| sith |
I would to build a single end amp based on KT88 tube and would like to use ECC82 (12au7) as a driver. Can it be done? Does anyone know where suitable schematics can be found? I have found one with ECC83 tube , can I replace it with ECC82?
I also wander what wattage I can expect , my guess is about 10-12 watts, but I've heard that some folks achieve to pull out around 18W. |
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| dhaen |
Don't think about just substiuting the ECC83 with an ECC82. The gain will be much reduced. (Of course you can use one for testing.)
I think you may get 8-10 watts in triode mode.
Quite a bit more in Pentode or UL (distributed load) mode, but there will be a lot of distortion unless you use negative feedback.
I like SE designs, but must say that IMO the 6550 /KT88 is better suited to PP designs. |
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| richwalters |
I agree a 6SN7 is a better bet than ECC82. As for ECC83 combination with KT88.......PLEASE.. NO...don't think of it....If you were forced to use the 82, okay but..alot of people don't like ECC82 sonically, (I'm one of them) and the mu of 17 is low. A tube with a higher mu would be better.....> At this stage I would examine other tubes with a mu of about 40-60. There are benefits. Using the two plates in parallel...... rp is halved,stage gain increases;noise halved; one couldn't ask for more.
If you are using the KT88 in pentode mode.....do not forget that the g2 requires a stabilised source. If not, you will get alot of THD.
there are loads of schematics, have a look at triode electronics homepage. It's a big site. Give yourself P.O time.
More problems...........keep throwing them
rich |
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| Positron |
Been testing Cryod JJ6922s and they certainly sound unbelieveable, beating the cryod Philips Jan 6922s, better inner detail, which is in spades. Better than 6sn7s with better hf response, higher gain too.
Well worth checking out with Kt88s.
Have a great new years. |
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| planet10 |
| quote: | Originally posted by Positron
Been testing Cryod JJ6922s |
Was talking with Bill Perkins just yesterday and he commented that he was quite impressed with the most recent batches of JJ tubes he has been cryoing & grading. He specifically mentioned the 6922s (i get the feeling that he still likes the Sovtek 6N23Pi/6922 at least as well thou.) I asked if he had any floor sweepings (tubes that don't pass) and he said he hadn't had any that failed the grade.
dave |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by sith
I would to build a single end amp based on KT88 tube and would like to use ECC82 (12au7) as a driver. Can it be done?
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Of course.
| quote: | Originally posted by sith
Does anyone know where suitable schematics can be found?
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All over the net. Just Google KT88 SE Amplifer Schematic, that should give you a good starting point.
My personal recommendation would be something that operates in what some people call "LM3" Mode. There is an extensive article illustrating this methode here:
http://www.lundahl.se/claus_b_se.html
With a little work and a slightly lower impedance, but higher current output transformer you can use a KT88 and get between 12 - 15W Output from this kind of Amplifier.
| quote: | Originally posted by sith
I have found one with ECC83 tube , can I replace it with ECC82?
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Most likely not.
Sayonara |
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| Jaap |
I have built a KT88 se with a 12hg7 (triode) and LL1660 interstage transformer and Amplimo (plitron) toroid outputtransformer.
Result is great ! |
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| Positron |
Yes, Japp, I have also worked with that tube some years ago, but not alot because of no current manufacturing of the tube. Otherwise I might have worked with it more.
Nice to hear the good sonic report on the tube. |
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| ashok |
Hi Dave ,
Bill Perkins web site has lots of good articles listed on it and the down load size is also mentioned. Unfortunately not a single download link works ! Can you check with Bill if this is going to be rectified or if it will no longer be possible to see those documents.
It's such a pity. Lots of interesting stuff. Bill has done a great job.
Cheers,
Ashok. |
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| Mikael Abdellah |
I've made my own SE-KT88 with 6N1P as "driver".
All you have to do is redesign the input-stage with values that match whatever tube you wan't to use. I've been using my amp for quite some time, and I love it. It sounds wonderful. I'm pulling roughly 5W from my amp, but if you load the KT88 a bit harder I guess 8-10W is possible at the expense of distorsion. |
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| Positron |
| Yes Mikael, I get 7 watts out of mine (some padding of output too) with no problems. |
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| planet10 |
| quote: | Originally posted by ashok
Can you check with Bill if this is going to be rectified |
I'll forward him your post. I know he is slowly working on this part of his site (he phoned me today with some html questions specifically related to this part of his site).
dave |
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| sith |
Thanx all for relplying....
The reason I want to build combo of ECC82 and KT88 is that I have a few KTs and almost dozen of 82s, I also have a power tranny and can acquire OPT easily. I know KTs are better choice for PP than SE but problem is the OPT....
I have searched the net and didn't find any schematics using these combo, so another question is if I can substitute 6SN7 with ECC82, and also I notice variations in OPTs primary impedances (eg. some are 5k some are 3k some are 2,5k).
What is the main difference? |
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| burnedfingers |
sith
Have you ever thought of using a KT90 instead of the KT88? This also might make for an interesting amp. Could anyone suggest some operating points for both tubes?
J |
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| sith |
| quote: | | Have you ever thought of using a KT90 instead of the KT88? This also might make for an interesting amp. Could anyone suggest some operating points for both tubes? |
Yeah, in future... 88s are original GEC and are practically new:))) |
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| Positron |
Hi Sith,
I am going to check out the KT90s and see how they sound in my designs. Will report back on my findings, but may be a month or so. |
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