Eros-2: I built it my way

[georgeged]

27K resistor: AMTRANS have Metal Oxide and Carbon Films. Most probably you recommend Metal Oxide ones, correct? If yes, what about Panasonic ERG-2 (2 watt)? I used them in DIY Nelson Pass amps - they are pretty good and small size too.

[Paul Birkeland]

I would go for the carbon film.  We will use metal oxide resistors in our products where they don't handle signal current (mostly R2 on C4S boards) or where there may not be other good choices (sometimes for really low value/high power filament dropping resistors).  Since there's a big cap across the 27K resistors, I wouldn't be too concerned about using a metal oxide resistor there, but technically I would consider it a downgrade from the parts we provide. 

[georgeged]

Thanks Paul

[canonken]

All I can say is that LOOKS amazing!  Very pretty!

[georgeged]

Resistors are changed. New ones are:
- 47K - Dale CPF3 3W
- 27K - Amtrans AMRT 2W
- 220K - PRP PR9372 1W

This resistors become really hot after an hour of listening. It was absolutely necessary to have more power here. Thank you PB!

[georgeged]

@PB and PJ

Are there any sonic benefits if I replace the 1000uf 6V electrolytic caps with SANYO OSCON polymers? Partsconnexion have stock of 1500uf@4V and [email protected]

[Paul Birkeland]

They are 10,000uF at 6.3V caps, and I don't see an OSCON cap that is anywhere near that big. 

The 1500uF/4V cap looks to have really short leads for PC board mounting, so that's certainly something to avoid. 

[georgeged]

Clear. Thanks Paul.

[Paul Birkeland]

You could try something like this:
https://www.mouser.com/ProductDetail/Nichicon/UKA1A103MHD?qs=ZkXqA7GzKJJAEEuOQa2CCw%3D%3D

[Doc B.]

IIRC we tried OSCON caps in one of the first iterations of the Eros and leakage was an issue so we abandoned the idea. But maybe I'm confusing my prototypes. Too many years and too many products.

[4krowme]

georgeged,

  I know that I am late to the party here, but your photos of the quality of your work caught my eye. I do not build as pretty as some, but better than others. That's about all I can say. I am looking at the shielding used for the power transformer. I have a question as to the material that you used. Was it Mu-metal, or something else.
 Also, I see that you mentioned building a PH2 phono. So did I. Let's just say it was an experience. A little beyond my real ability.
 I have tried 4 phono amps so far, and good and bad have come across my system. Maybe just not a good match in a couple of cases. Some were factory, some were kits.

[Doc B.]

Presumably you are asking about the shielding around the added filter choke. IMO a better solution than adding a source of magnetic interference and then trying to shield it is to put the 270 ohm resistor back in. The preamp has a shunt voltage regulated, constant current source regulated power supply and a power transformer designed for very low radiated magnetic field.

[4krowme]

  Thanks Doc for the correction and explanation. I find that in my builds that the 'what if' moments answer themselves later on. My latest what if came from using a smaller chassis than could be used. Not just in the physical sense but also electrical, and so the question came up about shielding. The better answer will arrive in a day or so. Yes, a larger chassis.

[Natural Sound]

From beginning It was build with upgrades.. Never heard stock model..

Too bad. Those "upgrades" might not amount to anything. Worse, they might degrade the sound as intended by the designers.