I am very sorry that Victor deleted the attached table which summarized all the changes suggested by Ferenc ....
I personally found them very useful. (...) It would be nice if all the people who found the suggested changes useful, testify their satisfaction here !!!
Thank you.
If someone could send me the latest TU-8200R manual in PM, I would update the spreadsheet for the new amp in order to avoid confusion. A few updates are not required anyway as Elekit already raised the values in the new model.
I don't know when Elekit updated the schematics with different part number(s), it did not create problems until recently.
The early version of the TU-8200R manual was still showing the 0.47 Ohm resistor as R64 as it was in the original 8200 model, even though R63/R64 had been introduced with the redesigned protection circuit. Elekit must have corrected it later, not sure if this affected the PCB as well.
I haven't yet checked but R63 may have also been duplicated. It is not affected by these mods though.
I haven't yet checked but R63 may have also been duplicated. It is not affected by these mods though.
Well it's Elekit that confirmed correctness of quite some of the capacitor updates (TU-8200) by raising values rather similarly in the later DX model of TU-8200 as far as I'm concerned.
I am very sorry that Victor deleted the attached table which summarized all the changes suggested by Ferenc ....
I personally found them very useful.
I also believe that Ferenc knows exactly the fact of him .... after all he has always been very helpful with everyone in explaining the theoretical assumptions behind the suggested changes.
I own a "modified" TU-8200 as suggested by Ferenc with 2x E80cc as driver + 2x 7581A as power tubes and 2 OPT Lundahls ..... to me, now, it sounds "divine".
It would be nice if all the people who found the suggested changes useful, testify their satisfaction here !!!
Table of modifications for the original TU-8200 model comes here:
Use at your own risk and enjoyment naturally
Solely use for TU-8200
Follow column structure:
Component(s)
Original Value
New Value
Suggested Model
Comment
Data starts here:
C22
180μF/400V
270-330μF/400V
Rubycon MXK 25x35
Significanty less hum on headphone output. Max length = 36mm
C23,C24
10μF/400V
22μF/400V
Panasonic EE 12.5x25
More delay to B+ voltage, protecting tubes after switching on the amp. Max length = 36mm
C7,C8,C11,C12
10μF/400V
15μF/400V
Nichicon CS(M) 12.5x20
Optional - gives a bit more room. Max length = 20mm
C31,C32
3300μF/10V
10000μF/10V
Panasonic NHG 16x31.5
Higher and better filtered DC heater voltage. Max length = 36mm
R64
0.47 Ohm
Short (0 Ohm)
N/A
Cut off a pin of a resistor, bend it twice
D7
DB107
DB207
Any DB20x is fine
Lower forward voltage drop. Required for driver update.
C34,C35
220μF/16V
220μF/16V
OS-CON; ⌀=8mm
Optional - gives better high frequency filtering of bias reference
C13,C14
220μF/16V
470μF/16V
Panasonic SEPC OS-CON; ⌀=8mm
The low ESR is very important
C33
220μF/16V
330-470μF/16V
Panasonic HD; ⌀=8mm
Better low frequency filtering of bias reference
Use at your own risk and enjoyment naturally
Solely use for TU-8200
Follow column structure:
Component(s)
Original Value
New Value
Suggested Model
Comment
Data starts here:
C22
180μF/400V
270-330μF/400V
Rubycon MXK 25x35
Significanty less hum on headphone output. Max length = 36mm
C23,C24
10μF/400V
22μF/400V
Panasonic EE 12.5x25
More delay to B+ voltage, protecting tubes after switching on the amp. Max length = 36mm
C7,C8,C11,C12
10μF/400V
15μF/400V
Nichicon CS(M) 12.5x20
Optional - gives a bit more room. Max length = 20mm
C31,C32
3300μF/10V
10000μF/10V
Panasonic NHG 16x31.5
Higher and better filtered DC heater voltage. Max length = 36mm
R64
0.47 Ohm
Short (0 Ohm)
N/A
Cut off a pin of a resistor, bend it twice
D7
DB107
DB207
Any DB20x is fine
Lower forward voltage drop. Required for driver update.
