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Right channel low level hum in Marantz 2270

Discussion in 'Marantz Audio' started by Supercool!, Nov 4, 2018.

  1. Supercool!

    Supercool! AK Subscriber Subscriber

    Messages:
    1,206
    Location:
    New York 10306
    I noticed a buzz in the right channel of my Marantz 2270 which has had some recapping done in the most critical areas. When I took it back to the same tech he said he spent a long time doing a work around on the grounding scheme to reduce it and that it was a flaw in the 2270 design..its still there but without the top end...very low level with you ear near the speaker at high volume but the left channel has no buzz/hum at all. The tech's explanation sounds very suspicious especially since he really didn't solve the problem...any suggestions on this matter and what might cause it and any suggestions on an outstaning experienced Marantz tech...especially near New York? Many thanks for your input!
     

     

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  2. embrown057

    embrown057 Active Member

    Messages:
    182
    Location:
    Apollo Beach,FL
    I've worked on several 2270's over the years and never had to modify any grounding on the unit. There is just no "recapping critical areas" without having the unit come back with additional problems. There is nothing short of a restoration that would bring that unit back to it's full splendor. A recap alone will not solve any long term reliability. I've seen this over and over, most shops, not all do not have the talent or the time to perform vintage service work. The next tech will have to un-do what he has done and correct the problems. I along with other tech's here have seen this over and over. This just makes our job even more time consuming. My suggestion is don't return the unit and contact one of us here to get your unit serviced correctly.
     
  3. Leestereo

    Leestereo Super Member

    Messages:
    2,126
    Location:
    Ottawa, ON
    IMO, the time necessary for a proper/complete restoration makes it difficult, if not impossible, for the majority of businesses to make a large profit on this type of work. For most hobbyists, the average remuneration for a restoration/upgrade project is much lower than any businesses' shop rate.
     
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  4. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

    Messages:
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    Location:
    Orange CA
    Yep.. ^^^--- what they said. To do a restoration correctly and SAFELY.. takes time and is more than just caps. Its hard for the average shop, actually, it's impossible for the average shop to make any money at it. The work is just too labor intensive even if they know what they are doing and most don't. There are a precious few dedicated shops that make money at restorations but they are like the Chip Fooses of the audio world :) They make works of art for the collector with pockets. Then there are the enthusiastic hobbyist ( I hate that word here). We either came from an electronics background and now it's a hobby vs a living or it was picked up along the way. Either way we learned how to do it and are happy to to the work for the fun (??) or beer money :) And for hobbyists, some of these guys are pretty damn good at what they do. Grounding can be an issue and a tough one to track down. i just went through this with a 2230 of mine. I didn't get a ground strap nice and tight with a clean enough surface. My bad.. not a design flaw.

    There is probably someone here who can do the work and not too far away and can come with recommendations. Word of mouth is a strong currency for restoration work.
     
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  5. embrown057

    embrown057 Active Member

    Messages:
    182
    Location:
    Apollo Beach,FL
    When I hit the lotto I"ll be doing this for fun, till then I have to bill for my services. Still I hardly ever get paid for the full amount of hours I have to put into each unit. Especially the ones someone's attempted to service and failed. After 35+ years in audio repair I have learned to never be surprised what someone has thought would be a "good fix". The OP should just hang on to the unit till you decide if you willing to invest into it.
     
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  6. Supercool!

    Supercool! AK Subscriber Subscriber

    Messages:
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    I understand everything you guys are saying here and I have someone local who may be willing to do the work but he is most familar with doing Sansui and Pioneer...If I give him the "parts list" and service manual would that be enough to get him through?...he's a really good person/tech and fits into the categeory of enjoying what he does without the duress of business and of course I am willing to pay to get this done right...

    I have had this amp since I purchased it in high school at Rabson's on 57th street in NYC. Its been with me everywhere in life and Ive already put significant $ into it, much of which has been worthwhile. Its now black face which I love, has WBT binding posts, an "asylum cable" for AC...new fast diodes, many new caps and sounds excellent, but I really want to take it all the way and do the whole parts list and get rid of that damn hum which is audible only with ear to speaker with the volume at an unrealistic level...it just bothers me its there. I also feel it may have to do with the speaker switch which has been cleaned many times ..so even going through it top to bottom wouldn't be impossible as the work done has generally been well done by a good tech, just without that comprehensive parts list and a fully comprehensive approach....and I do get what you are saying about a full resto and "other" tech's work, thats not lost on me..

    I think Im going to have a heart to heart with him and see what we can work out...I very much appreciate your input as it has really clarified approach for me.

    Thank you one and all!
     
    Last edited: Nov 4, 2018
    Mike Sweeney likes this.

     

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  7. Supercool!

    Supercool! AK Subscriber Subscriber

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    Btw..if you check my profile you can see the company it runs with...my ears are pretty experienced with a modern, vintage and studio pedigree, so overall my equipment performance is to a high standard. Its the kind of environment where you'll never see cheap cable, everythings been cramolined regularly, nothing is crammed together...its rotated... as acoustic optomization is observed, etc. So Im really trying to do this the right way. The sentimental attachment to this is very, very strong...
     
