Yea, those are more or less of what I would like as well. I would love a custom iron with 8, 32 and 100 ohm secondaries. Finding a good iron maker to make such an iron would be the biggest challenge, as most of the good iron makers are not interested in making custom headphone iron.
Elekit is still not that popular among the headphone crowd. But if Elekit can make a headphone version of the 8900 by making it 2A3 only and lowering the gain and using a different transformer, it might gain some traction.
Yep, connecting directly to the secondary of the OPT by using the VH connectors was my original plan. But I plan on driving both headphones and speakers from the 8900. Which is why I went with the 'internal headphone board without the resistor network' route.
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You cAn definitely drive both speakers and headphones by tapping directly at that R120/220. It depends on which one you plugged in.
***oh! You meant you do not want to use additional headphones socket.****
I am very happy with the TU-8900 with Hd800s and regardless of those said resistors. I will definitely keep an eye on the modifications for it though
***oh! You meant you do not want to use additional headphones socket.****
I am very happy with the TU-8900 with Hd800s and regardless of those said resistors. I will definitely keep an eye on the modifications for it though
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Yep, tapping at R120 would indeed be the shortest path to the headphone. But if I wanted to listen to headphones, I’d have to unplug the speakers and vice versa. Whereas, if I use the amp’s headphone socket, I can simply leave the speakers plugged in at all times and I can plug-in my headphones, when I want to use headphones and it would cut the output to speakers.
Another point I must add is, my DAC has a very good volume control. Which is also one of the reasons I didn’t mind removing the resistors from the headphone board, as I’ll have some flexibility to attenuate the signal from the source, so that I have enough headroom to play with on the amp’s volume control. Or I would simply max out the volume pot on the amp and use my DAC’s volume control.
Thank you, that is good to know and re-assuring. Btw, which jumper position are you using for your HD800S?
Another point I must add is, my DAC has a very good volume control. Which is also one of the reasons I didn’t mind removing the resistors from the headphone board, as I’ll have some flexibility to attenuate the signal from the source, so that I have enough headroom to play with on the amp’s volume control. Or I would simply max out the volume pot on the amp and use my DAC’s volume control.
Thank you, that is good to know and re-assuring. Btw, which jumper position are you using for your HD800S?
I see your point now. I never thought about using 8900 for speakers lol!!!
I am using Low gain on the HD800S. Regardless of the criticisms about the resistors, I have never heard the HD800S this way. The greatest soundstage, dynamic, details, controls, textures, finesses and bass quality. The performances see another boost with NFB enabled and WE300B tubes. I am not even pass 70 hours yet. Still a while to go for burn in, but there has not been any moment that I haven’t appreciated this TU8900 at all
If anyone wanted and desired different output transformers, perhaps that can be done with Victor helps ? But then again, I am using Lundahl 2785B and as mentioned above. I have never heard my 800s being this good
I am using Low gain on the HD800S. Regardless of the criticisms about the resistors, I have never heard the HD800S this way. The greatest soundstage, dynamic, details, controls, textures, finesses and bass quality. The performances see another boost with NFB enabled and WE300B tubes. I am not even pass 70 hours yet. Still a while to go for burn in, but there has not been any moment that I haven’t appreciated this TU8900 at all
If anyone wanted and desired different output transformers, perhaps that can be done with Victor helps ? But then again, I am using Lundahl 2785B and as mentioned above. I have never heard my 800s being this good
If I tap at R120, I can keep only the speakers or the headphones connected to the amp at any point in time. Meaning, if I have to run my headphones, I’d have to unplug the speakers. With the internal headphone jack, I can leave the spekaers connected to the amp all the time. The only thing I will be plugging and unplugging is the headphone.
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Any experience guys with pre tubes 12BH7(A) in this amp?
In case, with E80cc? I use latter in my TU-8200 (after changes required) and turned it into a very different amp vs. with 12au7 / ecc82 in. Upgrades by paczeltf.
Did not make any detailed checks but e80cc appear to draw same heater current at least so keeps me thinking about it. 12bh7a can be used in TU 8900 in the stock model besides 12au7.
Thanks
In case, with E80cc? I use latter in my TU-8200 (after changes required) and turned it into a very different amp vs. with 12au7 / ecc82 in. Upgrades by paczeltf.
Did not make any detailed checks but e80cc appear to draw same heater current at least so keeps me thinking about it. 12bh7a can be used in TU 8900 in the stock model besides 12au7.
Thanks
The E80CC has about 50% higher gain than the 12AU7 or the 12BH7A. It should not be an issue in non-feedback mode, but the cathode feedback resistors need to be set to a lower value in the first stage when global NFB is in use.
Any ideas for kit modification are welcome
But I want a responsible thread..
New diyers might follow your recommendation, but do not understand the rationale for the modifications.
I welcome your valuable contribution and support...
however:
-Please modify at your own risk.
-Please be specific when describing modifications.
-This is to prevent potential damage to your amp kit and of others...
I agree with Russ Sadd
This is what he posted few years ago
The E80CC is equivalent to an American 6085. This isn't, however, a 12AU7 /
ECC82. We're talking about a small double-triode, but one with very
different properties (i.e. mu of 37 instead of 17, using 6mA plate current
on average instead of 11ma). In conventional R-C stages, it may be possible
to directly substitute the two without anything going drastically wrong, but
you'll probably end up with more gain than you need and a good bit of extra
distortion. An E80CC won't be able to give the same 'kick' as an ECC82 when
used as a driver - it'll be putting out less power and with a higher anode
impedance.