C34,C35
220μF/16V
220μF/16V
OS-CON; ⌀=8mm
Optional - gives better high frequency filtering of bias reference
C13,C14
220μF/16V
470μF/16V
Panasonic SEPC OS-CON; ⌀=8mm
The low ESR is very important
C33
220μF/16V
330-470μF/16V
Panasonic HD; ⌀=8mm
Better low frequency filtering of bias reference
Sorry for creating a firestorm, everyone. That certainly wasn't my intent. My intent was not to bash this awesome amplifier either. I realize that my initial comments may have come across as condemnation of the unit. This is certainly not the intent. One of the areas of my current system that has always been lacking in my current system is bass. The improvement in bass that I can see from initial testing on the TU-8200R is impressive and exactly what I am after. I've built kits, modified commercial built equipment and built things from scratch. I get that these things are rarely perfect right out of the box and that some tweaking is involved. My ask was really about the ECC82's from JJ Electronics. The ones that my kit came with are their $12 variant. They have a $22 variant and obviously, there are tubes from many other sources. I don't have any experience with JJ's tubes and I don't have any other equipment that use ECC82/12AU7 tubes. Rather than buying a bunch and testing, I figured I would ask for others opinions.
I did run through the test points to verify that the voltages are within the specified ranges, but I may have missed something. I will double check all of the values this weekend. It didn't occur to me that there are multiple versions of the circuit board. On mine, the 0.47 ohm resistor is R70. Assuming the voltages are all within spec after a double check, I won't worry about that resistor and will leave it as-is. The only deviations I made from the original mods list was the "R64" one that started this discussion (it and R63 are their original 22k ohm values) and I wasn't able to find a DB207 rectifier bridge, so I substituted a similar specification DF210. My heater voltage with KT88's installed is 6.28v so it did the trick.
I guess I will order several 12AU7 variants and see what comes of it. Sorry for creating confusion, but hopefully the next person that encounters this thread will be able to tell that there are multiple versions of the circuit board and make better assumptions/choices than me.
I did run through the test points to verify that the voltages are within the specified ranges, but I may have missed something. I will double check all of the values this weekend. It didn't occur to me that there are multiple versions of the circuit board. On mine, the 0.47 ohm resistor is R70. Assuming the voltages are all within spec after a double check, I won't worry about that resistor and will leave it as-is. The only deviations I made from the original mods list was the "R64" one that started this discussion (it and R63 are their original 22k ohm values) and I wasn't able to find a DB207 rectifier bridge, so I substituted a similar specification DF210. My heater voltage with KT88's installed is 6.28v so it did the trick.
I guess I will order several 12AU7 variants and see what comes of it. Sorry for creating confusion, but hopefully the next person that encounters this thread will be able to tell that there are multiple versions of the circuit board and make better assumptions/choices than me.
Any ideas for kit modification are welcome
But I want a responsible thread..
For example, when mentioning TU-8200--- which version?
Please be specific when describing the type of modification...
If not, the consequences are potentially huge...
New diyers might follow your recommendation, but do not understand the rationale for the modifications.
When I saw vinlyaudio replacing/short R64 in R version, I was shocked. This is part of the protection circuit to prevent over current.
I knew something was not right.....
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...
But I want a responsible thread..
For example, when mentioning TU-8200--- which version?
Please be specific when describing the type of modification...
If not, the consequences are potentially huge...
New diyers might follow your recommendation, but do not understand the rationale for the modifications.
When I saw vinlyaudio replacing/short R64 in R version, I was shocked. This is part of the protection circuit to prevent over current.
I knew something was not right.....
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...
Last edited:
SandorS please update your thread accordingly......
your recommendation is for which version..
Mr Fujita told me (for R ) C14, C33, C34, C35 cannot recommend to use Organic Cap (low ESR)..... we want low leaking in these positons..
He recommends low ESR in these positions C1, C2, C5, C6 only...
your recommendation is for which version..
Mr Fujita told me (for R ) C14, C33, C34, C35 cannot recommend to use Organic Cap (low ESR)..... we want low leaking in these positons..
He recommends low ESR in these positions C1, C2, C5, C6 only...
