I thought I’d start a thread on what tubes people have tried and liked in their TU-8600S. Some of these only have a few hours on them so I’m not sure if they need more break in time.
12AX7:
Mullard - My favorite so far. Good bass, nice warmth to mids and crisp highs. Have a couple versions, both sound the same to me, one used and one NOS. Good soundstage.
Telefunken smoothplate, used - a little less bass, not quite as much air. Good soundstage.
Amperex NOS - less bass than Telefunken, pretty good mid through highs. Need to listen to this one more.
Gold Lion NEW (provided by Victor) - high treble heavy, mid and bass seemed good. extreme detail.
Sylvania 5751 3 mica black plate NOS - pretty good. Slightly milder sound than Mullard. Used Loki+ to boost bass and this is probably my second favorite 12AX7.
Awaiting delivery - Telefunken ribbed plate, Valvo Herleen.
12AU7:
Telefunken smoothplate (used) - missing something in mid bass, not as clear highs as RCA cleartop
RCA Cleartop (NOS provided by Victor) - Best I heard so far. Excellent balance across frequency range and depth to soundstage.
Brimer - a couple different sets in the mail, waiting to receive. 13D3 and long plate.
300B (all provided by Victor):
Cossor black plate NEW - high treble heavy. Sounds pretty good. Good bass.
Cossor WE300B NEW - a little warmer in the mids, treble balanced a bit better. Good bass.
Favorite combo: 12AX7 Mullard, 12AU7 RCA cleartop, Cossor WE300B
Gear: Bluesound Node2i running Tidal and using Shunyata digital power cord ($135), TU-8600S, Klipsch RP-600M with GR-Research crossover mod. I have a Schiit Loki+ to balance out the frequency response as needed. It very slightly decreases the upper treble and soundstage, barely noticeable. I don’t use it with the favorite tube combo. It runs hot by the way.
12AX7:
Mullard - My favorite so far. Good bass, nice warmth to mids and crisp highs. Have a couple versions, both sound the same to me, one used and one NOS. Good soundstage.
Telefunken smoothplate, used - a little less bass, not quite as much air. Good soundstage.
Amperex NOS - less bass than Telefunken, pretty good mid through highs. Need to listen to this one more.
Gold Lion NEW (provided by Victor) - high treble heavy, mid and bass seemed good. extreme detail.
Sylvania 5751 3 mica black plate NOS - pretty good. Slightly milder sound than Mullard. Used Loki+ to boost bass and this is probably my second favorite 12AX7.
Awaiting delivery - Telefunken ribbed plate, Valvo Herleen.
12AU7:
Telefunken smoothplate (used) - missing something in mid bass, not as clear highs as RCA cleartop
RCA Cleartop (NOS provided by Victor) - Best I heard so far. Excellent balance across frequency range and depth to soundstage.
Brimer - a couple different sets in the mail, waiting to receive. 13D3 and long plate.
300B (all provided by Victor):
Cossor black plate NEW - high treble heavy. Sounds pretty good. Good bass.
Cossor WE300B NEW - a little warmer in the mids, treble balanced a bit better. Good bass.
Favorite combo: 12AX7 Mullard, 12AU7 RCA cleartop, Cossor WE300B
Gear: Bluesound Node2i running Tidal and using Shunyata digital power cord ($135), TU-8600S, Klipsch RP-600M with GR-Research crossover mod. I have a Schiit Loki+ to balance out the frequency response as needed. It very slightly decreases the upper treble and soundstage, barely noticeable. I don’t use it with the favorite tube combo. It runs hot by the way.
Last edited:
Billah, I have similar experience and settled on Mullard 12ax7 and rca clear top 12au7 with 300B Cossor black plate. Gold Lion and Telefunken 12ax7 is my experience too.
Gear I use most : Node 2i for streaming, Sun Valley phono preamp with VPI Classic. Zu Audio Omen Dirty Weekend mk2 speakers
I am thinking about trying other 300B so maybe WE300B from Victor?
Gear I use most : Node 2i for streaming, Sun Valley phono preamp with VPI Classic. Zu Audio Omen Dirty Weekend mk2 speakers
I am thinking about trying other 300B so maybe WE300B from Victor?
