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Project: Marantz 2275

Super Noob said:
https://audiokarma.org/forums/index.php?threads/filter-caps-bypassed.336048/

They may not make a difference... but I have seen used by Sansui and some of the Gurus here. I typically use 2.2uF as a standard. Some say ~.01% of filter value.
Click to expand...
Hi
Is there any reason for not replacing film caps C710-C712 (0.1uF/200V) and C716-C718 (0.1uF/50V) and C720 (0.01uF/200V) in P700 board with WIMA? I have started the full restoration of my 2275 so it will be of great help for any insight on replacement of these film caps.
Thank you!
 
Nice, clean and methodical. That is what it should look like when it is done right..
Question, initial impressions, do you prefer the sound of the 2270 or 2275 and why? I would expect sound quality to have improvred significantly after restoration. 4 decades of slow audio degradation wiped away. When I hear Marantz gear sound of this era described as warm and full, I know the listener has never heard what these sounded like new. I was fortunate enough to spend time around the 70's gear onward from new, so I know how good it sounded, to me anyway.

My last 2275 was stolen in 1989, been looking for a replacement to restore for a while.
 
macman007 said:
Nice, clean and methodical. That is what it should look like when it is done right..
Question, initial impressions, do you prefer the sound of the 2270 or 2275 and why? I would expect sound quality to have improvred significantly after restoration. 4 decades of slow audio degradation wiped away. When I hear Marantz gear sound of this era described as warm and full, I know the listener has never heard what these sounded like new. I was fortunate enough to spend time around the 70's gear onward from new, so I know how good it sounded, to me anyway.

My last 2275 was stolen in 1989, been looking for a replacement to restore for a while.
Click to expand...

Thanks for the kind words.

I gifted the 2275... have too much gear. Both sound very nice. I personally like the 2275 over the 2270.

Have 2325 too... just can’t keep them all. Like Sansui, Kenwood, Yamaha, and Pioneer as well.

All restored in my free time over the last few years.

The restored SX-1250 squeaks out on top. Build quality is insane.

Recent did some AU-717s... very nice sounding units. Have AKAI AA-1200 too that is impressive.

Guess I could go on and on... Kenwood is also very impressive and not as popular.

anVHD664t4Wa12iZc89r58K-BA1G_koni0asJn8Vp447vtePVZq6lilOXOFgSrOvrpy2-pZp5KIjxZ7HFrObHPHPIwPsqfpnxt3RtC0d4M_RSBezMEewwQksbr7478c4RmBtfw9EMoDO2mJqFnZIe3I1ha9PXrVAbmjoYiiFkGnEOPhkoqdPCtOQlL0BLhZIjkW5zKr3RpYWqcXzeoV0EtWnj03IN-LgQHDDMtYzne-3QmfosfttkksLBjNfdAeKUO-DsVwY9seOIaBqGmPUE2Y1EncA12qn2cbsTNS_tctawslp7DvKGz2z-K4POTNI413rbRBNW7H_LnMX_AIVneWBDGJoDx84OxQ9Mj-COfup_Z5uVmI5bunFxQBtbdLqmiYVHJ9m7_xKlhJvAvxAwrtZrjQ7BUoqN4Qq6DlUcU1UcumAcG3zQeqVe6WN3ZgzsAMR0Ey-74rTECy2Zb03gePNfndTI9aVZEtV-Lhd9sxp8I9hfXGHycqRAnye9MNzhUte8X03F8FM0AhrowLI_c52re6cHR8Q61WrmPFxEB6gKSlyAeGONNBsew_8OeJ2MW28mwMXFLO-8HjZ-YLD1QyEZg6uQgl1W90J7d_Izc4RQU6JT6HaWW8GARZGBd2zuHJ4uFu_is84FcGgV8p3j7qgg-lZEYdElxCtzcVMAW1EGHua2aeCP8UB-SgZObJpPoZBSvBZr2I8U7HEItXzMLsTbwoZmXZ0k3xH_Fzrewy3dGPs=w1245-h1656-no
 
I've got a few receivers here too. Not the popular model number units like yours though. For example a Kenny-5030, Sansui 8080, Sansui QRX-999, Realistic STA-2000, Pioneer SX-780. They all need work, all were either abandoned, blown up by their owners trying to save $$ on repairs, deemed too costly for economic repair, or left with me in lieu of a check out fee. All look decent enough, are all there, and can be repaired-restored, the second being the goal once time allows.

