ELEKIT TU-8800 SET AMP

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mz543578854

Member
Joined 2015
Using the TU-8800 as power amp

Hello,

I am thinking abut purchasing the TU-8080, but I own a good digital preamp-DAC which would like to use as preamp.

Is it possible to identify the "pre-in" of the amp so I could wire inputs to that point the case? Or is it OK to just raise the volume of the TU-8080 to some point and leave it there and just connect the preamp to one of its inputs?

Thanks,
M
 
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Steve Morley

Member
Joined 2015
In my experience big tubes, KT120 and KT150, aren't used to their full advantage in an amp that doesn't bias them "hot" enough to get into their sweet spot. You might get better sound using a mid-power tube, KT77 or maybe an EL34, and save a bunch of money that you could put towards a Lundahl upgrade. :)

You might get slightly more power out of the "Big" tubes but not enough to make a significant difference.

My favourite tube by a long shot is the Gold Lion (Russian reissue) KT77.

Steve
 
P

paczeltf

Member
Joined 2018
Paid Member
Steve Morley said:
In my experience big tubes, KT120 and KT150, aren't used to their full advantage in an amp that doesn't bias them "hot" enough to get into their sweet spot.
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It is not just your experience, it has technical reasons. Oversized tubes work in a less linear region of their characteristics so that the distortion will be higher at the same output power. KT120 and KT150 are less linear than smaller power tubes anyway as there are artifacts in their transfer curves.

You might get better sound using a mid-power tube, KT77 or maybe an EL34, and save a bunch of money that you could put towards a Lundahl upgrade. :)
Click to expand...

The TU-8800 has 3 power settings, the EL34 and 6L6GC fall into the medium category. I am a bit surprised though why KT66 and KT77 are classified as high power tubes. Their limiting values are very close to those of EL34 and in case of KT66, the max. plate voltage is even lower.

You might get slightly more power out of the "Big" tubes but not enough to make a significant difference.
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I made a calculation for TU-8200 some time ago. There is negligible difference between 6L6GC, EL34 and KT88 in that amp in pentode mode in terms of maximum power even though the KT88 is able to provide about 40% higher output power than the other two if biased accordingly.
 
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mz543578854

Member
Joined 2015
If I understand correctly, the TU-8800 does auto-bias. What is changed by the high-mid-low setting? Bias level? B+ voltage?

After reasing a lot the past days about how tubes work only correctly "in their setup" (meaning correct B+, bias etc.), I am wondering, if the configuration in the TU-8800 is only "making other tubes" to produce sound (ok, purposedly being a little polemic here) with the high-mid-low.

Or if per setting there is one tube type only, which is ideal.

Or if the only ideal setup is only high with KT-88 (or why is it printed in bold?).

Can any expert shed some light here?

Thanks
 
vkung

vkung

Member
Joined 2005
ERYN's TU-8800








Hi Victor,

I would like to let you know my TU-8800 has finally finished. I did a few changes and it's really good (attached some pics for you):

- painted the chassis graphite black,
- replace the switch button extension rod with a carbon fiber one,
- use my favorite Nichicon lytic caps instead of the stock caps except the United Chemi-Con C114, C214,
- use Nichicon SEPC low ESR caps instead of the stock caps

Tubes I use KT88 and NOS ECC81, I've checked the voltage check points and they are quite close to the reference ones. I tested with my headphones and it sounds really good, should be even better after it burn-in for some time. It sounds quite different from the TU-8600. I think with the Lundahl opt will be even better.

Thanks!

Eryn
 
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