Essential restoration of phone and preamps cards for 1060 - 2230 - 2270 etc

[yak66]

I would like to keep and preserve as much as possible the original sound of the Pre Phono and if possible even more beautiful and precise.
I'm afraid of losing the original sound.
My old 1060, completely original, however, sound a little muffled and the two channels have a different sound, between them.
I would like some "essential" instructions for a good restoration.
Thank you

 

[Dingman]

Hello there, welcome.
Instructions will be in the form of the "Here's how I did it" threads. Some will be better, easier to read and follow and some others, not so much. So search this forum for your "1060 rebuild" or "1060 recap" or "1060 capacitor" - those sort of keywords will get the threads that you want.

Then read them. Then read them again.

If you already have the tools and know how to use them, just jump in, LOL.

Good luck.

 

[Dingman]

Oh, and on the subject of keeping "that Marantz sound" but "muffled"... Whew! that is tricky for sure.

A real recap will certainly change the sound, you just can't get around it. Also as certain, no one can accurately predict how much or how little that unit will benefit. There's a ton of variables. And a ton of threads discussion just this thing... you could go down the rabbit hole on that topic here.

 

[quadmatrix82]

Remember if you recap to original spec you are hearing the amp marantz intended It to sound - what you are hearing now is an old worn out amp

Highly recommend you change the film caps on the pre and phono boards makes a huge difference to the sound quality on these amps as a minimum

 

[yak66]

Thank you Dingman and quadmatrix82 for your advice.
I understood what you mean quadmatrix82.
Replace ALL the film caps on the two pre and phono boards, then ??
.... electrolytic or ALL (ceramic and polystyrene capacitors too? ...)

I want to keep the values close to original, to preserve as much as possible the original sound

 

[Leestereo]

This thread might answer some of your restoration questions: http://audiokarma.org/forums/index....oration-and-upgrade-of-a-marantz-2270.793805/

 

[slowpat]

Thank you Dingman and quadmatrix82 for your advice.
I understood what you mean quadmatrix82.
Replace ALL the film caps on the two pre and phono boards, then ??
.... electrolytic or ALL (ceramic and polystyrene capacitors too? ...)

I want to keep the values close to original, to preserve as much as possible the original sound

My understanding was to keep the film caps but replace all electrolytic caps, and a few of the noisy transistors. In your case, I would start with that first. Listen for a while , and then update the film caps to see if you can hear any improvement. I believe you will get 90% of the improvement with the e-caps and transistors. A couple of the diodes as well.

 

[yak66]

thanks slowpath. I brought my 1060 yesterday to a repair technician (for hobby) who has a 1060 and has already restored his amp.
He wants to replace all the electrolytics of the power supply.
I would like to replace as little as possible
replace by steps, it is the best choice !!!

 

[Mike Sweeney]

No.. replace all the caps. Its only as strong as the weakest link and when you start mixing very old with new, the old can have issues. These caps are circa 1975 ish.. about 40 years old and way past their life expectancy. If you are concerned about the "sound", replace the caps like for like.. don't bump the values.. don't bump the voltage.. don't use audio low ESR caps.. don't use films for the low values. But, the last three Marantzs I've done, the new low ESR caps did not "change" the sound other than make it clean. Even on my 2285B where not only did I replace all the caps, I changed out all the main amp transistors. The sound changed.. from a weak buzzing, snapping arcing mess to a rocking kick ass sound So I consider that a win. Maybe if I had the same ears I had in 1975 I could hear more of a difference but today, I really don't hear the difference of old parts vs shiny new ones other than they work and the old don't work or don't work well.
PS.. I'm not addressing all the "stuff" about using speciality coupling caps etc. Just a standard restore

 

[yak66]

Thank you Mike Sweeney for your reply.
very interesting

 

[Leestereo]

The "sound" is the result of the topology, the use of modern electrolytic and stacked film capacitors, low noise transistors/resistors...etc...only maximizes potential of the original Marantz design. There are many, many recap/restoration examples on AK that corroborate this.

 

[yak66]

very clear explanation.
Why did someone, not satisfied with the new sound, put the old capacitors back on?
(power caps, to be more correct ....)

 

[cortico]

...If you are concerned about the "sound", replace the caps like for like.. don't bump the values.. don't bump the voltage.. don't use audio low ESR caps.. don't use films for the low values. ...

Hi Mike, I thought that bumping up the cap voltage wouldn't affect the sound?! I remember bumping a couple 47uf 16v (C909-C910) up to 50V on my restoration

 

[Mike Sweeney]

Hi Mike, I thought that bumping up the cap voltage wouldn't affect the sound?! I remember bumping a couple 47uf 16v (C909-C910) up to 50V on my restoration

The higher voltage caps tend to have more resistance. If you take a cap at 16 volts and measure the ESR then take the came value but at 50 volts, you get a different ESR measurement. Also, keep mind there can be significant differences between brands and between types.. aka.. general purpose cap vs one for "audio". Some claim to hear the differences.. I don't hear the differences so I don't worry about it very much. I worry more about reliability. Most of my replacements get bumped in voltage except for the very small value caps. When the cap is something like .1uf at 16 volts.. if I have the electrolytic, I'll use them. Of late I've been using Wilma films and they work fine as replacements for the small values. I've seen a lot of discussion back and forth about that so I'll only say what I've seen and done personally

 

[Mike Sweeney]

Why did someone, not satisfied with the new sound, put the old capacitors back on? (power caps, to be more correct ....)

because they were being foolish. If for no other reason than safety. Why would you put a 40 plus year old cap back into the main power circuit? Thats dumb. I can see juggling the audio coupling etc.. but when it comes 120 volts and something around 50 to 300 watts or more, risking the gear and possibly your house with old leaky caps is a bad idea.
And they do leak most of the time. I have a tester for leakage.. not just resistance. I have had many caps that test "good" for ESR and fail miserably on leakage. In most cases, I move up in voltage for my filter caps and in capacitance. On my 2285B, the dual caps were rated at 63 volts and 6400 uf. One failed completely.. one leaked at 25 volts and the others leaked at 50 volts. The three that didn't fail completely passed the ESR tests. So the casual ESR test said they were fine but they were really time bombs for total failure in the near future.. sooner if I cranked it up and really started to pull some watts.

 

[Leestereo]

The higher voltage caps tend to have more resistance...

A plot of capacitor ESR vs. voltage will typically have a parabolic-like shape, i.e., as voltage increases, the ESR will decrease and after a certain voltage will increase again. For example (from a datasheet), a Nichicon PW 100µF capacitor will have an impedance of 0.6Ω @ 6.3V, 0.5Ω @ 10V, 0.25Ω @ 16V, 0.25Ω @ 25V, 0.12Ω @ 35V, 0.23Ω @ 50V and 0.256 @ 63V. Similar results are reported by Rod Elliot on his excellent webpage on Capacitor Characteristics: http://sound.whsites.net/articles/capacitors.htm#s40