Audio Asylum Thread Printer

Get a view of an entire thread on one page

FAQ / News / Events

Tweakers' Asylum

Is this your Marantz 250?

96.37.198.203

In Reply to: RE: Changing out an amp boards input cap value posted by airtime on July 06, 2018 at 08:02:16

If so, I'll start by saying I love old Marantz gear too. It's the equipment I lusted after when I was a teenager, and I still have a soft spot for it for that reason.

But if it is a Marantz 250, it's early 1970s solid state, and you're not going to transform it into a silky sounding amp with external wire, or even an internal input cap change.

That said, I'm going to assume the current cap is an electrolytic, given its 10 �F rating, because I doubt a film cap would fit. So if I were looking to make my amp less fatiguing, I'd be considering an Elna Silmic RFS for that position, given how many reports I've read regarding their "softening" of the signal, yet still delivering good bass. Nelson Pass once wrote that the Silmic was his favorite electrolytic when a polypropylene cap wouldn't fit.

You don't mention the cap's voltage, so the link below will show you the 10 �F Silmics available, from 16V to 100V. Good luck with your project.

"Suddenly, I'm not half the man I used to be. 'Cause now I'm an amputee" J. Lennon

https://www.mouser.com/Elna/Passive-Components/Capacitors/Al (Open in New Window)

Follow Ups:

RE: Is this your Marantz 250? - airtime 18:20:19 07/06/18 (2)
Oh HELL NO! Actually it is a NAD C275BEE amp. I've tried every thing to cut down on the brightness with no luck. I've gotten it to the point where it's "OK" but not to a good long term level.

Actually I'm listening to my 250m right now.

The cap in question is a polar cap - maybe a more "mellow" brand? Can a film be used in it's place safely?
- "maybe a more "mellow" brand?" - 1973shovel 09:01:26 07/07/18 (1)
  Yes, which is why I suggested that you might consider the Elna Silmic II caps, although knowing what brand caps are already in there might be helpful.
  
  If you can actually fit two 10 �F film caps in there, that's the route I'd go. I wouldn't randomly reduce cap microfarad value though, and two 10 �F film caps are going to be plenty big. That's why I related the Nelson Pass
  comment about using Silmics if polypropylene caps won't work.
  
  I'm going to guess the reason madisonears asked the input impedance of the amp is because you could also built a simple pair of resistor/capacitor high frequency filters on two RCA plugs and jacks to plug into the NAD input to roll off the top sooner, and wouldn't involve modding your amp. (link below). That said, I'd try the two 10�F Silmics, which are under $2 at Mouser for the pair, and see where that gets you.
  
  Good luck with the project.
  
  "Suddenly, I'm not half the man I used to be. 'Cause now I'm an amputee" J. Lennon
  - Low Pass Filters (Open in New Window)
  - RE: "maybe a more "mellow" brand?" - airtime 13:37:51 07/07/18 (0)
    When the weather breaks I'll try tacking in a film cap.
    
    But the Silmics look like a good option. I'll put an order in and in a few weeks I'll let you guys know how that turned out.
    
    Right now I'm using Nichicon FG series. A nice "clean" sounding cap. I'll put in a Solen film cap that I have kicking around for speaker use - just for a test. I may also look into WIMA caps as well.
    
    PS I'm assuming the Silmics are polar and I'm soldering them in parallel.

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.

This post is made possible by the generous support of people like you and our sponsors: