Lampizator - Fetishizator

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Very good again.
Seeking what is the Marantz HDAM and it serves and what does it do, I came across this article
http://www.lampizator.eu/LAMPIZATOR/FETISHIZATOR/fetishizator.html
I have read, but my knowledge is not sufficient to understand exactly what it does.
If anyone can explain what is and what is the role both as LAMPIZATOR HDAM / FETISHIZATOR from and I thank you.
In my ignorance, I saw the circuit and leave, so work up and interpose between the sound source and amplifier and give me greater dynamic range. It's like that ?. Greetings and thanks to whom I provide details.
 
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:)

The HDAM is a bit like a high quality buffer using separate transistors instead of an opamp.

The FETISHIZATOR attempts to replace all the transistors in the HDAM with a single FET. It might sound OK, it might sound 'nice', but it will fall far short of the original design on all counts.
 
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Hi ALPUY,
The HDAM would. The Marantz HDAM is only a diamond buffer and related extensions. Marantz used diamond buffers extensively in the early 80's. Some of their best equipment before Philips happened was sold then. I heard the new high end Marantz equipment in London in 2004. That stuff was excellent! That's when they packaged the diamond buffer as ... "HDAM" modules. They now have a few different ones.

I wouldn't replace an HDAM or diamond buffer with anything else. You can only go down from there.

-Chris
 
Thanks Anatech. I did not understand what function fulfilled the HDAM.
As I saw a circuit that reads the same function, I thought to enhance the dynamic build my phono pre.
I Guess I'll leave things as they are.
It all started because I was looking to buy a Marantz PM5005 amplifier and that of HDAM found there.
Regards.
 
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Hi ALPUY,
No worries. Marantz hid what the "HDAM" module was as long as they could. Shades of early Luxman when they potted subassy's inside plastic boxes. Nasty, made some units unrepairable. There are more than a few people who are unsure just exactly what an HDAM is. They make a few different (but the same basic thing) types of HDAM assemblies, and that only furthers the confusion.

I often recommend the high end Marantz products for people who really listen to the sound. They are hard to beat for the price in the commercial product world.

-Chris
 
:) used ,as headphone amplifier ......
Regards ,Alex
 

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Hi Alex,
Yes. I demonstrated one of my line drivers by driving headphones (sounded excellent), then a loudspeaker. An 8" 2-way that sounded okay, but you could tell it was running out of steam. It's pretty amazing how much juice you can get out of a little circuit. The outputs were 2SC3421 and 2SA1358 with +/- 25 V supplies. The buffer survived because it couldn't deliver enough current to hurt itself (by design).

Can we assume you like your headphone amplifier? :)

-Chris
 
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In the past I modded quite a few Marantz CD players and omitting the HDAM was an improvement every time. I slowly got the impression it was in the players just to be able to write it on the front cover. Those CD players had an opamp in front of the HDAM anyway. To me it is a bit like the X-10D. Superfluous, at least when an opamp is also used.
 
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Hi jean-paul,
The op amp provides a low impedance source for the HDAM. Its the same idea as using a buffer after an op amp except the HDAM doesn't need to be in the feedback loop.

Have you considered that the issue really might be something further upstream? A good buffer will make certain that every nuance shows up at your equipment input jacks. Removing the HDAM raises the output impedance of the CD Player. I think that is more likely what you are hearing. Besides, HDAM = Diamond buffer = extremely clean performance. Have a look at the other diamond buffer threads and the one thing that is common is how clean and open sounding they are.

-Chris
 
Exactly the same experience as jean-paul - the old HDAMs sucked big time, no idea if the new ones are any better. And how can removing the buffer raise output impedance in any meaningful way? Any half decent opamp has an output impedance of zero + a hundred ohms to protect against capacitive loads.

And besides old HDAM is not a diamond buffer
 
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I have never opened an old one up, so I don't know about those. The later ones do resemble what Marantz used in the early to mid 80's, and those are diamond buffers for sure.

