Building Mark Levinson 38 preamp chassis from scratch - diyAudio
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Old 3rd May 2004, 02:03 PM   #1
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Default Building Mark Levinson 38 preamp chassis from scratch

This thread is dedicated mostly to all brave people who decided to buy ML38 boards with a hope that some day they will turn it into a working preamp.

Well, for me such day finally came and here's my working version of that preamp.
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Old 3rd May 2004, 02:06 PM   #2
ergo is offline ergo  Estonia
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Beautiful work as usual

More pics please...

And a most important question "How is the sound?"

Ergo
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Old 3rd May 2004, 02:16 PM   #3
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For me it all started with this thread: Mark Levinson Display and Potentiometer

I got the main boards, but if it wasn't for Algar_emi, who up came with display boards (he made a layout and the boards), I would propably still not complete my unit
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Old 3rd May 2004, 02:33 PM   #4
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The biggest challenge was actually the chassis. I made the front panel yesterday and I am extremaly happy with a result. The board came with a small front panel piece (the one on the right, with ML logo), as this was from field upgrade so the new designation applies: 38 to 38S and panels had also to be replaced.

So the aim was to make the left front panel to match the existing one. The additional difficulty was the display window, which had to be inserted somehow in front panel.

One possibility was to order complete panel from some shop, but this is diy and we prefer to make things with our own hands

Few days ago an idea emerged, when I decided to use smoke acrylic. Initially I was intending to use acrylic as is, so the panel would be "see through".

But when I started working with it, I noticed than when brushed it looks almost like brushed and anodized aluminum, looking almost like the original panel.

I placed a piece of masking tape on a panel (cut to the shape of dispaly window) and brushed acrylic with Scotch Brite pads. It came up very well. When tape was removed, the perfect dispay window appeared. That is actually a very good technique to make front panels.

Again, printing was done using dry transfer lettering. They didn't have Arabic numbers, so I had to use Roman.
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Old 3rd May 2004, 02:38 PM   #5
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The sub plate to which everything is mounted was cut from 1/4" aluminum and alodined.
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Old 3rd May 2004, 02:41 PM   #6
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That's the display board made by Algar_emi. The most expensive part was dsplay units, but those are extremally nice.

I attached buttons directly to the switches with double sided tape, works very well this way. After adding front panel I extended the buttons by adding another piece on top. Those are slightly smaller than original, but it doesn't bothe rme.

Also the knob is only temporary and I plan to make the one that will be closer to the original ML stanard
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Old 3rd May 2004, 02:47 PM   #7
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Here's the rear panel. I made it out of 1/8 copper plate and added 40mil brushed and anodized aluminum sheet. The lettering is done again, with dry transfer (I think it's Letraset) . I made it slightly different than the original ML38, and closer to ML32, with additional bars on bottom. The upgrade sticker came with one of the boards
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Old 3rd May 2004, 02:50 PM   #8
hifiZen is offline hifiZen  Canada
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Looks great Peter! Now, like ergo, I'm curious to know... how does it sound?

PS - where do you get your dry transfer lettering from?
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Old 3rd May 2004, 02:54 PM   #9
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Here's the underneath look. I made bottom platform also out of 1/8 copper, and two 3 x 0.25 bars add stiffnes, lift the bottom up, so AC cable has more clearance. I didn't go for feet like on original unit and decided to use those spikes. They fit well.

Additional angles are riveted to those 3" bars on the sides and this allows for top cover attachment. The bars were alodined, copper is left unfinished.
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Old 3rd May 2004, 02:55 PM   #10
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Quote:
Originally posted by hifiZen

PS - where do you get your dry transfer lettering from?
I got it from graphics supply stores.
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