1060, cap coupled sound

[cortico]

I had one of these little amps a while back and have missed it to bits.

So, recently I got another 1060, it’s completely original. I have actually favored it when compared with a much more refined and accurate 2270... nonsense.

It sounds so cool to my hears to a point I don’t want to recapped, because sound will certainly different, more nonsense . So, I moved ahead and got second 1060, which I am planing to recap/upgrade and then AB with the original.

Basically, I am willing to make that original sweet distortion and coloration more reliable. I understand the benefit of increasing the capacitance of the main filter and local filters.

I am curious to know your option on bumping output coupling caps value and impact on tone?

 

[Steven Tate]

Interesting comparison. 1060/2270. In the early 70’s, I got my first quality stereo, a 2230. Had it for a year and played it every day when I had an apartment break-in and it was stolen. To console myself, I decided to save up and replace it with the 2245 I had originally lusted over, but decided I couldn’t afford. Of course, I had no idea at the time that the 2230 was cap coupled and the 2245 was not. All I knew was that the 2245 had more power. It was a bit of an A/B test since I was very familiar with the 2230 sound. Personally, I did not detect a “different” kind of sound (warmer, etc.). I just knew the extra power of the 2245 made my rock albums (now known as classic rock) sound better, with more punch. I just assumed it was the 15 more horsepower under the hood. But it may have been the different architecture. To this day, even though I have a 2270, 2275 and 2325, the 2245 is my favorite. Nostalgia? I don’t know. I just know that, while the cap coupled 2230 sounded great, the 2245 sounded better to my ears. I look forward to seeing the results of your A/B recapped/non-recapped 1060’s.
Steve

 

[Chrisxo55441]

my 1060 sounded great before it was recapped and its sounds great after it was recapped. an A/B comparison will be cool, but im happy with how it sounds now, ive had other amps/receivers where i heard a big difference (for the good) after a recap but this is one of the ones that seemed to stay the same.

 

[onwardjames]

This should be interesting. I miss my little 1030. 18 sweet little watts.

 

[quadmatrix82]

I’d suggest not to change values on the filter caps unless you upgrade the main rectifier and also you should change the power switch and safety cap which are prone to fail on this model. I had a 1030 with upgraded output coupling caps when compared to a stock 1030 the sound felt like it had a little more depth and headroom it was pleasant but different..both ways are good just different if you like the original tome I’d suggest keep everything stock values just freshen up with a recap so you get the sound marantz intended and easier when you decide to sell

 

[cortico]

Thanks guys! all above sound good.

I guess, I am steeping away of the upgrade idea, I do actually intend to keep the values close to original, with the exception of the main filter (C003) I am bumping from 4700uf to 6800uf just because I found one Jensen 4 pole for half the price. Looks a bit more tricky to wire but I understand that the + from rectifier goes to the "+ in," then the the amp board wire comes from "+ out." All the ground wires go to "-in," and the "- out" goes to that ground strap".

The coupling caps (C006-C007) will remain 3000uf or 4700uf max, planing to use Jensen here as well.

In addition to main filter and coupling in the first approach I will also replace all electrolytic on power supply board and all the local power supply filters, I have used Elna Silmic II on my 2270 but looking for something different and cool.

 

[CohibaJoe]

....Will be watching....

 

[nerdorama]

A 1060 was my first good amp. Bought it new in college. Wish I still had it for sentimental reasons.
Looking forward to your results.
John

 

[cortico]

Got the second unit in! It has an earlier serial number and looks pretty clean inside.
The right channel is weak and distorts I measured the following voltages:

Right Channel:
0mvdc between J713 and J715 (adjusting R729 as no effect)
~47vdc between J715 and ground (adjusting R723 as no effect)

Left channel:
7.5mvdc between J714 and J716
29vdc between J716 and ground (all seems good and adjusts well)

Could you help to troubleshoot this? where should I go first?
I have placed and order for power supply caps and speaker coupling caps. I was not expecting a bad channel and was going to start with this...

 

[cortico]

ok, I have done some homework. I will take a look at the transistor H709 (2SC959-2N3440) and H711 (2SA606-2N5416), also resistor R747 and R749 (0.24ohm 2W wire wound)...

 

[cortico]

For R747-749, would it be ok to use a .27ohm 5w in lieu of .24ohms 2w?

Thanks!

 

[CohibaJoe]

For R747-749, would it be ok to use a .27ohm 5w in lieu of .24ohms 2w?

Thanks!

R747-R750 - KOA Speer .24ohm/2W "660-MOX2CT631RR24J"

My Recap Thread....A good read: http://audiokarma.org/forums/index.php?threads/marantz-1060-recap.568728/

 

[cortico]

Thank you CohibaJoe, this is helpful!!

I will try to address the Right channel distortion issue first. rBuckner gave me a few tips (thank you!!) I feel confident that it wouldn't be a problem to bring it back to life.

Finally, the power amp board came out, I was surprised how easily the power amp module came out. I have flipped the board and attached it back to the heatsink to avoid bending the transistors leads to many times, and have easy access to both sides of the board.

Originally, I was considering only replace the electrolytic capacitors on the power amp board although I have expanded that to all resistors and the bad transistors (probably the H711) as the voltages are off.

H709
E: 43.7vdc
B: 57.0vdc
C: 72.0vdc

H711
E:43.7vdc
B:54.0vdc
C: 0vdc (no voltage)

 

[cortico]

I have made a few more measurements today and probably found the cause of the channel imbalance, resistor R743 measures more than twice its value!!

There are also other small discrepancies between L and R channel actual resistors readings. I guess, this just reiterates how important his to overhaul a vintage unit if it’s intended to use it everyday.

I will replace them all with audio grade Takman Rex carbon film resistors. They are specifically designed to have very low inductance and microphony. Supposedly, It will produce most of the warmth of a carbon comp without all the drift and noise...

R743 looks cracked:

 

[ioni]

I follow discussion, suddenly my 1060 has similar problems....:-(

 

[cortico]

Almost 1AM,

I finaly stoped procrastinating and did the power supply. Everything came out with the exception of the ceramic caps.

All electrolitycs, carbon comp resistors and transistor were replaced.

A few pics of the process

 

[cortico]

This is very exciting! The boards look so good after a clean up.

This is the scope for the main amp:
-Vishay trim pots
-Electrolytic, throughout
-Resistors, throughout
-Transistors as needed
-Mica insulators and compound
-Diodes H713-H714

Silver mica, film and ceramic cap will be left alone:



R743 was broken...

Saving all parts:


I got some transistors spares, lucky to source the original Hitachi 2SC897. Now I need to buy a transistor tester....

 

[The Fuxtor]

Wow! Going all out!! Looking fantastic! Never have heard a 1060, but i recapped a 1070 and it sounded great!

 

[cortico]

Thank you Fuxtor!

Wow! Going all out!! Looking fantastic! Never have heard a 1060, but i recapped a 1070 and it sounded great!

 

[cortico]

Board done and back on the heatsink: