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2 petercapo

62.105.143.210

Posted on December 7, 2015 at 01:59:42
miha_ru
Audiophile

Posts: 6
Joined: December 3, 2015



Hello friend! I need your opinion. As I said before my Dynaco Mark III has a modification and uses double triode E80CC instead of penthode-triode 6AN8. I've decided to restore it to the original status, but I've met a problem: this tube rare enough, quite expensive and hard to find it in a good condition. So I'm thinking about an alternative http://www.triodestore.com/mk3boardsparts.html or http://www.triodestore.com/diytubemk3.html
Can you offer me something else?

And the second question: my amplifiers need 117 VAC, but in Russia we have 230 VAC. Look at the picture in the attachment. 117 V (I use step-downtransformer) goes through white wire to the power transformer which has a black&white wire. Is it intended for european voltage? I can not come at this information. May be you know or yua know how to check this suggestion.

Hope you can understand my English )))

 

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RE: 2 petercapo, posted on December 7, 2015 at 07:40:14
petercapo
Audiophile

Posts: 451
Joined: December 29, 2012
I'm a little surprised to hear that you're having difficulty locating 6AN8 or 6AN8A tubes. I shopped for them a few years back, and they were plentiful and cheap. There should be a number of sources here in the U.S. that have them at reasonable prices (I think), but I suppose you'd get hit with international shipping costs. There are some tube sellers in Russia, though, like The Siberian Shop and others. Try eBay.

The forum sponsor, Joe Curcio, also has circuit board replacements for the Mark III. Shannon Parks of Parks Audio has boards for the Mark III. Roy Mottram of tubes4hifi has them. Gregg van der Sluys of Classic Valve Design in Canada has some, too. Triode USA has a lot of interesting things, but I am concerned about a number of reports of poor customer service that I also have experienced with them, but you could still give them a try.

If you want to restore it to the original Dynaco circuit, your best source for parts is Kevin Devaney at Dynakitparts

As far as your power transformer, can you quote the stamped markings on the end bell? I'll see if I can find some information about it and maybe someone else reading this could chime-in with any information.

 

RE: 2 petercapo, posted on December 7, 2015 at 13:08:41
petercapo
Audiophile

Posts: 451
Joined: December 29, 2012
Yes, okay, so if you can quote the numbers on your power transformer, it might help.

Also, there is an Italian website devoted to Dynaco. They might know about your power transformer, which may be dual voltage, hence one of the leads to the primary is capped-off. If you or anyone you know speak Italian, you might try contacting these folks:

 

RE: 2 petercapo, posted on December 10, 2015 at 03:22:28
miha_ru
Audiophile

Posts: 6
Joined: December 3, 2015
Hello!
Finally I have found 6AN8, but in Canada, not in Russia. Waiting the parcel at the moment ))
Now I'd like to know your opinion about resistors.I see many good feedbacks about old Allen Bradley resistors. Do you recommend them too?
Or resistor does not have any musicality but only value in Ohms?
And the last: do you remember my question about free wire of my power transformers?
Two transformers (a step-down 230/117V + original 117V) aren't good for sound quality therefore I hope that the free wire is intended for direct connection with 230V power socket. Is it real to find an information about transformer's terminal and what does each color of wire mean? The signs on transformer are:
1. Dynaco
454216
ZT0195
74-46
2. 494203
11713

Coul you suggest somethig?
Anyway I'm the one who ought to thank you.

 

RE: 2 petercapo, posted on December 10, 2015 at 17:04:51
petercapo
Audiophile

Posts: 451
Joined: December 29, 2012
The differences in sound quality among different resistors is more subtle than other things like capacitors. Here is a discussion that might be of interest: resistor discussion

If the original resistors measure within tolerance, they should work fine.

For your power transformer, I was not able to find any documentation on it. I'd like to say it is as simple as swapping the wires (which might really be the case), but I don't want to tell you the wrong thing. You might try posting in some other forums like Audiokarma or tubes4hifi. Someone might know with more certainty. You might try e-mailing Dave Gillespie who frequents Audiokarma - he is a Dynaco expert.

 

RE: 2 petercapo, posted on December 10, 2015 at 22:10:11
miha_ru
Audiophile

Posts: 6
Joined: December 3, 2015
I'll try to use this approach: I have an autotransformer and increasing an input alternative voltage from 0 Volts on a vacant black-white wire I'll try to measure a voltage on the rectifier tube (pin 4-6). Very carefully ))

 

RE: 2 petercapo, posted on December 11, 2015 at 00:07:41
petercapo
Audiophile

Posts: 451
Joined: December 29, 2012
That sounds like a fine idea. You could also temporarily connect the wires in question to a temporary terminal strip and then just measure the voltages between them as you turn the mains voltage up gradually.

 

RE: 2 petercapo, posted on December 11, 2015 at 00:33:35
miha_ru
Audiophile

Posts: 6
Joined: December 3, 2015
Thanks again and my best recommendation!

 

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