I finished building the TU-8600 with full upgrades and Cossor tubes a few days ago. I'm at about 30 hours time on it now and it has smoothed out considerably from the first day. it sounds absolutely wonderful. I'll spare you the long list of adjectives; see Herb Reichert's review, yea, that's how it sounds.
The process wasn't without a couple of hiccups. I used too much heat on the connector pins and they moved, so I couldn't connect the transformers until I got that straightened out. If it had only been one or two I could've probably moved them back into alignment, but I decided I needed to replace them and Victor FedEx'd me a new set. Then, I thought I was ready and flipped the switch but nothing happened. Victor said it had to be either parts out of place, backwards, or a bad solder. I had already checked everything carefully, and continuity was good in the circuits, but I checked and rechecked a few more times and couldn't find it. So I decided to take it to an electronics guy to have him to check my work and troubleshoot the issue. It turned out that the power switch wasn't making contact (which I suspected, but didn't have the confidence call it), and he was able to repair it. The voltages checked out. Done. I was relieved (to say the least). With the benefit of practice and experience, it would be fun to build another.
My reference was the Bottlehead Stereomour 2A3 I built several years ago, and have thoroughly enjoyed. This 300B is quite different despite also being a SET amp. This is just a different category, probably my end game amplifier. I have some of the most sensitive speakers ever made, and this amp is dead silent with the volume well above listening levels. Clarity, space, tone, detail, tight bass, soundstage... piano being one of the more difficult instruments to reproduce well, for me it's really satisfying hear realistic richness-depth-nuance-power in solo piano. Martha Argerich's Legendary 1965 Recording... Oh my goodness! And the Bach Toccata and Fugue in D minor BVW 565 recorded by Peter Hurford on the Rieger organ in the Ratzsburg Cathedral - I hope the neighbors appreciate it as much as I do!
@Victor, thank you for all the great support!
The process wasn't without a couple of hiccups. I used too much heat on the connector pins and they moved, so I couldn't connect the transformers until I got that straightened out. If it had only been one or two I could've probably moved them back into alignment, but I decided I needed to replace them and Victor FedEx'd me a new set. Then, I thought I was ready and flipped the switch but nothing happened. Victor said it had to be either parts out of place, backwards, or a bad solder. I had already checked everything carefully, and continuity was good in the circuits, but I checked and rechecked a few more times and couldn't find it. So I decided to take it to an electronics guy to have him to check my work and troubleshoot the issue. It turned out that the power switch wasn't making contact (which I suspected, but didn't have the confidence call it), and he was able to repair it. The voltages checked out. Done. I was relieved (to say the least). With the benefit of practice and experience, it would be fun to build another.
My reference was the Bottlehead Stereomour 2A3 I built several years ago, and have thoroughly enjoyed. This 300B is quite different despite also being a SET amp. This is just a different category, probably my end game amplifier. I have some of the most sensitive speakers ever made, and this amp is dead silent with the volume well above listening levels. Clarity, space, tone, detail, tight bass, soundstage... piano being one of the more difficult instruments to reproduce well, for me it's really satisfying hear realistic richness-depth-nuance-power in solo piano. Martha Argerich's Legendary 1965 Recording... Oh my goodness! And the Bach Toccata and Fugue in D minor BVW 565 recorded by Peter Hurford on the Rieger organ in the Ratzsburg Cathedral - I hope the neighbors appreciate it as much as I do!
@Victor, thank you for all the great support!
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I have Klipsch LaScalas, 1982 model with ALK Type A crossovers, and a SVS PB-1000 subwoofer. The tone, presence and dynamics are really nice with the TU-8600S.
Only the 12ax7 tube. I've tried a Mullard/Eico from around 1960, Valvo-Siemens E83CC, and a Genalex Gold Lion (current production). The 12au7's are RCA 12au7A. The 300B's are Cossor (Linlai) Black Plate.
The Mullard is warm and dark as would be expected, and the Valvo-Siemens detailed and much more neutral in tone. Both have good tight bass and treble that clear without being too bright.
I am ready to try the 12au7's with similars to these two opposite profiles. I'm sure having three Siemens together will sound great, but wondering if three Mullards might sound overly colored. And it costs to find out so haven't done it yet. Also contemplating a 300B upgrade and wondering which one I'd like best.
12au7
but wondering if three Mullards might sound overly colored
In my experience,yes. Mullards are sweet tubes but very much on the warm side of neutral. I put them in my pre when listening to female vocals, Maria Callas etc. For other music i settled on Telefunken rib plates. A bit on the warm side but not much and lots more detail than the mullards. If you can get some at a decent price, try em. Am sure you won't be disappointed.
Regards, J.D.
but wondering if three Mullards might sound overly colored
In my experience,yes. Mullards are sweet tubes but very much on the warm side of neutral. I put them in my pre when listening to female vocals, Maria Callas etc. For other music i settled on Telefunken rib plates. A bit on the warm side but not much and lots more detail than the mullards. If you can get some at a decent price, try em. Am sure you won't be disappointed.
