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Frankenstein Dynaco MK VI
Frankenstein Dynaco MK VI
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Old 30th June 2017, 08:37 PM   #21
mjstriker5 is offline mjstriker5  United States
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I went ahead and decided to stick with the original since I am using KT88 output tubes. It has been shipped off to Heyboer to be copied and two new ones made. The original had a few wires cut extremely short so I figured two new ones would be best.

Also had a chance to strip down one of the chassis. The more I get into this project the more I am amazed at what was done. The guy who masterminded this didn't care about any sort of quality or safety. There were exposed ground bars bending around all over the place and almost touching lots of other wires. Several areas looked burnt like something shorted and actual soldering was subpar. Crazy to think these amps actually worked (at least that is the story).

They builder drilled quite a few extra holes and epoxied many of the caps to the chassis. Overall the chassis isn't terrible. There is some surface rust mainly underneath but I improbably going to partially strip and repaint. Really want to keep the lettering on the back.

The faceplate isn't terrible easier. Biggest issue is a little strip of rust on the bottom. These amps were basically sitting in a barn for several years. Actually when I picked them up I had to walk through several inches of water to get to them. Luckily they were up on a shelf.

I also have quite a few transformers now. I think there were 4 power transformers used for each amp. Checked a few and they are working. At least it gives me a few parts to offset the price of rebuilding these.

The tubes included for the pre-amp stage aren't half bad either. Not sure if they work at this point thought

If anyone has some suggestions on cleaning up the chassis I am all ears. I also am on the hunt for some decent replacement VU meters. The current ones are garbage. I heard the originals were Modutec. Have a few potential replacements but trying to confirm dimensions.
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Old 12th August 2017, 08:27 PM   #22
mjstriker5 is offline mjstriker5  United States
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Been a slow process but things are moving along. I sent the chassis to another fellow diyaudio member to strip and redo, and the power transformers are still being put together.

I also realized the one amp without the original transformer was missing the original choke. I lucked out and found a person in Germany selling two NOS chokes which are currently underway.

Last thing, I found two vintage Modutec VU meters that should fit in the faceplate cutout.

If all these arrive safely I should have all the major parts to put these amps back together.
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Old 13th August 2017, 12:14 AM   #23
Shef is offline Shef  Canada
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To get the most superb outcome I would:
a) rip the old wiring off and re-do the whole thing with silver and with tights, geometrically aligned. Otherwise it is the same sh. . shot taken from a side;
b) replace all el caps with films, they are affordable and compact nowadays.
my $0.02

That's at least. Further would be the noise-examining of all resistors (with replacing of what makes sense), and certainly the experimenting/adjusting on the operating points.
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Old 13th August 2017, 02:37 AM   #24
mjstriker5 is offline mjstriker5  United States
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The amps have been completely gutted and none of the old resistor, caps, etc. remain. Plan is to essentially build a completely new amp under the hood of the original chassis. There are couple of very generous MK VI owners who are lending their expertise and experience for this process.
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Old 13th August 2017, 09:59 PM   #25
wa2ise is offline wa2ise  United States
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Quote:
Originally Posted by mjstriker5 View Post
Haha! Ya I thought it was pretty ridiculous when he said that. It's like he felt everything was justified by claiming the guy worked there. I didn't want to be rude but I wanted to laugh out loud when he said that.
Maybe he was the guy who said it's okay to launch Challenger that frigid day in Jan 86..., "Oh, don't worry about those O rings"...
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