johnsonwu
Responses from johnsonwu
| Review: Audio Research D-70 mkII Tube amp Drivers are capctatively coupled to output You just need to tweak the 10k pot not the power tubes bias pots. Much easier than biasing power tubes. | |
| Thoughts on Audio Research D70 All tubes are known good tubes from my collection. All voltages were checked and verified AOK.I have no way of checking how good the lytics are cos I dont have a big cap meter and I dont want to pull out the lytics.Foggy is expected of the Rel-cap... | |
| Review: Audio Research D-70 mkII Tube amp If you think D70 is difficult to work on try biasing a D-115 mkII like the one I just got! Even tigher space and I ended up having to mod md DVM probes with heatshrink. | |
| Thoughts on Audio Research D70 So the verdict for my unit is:Faceplate is dinged up and dented. Supporting bar bent. I cant get a replacement from Audio Research as they are out of spares.Seller graciously offered a partial refund which is very nice of them. The 1A fuse popped ... | |
| Counterpoint SA-11, worthy looking for? This pre amp is great but extremely hard to service. You are better off buying the schematics from mike and commission someone local to build one point to point for you. Seriously its not going to be any more $ | |
| Thoughts on Audio Research D70 Oh well. So much for the exciting anticipation for the amp.Seller allegedly got talked OUT of including the original outer box by the FedEx people and the unit was shipped in the inner box only with less than a few pages of newpaper in the box so ... | |
| Thoughts on Audio Research D70 @Hifigeek1: Yes indeed triode vs NON-Ultra-linear fixed bias tetrode mode. But same B+ @ output stage.420V B+ is a bit low for my liking but with 4 tubes per side power should be more than enough.I have every intention to convert that to triode at... | |
| Thoughts on Audio Research D70 @DaveyF: Totally understand the risks. I think the circuit is in many ways superior to the Classic 120s and VTXXXs I used to own, and provides more opportunities for asjustments, thats why my quest for this amp.@HifiGeek1: Thx for the cautions. Gu... | |
| Thoughts on Audio Research D70 Found a D115 mkii. Can't wait to hear how it sounds.Will definitely verify each test points voltage and go through the usual hexfred/schottky diode mods and coupling cap upgrades... then triode of course.The circuit begs for a better driver tube t... | |
| Any Counterpoint SA-3 Owners? Motor boating is not ground loopLikely a decoupling cap that is not touching ground. Check for cold solder joint or burnt traces | |
| Psvane Teflon capacitors real or fakes? Sorry but have to disagree. Even the cheap Russian teflons make the mid and high transients very linear and never overshooting (glare) for as long as the circuit is neutral. | |
| Thoughts on Audio Research D70 Thanks for the opinions. Now to find an old beat up unit for an affordable price so I can do a complete rebuild. | |
| Thoughts on Audio Research D70 Anyone want to part with their D70? No tubes OK (even better). Itching to do a total rebuild project with it. | |
| Bass tones and low cost tubes for a Jolida 502B Before you swap power tubes on the Jolida you ought to set bias to the LOWEST and turn up accordingly.Get a replacement KT88, they sound better than 6550Cs any day.Also the glassy sound has everything to do with the cheap components in the amp. Po... | |
| Looking for brighter tubes I went as far as completely rebuilding one.Only the trannies are left original.Not sure if Jolida Maryland simply changed Kung Pao caps to Mushu caps.But mine went as far as V-caps and Mundorf SGO.Hexfred Diodes, Low ESR Panasonic or Nichicon Filt... |