Regards, J.D.
Will do!
I changed the amp over to some 4 ohm custom 3 way way tower speakers and the frequency response is vastly different from my RP-600M’s. Good news is that the amp runs them well at normal listening level. I had to EQ bass down about 3 db and upper midrange and treble up about 3-4db.
Now all my frequency response comments from above are off from an absolute standpoint but are still valid relative to each other of more or less.
I changed the amp over to some 4 ohm custom 3 way way tower speakers and the frequency response is vastly different from my RP-600M’s. Good news is that the amp runs them well at normal listening level. I had to EQ bass down about 3 db and upper midrange and treble up about 3-4db.
Now all my frequency response comments from above are off from an absolute standpoint but are still valid relative to each other of more or less.
I'm running Takatsuki 300B currently, but any comment on the Sophia Electric 300B Blue Glass? It's not cheap.
Sophia Electric Classic 300B Tubes with Vintage WE 300B Soul Inside an
I decided to try a pair of Valvo (Siemens Halske) in the 12au7 slots alongside a simiar Valvo 12ax7. They sound fantastic so far and only have 20 hours on them. I also upgraded to Cossor WE300B recently (also low time). To further complicate my ability to judge each independently, I upgraded from an Ares DAC to a Pontus at about the same time- and then went away on vacation for a week. I do know that the Valvo tubes are giving me beautiful airy highs and tight bass without unneeded emphasis on the mids. I think I’ll just roll the RCAs in with the one Mullard when I want to sweeten up for variety or certain music.
I’m with Victor. For my 300B tubes, next stop is Western Electric 300B. I kind of wish I just spent the extra $$ but it was hard to justify this year when I spent so much already on the other tubes.
I noticed that some of the 12AX7 and 12AU7 NOS tubes go through a period where the treble increases during break in and then settles back down. Some got over it in a few days. I think a few still aren’t broken in. My wife thinks I’m messing with her when I leave the music on and leave the room. She thinks I’m insane when I tell her it’s breaking in.
I noticed that some of the 12AX7 and 12AU7 NOS tubes go through a period where the treble increases during break in and then settles back down. Some got over it in a few days. I think a few still aren’t broken in. My wife thinks I’m messing with her when I leave the music on and leave the room. She thinks I’m insane when I tell her it’s breaking in.
The 12au7's are tilted getter w/ Valvo label, but the same tube may be found with other labels or no label. $150/pair from Brent Jessee. He says they're hard to find, but that's true of many so I'm not sure how rare (he seems to be a respected source). The price seems reasonable. My 12ax7 is actually an E83CC, which is a premium, ultra low noise for military applications, said to be quite rare, and and sell for $175/each.
Both of these Valvo-Siemens are German tubes described as "similar to Telefunkens" that cost a lot more. I bought them as a less expensive alternative. I think they're a significant bump from the RCA and Gold Lion that I got with the amp, as are the Cossor WE300B clones over the black plates. I'm good with where I am now. Unless you're just into tube rolling as sport I'm not sure I'd buy these if you already have a good set of Telefunkens that you like, as the difference is probably subtle.
I'd love to try the new Western Electric 300B, but since they've just started shipping we really don't know much about them yet. Initial reviews are positive but reviewer are being reserved with the praise given the high price. I am going to wait, which gives me something to look forward to while I recover from this spontaneous happy spree.
Both of these Valvo-Siemens are German tubes described as "similar to Telefunkens" that cost a lot more. I bought them as a less expensive alternative. I think they're a significant bump from the RCA and Gold Lion that I got with the amp, as are the Cossor WE300B clones over the black plates. I'm good with where I am now. Unless you're just into tube rolling as sport I'm not sure I'd buy these if you already have a good set of Telefunkens that you like, as the difference is probably subtle.
I'd love to try the new Western Electric 300B, but since they've just started shipping we really don't know much about them yet. Initial reviews are positive but reviewer are being reserved with the praise given the high price. I am going to wait, which gives me something to look forward to while I recover from this spontaneous happy spree.
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I have mine running over a week now. At first the highs were a bit harsh like my old solid state amp but it is settling down now. I thought the TU-8200 was good enough after the Lundahl Transformers and cap upgrade. The TU-8600 makes the TU-8200 sounds dull now (it has been put to the side since)! Many thanks for Victor's countless hours of dedication for testing and find the best components and his expertise on recommending the upgrade components. I think I am settle too for the next while and now it is time to rediscover my CD collections...
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A noob question: my son has JBL ES80s and a passive 4 ohm subwoofer. The specs for the JBLs show a sensitivity of 91db, so I think they would play well with either the 8500 or 8900. But not sure about how to wire in his subwoofer? I've seen conflicting advice on this online after some initial poking around - from it's not a good idea and certainly not recommended to no problem ... Thanks in advance for any tips and suggestions you can offer.