johnsonwu
Responses from johnsonwu
| Review: Audio Research Corporation HD 220 Amplifier Cant help myself but to revive this thread after all these years.Those who are reading this must either have a broken SD135/HD220, or got a bit annoyed with the progression from a positive "dimensionality instead of paper cut outs and fixed images... | |
| Review: JM Labs Diva Utopia Be Speaker 75 is plenty for a ported medium sized speaker like the Diva.The 2 inductors connecting the bottom woofers suck out power so you'd be wasting money on monster amps that don't sound as good as the CJ11. | |
| recommendation for speaker wire to soften the highs if possible @nasaman I can start a dissertation on how to use LTSpice to run simulation on how an LC filter strapped in parallel to an LCR load (speaker) will work to roll off high frequencies at which point by how much of a slope, or I can just suggest with... | |
| recommendation for speaker wire to soften the highs if possible Strap a 4 ohm resistor and a 0.33uf cap wired in series across the speaker terminal/binding posts. That creates a very crude low pass that rolls off highs. Let your ears be the judge. Cost you $2 or so. Better than buying $500 snake oil. | |
| My Amp is Broken - Not Sure What to Do - Any Recommendations? 3 matched devices per phase per channel on the SD135.Usually you can get a matched triplet every 10 devices AT LEAST.Now if the SD135 had say 10 devices per phase per channel that’s a completely different story.Getting 3 devices to match is much m... | |
| My Amp is Broken - Not Sure What to Do - Any Recommendations? Not hard for a guru like you Ralph! But I have had the pleasure of dealing with botched jobs of those $25/h audio repair experts who couldnt figure the difference between emitter and collector that I think dealing with a 5 pin output device would... | |
| My Amp is Broken - Not Sure What to Do - Any Recommendations? Even the manual found online says the original devices are 3281D and 1302DReplace the defective channel's output devices with MATCHEDDG versions and you are good to go. | |
| My Amp is Broken - Not Sure What to Do - Any Recommendations? OP lucky you the schematic is HERE:https://elektrotanya.com/PREVIEWS/63463243/23432455/audio-research/audio-research_sd135_amplifier_sc...I bet not everything is toast likely 1 phase of 1 channel.Get a tech WHO KNOWS HOW TO MATCH OUTPUT DEVICES.Bu... | |
| My Amp is Broken - Not Sure What to Do - Any Recommendations? https://www.mouser.com/ProductDetail/ON-Semiconductor/NJL3281DG?qs=sGAEpiMZZMvFp%252byPHbnZYyVkaBWrH...3281D was INDEED obsolete.Original collateral dated June 2006http://www.onsemi.com/pub/Collateral/NJL3281D-D.PDFreplaced by 3281DG Same applica... | |
| My Amp is Broken - Not Sure What to Do - Any Recommendations? The parts did not go obsolete. Check OnSemi, aka ON Semiconductor who manufactures the parts. Audio Research EOLed the SD135 and HD220. | |
| My Amp is Broken - Not Sure What to Do - Any Recommendations? I have a Thermaltrak equipped HD220 myself and Audio Research would ABSOLUTELY refuse to return my repeated calls AND repeated emails. The good old days of Leonard and Kalvin are gone.A $25/hr tech... GOOD LUCK finding one who knows what the 5 pi... | |
| My Amp is Broken - Not Sure What to Do - Any Recommendations? Here’s the problem with ThermalTrak devices that supposedly was solve by Ayre but not AR https://www.stereophile.com/solidpoweramps/407ayre/index.htmlON Semi only made 1 set of thermaltraks, and yes I just confirmed that Mouser has them in stock.B... | |
| My Amp is Broken - Not Sure What to Do - Any Recommendations? Ralph the OP was referring to thermaltrak output chips made by OnSemi. Can’t be bypassed. They were discontinued for a while. Now back inthe market. | |
| My Amp is Broken - Not Sure What to Do - Any Recommendations? You can still get thermaltrak chips on mouser or digikey last I checked. | |
| Review: JM Labs Diva Utopia Be Speaker I am assuming you didnt detect and harhness/brightness immediately after the mod like llkmi7 observed right? |