A buffer often has output impedance in the ohms or tens of ohms without feedback. Op amps may have a low output impedance due to feedback, but they are extremely limited in the actual current they can deliver. That gives rise to distortion at higher frequencies or with some low impedance equipment. There is a reason why there have always been buffers available (the BUF series are diamond buffers). Buffers are used extensively at video frequencies and up, and they sure do a lot to maintain sound quality in some audio applications. As you well know, small signal output impedance isn't even close to actual performance at higher signal levels.

Do you have information on the old HDAM circuits? I would be interested in seeing what they started with.

-Chris
 
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Hi analog_sa,
Ah ha, thank you. It didn't strike me as being the HDAM in question, but that's what you get for skimming over a long web site.

No, that one isn't the classic HDAM at all. But, from the appearance it should sound good. I guess I'd have to build one to test it. Maybe less expensive to find a dead CD-67 somewhere and check the real thing. These must be the original discrete op amps.

-Chris
 
Hi,

I used Fetishizator in my Philips Cd600 (TDA1543) and CD460 (TDA1541). Sounded way better than the original op amps (but mind I haven't replaced the coupling caps in the original op amp version). But still it was not the final stop. Later I replaced the 1541 version with D1 I/V conversion which was waaaaaay better.

Greg
 
This is the early HDAM schematic as used in the CD6000OSE and a bunch of others:

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Some of the players tested better (lower THD) when they were bypassed. I've got a PMD325 (the professional version with XLRs and RS232 etc) here on my bench that has the same HDAM in it (not in a tin can with HDAM stamped on it) and its THD+N 1Khz at 0dB is 0.0016% (tested).

HDAM was a pure and simple a marketing device. It was a mystery box in a copper can that Marantz cleverly used to differentiate their products from others. They still do it. Just like the potted buffer stages Chris mentioned. A few German high end manufacturers potted their 'magic' buffer/gain stages too. Even Sony did it in the 1970s in their esprit preamps IIRC.

Potting and grinding off part numbers is an ancient way of protecting IP- it's pretty funny now when you think about it, except when you are trying to grind through an epoxy block to fix a few vented SMPS capacitors in your (my own one!) washing machine control board (yes Samsung, I'm talking to you). But, two hours and two capacitors later, my 'unrepairable' front loader is happy again.
 

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...when you are trying to grind through an epoxy block to fix a few vented SMPS capacitors in your (my own one!) washing machine control board (yes Samsung, I'm talking to you). But, two hours and two capacitors later, my 'unrepairable' front loader is happy again.

Surely, the trick is knowing that all you have to do is replace those caps. If you didn't know that you'd be stuffed. How the heck did you know ?
 
Surely, the trick is knowing that all you have to do is replace those caps. If you didn't know that you'd be stuffed. How the heck did you know ?

The epoxy was clear/yellow and I could see through it enough to see the vented and blackened caps around the base, and the blown fuse in its potted holder. All else looked good. I also drilled down to a few components to test with my meter probes before jumping in.

Grinding down to the PCB mounted fuse holder (seriously, who pots a fuseholder??) was fun as I wanted to retain it, the caps I could grip from the top. It was the solder side that was the tricky part as the whole pcb was potted into a plastic back and so I cut an access hole and attacked the potting compound from the back. I decided that if the SMPS mosfets, bridge or SMPS controller IC were bad- I'd write it off as it would have been too hard to extract the extruded heatsink with bridge rectifier and mosfets from the epoxy.

It was worth it, the controller PCB is obsolete/NLA and a new machine would have been $600 or more.

That said, the noise and smell of grinding epoxy and the powder/dust mess it makes isn't exactly enjoyable. I was muttering under my breath the whole time things like "you aren't going to win you Samsung f@#&ers" and "come on you Bas%$#d thing" etc. :)

I took a few pics as it was a kind of victory:

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The interesting thing about the epoxy under the PCB was that it had never completely hardened- it still had that curing smell and was virtually impossible to cut. It clogged up milling bits and I ended up clipping of chunks with side cutters and the dremel. I cut a bigger hole in case the diodes/controller IC were bad- they weren't.
 

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