I’m still breaking in my Cossor WE300B and really like them. It’s not as big of a difference as the 12AX7 tube rolling but it does sound better to me. The shipping from Victor was really fast!
Just bought some NOS RCA blackplate 12AU7 but have to wait to receive them.
Nice turntable and speaker setup! I bet that sounds great.
Just bought some NOS RCA blackplate 12AU7 but have to wait to receive them.
Nice turntable and speaker setup! I bet that sounds great.
Thx Billah. The Node 2i is a killer streamer at its price - I have had several $$$ streamers and this was the best sounding (to me) at the price point I was looking at. I also have 12AX7 LaFayette??, EI and Amperex which I still have yet to try.
With just the rca cleartops and mullard 12ax7 together with the node 2i, i8600S is just perfectly balanced to me, not harsh and not overly warm. But when I use my Sun Valley with the 8600S, it is over analytical sometimes. I love it but also hate it because sometimes I end up messing with the tubes in my 8600S to balance it out. I am planning on taking out the Odam caps and replacing them with something just a little warmer - because despite tube rolling, I can never get it to sound "warmish" even with Mullards in the Sun Valley. Oh btw I have Audience Auricap XO in my 8600S - it is not over analytical but still gives you spades of detail.
Keep us posted on your tube rolling
With just the rca cleartops and mullard 12ax7 together with the node 2i, i8600S is just perfectly balanced to me, not harsh and not overly warm. But when I use my Sun Valley with the 8600S, it is over analytical sometimes. I love it but also hate it because sometimes I end up messing with the tubes in my 8600S to balance it out. I am planning on taking out the Odam caps and replacing them with something just a little warmer - because despite tube rolling, I can never get it to sound "warmish" even with Mullards in the Sun Valley. Oh btw I have Audience Auricap XO in my 8600S - it is not over analytical but still gives you spades of detail.
Keep us posted on your tube rolling
I’m running he VCAP CuTf in the TU-8600S. Have you played around with the rectifier in the Sun Valley?
On the Node, I found that using the airdrop function from IPAD by pulling down the top right corner of the screen to access the controls for volume, screen brightness, etc and clicking the paper right airdrop icon provides the best sound. I tap the airdrop icon and wait a few seconds for it to find the node, then click that. For some reason, when I try different methods such as airplay from the YouTube screen, it doesn’t sound as clear.
On the Node, I found that using the airdrop function from IPAD by pulling down the top right corner of the screen to access the controls for volume, screen brightness, etc and clicking the paper right airdrop icon provides the best sound. I tap the airdrop icon and wait a few seconds for it to find the node, then click that. For some reason, when I try different methods such as airplay from the YouTube screen, it doesn’t sound as clear.
Well I tried to edit the last post. The Brimer seem to have a little more treble sparkle and bass heft than RCA and similar soundstage. It sounds very natural to me without over emphasis on any frequency ranges.
When I turn it on, sit down and listen to music, the sound draws me in.
Fantastic amp Victor, well done!
When I turn it on, sit down and listen to music, the sound draws me in.
Fantastic amp Victor, well done!
Hi Billah, really glad I found this thread I've just started rolling on my 8600SVK which I built in March. I had Gold Lions throughout and the amp sounded great fresh out of the box but then a friend pointed me toward a 1960's Brimar 12AX7 and this thing was a night and day improvement over the GL 12AX7. More texture, space and punch and just as much bass as the GL.
Next I replaced the 12AU7's with 6189 Kb/ad Brimar's not such a jump to be honest, initial reaction is it sounded slightly darker, richer can't actually remember
Not started on the 300b's as this is where things get expensive and i'll probably look at other upgrades before then so would welcome any thoughts you had here?
Oh and I should add I hVE tried a Electro Harmonix 12AX7 and it was a limp, sibilant mess. May have just been a dud though...
Pretty simple set up here Novafidelity X35 > TU-8600SVK -> Living Voice Avatars.
David
Next I replaced the 12AU7's with 6189 Kb/ad Brimar's not such a jump to be honest, initial reaction is it sounded slightly darker, richer can't actually remember
Not started on the 300b's as this is where things get expensive and i'll probably look at other upgrades before then so would welcome any thoughts you had here?
Oh and I should add I hVE tried a Electro Harmonix 12AX7 and it was a limp, sibilant mess. May have just been a dud though...