I've been watching for a 2275 or 2325 a long time, locally and online, something cosmetically a 9 but internally a 5, not priced as if it was unobtanium...Something all there, but in need of time, components, and attention. I've got a bench, test equipment, tools, maybe some talent, just not enough time to get 'em all done. I will though, this is my 2020 resolution. I'm currently waiting on Mouser to ship me the rest of the components needed to finish up my RT-909, one of 20 or so tape decks, cassette and open reel waiting for the same. My goal? Simple finish one per month. Not unreasonable, right?

I do have stuff sent here for service, mostly stuff other techs wanted nothing to do with, Tandberg and Akai Reel decks. Nothing comes in the door until each one is done and gone. Then I'll thin MY herd. Perhaps eventually find myself a decent 2275 or 2325, AFTER I finish and find these other receivers homes.
 
Gear stacks up fast.

I like Realistic as well... have two recapped STA-2100. One here the other at my father-in-law’s dojo.

Recap STA-2000 like yours in my daughter’s room mated with some HPM60s. Nice setup to say the least.

I did some @rcs16 darlington replacement on a RS-2010. Wow it turned out amazing. That SX-780 you have was the target of the STK-0050 replacement.

If you would venture down that build - am sure you would be pleased. Those xx80s sure are nice looking units.

One in and one out is the best process for sure... but sometimes a smoking deal just pops up. My next rebuild will be this basket case.

27np1PxcYQr0sCO36PYq0_1T_XEEB6cv0tbJbPGE4Xf_XcH0yWqIGaGUDgKNsrCYXjwKsYAHZWrFNCRmO-XumaTKJrVuzY94EQylUgfEaFSUuW0YgCTk3iRoLrGXxfVBycJtRfDF9A=w800-h600-no


Just finished this peace - wowzers.
MBixc66dq8tYv0ckXow5HE4G3Bb-Jof0h3QlzjdyPfMFtha0QuIZ_d1_nFxmeRvadxjpyTjkV_l1qxolH29KisEsnHYov7Z_0CazPAYntrcOJjB4MppHzaXEmeoB8bM7rVpgwwxkVhEKwAYFEBUEjzvK5QMuIq12uKGdOMqr4LD4QzPBrCAwUN999z-r7HZ5TR2rcbr9KK4Aqljlt-D0yjM7mWJHSvkTu-ZtS0lf25UMCCihhUPUHV-KkcbVgM1coTzyW9QK6Xi1XF1RQHlEvUzn4S2psujiIw9KL47-MsP52gVdHp-0bB9iC9nT-1GYP5e1Eyl6GwYREVpi6vkmJ0GnvrHR6wgEeDOyypjrlsizkk1CEbF2MWFl6eXQNGNbOkwSOfia6B-7ySAA-ibwTvTndp1tR7b405wvEZEUCmpxGANK4qbGnrL891S43y43mmFD9PCwyef0cBmb_faAxkmkTnlzuIwAWmNNNk_GANU7q2QqKHCOP60TetJhPFIWv-8Hkn3IJ2AjLcLAOFhPtnviLGNFsj-arS7tcX0W6FB2MGjIzmf3hCBZomh69Ks5i3L6UaRkM6xUN-hXvnCtK__YtSsHBhCWIHxFmFXCQLL2gDObyt44WPrW9vmL-9Dabx297YJC3UWSctf54GUA2e-wNnYiw5M-9YY1Aw5IsD4-Joxtno6BgXco_E4MFfROMSgsuIpyVH3QYBZ0wtrgkTyQ6Vf9P8KNFDYR_IRU0v9Bne9k=w1242-h933-no
 
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That's great work, thanks for sharing.
I have a stock 2275 here that I need to get to some year. Your work is an inspiration.
 
