• Please note that Audiokarma will be offline briefly for updates early on Monday morning, September 28th.

Marantz 2215 hiss and hum

Building a current limiter, also known as a Dim Bulb Tester, is cheap, and really important. If you get a short in there when replacing parts, you could kill the transformer or damage things.

This is how I did mine:
67dcA79.jpg


There's a metal tab on the left side of outlet that you break off so the current goes through the upper socket and bulb first, and then it passes to the lower socket:
PP3zfjd.jpg


Then leave the tab on the right side to connect the power from the bulb to the lower socket:
ZTijsu2.jpg


ELZ9krv.jpg


There's many ways to do this, but I wouldn't restore and test without one of these. A 60W bulb or better would be best for the 2215 30 watts.
 
bdondo said:
Thanks! I've heard of this.. I'll look into it more.
Click to expand...
Amazon order, maybe $20:
A 3-prong power cord from any old PC
Plastic dual-gang electrical junction box
one SPST regular wall switch
regular outlet
Plate
the bulb socket

The incandescent bulb is the hardest part to find these days, 100W is great if you can find one.
 
Last edited:
bdondo said:
Here's where I get bogged down looking for parts -- as an example, for the C707 (47uF/50V cap), which of these should I choose? https://www.mouser.com/c/passive-components/capacitors/aluminum-electrolytic-capacitors/aluminum-electrolytic-capacitors-radial-leaded/?q=nichicon&capacitance=47 uF&diameter=6.3 mm~~10 mm&product=Audio Grade Electrolytic Capacitors&voltage rating dc=50 VDC&instock=y&rp=passive-components/capacitors/aluminum-electrolytic-capacitors/aluminum-electrolytic-capacitors-radial-leaded|~Diameter
Click to expand...

Try to keep the same uF, you can go with more Voltage, but the more voltage generally means the physical size of the cap is larger too.

If you look at the datasheets, you can see that the electro-caps are rated for heat and longevity. In the power supply is where the high temps are, so maybe you'd select 105C caps, if you wanted the best. I actually went with 85C audio grade Elna II's in everything on my 2215, power supply too.
 
Next question: I was about to order some KSC945YBU for H701-H702 -- is the standard practice to buy several and test them to find matched pairs? If so, I suppose I need something that can test these? Something like a DCA55? I see a wide range of prices for semiconductor testers, but not sure what is really required.
 
bdondo said:
For C711 and C712, Nichicon doesn't have any 10uF/35V audio-grade caps -- should I try to find a different brand, or should I get their 10uF/80V version (UFG1K100MEM1TD)?
Click to expand...

When you start getting to the 10uf and below mark, some use WIMA film caps instead.

Some say the WIMA are a bit sterile, or don't have that Marantz warm sound when you use them in the tone board. Hard to say, but this is where I would imagine the choices matter most, if you're particular. I used Elna II's at the 10uf mark, and WIMA smaller than that.

This is all subjective, unless you are actively listening with the exact source material/volume/speakers/headphones, you may not catch the difference as you move on with each board you restore. Best to restore one board at a time and listen to something familiar with each board you fix, so you can pinpoint changes in the tone/overall sound stage.

bdondo said:
Next question: I was about to order some KSC945YBU for H701-H702 -- is the standard practice to buy several and test them to find matched pairs? If so, I suppose I need something that can test these? Something like a DCA55? I see a wide range of prices for semiconductor testers, but not sure what is really required.
Click to expand...

The transistors are usually cheap, I got a dozen of each one to test and match hfe, I am personally particular about matching hfe as close to original as possible, and as symmetrically close L&R, overall. I would not recommend changing every transistor, or resistor, it's not necessary, and some of the soul can get stripped out of these.

The DCA55/75 are great, but they only test at low voltages, and can't be as thorough as a curve tracer would be. The Peak Atlas handhelds are great, but without being able to simulate the high voltages that go through the components, they don't always get it exactly right, but much better than nothing and really good, I'm just being 100% honest.
 
Thanks, I was thinking of using the WIMA film caps for the lower-capacitance caps. I would bet a lot that nobody could tell the difference in a blind test. Most people can't even pick out Pepsi over Coke head-to-head, let alone objectively discern the difference between a couple of capacitors in a non-blind, non-head-to-head test.

Interesting about the DCA55/75. I didn't consider the low voltage thing. Hmm. I suppose I could built a test circuit and measure gain, but that could get tedious.

But also a good point about replacing the transistors. Maybe I'll just replace capacitors for now. I know for sure that one is bad, so hopefully that's the cause of the hiss. If I got rid of that hiss, it would sound great to me. I'd probably replace all the electrolytic caps anyway though.
 
The 945, and 458's are known bad transistors, those are worth getting rid of while you're in there. There's also what's known as blob diodes, or gum drop diodes, those should be replaced in the signal path.
 
The DCA55 or 75 can do audio transistors very well, they are low voltage, definitely great for hfe and many other functions. I just wanted to make sure before you put up good money, you know there can be a limitation with some components.

I have the Atlas Peak ESR70 for testing caps, and the DCA75, very happy with them.
 
You must log in or register to reply here.
Back
Top Bottom