johnsonwu

Responses from johnsonwu

Review: VAC Phi Beta 110i
I have one I need to sell for JWaugh’s family.  sadly he passed away recently.   
amplifier longevity
@bigkidz I beg to differ. Keystone makes those white Q Covers with 4 holes, 1 hole, and no hole. The holes are not for ventilation but for a tech to use a probe to check rails voltage. There is no difference in temp disspation between the conventi... 
amplifier longevity
Re: the comment on Counterpoint Mosfets and heat It’s common practice for TO3 devices, mosfet or bipolar, to be covered by plastic covers.  They are there to prevent law suits when people get zapped by the + - rails voltages.  The heat of these de... 
Are Quicksilver power tube amps in the same league as VAC, VTL, BAT, ARC, ...?
@donvito The HD220 is entirely fixable. It’s loosely based on On Semi’s reference design for thermaltrak devices. The old production non DG designated output devices are End of Lifed but new ones are available on Mouser or Digikey. Unless your fri... 
The "Snake Oil" Trope
I love it when people try the Jedi mind trick “what? You mean… as a high end audiophile for 40 years you tell me you can’t hear this night and day difference?  You, among all the audiophiles?!”And all I need to to do is smile.   
Counterpoint SA-3000 Preamplifer
The SA3000 has a single tube line stage.  Each triode in that tube is cathode-driven with a JFET input stage and the plate goes to an ancient old OpAmp as buffer.The phono is also rather similar.  I would not spend much on it. 
Tube Preamp - What to buy?
@rbmaudio1 Counterpoint gear is not nearly as hard to service as urban myth has it and there is no need to "rebuild" with new boards all the time.  I have 2 of each of the popular models (SA100, SA20, NPS200, and NPS400) and I service them myself.... 
BEWARE OF FRAUD with this member
It sounds like a transhipper operating out of Oregon.Happened to me selling a pair of LS3/5a to a mainlaind Chinese scammer.  Paypal address was Oregon and months later he complained about slight color difference between crossover PCB (heck they w... 
Received a Bill for State Tax on An Amp Bought in Canada Last Year
I just love the CA bashing from sour 🍇 folks.  Just came back from San Antonio and Austin.  Never in my entire life have I seen that many homeless and crazies.  Not Oakland, not San Diego, not San Francisco.  
Technics SB-R1 Reference Speakers
The Panasonic showroom at Umekita Osaka is my must go place every time I visit Japan.  I currently own Eidolon Diamond and YG Haileys and my reference monitors are the SBC700.  A friend of mine bought the R1 after he borrowed my C700s for a month ... 
The one tweak most Focals need ...
Almost anything is better than the stock Solen PPA 250V caps.There is also the inductor used for the woofer.  The wire thickness of the series inductor is embarassing.  You can measure a whole 1Ohm DCR in some cases. 
A civil discussion about the state of Audio Research
And as long as the units are less than say 5 years old AND you buy them new froma dealer.   I have not been able to get Audio Research to return my emails or phone calls since Kalvin left.  
A civil discussion about the state of Audio Research
The way audio research picks the operating point of the 6H30 driver often makes it possible to use 6922s without mod.  Tube rolling is possible and perfectly safe in some units.  Basic ohms law.   
Is there a best or top-tier capacitor for a Zobel network?
It doesnt matter. The Zobel is a shunt. Even a $1 bipolar electrolytic will do. The whole reason for the Zobel is to induce high frequency LOSS for the woofer. The lossier the cap is the better. Save money for the high pass cap for the midrange an... 
Review: Audio Research Ref-3 Tube preamp
Common for aging preamps.  You can send it in to Audio Research and get fleeced or get an honest competent tech to check the tubes and B+.  If both channels wheeeeee and you swap the tubes from left to right channel and it stays the same then the ...