I use 7581A in my TU-8200, and the TU-8800 has very similar input sensitivity and output power compared to the 8200 using the same tubes. These 300 Ohm phones should be loud at 10 o'clock even if the HD580 is less sensitive than HD600.
The >12 o'clock volume pot position overloads the amp when being driven from a regular 2V digital source.
I do not have the schematics for the 8800 but if you send me a photo of the headphone output section, I may be able to give you some advice on how to increase the output level.
The >12 o'clock volume pot position overloads the amp when being driven from a regular 2V digital source.
I do not have the schematics for the 8800 but if you send me a photo of the headphone output section, I may be able to give you some advice on how to increase the output level.
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send your phono number to my email info@vkmusic.ca . I can chat with you to understand your issue
Maybe clipping isn't the right word, but it sounds like all of the clipping I've ever heard before. At around 12 oclock on the knob, there is crackling on loud notes in the music, and bass becomes flabby and sounds like its flapping. But I can keep turning the knob up and it gets much louder still, but the crackling sounds also become worse.
I talked to Victor on the phone and he suggested that I'm driving my headphone too hard and causing the driver to clip. However I do not think this is the case, because I can play the same track with the same DAC through a different amp and go much much louder without any crackling noises.
I've also talked with SonnyMarrow from this thread, and he does not have the same problem with the same headphone, same tubes, same ZOUT setting as me. I even sent him the test track I'm using.
To be clear: I do not think anything is wrong with the base design of this amp. I think whoever built my amp either made a mistake, or some parts used in my amp are faulty. I am trying to figure out what is wrong with my amp.
Have you tried the amp with speakers at the same volume settings?
This amp outputs almost 8V before it starts clipping, that is deafening level if you connect these Sennheisers directly to the OPTs.
I believe your problem is that you are clipping the input stage of the TU-8800. You need to reduce the level coming from your DAC.
The published input sensitivity of the 8800 is 360mV. Compare that to the output of your DAC (mine is 2.15V for comparison). I was experiencing a similar issue, and like you, I thought maybe I had done something wrong in the build. However, I then realized that even at lower volume levels, loud rock music sounded clipped no matter where the volume was set. Through trial and error, I determined that I need to have my Roon volume set at 49 to keep my DAC->amp signal clean and clipping-free. Since I made that adjustment, I can turn the volume up all the way with no clipping. If I move the Roon level to 50, it clips immediately on loud passages, no matter the volume setting on the amp.
For comparison, my solid state headphone amp - connected via another input to the same DAC - can handle the full output from the DAC.
The published input sensitivity of the 8800 is 360mV. Compare that to the output of your DAC (mine is 2.15V for comparison). I was experiencing a similar issue, and like you, I thought maybe I had done something wrong in the build. However, I then realized that even at lower volume levels, loud rock music sounded clipped no matter where the volume was set. Through trial and error, I determined that I need to have my Roon volume set at 49 to keep my DAC->amp signal clean and clipping-free. Since I made that adjustment, I can turn the volume up all the way with no clipping. If I move the Roon level to 50, it clips immediately on loud passages, no matter the volume setting on the amp.
For comparison, my solid state headphone amp - connected via another input to the same DAC - can handle the full output from the DAC.
8800 with Quad 57 Electrostats?
Does anyone have experience with the 8800 driving the original Quad eletrostats? And if so, what tubes were used? Where can I get a list or source of the Mundhoff capacitors that others have used to upgrade the amp? I'd like to install the best caps as I build rather than add later.
Thanks!
Does anyone have experience with the 8800 driving the original Quad eletrostats? And if so, what tubes were used? Where can I get a list or source of the Mundhoff capacitors that others have used to upgrade the amp? I'd like to install the best caps as I build rather than add later.
Thanks!
Upgrade caps for the 8800
Thanks for the note regarding the V-Cap CuTF upgrade for the 8800. All of a sudden it appears there are none of these in amplifiers in stock from US sellers. Guess I'll have to wait. Want to get the amp ordered before ordering the caps.
I don't see the caps listed on the VK Music website, if you have more details please let me know at ajcatan@hotmail.com. Thanks!
Thanks for the note regarding the V-Cap CuTF upgrade for the 8800. All of a sudden it appears there are none of these in amplifiers in stock from US sellers. Guess I'll have to wait. Want to get the amp ordered before ordering the caps.
I don't see the caps listed on the VK Music website, if you have more details please let me know at ajcatan@hotmail.com. Thanks!
I would strongly suggest you reach directly to Victor if you are interested in the amp and the capacitors. He is very responsive, and he will either quote you a price for them or tell you when he will have more kits in stock. In my experience, he as more items in stock than you will find on his website - the most accurate information is in this forum, or if you reach out to him directly.
Hi,
the rated input is 0.36V which seems quite low.
My DAC outputs 2V RMS ... would it work to connect that directly as I can control the volume digitally from the streamer, or should I put a pre-amp in - my pre is Cambridge Audio AZUR 841E which maxes at 8V in 100 steps, so I'm assuming that's 0.08V per step which would give me 4 steps from nothing.
would either of those be a good option for the 8800?
thanks
Jonathan.
the rated input is 0.36V which seems quite low.
My DAC outputs 2V RMS ... would it work to connect that directly as I can control the volume digitally from the streamer, or should I put a pre-amp in - my pre is Cambridge Audio AZUR 841E which maxes at 8V in 100 steps, so I'm assuming that's 0.08V per step which would give me 4 steps from nothing.
would either of those be a good option for the 8800?
thanks
Jonathan.
Japan mainly uses 100V for domestic appliances. Specifically, as Victor is indicating, that's not 110V as used in many other countries.
There are also, sometimes at least, 200V outlets in Japanese residences. They tend to be for air conditioners. For which reason, and possibly safety as well, they are usually located just below ceiling height. (Additionally, some of those elevated aircon outlets may be only 100V, as many aircon units are 100V models.)
So most of the time, it's 100V 50Hz in eastern Japan, 100V 60Hz in western Japan, and you'd have to look at a map to see which side of the line some of the more central locations would fall.
Modern audio equipment in Japan is almost invariably (I'm assuming it's a requirement by now) be specified as 50/60Hz. For vintage gear from the 1970s or earlier, that is far less the case.
And either way, Japan has no exact equivalent of 110V/60Hz.
Regionally speaking, 220V (or thereabouts) and 50Hz is most common in almost the whole of Asia. One exception is Taiwan, which is 110 (not 100, despite its Japan connections pre-1945).
There are also, sometimes at least, 200V outlets in Japanese residences. They tend to be for air conditioners. For which reason, and possibly safety as well, they are usually located just below ceiling height. (Additionally, some of those elevated aircon outlets may be only 100V, as many aircon units are 100V models.)
So most of the time, it's 100V 50Hz in eastern Japan, 100V 60Hz in western Japan, and you'd have to look at a map to see which side of the line some of the more central locations would fall.
Modern audio equipment in Japan is almost invariably (I'm assuming it's a requirement by now) be specified as 50/60Hz. For vintage gear from the 1970s or earlier, that is far less the case.
And either way, Japan has no exact equivalent of 110V/60Hz.
Regionally speaking, 220V (or thereabouts) and 50Hz is most common in almost the whole of Asia. One exception is Taiwan, which is 110 (not 100, despite its Japan connections pre-1945).
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