Marantz 2270 main filter cap value

[showett]

I am starting to re-cap my 2270 and was looking into options for the main filter caps, I have read the factory value is 9000uf and are being replaced with 10000uf. Mine has 22000uf caps that look original to me and don't know what to do. The main problem with unit is a loud 120hz hum at 20v at the speaker terminals with or with out the pre/power jumpers installed.

 

[Hipocrates]

I don think they are originals, I don't think they will fit 22.000uf cans.
The schematic shows 55V 6800uf, (I would put some 63V 10.000uf caps) can you post a picture to see what's going ona maybe I can help you?

Cheers

 

[showett]

Here are a couple pics of the top and bottom. If they were changed I think it was a while ago, they look to have aged the same as the rest of the unit. The serial number is 28xxx

 

[Leestereo]

I agree with @Hipocrates, the 22,000µF capacitors are not original (soldering does not look original) and they were not available at the time that the 2270 was in production.

Original installation with 9000µF (measured ~12,000µF) capacitors.


I have installed Kemet 15,000µF/63V capacitors (with a "star ground") to good effect.

 

[showett]

Thanks for the info, now I will start checking to see what els may not be stock and mabey clear up my hum issue while I wait for my new caps to come in.

 

[sssboa]

I am starting to re-cap my 2270 and was looking into options for the main filter caps, I have read the factory value is 9000uf and are being replaced with 10000uf. Mine has 22000uf caps that look original to me and don't know what to do. The main problem with unit is a loud 120hz hum at 20v at the speaker terminals with or with out the pre/power jumpers installed.

I had 18,000uF/55V in mine that looked like from the era and they were same Elna series as original 9,000uF, same dimensions too.There was a fad among kids in the 1980s of putting in very large filter capacitors which was supposed to add bass but I don't think it did. They would have done better fiddling with tone board caps I guess.

I think filter caps in 2270 don't have hard life. The temperatures are low, so is voltage. They usually measure excellent capacitance and ESR. I went for Nichicon audio type caps 10,000uF/63 although normally I use industrial parts in units of other brands for durability.

 

[Scotteboy]

I have repaired a lot of these and all were original. The only values I have ever seen were the original 6800uf and then later the 9000uf. I have tried both values and have not really heard a lot of difference. I usually use either 10,000uf nichicon gold tune most times and occasionally will put in the 10,000uf nichicon super throughs or even mundorfs at 10,000uf . Pat Font did a lot of work on this and leaned toward the Mundorfs If I remember correctly. I tend to pay attention to everything in restoring these and the hum could be present in say your power supply/relay area rather than just the main caps but I understand your current focus, i certainly agree it is probably related to a capacitor somewhere and first thing to check into.

 

[showett]

Thanks again, I am sure the hum problem is with the power supply since it affects both channels equally with out the jumpers in, I have ordered new rectifier diodes along with all new caps per some of the other restoration threads. It was curve ball when I saw the 22000uf caps in mine after reading about what others had replaced them with and with sssboa said makes sense since they definitely look old and were just as dusty as everything els under the hood. I am looking forward to getting it up and running since I have sold my 2230 already and miss the marantz sound already.

 

[Scotteboy]

Yep, they have a nice sound for sure. I haven't gone "all the way" replacing everything, but have some nice surprises along the way for getting the best sound. Overall the biggest overall bang for the buck beyond full recapping is 25 turn potentiometers for bias and dc offset. Getting the dc offset nailed is about the most overlooked item in restoring an amp/getting great sound vs okay sound. The post at the beginning of the forum on this "Amplifier distortion,dc offset and you" is well worth reading many times...Hats off to EchoWars on that valuable write-up !!

 

[rBuckner]

Umm hmmm, the larger caps pulled over twice the surge current than they should have and if the rectifiers are blown are the likely reason why. This is why I heartily recommend not going up any more than 20% in capacitance on these.

 

[showett]

After a closer look only one of the caps is 22000 uf, the other is the stock 9000. I have ordered new 12k caps and will take the advice on the trim pots as well and of course new lamps. Thanks again for the advice.

 

[sssboa]

What I found in 2270

 

[squeel]

Scotteboy, Saw an old post that you were trying to fix up a McIntosh MI-200. I see it really is a : A-109 amp (Mac calls it a K-107) not a MI-200. I have a pair of them. Do you still need help with it ? squeel

 

[sssboa]

I have repaired a lot of these and all were original. The only values I have ever seen were the original 6800uf and then later the 9000uf. I have tried both values and have not really heard a lot of difference. I usually use either 10,000uf nichicon gold tune most times and occasionally will put in the 10,000uf nichicon super throughs or even mundorfs at 10,000uf . Pat Font did a lot of work on this and leaned toward the Mundorfs If I remember correctly. I tend to pay attention to everything in restoring these and the hum could be present in say your power supply/relay area rather than just the main caps but I understand your current focus, i certainly agree it is probably related to a capacitor somewhere and first thing to check into.

Does it really make sense to replace the filter caps in 2270? I am restoring the second one with original 9000uF caps. They measure excellent, the receiver sounds excellent. This one for some reason sounds better than two I had previously. I recapped all boards but tuners. I measured all caps and they measured much better than in the previous restorations. The filter caps measure in circuit same as in previous one. And those out of circuit measured excellent in ESR terms and voltage loss.
I have 10000uF Nichicon Gold ready but afraid it could more likely make negative change if any.

 

[Steven Tate]

I have put those Gold Tunes in a half dozen 2245's and 2270's. In every case, the sound has opened up on both ends of the spectrum - at least to my ears. Worst case scenario, you put the new ones in, don't like the sound and put the old ones back. They aren't that hard to change. But I think you will find the sound to be better.
Steve

 

[sanjib]

Hi
In my Marantz 2270 both of the power amps and power supply board were fully rebuilt and bias was set couple of months ago but filter capacitors were not replaced at that time. If I replace the filter capacitors now do I need to do the bias adjustment again?
Please help. Thanks

 

[Steven Tate]

I would definitely check it and tweak if needed. I would do the same for DC offset.

 

[sanjib]

I would definitely check it and tweak if needed. I would do the same for DC offset.

Thanks