Free Shipping on All Orders 1-866-764-1801

Vist our Online Store
+ Reply to Thread
Results 1 to 12 of 12
  1. #1

    Member Sales Rating: (0)

    Join Date
    Oct 2005
    Location
    Hampshire, United Kingdom
    Posts
    3

    Default Upgrading the power supply capacitors and rewiring with braided OFC cable.

    Hi, My n-name is Telefunky and I'm from Hampshire, UK. I'm new to this forum so if I've posted this in the wrong place I'm sorry.
    I would like some help. Some years ago I had a 1970s Rotel Transistor Amp, I think it was a RA???(insert number) any hoo I had the power supply capacitors upgraded and it was re-wired with shielded OFC Braided cable by an amateur HI_FI enthusiast. It sounded great after this inexpensive upgrade but alas has long since gone to transistor heaven.

    So my question, do I copy the values of the o.e when replacing the psu caps? Do I use the best quality I can afford? Is it best to do this to a simple transistor amp with no built in tuner or does it not matter. ( I guess it does 'cos a modest Tuner/Amp will have hundreds of cheap and nasty components for the sake of the many erroneous functions needed for the product to appear to be "Good Value"

    My old Rotel had a source selector, Volume, Bass, Treble, Loudness, and a Power Switch. It responded very well to the upgrades and the dynamics of the frequency range were cleanly defined in the same way real life ambient sounds are.
    Some music was out of this world, Zappa studio albums like "Apostrophe" and "Joes Garage with properly tuned drums, toms and snare, delighted the listener with what sounded like an impossibly slow widened square wave turned thru 90 degrees. Panning with good/speakers x-over coils was 10 times better after the mods.
    Yes I know I should get some valve bi-amps but trannies can sound o.k for most use.
    I pay Homage to the technicians on this site, for your task is a noble one,'cos u create audio illusions for the human ear. Even a high-hat sounds great "tisch-tish-tit-tit-tit" thru good Hi-Fi
    Cheers
    TelefunkenU-47
    I buit my speakers with the help of my friends testing facilities , nothing too silly, in fact as cheap as I thought I could get away with.
    A)s Vistation Ribbon Tweeters,
    Morel MW142 75mm aluminium Hexatech v-coil Woofers, 35mm bass port tube, Visation film cap&graphite coil x-overs tuned to computers analysis after initial build, wired with OFC silicon cable in computer designed 35 liter cabinets that I built from 1" Oak laminated SMDF with full mitred joints and flush fitted units.
    B)s Visaton G20 FFL Tweeters, Visaton W100S midrange, Morel MW142 Woofer, X-Over tuned as before and fitted into 55Litre Cabinets sprayed with auto paint black, this time Midrange at the top , tweeter in the middle etc. 2X 20mmby60mm Port Vents either side of the tweeter.
    The A set look like something from the 70s and the B set, late 80s just after the ghastly plastic fake wood look faded out and the "shows up dents and dirt" black was popular. Still, they sound great at modest volume levels.
    Last edited by telefunky; 10-12-2005 at 12:51 AM.

  2. #2

    Member Sales Rating: (13)

    Join Date
    Mar 2002
    Location
    The Mars Hotel
    Posts
    31,287

    Default

    Welcome to the forum.

    What amp are you thinking about upgrading, another Rotel? If so and IMO, you'd be better off buying a high end SS amp to start with. Since you're in England, may I suggest Musical Fidelity.
    'Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end."

  3. #3
    Stronzo
    Member Sales Rating: (7)

    Join Date
    Apr 2002
    Location
    Over Yonder
    Posts
    7,885

    Default

    It is typically a rule of thumb to use the same values when conducting a 'drop and plop' routine on equipment. This rule should be practiced if you are a bit new behind the wheel and lack complete understanding of the how’s and why’s of circuitry.

    Unless the component you are working on sports great design with remarkable parts, investing much money into better replacement parts (like capacitors) may yield only minimal improvements. Black Gate is a company that is trusted by many, and is a popular choice for modders on a budget.

    As F1 suggests; If you can wing a new piece, there are certainly a boat-load to chose from across the pond. Creek / Musical Fidelity / Arcam / NAIM (pride of the Royal Hi Fi), Talk Electronics / and a whole host of others offer affordable, yet brilliant pieces all meant to take you to audio nirvana!

    Cheers, and welcome to club-polk M8.

  4. #4

    Member Sales Rating: (0)

    Join Date
    Oct 2005
    Location
    Hampshire, United Kingdom
    Posts
    3

    Default

    Cheers Guys, what a friendly welcome even though I typed on and on.
    Two more things when I tweaked my old Rotel my mate said get a new volume potentiometer that has distinct increments controlled by resistors as this was better than the not very exact method of the carbon track. Is this a good investment? Could save a few quid on Servisol tho!

    Second PSU caps; I take it that the price range is from tens of pence/cents to several pounds/dollars per item or is there a cap-king made from materials that cost 1000% more but only perform 5% better. 'cos the law of diminishing returns is the privilege of rich hi-fi snobs.
    I don't mind if it has the legend POWER CAP Emblazoned on the side in some kind of High-Voltage font like some kinda BS conspicuous Sub-Woofer branding that teenagers love so much.