  8. Supercool!

    Supercool! AK Subscriber Subscriber

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    Just one more general question..I prefer decent poly film caps where possible...is there any preference and rationale for electrolytics if polys are available/cost effective?...I know that is a whole nother can of worms...
     
  9. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

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    Location:
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    umm. they last damn near forever without drying out ? Thats a pretty good reason.. but not the only one. From a pure electrical POV, they do work differently but.. and this is a big but.. will you ever see that difference on 40 year old gear? really unlikely. You *may* see it on really good audio gear in a lab but I have yet to hear it on my own gear. I use films for under 3.3uf and electrolytic for 10uf and up. And frankly, the cost is not the parts, it's the time to take the unit apart and put it back together again. The parts are cheap. I've seen people not bat an eye at 100 dollars for a movie that lasts 2 hours ( 15 each to get in plus parking plus food) and bitch and whine about the difference between a 10 dollar filter cap and a 15 dollar filter cap for something that should last another 20+ years. Hell, they paid more for the coffee they are holding :/ Anyways.. thats my opinion.. and it will be varied around here. A lot of folks like Wima films.. I use them plus Panasonic and "orange drops" ( mostly on my tube gear) I bought some cheap films off Amazon and they were JUNK.. I sent them back.
    What I cannot address are the boutique caps. I don't buy them or use them. So someone else can address those for you. And someone may be able to do a deep dive into the pros/cons of films vs electrolytic caps in consumer audio gear.
     
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  10. Supercool!

    Supercool! AK Subscriber Subscriber

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    Hey Mike I couldn't agree more! Why waste the effort on something...er "less" . I've used Orange Drop and Panas on a lot of my tube gear...and If I understand you correctly, where feasible a solid quality Poly cap is preferable in the lower values and where feasible by size or availability or reasonable cost..correct me if I'm wrong..

    I'm finding Patfont's documented journey into cap replacement quite interesting and can't say enough about how I respect his effort...It will definitely guide me as I seek to get the final 5-10% from this very beloved amp...if it could tell stories they would be the stories of my life..43 years of my life!
     
  11. Leestereo

    Leestereo Super Member

    Messages:
    2,126
    Location:
    Ottawa, ON
    +1
    My own approach to restoration/upgrade of these vintage units may be a bit different than some, as I don't typically just do a "part for part replacement". The circuit is analyzed to see where worthwhile improvements can be made without modifying the PCB (e.g., increasing or decreasing capacitance of capacitors, use of film capacitors instead of electrolytics, C0G instead of regular ceramics...etc...). This is largely possible these days due to the use of modern technology (e.g., low ESR caps, stacked film caps) that has miniaturized many component types. Another consideration is maintaining the original look; to the casual observer, the restored/upgraded unit will look stock, only when one looks carefully at the actual components, does one notice that it contains high quality, modern components. I am convinced that the original designers would have wanted to use the better parts had they been available or had not been limited by the company's bean-counters (for profit margins). IMO, it is by leveraging technological advances in passive components that the sound performance and reliability of these vintage pieces is improved to better than when they were first manufactured. For example, this 2270 AK thread uses this approach and may be useful for your own 2270:
    http://audiokarma.org/forums/index....oration-and-upgrade-of-a-marantz-2270.793805/
     

     

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  12. Supercool!

    Supercool! AK Subscriber Subscriber

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    Thank you..I’m making a list of resources and links to pass along to a tech for consideration and will be reviewing for salient insights to pull out as priority concerns. Some of this is above my experience but in those cases Ill just pass those along for more insightful consideration. You guys are really wonderful in sharing so much and I can’t say enough how much I appreciate your sharing
     
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  13. Mike Sweeney

    Mike Sweeney AK Subscriber Subscriber

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    Truth!!! very much truth.. What we can get for pennies today could only be dreamed of 40 years old or was so costly to make it unreasonable for consumer or even prosumer gear. The high end stuff was a different breed but even in that space, there have been improvements. However, I think that the consumers in days past were more demanding. The case in point is I have a dozen "average" consumer receivers that are more sensitive and sound better with 40 year old designs than the new stuff I have with all the fancy phase locked loops, op amps and so on. But today's consumer thinks the new stuff sounds "fine" Maybe because they have been brainwashed into thinking that highly compressed sound is "fine" with all the streaming audio available today or on disk. Now i"m off topic ;)
     
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  14. Steven Tate

    Steven Tate AK Subscriber Subscriber

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    If you want the best restoration possible, you have one of the best in upstate NY. Talk to Bob Speece (AK member wlhd1610.). He is very experienced with Marantz and his final product is a work of art.
     
  15. Dudeman7

    Dudeman7 Member

    Messages:
    92
    Location:
    Michigan
    I recently was chasing down a low-level hum in the right channel of my 2245. The culprit turned out to be a wire from the right amp board that was routed right next to the transformer. Moved the wire, the hum went away.

    Good luck getting yours sorted!
     
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  16. Dingman

    Dingman Do you know where your towel is? Subscriber

    Messages:
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    Des Moines, Ia
    My experience is that those hard to find hums are often either the ground attachment or wires routed to close to the transformer.
    Heh, I should have said "my limited experience".
    But good find here.
     

     

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