pcr@xait.UUCP (Perry Rothermel) (10/12/90)
I just received in the mail a catalog from a company called "Audio Advisor". They offer to do modificaions and upgrades to amps (i own an Adcom 545). The catalog states they do this by increasing the sound range and replacing some factory hardware with their own (capacitors, wiring, etc). I am very interested in this. But... is this legit??? Do these modifications improve the sound of your amp? Is this a rip-off? Has anyone ever had this done to their amp? What was the result? Are there other companies that offer this service, but are better? Anyone with knowledge or experience about this, I would really like to hear from. I would hate to send my amp to them and have it come back sounding worse or worse not come back at all. Please reply. Thank You!
kens@hplsla.lsid.hp.com (Ken Snyder) (10/18/90)
rec.audio.high-end / info-high-audio-request@csd4.csd.uwm.edu.HP.COM > I just received in the mail a catalog from a company called "Audio Advisor". > They offer to do modificaions and upgrades to amps (i own an Adcom 545). > The catalog states they do this by increasing the sound range and replacing > some factory hardware with their own (capacitors, wiring, etc). > I am very interested in this. But... is this legit??? Do these modifications > improve the sound of your amp? Is this a rip-off? Has anyone ever had this > done to their amp? What was the result? Are there other companies that offer > this service, but are better? I have not done business with the "Audio Advisor" but your question about whether or not mods can help an amplifier I can shed some light on. A few years ago I upgraded a Hafler DH-500 with a Musical Concepts modification kit. It consisted of upgraded components and instructions on modifying the actual circuitry topology. (I did the mods myself.) I can say without hesitation that these mods made the '500 sound much better. (I have an unmodified '500 I'm using as a subwoofer amp so I can make comparisons.) The circuit topology changes lowered the forward gain of the amp, did away with a darlington pair of transistors and lowered the feedback at the same time to keep the overall gain constant. This was not just a component swap mod. Most amps, especially reasonably priced ones, have design/cost considerations in connectors, wiring, etc. that aftermarket dealors can improve on. I've seen the Audio Advisor ads also and would be interested in hearing from anyone actually having heard their mods. I would rather do the mods myself because I have the necessary skills/equipment available and like parts, time is a cost, and I can supply lots of that. _____________________________ K _ E _ N __________________________________ | | | Ken Snyder ms/loc: 270 / UN5 | | LSID div : Lake Stevens Instrument Division | | Hewlett-Packard Co. gte/tn: (206) 335-2253 / 335-2253 | | 8600 Soper Hill Road HPDESK: Ken_Snyder@hpa100/ux | | Everett, WA 98205-1298 un-ix : kens@hplsla.HP.COM | |__________________________________________________________________________|
peter@apple.com (Peter Tapscott ) (10/22/90)
Does anyone have a source for large, high voltage electrolytic capacitors that could be used for a power supply for an amplifier of about 200 watts? Digi-Key has pc-mount caps, but the largest are: 10,000 uf @ 63 V (Not bad) 4700 uf @ 100V TSU 3300 uf @ 100V TSNH All 36mm X 51mm (1.4" X 2") Diameter X Height What are peoples opinions on using a 100V cap for a 90V DC voltage? The next step up in voltage is 200V. Is it necessary to use TSNH instead of TSU? Large capacitors mounted to the chassis really seem preferable. (I have never seen a high-end amp that used PC mount caps.) -- |----------------------------------------------------------------------| | Peter Tapscott {ames|apple|leadsv|pyramid|sun}!versatc!peter | | Versatec, 2805 Bowers Avenue, Santa Clara, Calif (408)982-4235 | |----------------------------------------------------------------------|
wkb@cbsck.att.com (William Keith Brummett) (10/24/90)
In article <7133@uwm.edu>, versatc!peter@apple.com (Peter Tapscott ) writes: > Does anyone have a source for large, high > voltage electrolytic capacitors that could > be used for a power supply for an amplifier > of about 200 watts? > ... > 10,000 uf @ 63 V (Not bad) Well, until a few months ago, *I* was a potential source. I had a bunch of surplus Sprague Powerlytic computer-grade caps (bright blue cover). They were chasis-mount, and the largest were about the size of a Sapporo beer can (~2.5" x ~8"). They were in two's and four's, and ranged up to 60,000uf @ 75VDC, as I recall. I sold them at the Dayton Hamvention for about 2 bucks apiece. I saw other similar caps there for similar prices. I suggest you check out the next nearby electronics flea market or computer fest. > What are peoples opinions on using a 100V > cap for a 90V DC voltage? The next step up > in voltage is 200V. Someone once told me that you could push the Spragues a bit above their rating, but to be real careful about japanese caps -- they just barely make their specs. Be conservative. I once connected a small cap to a circuit backwards. Have you ever had a 12-gauge shotgun shell go off in you face? Trivial in comparison. I was picking bits of paper out of my hair for hours. Good thing I wear hardened glasses. > Is it necessary to use TSNH instead of TSU? Dunno. -- Keith -- | W. Keith Brummett (614) 860-3187 AT&T, Room 3B-202 | | att!cblph!wkb 6200 East Broad St. | | or, wkb@cblph.ATT.COM Columbus, OH 43213-1550 | `----------------------------------------------------------------------'