• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Scary repair - 2285B dual-section caps failed

Thanks Jim - it was interesting to do! I'm happy to report that 5 years later, the receiver is still working beautifully. I use it pretty much every day. A few weeks ago I gave the switches a clean, and took the opportunity to replace the spring terminals with binding posts for one speaker set. It was surprisingly simple to do, actually.
 
596657-beffa7b865cb2a8ec47eb1080ae65b97.jpg

These were sold as adaptors for speaker wire to spring terminals, so they have a binding post leading to a small solid metal "tail". I glued them using epoxy through holes I had drilled in two sheets of acrylic plastic with the same spacing as the spring terminals.
596658-2a1165456939c995ec05884735d39c82.jpg

By unscrewing the plate for the upper spring terminals I was able to fold them out of the way, soldering the tags of the spring terminals to the tails of the binding posts. Unfortunately I had to fold the tags to fit in the space, and ended up having to remove the original terminals.
596659-ddd39b4afdc1abd82fc8f866ec9745de.jpg

A pilot hole through the sheet of acrylic allowed me to use the original screws to hold the new terminals. Works perfectly with a much better connection to large wires.
 
Hi everybody:

I will recap my MARANTZ 2285B in a few months (right now I'm restoring my Pioneer SX-1010) and this is what I came up with, not sure if the board will fit, it may need a little trimming and four standoffs. I will use 8 caps. The caps are nichicon Gold Tune audio grade caps LKG1J472MESBAK, 4700uF at 63 V, so I will increase a little the capacitance, from 6800 to 9400 uF on each channel, (I know about the inrush current but I don't think it will damage PS diodes, main switch or transformer, it is not that much). The circuit board is from ebay. Here are some pictures. Hope this will help


IMG20230301123422.jpg IMG20230301123231.jpg IMG20230301123327.jpg IMG20230301122952.jpg
 
Last edited:
Thanks in this instance does having audio grade equipment matter? As its not in the audio signal path? Its use is just for the storage of energy not so much the filtering capabilities…
 
HI sanicrew87:

Well, talking about capacitors is like opening a big can of worms. But in my own experience, they really make a difference. One of my first projects was a Marantz amplifier, and it had a split power supply, and I have finished recapping it. So I made an experiment, on the left side I replaced one of the new caps with Nichicon UFG series cap, and to my surprise it sounded better.... mmmmmm, I think I'm biased, so I called one of my daughters and she immediately said left channel sounded better. Then I called my wife, she also said left channel sounded better. Then I replaced same cap in the other side, and both channels sounded equal.

Also recapping with hi quality caps make a difference. I made another experiment: I replaced all caps from my vintage ADC graphic equalizer on the left channel (all the removed caps from left channel tested really OK) and what a surprise... bass was tighter, mids more open and clearer, and really crisp highs. So for me, yeah, quality caps make a difference. BUT, to hear the difference, you need a high quality audio source, a good amplifier and really good speakers. You won't hear any difference using cheap components.

So, I will always use quality caps and I will always change ALL electrolitic caps. I use nichicon UFG, nichicon UKT, elna SILMIC II, etc. and always buy from a reputable vendor, like Mouser.
 
sainicrew87 said:
Thanks in this instance does having audio grade equipment matter? As its not in the audio signal path? Its use is just for the storage of energy not so much the filtering capabilities…
Click to expand...
No it doesn't matter. If anyone says they can hear the difference and their career isn't in auditory technology, they're lying.
 
Im also just about to service my 2285b, what would be good bypass caps for the main filter caps if going the 2 per channel method like original? Where would it be connected?
 
sainicrew87 said:
Thanks in this instance does having audio grade equipment matter? As it’s not in the audio signal path? Its use is just for the storage of energy not so much the filtering capabilities…
Click to expand...

It kind of matters:


A primary purpose of these capacitors is to smooth out voltage fluctuations in the DC power supplied to the main amplifier. Even though the audio signal does not go through these capacitors per se, any remaining voltage fluctuations in main amp’s DC power get mixed with (i.e., added to) the audio signal prior to amplification, and then amplified along with it. This can cause hum, noise, and other icky effects.

In theory, all caps of equal capacitance and voltage rating should perform this function equally well. If that were really true, though, then you could build and use a capacitor to spec out of a roll of tinfoil and butcher paper (pro tip: don’t). I suspect you might notice the difference audibly, despite the capacitance meeting spec, and despite the audio signal not going through it.

Capacitance is a rather blunt metric, and many of the properties of audio grade capacitors that produce desirable aesthetic characteristics are difficult to quantify. In the case of power supply bypass caps, those properties “shouldn’t” matter in theory, but many people claim to notice differences between different models. The right solution seems to be somewhere between a tinfoil cap and the audiophile-grade one made out of meteorite gold and Burmese silk dipped in the blood of twelve virgins. In practice, even good capacitors are pretty cheap, so I just assume default to using reputable components that other people have reported enjoying.

How’s that for a non-answer?
 
Last edited:
Thanks for the responses guys, im going with some nichicons 6800uf 63v. In one the other posts i noticed people using bypass caps and resistor bridges what are the advantages of the resistors? For the bypass caps what would be a good cap to use and how exactly do i bypass the double cap or would each cap ie all 4 have a bypass on it? What capitance and voltage would be best? If using added resistors what would you use?
 
Sorry if im confusing you, on another thread that someone posted about the main filter caps ie the big ones, they had a red film cap? Square looking thing that had a resistor between the two legs and that was somehow attached to the big/main filter caps im trying to find the thread but seem to have lost it ill search again when im home on pc and see if i cant link it.
 
Thanks for the info appreciate it, appears i don't really need them, i like the sound of the marantz pre replacement of parts so i dont think i should tinker too much in trying to “upgrade” it.
 
I'm working on a Sony STR-3800 (the first generation, not the later L revision).

it has a large Nichicon Dual-C, rated 5600uf + 5600uf 50wv (I'm pretty sure that wv is the same as the modern convention of 50v, is that right?)

It measures approximately 45mm wide, and 80mm tall.

I've been over several of these threads repeatedly the last few days. I'm very much a visual person, and many of the older posts are now completely missing their original photos.

I'm also still on the newer side of recapping.

I can ONLY seem to find 5600uf 50v caps that that are "snap in" -- so those angled terminations meant to snap into a board.

I'm really not keen on attempting a "cap" stuff project for this.


Question 1) How would I go about repalcing this, in this scenario, with two new "snap in" caps? Is there an easy way, here, or many different complex ways I could go about it?

Question 2) Here are some matching caps I found on Mouser. I'm leaning toward the Cornell Dubelier CDE -- the cheapest -- but I really have no idea how big a concern things like Ripple Current or ESR for this particular replacement.

Any wisdom anyone can provide is much appreciated, as this is my first time replacing a dual cap like this. Thank you!

dual-c-01.jpgdual-c-02.jpg
 
PS. I'm interested in persuing this because I had read/ watched some things that said, at a min., when performing a refurbishment, you should start by replacing the big filter caps. And my assumption is that is exactly what this Dual-C is, in this particular receiver.
 
You must log in or register to reply here.
Back
Top Bottom