Marantz 140 Stereo Power Amp – Restoration Work

[labatt242]

Hello !

I am about to remplace the big dual caps for 2 Mundorf 15 000uF - 63VDC on my Marantz 140. The only thing is... I saw the picture from Flaxmill19 there is 2 cables for the ground screwed into the amp. But, where are solder these cables? On the lug between the Mundorf caps?


I'm not comfortable with electronics and I do not want to break anything

Thanks !!

Guy

 

[bryans12v]

You'll need to remove the old ground bar, the one that has two 90 degree bends and screws to the chassis. It will no longer work using the two new mundorfs. The mundorfs come with a glue on ring on the solder tab side, I carefully transfered it to the bottom and glued them to a small 3"x3"(ish) piece of 1/8" lexan.

I used a 2" copper pipe coupling. Cut it flattened it and drilled holes for the wires, worked great.

 

[Flaxmill19]

Hello !

I am about to remplace the big dual caps for 2 Mundorf 15 000uF - 63VDC on my Marantz 140. The only thing is... I saw the picture from Flaxmill19 there is 2 cables for the ground screwed into the amp. But, where are solder these cables? On the lug between the Mundorf caps?
Guy

Hi labatt242,

I ran two ground wires from the bottom side of the copper strap between the two capacitors, you could probably use one, but I just wanted to be sure I had a good ground connection to the amplifier chassis.

Tony

 

[labatt242]

Hi labatt242,

I ran two ground wires from the bottom side of the copper strap between the two capacitors, you could probably use one, but I just wanted to be sure I had a good ground connection to the amplifier chassis.

Tony

Dear Tony,

Thank you for the info !! Can't wait to replace this dual caps for the Mundorf !

Thanks again

Guy

 

[labatt242]

Hello !

Here a little update. I finally get rid of the old dual caps. I am about to solder all these wires at the right place. Little question, can I solder all the black wires in only one wire and solder this single wire between the two caps? Or I absolutly need to solder these wires between the two caps? The single wire on the power transfo is for the ground.

UPDATE : I added a picture of my progress. Only ground wires left!

Thanks!

Guy

 

[Flaxmill19]

Hello !

Here a little update. I finally get rid of the old dual caps. I am about to solder all these wires at the right place. Little question, can I solder all the black wires in only one wire and solder this single wire between the two caps? Or I absolutly need to solder these wires between the two caps? The single wire on the power transfo is for the ground.

UPDATE : I added a picture of my progress. Only ground wires left!

Thanks!

Guy

Hi Guy,
Looking good, yes the white wire from the transformer goes with the black ground wires. You could solder all the wires together on one capacitor terminal and then run a wire to other capacitor terminal, I would probably run two just to make sure I have a good ground connection. Or you could put half the black wires on one terminal and half on the other then run the two wires between.

Tony

 

[labatt242]

Hi Guy,
Looking good, yes the white wire from the transformer goes with the black ground wires. You could solder all the wires together on one capacitor terminal and then run a wire to other capacitor terminal, I would probably run two just to make sure I have a good ground connection. Or you could put half the black wires on one terminal and half on the other then run the two wires between.

Tony

Hi Tony,

Thank you for your reply!

I see there are some posibilities to do the ground wires. I prefer to do a clean job with a metal plate between the two caps. I will drill some hole to solder the wires easily. I will post the final result this afternoon once I have the correct tools to do the job.

I will do a second wire for the ground to the chassis as you recommended.

Thanks again!

Guy

 

[labatt242]

Hi Tony,

Here some updates for the filter caps restoration. It doesn't fix my buzzing issue but I am happy of this work !!!

 

[labatt242]

For the buzzing issue, it seems it only arrives for the left amplification. The VU meter moves and we can hear the buzzing very well. The issue is "resolved" when I power off and power on the amp and I am good for several minutes. What is your thought guys? All caps has been replaced on both amp section.

Thanks,

Guy

 

[labatt242]

Ah well odd thing, the "hum/rumble" issue is resolved. It seems I have a grounding issue in my housing. I live on the 2nd floor and the house owner on the ground floor has just unpluged and removed the AC last week end for the winter and no more hum issue ! Maybe something with the outlet....

I hope it will help some people with this issue!

Thanks,

Guy

 

[Flaxmill19]

Glad you found your buzzing problem, grounding is a subject in it's self that one can spend a lot of time on.

Enjoy the sounds of your 140.

Tony

 

[Flaxmill19]

Marantz 140 Amp 4 Pole Main Filter Capacitors – Restoration Part 5

Thanks to Bert1100 who asked Mundorf how to wire their 4 pole main filter capacitors into a power circuit. I have now rewired both my 140 amps to the schematic supplied by Mundorf, via Bert1100. I have now had the amps running about 200 hours with the new wiring. I must say at this stage I cannot hear a significant difference between the old and new wiring connections. I even did and A/B comparison when I had one amp with the new wiring and one amp with the original wiring, I couldn’t pick a difference.

I must say, that the wiring now seems more logical and therefore I happy that I have changed the wiring over.

I have attached a new schematic for wiring these 4 pole filter capacitors into a 140 amp for anyone interested in fitting these 4 pole caps, enjoy.

Tony

 

[Bert 1100]

Great, thank you for the news !

 

[patfont]

Looks nice!