Pretty simple set up here Novafidelity X35 > TU-8600SVK -> Living Voice Avatars.
David
Last edited:
I found Telefunken 12ax7 a little too top end for me but that just shows that it depends on each person. It is subjective no matter what other people say. If it works for you, that’s all that counts.
@Neville: Try listening to the telefunken for a little while. Some of my NOS tubes had exaggerated high frequency response for a couple days (1-3 hrs listening, then turn off and listen again the next day). They settled in with more even response after.
@Dave: glad to hear! I bought the Cossor WE300B from Victor and am super happy with them! He knows what tubes work well with the amp. Not as much difference as 12AX7 tube sound changes but it sounds spectacular on my setup.
I went to a moving sale this weekend and heard a couple different tube amps with some old Cornwalls. The TU-8600 is on another level compared to what I heard.
@Dave: glad to hear! I bought the Cossor WE300B from Victor and am super happy with them! He knows what tubes work well with the amp. Not as much difference as 12AX7 tube sound changes but it sounds spectacular on my setup.
I went to a moving sale this weekend and heard a couple different tube amps with some old Cornwalls. The TU-8600 is on another level compared to what I heard.
Any change with the telefunken?
I settled on NOS Mullard 12AX7 (not sure on version), NOS Brimer 12AU7 (CV4004 version) and the new Cossor WE300b. No EQ needed but the treble is still a little exaggerated on the modified RP600M speakers. Not running subs at this time in a small office. Has enough bass to hear the low frequencies throughout the 3100 square foot house and bug the family.
I settled on NOS Mullard 12AX7 (not sure on version), NOS Brimer 12AU7 (CV4004 version) and the new Cossor WE300b. No EQ needed but the treble is still a little exaggerated on the modified RP600M speakers. Not running subs at this time in a small office. Has enough bass to hear the low frequencies throughout the 3100 square foot house and bug the family.
I have a couple for both the 12AX7 and 12AU7. They sound fantastic also! I like the ribbed plate more than the smooth plate telefunken but I’m not sure if it’s something with these particular tubes or if it’s a generalization of the sound profile.
There is still some room to upgrade 300B tubes to Western Electric or Elrog but I think I want to work on the sources or speakers next.
Tube collection so far:
12AX7
Mullard x 2 but not sure on versions
Phillips Miniwatt Heerlen
Valvo Heerlen
Siemens 273 code on top, made in Germany on side
Hytron 12DT7
Sylvania 3 Mica Black Plate
Telefunken smooth plate
Telefunken ribbed plate
Gold Lion new
WE 5755 with adapter - might have been causing distortion
12AU7
Brimer 4068 / 13D3. I incorrectly stated 4004 above.
Brimer long plate, red box, yellow Brimar T triangle logo on side
Phillips Jan 5814A blue-green logo, black plate
RCA Black Plate
RCA clear top
Telefunken smooth plate
300B
Cossor black plate
Cossor WE300b
There is still some room to upgrade 300B tubes to Western Electric or Elrog but I think I want to work on the sources or speakers next.
Tube collection so far:
12AX7
Mullard x 2 but not sure on versions
Phillips Miniwatt Heerlen
Valvo Heerlen
Siemens 273 code on top, made in Germany on side
Hytron 12DT7
Sylvania 3 Mica Black Plate
Telefunken smooth plate
Telefunken ribbed plate
Gold Lion new
WE 5755 with adapter - might have been causing distortion
12AU7
Brimer 4068 / 13D3. I incorrectly stated 4004 above.
Brimer long plate, red box, yellow Brimar T triangle logo on side
Phillips Jan 5814A blue-green logo, black plate
RCA Black Plate
RCA clear top
Telefunken smooth plate
300B
Cossor black plate
Cossor WE300b
Last edited:
I ended with Bugle Boy 12au7 and Mullard NOS 12ax7. Bugle boys are very good at 3D presentation but at the expense of being little bright but the Mullard tames it down so a perfect couple. I only have couple Bugle Boys so generally try to only use these in preamps where there effect is more prominent.
I also have several 12au7 I have not tried from Sylvania, tung sol, cite and GE 5814A I still need to try. If anybody has tried these, would like to hear your feedback.