Dingman said:
That's great work, thanks for sharing.
I have a stock 2275 here that I need to get to some year. Your work is an inspiration.
Click to expand...
The 2275 is not too hard to work on = nice that the AMP modules just unplug. Your 2275 is worth the effort.

Goold Luck!
 
Thanks. I believe there were two different versions of the amp board. I noticed the transistor H709 on mine is vacant. I'm following your work on mine. Thank you for a very well documented restoration.
 
I cannot stress enough how great this thread is. I just wished I had one like this for every receiver I intend to work on in the future. Impressive detail and clarity. Thank you for that.

I have 2 questions:

- P400 PHONO Pre-AMPLIFIER
What is the logic behind swapping C413 – Originally 100uF 35v for a 220uF capacitor? What does that specifically do to the audio signal?
I believe it should bring the cutoff frequency down when increasing the capacitance (x2 in this case), which means that more LOW END is allowed to go through the amplification stage
In another post by Leestereo and his work on a 2270 he speaks about other capacitors (that I believe in the 2275 they already have the new values mentioned in his post) and for C413 (C713 in the case of the 2270) suggests a value of 270 uF.
I had already replaced the original C413 for a new 100 uF (original value) before reading these posts and would like to understand if it makes sense to go back and swap that cap for a new one.
In a nutshell, why a higher value and why 200 and not 270 uF?

- SEVERAL DIODES AND TRANSISTORS
I have been prudent in the past about changing transistors because I am more prone to damage traces when desoldering :/
I was wandering if all the diode and transistor changes listed in this thread are targeting audio quality improvement or reliability.

thanks!
 
https://audiokarma.org/forums/index.php?threads/2275-rebuild-project.735510/

If @Leestereo does it, then I typically follow blindly. He is light years smarter than me. I can be classified as a solder jockey - not much more than that. My true electrical understanding is really limited.

New silicon debate is a common one with people being a strong supporter on one side or the other (typically mutually exclusive). At a minimum, target those problematic transistors known for failure or to become noisy (leaky).

I try to study each transistor, and if a good modern replacement can be source with similar characteristics then I usually go that direction; however, sometimes good replacements don’t exist.

If you stuck in original capacitor value, then just stick with them (I wouldn’t go back in and change).
 
I will answer the phono preamp question. C413 is a local power supply filter and not in the audio path. Some will call me an idiot for the audio path thing! This cap going up in value, and I use 220uF, knocks a couple of dB from the noise. It is safe to do so because it is fed by a 100 ohm resistor (R434) which limits the inrush current at power on and so won't stress out the power supply.

I'm not a fan of upping coupling caps to expand the low end response such as input caps C401/2 and output caps C414/5. The circuit already has a flat enough audio response and you open up the possibility of low frequency feedback AKA "motorboating" and the like. Another famous example is in cap coupled receivers like the 2230 where folks radically up the large sized audio output caps and also the main filter the latter of which increases the stress on the power switch and rectifier diodes at power on.
 
thank you @Super Noob and @rBuckner for the replies. Based on that I will leave everything as is for the time being (I did change some of the transistors and diodes) and maybe with my next MOUSER batch I'll ask for a 220 uF cap.
 
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Appreciate you listing all the parts/locations that you think should be changed out on these boards. I'm getting ready to rebuild my 2250 and it has most of the same boards and values as the 2275.

-P150
-P300
-P400
-P800
-PE01
-PC01

Unfortunately, different P200 and P700s.

Definitely gives me an idea what is typically replaced besides the electrolytic caps.

Thanks-

Paul

BTW- I think the part number for C168/C170/C172 (UPW1V191MPD) should be UPW1V101MPD.
 
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@Super Noob

BTW, for anyone using this thread as a basis for their 2276/2265 rebuild, I noticed that the part number given for CE39 on the PE01 Tone board is actually a 470uf 35v not the 330uf specified as stated in post #4. Didn't notice it until I went to install it.

"CE39 – Originally 220uF 35v / Now 330uF 35v (UPW1V471MPD)"

If this is supposed to be a 330uf then the part number I found is UPM1V331MPD (35v) or UHW1H331MPD (mini version, 50v).
 
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