1030 recap progress and questions

[invalidbuffa]

I recently completed a recap of my 1030 using mostly the same compliment of parts as Pat did here with the intent of using it as a daily driver for my A7's. The output caps are 6800uf in the image but I've since changed them to 2200uf per factory spec. I wanted to mitigate phase shifting as much as possible and upped the value. It sounded fine through headphones, but on speakers the high frequencies were severely attenuated (foil inductance?). I ran the numbers...as it turns out, for a 2200uf cap, the phase shift is only 8.5 deg at 30Hz with a 16 ohm speaker, so there's essentially no benefit to increasing these.

I took it a board at a time and listened after each one. The EVOs went in last... The input cap position seems to make the biggest change in sonics.



Do you guys typically replace the green chicklets on the tone board?

Parts used:
Amp filter: Nichicon KG Super Through 4700uf/63v
Amp coupler: Nichicon KG Super Through 2200uf/50v

P800
H802, 803: UF4005
C803: Nichicon KG 680uf/100v
C804, 805: Elna Silmic 100uf/50v
C806: Elna Silmic 220uf/100v

P900
C901, 902: Wima MKS2 1uf/63v
C909, 910: Elna Silmic 100uf/16v
C924, 925: Silmic 10uf/35v
C919: Nichicon FG 47uf/63v
C926, 927: MKS2 2.2uf/63v

P500
C501, 502: Mundorf EVO AL+Oil .22uf
C504, 505: Silmic 4.7uf/35v
C506, 507: MKS2 1uf/63v
C509, 510: Silmic 100uf/16v
C511, 512: Silmic 10uf/35v
C515: Silmic 100uf/35v
C513, 514: MKS2 3.3uf/63v

P700
C701, 702: MKP2 0.47uf/100v
C703, 704: Nichicon KW 470uf/100v
C707-710: Nichicon FG 47uf/63v
C711, 712: Silmic 10uf/35v
C715, 716: Silmic 100uf/6.3v
C717, 718: Silmic 22uf/35v

 

[Lavane]

Some do replace them. I didn't on the one 1030 and both of the 1060's I restored. Since I had two 1060's, I was able to play around a bit with different film caps, and do some A/B testing.
I used the BOM BKtheking posted several years ago. I wound up putting the green caps back in both the 1030 and 1060's, along with the fat brown film caps. Replacing them changed the overall sound that I liked in the first place. With one of the 1060's I went as far as replacing all the carbon film resistors with tight tolerance metal films.
I'm not sure the time spent was really worth the small increase in clarity though.

 

[invalidbuffa]

Thanks for sharing your experience. I think I'll leave the ones in the tone circuit alone, but I may change the loudness ones, as I find myself using the setting with my Forte IIs more often than not. I always keep the old parts if I choose to revert.

Did replacing resistors with metal films improve the noise floor in your 1060? My 1030's preamp section exhibits a fair amount of background hiss and I'm wondering if replacing some of the resistors (especially in power supply positions) with metal film would quiet it down. I am also considering changing out the 2sc1213 on the power supply board to see if that reduces noise. All the 458's have been changed out.

At this point I think the 1030 is mostly burned in. Besides the background noise, it's sounding pretty darn good through both my A7s and my Fortes. Deep, defined bass, velvety mids, and a detailed but slightly pronounced top end. Soundstage has depth as well as width and good focus. It doesn't sound as convincing as my tube gear but maybe with some changes I can get it closer to what I'm after. It's all just a game of synergy...

 

[EastPoint]

.

Did replacing resistors with metal films improve the noise floor in your 1060? My 1030's preamp section exhibits a fair amount of background hiss and I'm wondering if replacing some of the resistors (especially in power supply positions) with metal film would quiet it down. I am also considering changing out the 2sc1213 on the power supply board to see if that reduces noise. All the 458's have been changed out..

Change out all the preamp transistors and see what that does.

 

[patfont]

""Do you guys typically replace the green chicklets on the tone board?""(QUOTE)

The green films at the preamp inputs and the brown films on the phono board (2230/2245/2270) are part of the Marantz sound.
IMHO if replacing the green caps you need to go to the Mundorf EVO Oil cap like in your pic.
I used to use Sonicaps on the phono but they discontinued the size/value I was using. So I leave the brown caps on board.

Hope this helps!

 

[invalidbuffa]

Thanks for chiming in, Pat. I've always left the brown caps alone, as recommended by you and others here. FWIW I really like the Mundorfs in the input position better than the original mylars. They're more neutral to my ears and sound very pleasing when the amp is used with horn speakers.

Change out all the preamp transistors and see what that does.

All of the 458s, including the six on the preamp board were replaced with KSC1845s at some point. I can't remember if I did them or the person before me did.

Just to expand, the level of the background noise doesn't seem abnormal, but it's audible from my listening position. The amp section by itself is adequately quiet. I'm hoping that selectively replacing resistors in the power supply and preamp with metal film types will help. Some experiments to follow...

 

[patfont]

Thanks for chiming in, Pat. I've always left the brown caps alone, as recommended by you and others here. FWIW I really like the Mundorfs in the input position better than the original mylars. They're more neutral to my ears and sound very pleasing when the amp is used with horn

In fact that is your best option IMHO.

Pat

 

[invalidbuffa]

Oh dear... Last night I was enjoying some Dave Holland Quintet and I may have gotten a little overzealous with the volume control. I noticed the left amp channel had begun to crackle during transients, however it still sounds fine at lower levels. The way the sound breaks up seems consistent with the effects of a bad capacitor, although it only occurs when the output is loaded. I verified this by connecting 8 ohm power resistors to the outputs and listening on headphones while I switch the output on and off. With headphones only the sound was clean at any volume level, but introducing the load caused the problem to return.

I suspect I'll find the fault somewhere in the output circuit, but I'm a little perplexed. It can't be the filter cap because that would equally affect both channels (and it's brand new), and from the behavior I don't think it's an output transistor either... Back to my lab it goes.

 

[invalidbuffa]

The caps all measured fine with my LCR tester...there were no anomalies when compared against the caps in the working channel. Output transistors test good... I checked the 1N60s, no problems there. I double checked the polarity on the caps with the schematics and everything is correct, including the screen printed markings on the board.



All the TO-92s seem to test OK. The only thing that sticks out is that the transistors in the current limiter circuit (2SC371, 2SA562) were replaced with 2SC945 and 2SA733 respectively, but I think they're suitable parts.

The next thing I'll try is probing around with my scope to see if I can locate the origin of the fault.

 

[invalidbuffa]

It's all fixed...turns out the current limiter transistors were installed incorrectly. I switched the base and collector leads, and now everything works normally.