Last edited:
Hi there,
I use e80cc after the required updates made, but have used ecc82 before, particularly Telefunken that I found a big improvement over the JJ one.
The JJ sounded sterile to my ears; and missed particularly midrange, too. The Telefunken has had mids, maybe too much even.
Or, just because is a better product, may show the character of the ecc82 that's not really natural to my ears (others may describe as non-linear).
Cheers
I use e80cc after the required updates made, but have used ecc82 before, particularly Telefunken that I found a big improvement over the JJ one.
The JJ sounded sterile to my ears; and missed particularly midrange, too. The Telefunken has had mids, maybe too much even.
Or, just because is a better product, may show the character of the ecc82 that's not really natural to my ears (others may describe as non-linear).
Cheers
To clarify, below list of modifications shared have been for the original (first) TU-8200 model, by paczeltf, as posted originally in this thread.
My comments: Solely use for TU-8200. Not applicable for DX version as-is; not for TU-8200R as-is either.
Please read carefully the thead through to be sure if the modifications apply for your amp as are, and may see further hints in this matter.
I can't edit my prior post, thus this post.
Follow column structure:
Component(s)
Original Value
New Value
Suggested Model
Comment
Data starts here:
C22
180μF/400V
270-330μF/400V
Rubycon MXK 25x35
Significanty less hum on headphone output. Max length = 36mm
C23,C24
10μF/400V
22μF/400V
Panasonic EE 12.5x25
More delay to B+ voltage, protecting tubes after switching on the amp. Max length = 36mm
C7,C8,C11,C12
10μF/400V
15μF/400V
Nichicon CS(M) 12.5x20
Optional - gives a bit more room. Max length = 20mm
C31,C32
3300μF/10V
10000μF/10V
Panasonic NHG 16x31.5
Higher and better filtered DC heater voltage. Max length = 36mm
R64
0.47 Ohm
Short (0 Ohm)
N/A
Cut off a pin of a resistor, bend it twice
D7
DB107
DB207
Any DB20x is fine
Lower forward voltage drop. Required for driver update.
C34,C35
220μF/16V
220μF/16V
OS-CON; ⌀=8mm
Optional - gives better high frequency filtering of bias reference
C13,C14
220μF/16V
470μF/16V
Panasonic SEPC OS-CON; ⌀=8mm
The low ESR is very important
C33
220μF/16V
330-470μF/16V
Panasonic HD; ⌀=8mm
Better low frequency filtering of bias reference[/QUOTE]
My comments: Solely use for TU-8200. Not applicable for DX version as-is; not for TU-8200R as-is either.
Please read carefully the thead through to be sure if the modifications apply for your amp as are, and may see further hints in this matter.
I can't edit my prior post, thus this post.
Follow column structure:
Component(s)
Original Value
New Value
Suggested Model
Comment
Data starts here:
C22
180μF/400V
270-330μF/400V
Rubycon MXK 25x35
Significanty less hum on headphone output. Max length = 36mm
C23,C24
10μF/400V
22μF/400V
Panasonic EE 12.5x25
More delay to B+ voltage, protecting tubes after switching on the amp. Max length = 36mm
C7,C8,C11,C12
10μF/400V
15μF/400V
Nichicon CS(M) 12.5x20
Optional - gives a bit more room. Max length = 20mm
C31,C32
3300μF/10V
10000μF/10V
Panasonic NHG 16x31.5
Higher and better filtered DC heater voltage. Max length = 36mm
R64
0.47 Ohm
Short (0 Ohm)
N/A
Cut off a pin of a resistor, bend it twice
D7
DB107
DB207
Any DB20x is fine
Lower forward voltage drop. Required for driver update.
C34,C35
220μF/16V
220μF/16V
OS-CON; ⌀=8mm
Optional - gives better high frequency filtering of bias reference
C13,C14
220μF/16V
470μF/16V
Panasonic SEPC OS-CON; ⌀=8mm
The low ESR is very important
C33
220μF/16V
330-470μF/16V
Panasonic HD; ⌀=8mm
Better low frequency filtering of bias reference[/QUOTE]
Let me add a few comments:
- Should you have any problem with part value and number mismatch, please contact me before posting to the thread.
