry to hear it's broken again. Your post wasn't visible when I replied - just your previous one where you said it was working.

btw I think I might've actually found a supplier for a toroid, so I may not have to buy an entire amp after all.
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Old 26th March 2011, 11:20 AM   #365
triocat is offline triocat  England
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putting in 15000uf now as the 22's are too big i think, they do not charge fully and slow blow the fuse.

it was sounding good with the 12's anyway.

Tc
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Old 1st April 2011, 08:54 AM   #366
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Default Latest pic

Here's the latest pic of my amp. IEC is now a basic Furutech inlet. Since my last pic, all electrolytic caps on main board and phono stage have now been replaced with Black Gates.

I realize BGs aren't always worth it, and may not be the best choice anyway, and it could all just be a trick of the brain, etc., etc. but I'm sort of addicted to putting them in, spurred on by the urgency of the fact that stocks are almost gone.

Anyway, the phono stage is one place where the Black Gates, albeit up-rated ones, have made a huge improvement. Records sound amazing now. I'm looking suspiciously at the op-amp now though since I recently upgraded my CD player's op-amps to LM4562HA. Not sure what I'd replace it with; I'm tempted to go the other way and try a discrete one.

Click the image to open in full size.
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Old 1st April 2011, 09:31 AM   #367
triocat is offline triocat  England
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looks good!

ahah the phono stage i have looked at this in detail too, which caps did you change in the end?

Tc
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Old 1st April 2011, 11:46 AM   #368
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Quote:
Originally Posted by Ben Hanke View Post

Anyway, the phono stage is one place where the Black Gates, albeit up-rated ones, have made a huge improvement. Records sound amazing now. I'm looking suspiciously at the op-amp now though since I recently upgraded my CD player's op-amps to LM4562HA. Not sure what I'd replace it with; I'm tempted to go the other way and try a discrete one.

Click the image to open in full size.
Looking good. The HAs are normally pretty special in phono stages. You could also run that pcb off a dedicated psu with say a 15Va toroid from RS and a nice little psu.

Also bypassing the ribbon cables for the signal path is a good idea. Input pcb --> pot --> power pcb

Brent
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Old 2nd April 2011, 07:06 AM   #369
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Thanks guys!

@tc: I changed ALL electrolytic caps on main board and phono for the highest rated Black Gates I could get. From memory they're mostly FK, and the very small values are PK. I also did the 1% silver micas listed by Brent, except the 150pf, which I bought but can't find on the PCB!

@Brent: OK, I'll keep a lookout on eBay for another HA at a reasonable price. Nice idea about the dedicated PSU. Yep, I already did the source direct bypass as per your recommendation with Kimber TCSS red/black twist.

Still no luck on the transformer front. Signals won't get back to me after initially saying they had the part, but I think they got it mixed up with the standard SE frame. I've also e-mailed Nuvotem.
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Old 4th April 2011, 07:48 AM   #370
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I've asked Nuvotem in the past for a 63KI tx and they said it was licensed to Marantz and could not supply one

Brent
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