Little DOT MK III Mods??
Aug 11, 2009 at 7:37 PM Thread Starter Post #1 of 198

Frihed89

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Can some of you please summarize the successful modifications (mods) you have made to your LD MKIIIs? I am not talking about tube rolling. I am talking about things like changing/substituting/adding/removing parts, such as capacitors, resistors, transformers, wire, etc.

Maybe this pic will help of the top side of the board:

MKIII%20PCB.jpg


Here is the MK IV Per Sebastian's request. You can also cover this

MK4%20PCB.jpg


I found a pic of the bottom of the IV. The 22uf 400V (DC?) black caps look as if they are the coupling caps from what I can see of the bottom, but it's hard to see. Take a look: oops, maybe they are input caps. The small tubes are not the output tubes, are they?

Where are all the experts!

MK%204%20PCB%20Tube.jpg
 
Aug 12, 2009 at 12:48 AM Post #2 of 198

SebastianL

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Quote:

Originally Posted by Frihed89 /img/forum/go_quote.gif
Can some of you please summarize the successful modifications (mods) you have made to your LD MKIIIs? I am not talking about tube rolling. I am talking about things like changing/substituting/adding/removing parts, such as capacitors, resistors, transformers, wire, etc.

Maybe this pic will help of the top side of the board:



Mods on the LD MKIV are welcome as well.
 
Aug 12, 2009 at 6:42 AM Post #4 of 198

SebastianL

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Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif
Those 220uF/200V look like output caps - my first suggested upgrade.
0.22uF coupling caps are a close second.



Replace them with Black Gate or Auricap? What effect will it have soundwise?
 
Aug 12, 2009 at 7:29 AM Post #6 of 198

Frihed89

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Find out the caps through whih the most signal passes: On the MK 1V, there are in a row: the 2 blue mallories, next to them, 2 small yellow caps, and then do big red "orange drop"-like looking things(?). Is there a picture of the bottom of the board?

The two round black ones...I just saw them. I have no idea.

get the make and impedance and voltage specs from all the caps. You can then reference tham and find out the construction, and by then someone should be here that knows what they are doing?
 
Aug 12, 2009 at 8:09 AM Post #8 of 198

MikePio

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Great thread, have been waiting for one like this... I have a LD MKIII and would love to mod it a bit, I will wait for more entries, Cheers,
 
Aug 12, 2009 at 3:00 PM Post #9 of 198

Frihed89

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Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif
For interstage coupling - Russian Teflon TF3 0.22 at about $8 each, best bang/buck
Output caps - your choice, aren't too many "great" options.



First of all, thanks for replying. Many owners need more information, though, to take cation because they lack your understanding and experience, such as:

1. Are you refering to the LD iii or IV or both?
2. Which caps are the inter-stage coupling caps?
3. What is a "Russian Teflon" cap; how many Volts DC? (22uf is the capacitance), and where do you get them?

Thanks again. Please continue helping
 
Aug 13, 2009 at 8:27 AM Post #10 of 198

SebastianL

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Negatron has supposedly done some 'major mod' on his MKIV and a 'mod' on his MKIII. I've been trying to PM him, but his inbox is full.
Maybe he could comment on his mods?

I agree, interesting thread.
 
Aug 13, 2009 at 8:36 AM Post #11 of 198

SebastianL

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Quote:

Originally Posted by Frihed89 /img/forum/go_quote.gif
The two round black ones...I just saw them. I have no idea.


The two black caps are Solen 2,20µFJ 400V caps of french make. Not bad caps at all, but I think both Black Gate and Auricap are better caps. Perhaps Vishay as well.

MK%20IV%20Caps.jpg
 
Aug 13, 2009 at 10:22 AM Post #12 of 198

ulyses

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What is the difference between little dot mk3 and mk2? They look have same components. In adition to this, would I try these mods for my little dot mk2?
 
Aug 13, 2009 at 3:34 PM Post #13 of 198

Frihed89

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Quote:

Originally Posted by SebastianL /img/forum/go_quote.gif
The two black caps are Solen 2,20µFJ 400V caps of french make. Not bad caps at all, but I think both Black Gate and Auricap are better caps. Perhaps Vishay as well.

MK%20IV%20Caps.jpg



Yes, but what do they do? They look about the right size to be coupling caps for the output tubes, but I can't see the connections on the printed circuit board. These are Metallized Polypropylene fast caps. Whatever they do, I would not replace them with an electrolytic of any kind. Some kind of PIO type might be better, like Auricaps, Jensen, Audio Note (not cheap even for copper foil), Mundorf silver in oil (all these cost money): The vintage Russian, K-40s on Ebay are cheap and sound very good. But, hey find out what this cap does first. You can change caps and have practically no influence on the sound.

That's why it would be nice to have someone here who knows the circuit.
 

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