  5. #5

    Member Sales Rating: (17)

    Join Date
    Jul 2001
    Location
    Northern Colorado
    Posts
    12,073

    Default

    The stepped attenuators are a reasonable upgrade but I wouldn't spend the extra quid... Did I use the term quid appropriatly? :)

    Welcome to the forum!
    madmax
    Vinyl, the final frontier...

    Avantgarde horns, 300b tubes, thats the kinda crap I want... :D

  6. #6
    Stronzo
    Member Sales Rating: (7)

    Join Date
    Apr 2002
    Location
    Over Yonder
    Posts
    7,885

    Default

    As the 'mad' max stated, your friend is refering to a stepped attenuator, which indeed can make a reasonable impact on most good designs that happen to lack such a beast.

    PSU Caps is field that requires trial and error. The law of dminishing returns is simply where that line is drawn. As mentioned before, Black-Gate capacitors are relatively famous for their performance / cost. There are sonicaps and auricaps which can cost quite a bit more...

    And now in my best britt voice;

    "bloody 'ell m8, if you're looking for gold than you bloody well should get gold. Now read above and bring home a nice fresh unit, and bobs your uncle - you got hi-fi" !

  7. #7

    Member Sales Rating: (0)

    Join Date
    Oct 2005
    Location
    Hampshire, United Kingdom
    Posts
    3

    Default

    wouldn't spend the extra quid... Did I use the term quid appropriatly? :)
    Yes, indeed.

    Thank You my Brethren Cousins. With so much flashy electronics out there that is NOT Hi-Fi it’s good to know there’s a site like this.

    I’m from Hampshire, which like Dorset and Devon are Farming Counties. Hampshire and Devon have mostly arable farms, so the countryside looks all pretty, a green patchwork quilt of lots of tiny farm and woodland copses sprinkled about. Dorset is dark brown quagmire of piss mud and **** mud, that’s right it’s mostly Dairy Farms. So I don’t sound like Bart Simpson’s impression of an 18th Century of a Cockney Shoe Shine Boy more like the Southern Farmers accent. Including of all places Plymouth. So a bit like some of the founding Fathers before they started doing that John Wayne thing but not as intense and we sometimes drop the odd vowel.

  8. #8

    Member Sales Rating: (1)

    Join Date
    Jul 2001
    Location
    FL 320
    Posts
    5,021

    Default

    Welcome to the forum. I like your name.

    Like F1 mentioned, you're probably better off buying a high end amp. If you buy another Rotel, pay parts and labour to your technician, you may be spending as much as a better quality amp like MF. Also, if you buy new and have your techie work on the amp, you will void the warranty.

    Maurice
    CD Player: Original CD-A8T
    Receiver: Harman/Kardon HK3390
    Speakers: Polk Audio RT1000p
    "I would rather have a cup of tone than an ocean of power" **Dr. Harvey Rosenberg**

  9. #9

    Member Sales Rating: (0)

    Join Date
    Dec 2009
    Posts
    1

    Default

    Like F1 mentioned, you're probably better off buying a high end amp.

    However I heard about http://www.amazingwatcher.com which is a free website that will “watch” items for you on Amazon and let you know when amazon has them in stock at regular retail price.:)

  10. #10

    Member Sales Rating: (0)

    Join Date
    Sep 2008
    Location
    Fairchild AFB WA.
    Posts
    3,630

    Default

    ^^Reported
    HT Rig
    Receiver- Onkyo TX-SR806
    Mains- Polk Audio Monitor 70
    Center- Polk Audio CS2
    Surrounds- Polk Audio TSi 500's :D
    Sub- Polk Audio PSW125
    Retired- Polk Audio Monitor 40's
    T.V.- 60" Sony SXRD KDS-60A2000 LCoS
    Blu-Ray- 80 GB PS3


    2 CH rig (in progress)
    Polk Audio Monitor 10A's

    It's not that I'm insensitive, I just don't care.. :D

  11. #11

    Member Sales Rating: (6)

    Join Date
    Sep 2003
    Location
    Arizona
    Posts
    16,493

    Default

    Welcome aboard!

    Transport: Oppo BDP-103/USB HDD (flac)
    DAC/Preamp: Benchmark DAC/PRE
    Power Amp: Parasound HCA-1500A
    Speakers: Harbeth Compact 7ES-3 Monitor
    Cables: Kimber Hero/8TC; DH Labs D-75

  12. #12

    Member Sales Rating: (0)

    Join Date
    Jan 2009
    Location
    Rocky Top TN
    Posts
    402

    Default

    To answer the original question....blanket upgrading ps caps may or may not be the place to start. Usually, coupling caps are a better investment, for instance. Or the attenuators, as you mentioned.

    Raising the capacitance values of the caps depends again, to some degree, on the circuit. If it's all solid state, then usually. The last cap in the ps is the one that effects sonics most. Something like a Blackgate powertank there might pay, as they are excellent sonically. Generally, high performance caps mean upping the temperature rating and more importantly getting better ESR ratings, which mean they perform better with higher frequency trash getting to them.

    Which leads to another place for very effective upgrading...better rectifier diodes. Soft recovery diodes throw much less trash into the ps and the audio.

    CoolJazz

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

     

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts