Hello gotan,
Very interesting.
Maybe it's the tubes rather than the Elekit.
In any case, I don't do much critical listening before at least 100 hours usage of power tubes. (As long as the distortion you experience still allows listening..).
I experienced, similar to others like Sunil, 807s need quite a lot of time to burn in.
Technically, to my understanding and checks I made, 807 tube matches the 6l6gc specifics. I think I checked the relevant parameters and they are identical. Think 807 is the evolution of this line actually, the latest developed tube.
When I asked Elekit, they said they didn't test 807s in the amp so can't authorize, but they are aware that quite many people use them in this amp with no issues.
Yes, I've used Philips/Valvo 807s. I've cut down the negative feedback this amp uses to a lower level. Since then, I use RCAs. My speakers are 94 dB sensitive and over time they seemed to get hm.. boomy in the bass. Since I reduced the negative feedback, I got a more lean sound that somehow matches my RCAs better. This sound ie. with less negative feedback could be more flat but more.. direct maybe the right word. Violins sound violins more.
I tried with no feedback too and even that it was kind of flat, I appreciated it, even more direct somehow. Still kept some of the feedback thus keep the original design to some extent.
Kind regards
Sandor
Very interesting.
Maybe it's the tubes rather than the Elekit.
In any case, I don't do much critical listening before at least 100 hours usage of power tubes. (As long as the distortion you experience still allows listening..).
I experienced, similar to others like Sunil, 807s need quite a lot of time to burn in.
Technically, to my understanding and checks I made, 807 tube matches the 6l6gc specifics. I think I checked the relevant parameters and they are identical. Think 807 is the evolution of this line actually, the latest developed tube.
When I asked Elekit, they said they didn't test 807s in the amp so can't authorize, but they are aware that quite many people use them in this amp with no issues.
Yes, I've used Philips/Valvo 807s. I've cut down the negative feedback this amp uses to a lower level. Since then, I use RCAs. My speakers are 94 dB sensitive and over time they seemed to get hm.. boomy in the bass. Since I reduced the negative feedback, I got a more lean sound that somehow matches my RCAs better. This sound ie. with less negative feedback could be more flat but more.. direct maybe the right word. Violins sound violins more.
I tried with no feedback too and even that it was kind of flat, I appreciated it, even more direct somehow. Still kept some of the feedback thus keep the original design to some extent.
Kind regards
Sandor
Hello Sándor,
thank you very much for sharing your experience with me.
More and more, I'm coming to the conclusion that the thing is strongly dependent on the valve. As I mentioned, a pair of Tungsrams does not distort even after 12 hours (and here the music is already disturbingly loud, or at least very loud within 1-2 meters or my listening position).
The other tubes bleed at the 8-9 o'clock position.
But right now I'm listening to the chunky version of the 807, the 5933. Flawless in Triode, just like Tungsram
pair of tubes (in terms of distortion). For the given sound the experience is still raw yet, since I've only been listening for about half an hour (they just arrived). In any case, they are very promising.
thank you very much for sharing your experience with me.
More and more, I'm coming to the conclusion that the thing is strongly dependent on the valve. As I mentioned, a pair of Tungsrams does not distort even after 12 hours (and here the music is already disturbingly loud, or at least very loud within 1-2 meters or my listening position).
The other tubes bleed at the 8-9 o'clock position.
But right now I'm listening to the chunky version of the 807, the 5933. Flawless in Triode, just like Tungsram
pair of tubes (in terms of distortion). For the given sound the experience is still raw yet, since I've only been listening for about half an hour (they just arrived). In any case, they are very promising.
This seems to be the best thread for this question:
Are the KT170 suitable for the TU-8200R, and would there be any point to using them? The output transformers (70 mA Lundahl 2777B) limit the current, so installing higher current capable tubes is not going to increase the power, right?
A second question: Does anybody have any experience with Psvane Horizon KT88? Is there any point in trying these compared to the 6L6GC the amp (TU-8200R with Lundahl 2777B output transformers) comes with?
Are the KT170 suitable for the TU-8200R, and would there be any point to using them? The output transformers (70 mA Lundahl 2777B) limit the current, so installing higher current capable tubes is not going to increase the power, right?
A second question: Does anybody have any experience with Psvane Horizon KT88? Is there any point in trying these compared to the 6L6GC the amp (TU-8200R with Lundahl 2777B output transformers) comes with?
Hi Gruesome, I think the heater current is the main probleme with KT170. It is too high for the 4A of main transformer. There is only 4A 'capacity' for driver and power tubes.
Yes, they need 2A for heating so nothing remains for the pre tubes. A KT88 draws 1.6 Amps. To me, KT88 is already a bit of overkill in that amp..
Even if the transformer could provide enough current, KT170s would not work well with low plate voltage as they are less linear in that region.
Even if the transformer could provide enough current, KT170s would not work well with low plate voltage as they are less linear in that region.
Thanks a lot, gotan and paczeltf! So, even if I fed the heaters from an external 6.3V DC supply, the bias voltage puts the KT170 into a not-so-linear regime, if I understand you correctly.
The KT88 would work though? Or would they also need higher bias? I'm not sure how I should interpret 'overkill'. Heater current draw already too high? Or are you referring to performance: potentially better, or potentially higher power, but not in this amp?
The KT88 would work though? Or would they also need higher bias? I'm not sure how I should interpret 'overkill'. Heater current draw already too high? Or are you referring to performance: potentially better, or potentially higher power, but not in this amp?
KT88 is supported by Elekit in TU-8200. You may get marginally higher output power compared to 6L6 GC but it has similar issues as KT170 just to a lesser extent. The bias current in the TU-8200 is between 70 and 75 mA for all tubes, and for KT88 approx. 110 mA would be ideal with the plate voltage available. TU-8800 is the amp that was designed for KT88. Try KT66 if you want a non-6L6GC variant.