My advice is always to take an eBay "substitution" with more than a pinch of
salt. I've seen too many 12E1 sweep tubes sold as "KT88 equivalents", not to
mention Mullard ECC32s sold as "premium 6SN7s"! This kind of sale is
guaranteed to (1) make the seller a lot of money and (2) gives the buyer a
good chance of burning out the valves along with his or her amplifier.
Thankfully, this "equivalence" is relatively harmless, and may only result
in decreased performance.
Best regards,
Russ Sadd
Birmingham, UK
But I want a responsible thread..
New diyers might follow your recommendation, but do not understand the rationale for the modifications.
I welcome your valuable contribution and support...
however:
-Please modify at your own risk.
-Please be specific when describing modifications.
-This is to prevent potential damage to your amp kit and of others...
I agree with Russ Sadd
This is what he posted few years ago
The E80CC is equivalent to an American 6085. This isn't, however, a 12AU7 /
ECC82. We're talking about a small double-triode, but one with very
different properties (i.e. mu of 37 instead of 17, using 6mA plate current
on average instead of 11ma). In conventional R-C stages, it may be possible
to directly substitute the two without anything going drastically wrong, but
you'll probably end up with more gain than you need and a good bit of extra
distortion. An E80CC won't be able to give the same 'kick' as an ECC82 when
used as a driver - it'll be putting out less power and with a higher anode
impedance.
My advice is always to take an eBay "substitution" with more than a pinch of
salt. I've seen too many 12E1 sweep tubes sold as "KT88 equivalents", not to
mention Mullard ECC32s sold as "premium 6SN7s"! This kind of sale is
guaranteed to (1) make the seller a lot of money and (2) gives the buyer a
good chance of burning out the valves along with his or her amplifier.
Thankfully, this "equivalence" is relatively harmless, and may only result
in decreased performance.
Best regards,
Russ Sadd
Birmingham, UK
This is the reply from Mr Fujita..
Regarding your question,
Basically e80CC cannot be used for TU-8900 because the μ of the tube
is a lot different from the tubes we specify for TU-8900.
If we used E80CC, there is a possibility of oscillation.
So please refrain from using e80cc for TU-8900.
***
Also,
Mr.Fujita says that if non-NFB setting, it is OK to use e80cc,
but in that setting the gain will be too high, so the volume control will not function properly..
Regarding your question,
Basically e80CC cannot be used for TU-8900 because the μ of the tube
is a lot different from the tubes we specify for TU-8900.
If we used E80CC, there is a possibility of oscillation.
So please refrain from using e80cc for TU-8900.
***
Also,
Mr.Fujita says that if non-NFB setting, it is OK to use e80cc,
but in that setting the gain will be too high, so the volume control will not function properly..
Thank you, and others for inputs! Appreciated.
I miss the skills to even think in details here or calculate the values of cathode feedback resistors, would I use e80cc. At my own risk of course..
I'm also much interested in try comparing TU-8900 and TU-8200 in triode mode that I use.
My thoughts: I guess triode mode for a tetrode like 6l6gc is less linear than a real triode's as 300b or 2a3 are. Is it much off? Don't know.
Then, does one (me) really need the higher watts TU-8900 can actually give, higher than the estimated 1 watt or less I really use with TU-8200 (triode mode)? Don't turn volume knob to a third of what it allows (TU-8200); that gets loud enough on my loudspeaker (not a very efficient one but provides 94 dB on paper, AudioNote AZ3 Hemp). It's actually too loud for a 24 m2 room. True though, over this level the TU-8200 starts to distort quite a lot, to my ears (triode mode).
The OPTs there could be bigger, still I could live with them for 2 years now.
Then, how does 12b7* perform as compared to e80cc? Latter is just fantastic (generally speaking). I have no experience with 12b7* at all, nor any reports how it sounds in TU-8900. Any experience with 12b7 and particularly vs. 12au7 in TU-8900 would be great to hear about.
Thanks
I miss the skills to even think in details here or calculate the values of cathode feedback resistors, would I use e80cc. At my own risk of course..
I'm also much interested in try comparing TU-8900 and TU-8200 in triode mode that I use.
My thoughts: I guess triode mode for a tetrode like 6l6gc is less linear than a real triode's as 300b or 2a3 are. Is it much off? Don't know.
Then, does one (me) really need the higher watts TU-8900 can actually give, higher than the estimated 1 watt or less I really use with TU-8200 (triode mode)? Don't turn volume knob to a third of what it allows (TU-8200); that gets loud enough on my loudspeaker (not a very efficient one but provides 94 dB on paper, AudioNote AZ3 Hemp). It's actually too loud for a 24 m2 room. True though, over this level the TU-8200 starts to distort quite a lot, to my ears (triode mode).
The OPTs there could be bigger, still I could live with them for 2 years now.
Then, how does 12b7* perform as compared to e80cc? Latter is just fantastic (generally speaking). I have no experience with 12b7* at all, nor any reports how it sounds in TU-8900. Any experience with 12b7 and particularly vs. 12au7 in TU-8900 would be great to hear about.
Thanks
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