- Build the stock amp first. I wrote at the beginning of the thread: "If you build the amp with the mods in the first place, you won't know how it sounds with the stock components". If you have sonic problems with the modified amp then post your doubts to this thread only if you had experience with the stock model.
In a few days I will post a consolidated spreadsheet for both models with all known part numbers. It does not make sense that everyone has to contact me in PM for a parts list.
I still stand by these changes.
- Should you have any problem with part value and number mismatch, please contact me before posting to the thread.
- Build the stock amp first. I wrote at the beginning of the thread: "If you build the amp with the mods in the first place, you won't know how it sounds with the stock components". If you have sonic problems with the modified amp then post your doubts to this thread only if you had experience with the stock model.
In a few days I will post a consolidated spreadsheet for both models with all known part numbers. It does not make sense that everyone has to contact me in PM for a parts list.
I still stand by these changes.
Here are my test point values on the TU-8200R with KT88:
1 - 3.51v
2 - 3.40v
3 - 3.49v
4 - 3.49v
5 - 115.8v
6 - 119.5v
7 - 118v
8 - 117v
9 - 212.8v
10 - 212.7v
11 - 1.14v
12 - 1.14v
13 - -25.7v
14 - -25.2v
15 - 288.5v
16 - 287.1v
17 - 0.51v
18 - 0.52v
19 - 276.2v
20 - 276.1v
21 - 269.5v
22 - 270.0v
23 - 282.8v
24 - 283.1v
25 - 298.0v
26 - -34.2v
27 - -35.0v
28 - 6.26v
29 - 6.45v
13 & 14 are slightly high as are 23 & 24. Everything else is in spec. Should I be concerned about these values that are out of spec? The bias seems the most concerning on KT88. With 6L6GC, TP13 & 14 are 17.5v and 18.0v respectively.
1 - 3.51v
2 - 3.40v
3 - 3.49v
4 - 3.49v
5 - 115.8v
6 - 119.5v
7 - 118v
8 - 117v
9 - 212.8v
10 - 212.7v
11 - 1.14v
12 - 1.14v
13 - -25.7v
14 - -25.2v
15 - 288.5v
16 - 287.1v
17 - 0.51v
18 - 0.52v
19 - 276.2v
20 - 276.1v
21 - 269.5v
22 - 270.0v
23 - 282.8v
24 - 283.1v
25 - 298.0v
26 - -34.2v
27 - -35.0v
28 - 6.26v
29 - 6.45v
13 & 14 are slightly high as are 23 & 24. Everything else is in spec. Should I be concerned about these values that are out of spec? The bias seems the most concerning on KT88. With 6L6GC, TP13 & 14 are 17.5v and 18.0v respectively.
Last edited:
Mr.Fujita says they are all OK.
The referenence test points are based on 115V environment. If your power line is higher than 115V ie 120V
It is natural to have a bit higher voltages than reference voltages.
Also, he says that the voltages can vary due to which tubes to use.
So there should be no issue.
Zenfolio | MY STUFF | PICS FOR DIYAUDIO-photos
Hope the pic shows up... Several tries to get the pic to work, all i could get was a link. Ugh...
.
Question - Lets say I want to install nice silver plated rca plugs in place of the stock. How would the wiring go?
Hope the pic shows up... Several tries to get the pic to work, all i could get was a link. Ugh...
.
Question - Lets say I want to install nice silver plated rca plugs in place of the stock. How would the wiring go?
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If you can live without the small jack auxiliary input, I strongly recommend removing Unit 6 completely, installing high quality RCA sockets, and wiring them to Unit 5 directly. I did that myself because the stock sockets have a thin metal plate to connect the internal pin of the RCA plug, and they were simply not reliable causing signal drop-outs when moving cables around.
Be careful though as regular sockets may not fit due to the diameter of the holes on the chassis and their close placement.
I also suggest you forget silver plated connectors, which are probably in the top 3 stupidest things in audio. They were introduced when gold plated connectors became common so they were no longer considered "high-end". Unfortunately, pure silver exposed to air inevitably corrodes. That nice shiny surface may become gray in just a few months, and silver sulfide is not the best possible conductor.