 

[gotoma8]

Hi All,

Just got a 140 as well! It's in great working condition but after reading all these upgrades I want to do it too, but maybe just hold off. I wanted to know if anyone can comprise a list of the parts and items that they replaced, etc. and why they did it! I would also like to see a pic or two of the new LED lights on the UV Meters.

Thanks!

 

[Morgan250]

Hello everyone
First of all, sorry for my bad english, i'm french and I really enjoyed seeing all your tips on this blog for the restoration of the amp Marantz 140/3200, it helped me a lot. Indeed, I have a 140/3200 and I decided to fully restore: Change all capacitors by Nichicon FG, KZ on the 3200 and elna silmic II, mundorf supreme (for gray film capacitors ) and 2x Mundorf for the big filter capacitor on the 140. I'm quite happy with the result, on the other hand I have difficulties to adjust the DC balance and offset / bias on the 140, could you help me? On the 3200 it was very easy, 75v as it is recommended on the manual
Thank you in advance, and again, thank you for all your many tips, I took great pleasure in reading you and applying your recommendations.

Morgan

 

[Flaxmill19]

Hi Morgan

Welcome to Audiokarma and I am glad that you gained some help in your restoration from my experiences. Both my 140's operate for about 2 hours a day almost every day and sound great (in my opinion).

Regarding your adjustment for DC off set and Bias, I reviewed my notes and I have followed the Service Manual on both my 140's and have not had any problems, maybe if you provide more details on what is happens the other members or i may be able to assist.

Tony

 

[Morgan250]

Hello Tony,
A big thank you for your quick answer Very nice installation !!!
For the adjustment of bias / DC balance, I followed the manual, it seems to me that it was easier than I thought, I hope I did not make a mistake: For the DC balance I plugged my multimeter on the left speaker outputs and I set with the variable resistor R741 to 0Mv on each channel. For the bias, I plugged my multimeter on J701 and J702 and I set with R742 on 10Mv on each channel. Is this the right way? I had a doubt because my 140 is in 240V whereas on the manual the procedure is for 120v (US model). In any case, I noticed an improvement of the sound (more bass, its less "metalic" ...).

At the moment I'm using the 140 with the preamp part of the 1060, I'm still waiting for some capacitors for my 3200. I want to change the film capacitors of the phono part (the gray 1uf 250V) and change the connectors RCA by Neutrik gold. Do you think I can put supreme mundorf like for those of 140? I saw that some used SONICAP or JANTZEN SUPERIOR z ... Also, for the 2 X Mundorf, I used the original bar that I cut and I welded a ground wire connected to the chassis do you think it's ok? The ground wire is enough?

Once again thank you !

Morgan

 

[Morgan250]

Hi Morgan

Welcome to Audiokarma and I am glad that you gained some help in your restoration from my experiences. Both my 140's operate for about 2 hours a day almost every day and sound great (in my opinion).

Regarding your adjustment for DC off set and Bias, I reviewed my notes and I have followed the Service Manual on both my 140's and have not had any problems, maybe if you provide more details on what is happens the other members or i may be able to assist.

Tony

Hello Tony,
A big thank you for your quick answer Very nice installation !!!
For the adjustment of bias / DC balance, I followed the manual, it seems to me that it was easier than I thought, I hope I did not make a mistake: For the DC balance I plugged my multimeter on the left speaker outputs and I set with the variable resistor R741 to 0Mv on each channel. For the bias, I plugged my multimeter on J701 and J702 and I set with R742 on 10Mv on each channel. Is this the right way? I had a doubt because my 140 is in 240V whereas on the manual the procedure is for 120v (US model). In any case, I noticed an improvement of the sound (more bass, its less "metalic" ...).

At the moment I'm using the 140 with the preamp part of the 1060, I'm still waiting for some capacitors for my 3200. I want to change the film capacitors of the phono part (the gray 1uf 250V) and change the connectors RCA by Neutrik gold. Do you think I can put supreme mundorf like for those of 140? I saw that some used SONICAP or JANTZEN SUPERIOR z ... Also, for the 2 X Mundorf, I used the original bar that I cut and I welded a ground wire connected to the chassis do you think it's ok? The ground wire is enough?

Once again thank you !

Morgan

 

[Flaxmill19]

For the adjustment of bias / DC balance, I followed the manual, it seems to me that it was easier than I thought, I hope I did not make a mistake: For the DC balance I plugged my multimeter on the left speaker outputs and I set with the variable resistor R741 to 0Mv on each channel. For the bias, I plugged my multimeter on J701 and J702 and I set with R742 on 10Mv on each channel. Is this the right way? I had a doubt because my 140 is in 240V whereas on the manual the procedure is for 120v (US model). In any case, I noticed an improvement of the sound (more bass, its less "metalic" ...)

Hi Morgan,
For adjustment of the DC Balance I do as you do, there is a large post by EchoWars on the subject of DC Offset, makes and interesting read, especially the first part, http://audiokarma.org/forums/index.php?threads/amplifier-distortion-dc-offset-and-you.5634/

As for the Bias, I adjust the pot fully CCW and then what ever the reading is at that point on your multi-meter I adjust the pot to add 10mV to that figure. And both channels may be slightly different.

Regarding capacitors, I believe they are very personal to each persons preferred sound, I have used many over the years, and they all have their own sound. Regarding your 3200, mine has many modifications including about five different configured phono boards. My current board has WIMA's in C415, C416 & C414, C413 positions, but that's for another post.

Tony