Thank you paczelft. I Appreciate you opinions and assistance on the elekit threads. I will do just that. But I will use silver, as I always have. I like as much silver an I can afford in my system. My understanding is that shiny gold plating requires a layer of nickel beneath for the shine. Just plain gold would be matte. I never did deeper research, but need to.... I have silver plugs that fit perfect and a tube of deoxit!
Hi Ferenc, could I ask for this modification spreadsheet for TU-8200R version, while still be able to use 12au7 or variant of it.
Thank you/ Patrik
I completed the modifications outlined in the spread sheet. What an upgrade 👍 Talk about a detail monster! This little tube amp is rocking my 89db sensitivity speakers!
paczeltf, thank you for your thoughts!
paczeltf, thank you for your thoughts!
I am glad you like it. I also use the amp with 89dB/W speakers, and with headphones of course.
Right now I'm using JJ 6L6 and JJ 12AU7's. I have some JJ802's Coming as well as a 6AR6 Tung sol tubes and adapters.
Before the amplifier would fall apart a little bit with the speakers. Now it seems to handle them a lot better.
I'm thinking if you had a set of speakers that were around 93db or higher sensitivity, you could pretty much play this camp with relatively low distortion at ridiculous listening levels
Before the amplifier would fall apart a little bit with the speakers. Now it seems to handle them a lot better.
I'm thinking if you had a set of speakers that were around 93db or higher sensitivity, you could pretty much play this camp with relatively low distortion at ridiculous listening levels
Hi Ferenc, I have the 8200R and like to have the spreadsheets/info for the following:
(1) modification while still having the ability to use the 12au7
(2) full modification to use the E80CC
Thanks Nick
(1) modification while still having the ability to use the 12au7
(2) full modification to use the E80CC
Thanks Nick
Checking in to tell that i removed the cathode bypass caps(C1-C2, C5-C6) of my TU-8200R, to get a bit more usable pot range with my hot DAC (4.5Vrms Abbas DAC 0.1SE). Works like a charm, i have a useful range on my volume pot again. It's still warming up after the mods but it could be a bit more extended highs. Have a pair of E80CC to try but i'm still on stock rectifier and i really don't need the gain. Running it with the stock JJ 6L6GCs, Webcor-branded Mullard ECC82s. Had some EL12spez in earlier, great sound, but they unfortunately developed noise. It feeds a pair of B&W CDM-1 as well as a pair of Hifiman Anandas that sound OK but could probably play around with the resistors a bit more. All in all, a great little amp and with the excellent mod support by Vkung and paczeltf, definite keeper.
If you removed these caps and still want to use ECC82 then I recommend increasing the value of R3/R4 to 27 Ohms, which will restore the global negative feedback close to the original amount, and slightly further decrease the gain. Not surprisingly, to me the amp sounds the best with the original feedback ratio.
Hi Ferenc,
I made the changes based on the spreadsheet you sent me a while back except for the ones needed for the E80CC ie removing bypass caps since I wanted to listen to the amp for awhile before making the swap to using E80CCs. It sounds musical as is (my amp uses the LLundahl OPTs) so the next step is for me to try out the E80CCs.
By the way what is amount of global Neg Feedback in dB terms that was in the original design?
Thanks
Nick
According to my calculations, GNFB is 5.7 dB in pentode mode, and 2.5 dB in triode mode with stock configuration. UL mode is somewhere in between, I could not find reliable plate curves for that one.
These values are quite usual for SE amps.
These values are quite usual for SE amps.
I decided to try some E80CC out instead, the amp sounds great with them, seems the little 1.5A rectifier in my 8200R can cope, at least short-term. Can i please have the spreadsheet by the way?
Hi All,
FYI - anyone making the change to E80CC I just wanted to report my experiences that the stock rectifier in the TU8200R (DB1510 rated at 1.5A, 1kV) isn't enough to support 2 E80CCs. Amp just shutdown after about 30mins. With a smaller current draw i.e. by running one channel with 12AU7 and the other channel with E80CC, the amp exhibits no problems at all. So the clear solution is to just upgrade the bridge rectifier.
nick
FYI - anyone making the change to E80CC I just wanted to report my experiences that the stock rectifier in the TU8200R (DB1510 rated at 1.5A, 1kV) isn't enough to support 2 E80CCs. Amp just shutdown after about 30mins. With a smaller current draw i.e. by running one channel with 12AU7 and the other channel with E80CC, the amp exhibits no problems at all. So the clear solution is to just upgrade the bridge rectifier.
nick
It is not the rectifier that shuts down the amp. You need to upgrade PTC6 to RHEF400 and change R69 from 0.47 to <0.3 Ohm as well if you want to use preamp tubes with 600mA heater current, and use a 6L6GC variant to avoid power transformer overload.
Here is my testimony: I also made Ferenc's modification to my TU-8200 after building it stock and not being satisfied. It was as though there was a beast in there ready to be released before the mods, and he came out after. In addition, I upgraded to the tubes and setting (ultralinear) he suggests, AND upgraded to Mundorf Supreme Caps from Victor Kung. I run the amp through two folded horn enclosures using Tang Band W-8-1772 drivers. I have some experience listening to high end (above $5K) systems, although I've never owned one. What I can tell you is that my system sounds "divine" too. It is sweet, dynamic in the highs mids and lows, and has a very alive sound stage. Acoustic music/jazz and vocals are where it shines, but it handles everything I throw at it except really distorted/loud rock, because there is just too much distortion for the full range drivers to sort out. The detail is amazing: inhalations and other vocal details are now heard, woodwind breath attack, acoustic string detail, percussion detail, all are rendered very realistically and with that lovely tube roundness, sustain and decay. I think Elekit+Victor+Ferenc=Best deal in audio today. The system cost me about $2K total. I feel like I've unlocked a secret! Thanks everyone!
I second that too, when I did the change to the E80CC it sounded clearer, better detail. Maybe one day, someone will measure the difference in the distortion/freq bw etc before and after the change to see if what we think we are hearing is real or "all in the mind" ie placebo effect. I like to think it's a real difference for the better.
Thank you both for your kind words. I have been very busy with home and garden refurbishment projects as well as work related stuff for the last month so I have not had time for diyAudio or other forums even to read through the latest posts. Even some personal conversations are awaiting answer.
Victor removed the spreadsheets because the TU-8200R manual has various releases with different part numbering at some places. Even though both the old and new values were explained clearly, unfortunately, one member who got confused by this created a lot of noise in the forum instead of contacting me in the first place for clarification. If you open a conversation, I can send you the parts list for the TU-8200 or TU-8200R, or even for the TU-8150 if you have one.
I use my 8200 almost every day with headphones or for lower level listening with speakers, it just works and sounds great. Output power is limited of course, but buying and building bigger sized Elekit amps would make a significant difference either. Distortion kicks in at a few Watts in all cases.
Victor removed the spreadsheets because the TU-8200R manual has various releases with different part numbering at some places. Even though both the old and new values were explained clearly, unfortunately, one member who got confused by this created a lot of noise in the forum instead of contacting me in the first place for clarification. If you open a conversation, I can send you the parts list for the TU-8200 or TU-8200R, or even for the TU-8150 if you have one.
I use my 8200 almost every day with headphones or for lower level listening with speakers, it just works and sounds great. Output power is limited of course, but buying and building bigger sized Elekit amps would make a significant difference either. Distortion kicks in at a few Watts in all cases.
hi, i just got my 8200-R and ordered the lundahl opts and evo caps - do you my sharing your mod spreadsheet with me pls ?