AudioSector-chip amp kits, dacs, chassis

[sianturi]

Originally Posted by Peter Daniel

I use machine screws in Patek (10-32). Before threading the wood, I soak the hole with crazy glue which adds durability.

In a DAC I use wood screws.

Peter, when you said "threading the wood", does it mean that you tapped the wood? I am particularly interested in how you fixed the two screws in the image attached here. The two screws in the image are wood screws? Or do you mean that you use wood screws at the side panel to attach the wood (not the ones shown by arrows in the attached pic)? I happen to you the same wood (wenge) for my chassis!

[Peter Daniel]

Yes, the wood screws are used on side panels (from the inside). The screws in rear panel (as indicated in your pic) are #4-40 machine screws; the wood is tapped after treating the holes with crazy glue to add stiffness to the thread.

[BigE]

There are threaded metal inserts that I find are preferable, as you cannot strip them.

Also, ski shops have the "helicoil" that they use when binding holes in the ski become stripped. Vast holding power.

[Destroyer OS.]

Peter have you noticed any affect to changing capacitors mounted on the 3875 chip boards and dampening factor? I am using some fostex based speakers and find the noise slightly overbearing and perhaps a touch on the flat side dynamics wise. I am thinking about seeing what I can do to experiment a little. Also what pins do you put a 330pf capacitor on if you get FM again? I now live next to a different radio station....

[Peter Daniel]

The capacitor placement was explained here: Commercial Gainclone kit- building instructions

I didn't do any observations with regards to dampening factor.

[tally3tally]

Hi Peter
I need to build a 100w p/c amplifier to drive my 8 ohm speakers.
I was looking at various options and have come to the conclusion that LM4780 bridging would solve my problem, in the least no of parts.

But going through the application notes/overture design guide, i have realised that heat would be one major concern and as i live in India the ambient temp is also not close to 25C throughout the year. so here are my queries

1. How much power for an 8 ohms load, would one of your boards(having one 4780) provide, in mono config?
2 . If i bridge the boards how much power should i expect realistically,for say +-28V PS, keeping in mind the heat issues?
3. Will a BPA design as seen here be possible using your boards.

regards
anurag

[Peter Daniel]

In bridge mode you can expect approx 120W from a single chip. You need an additional circuit though to convert unbalanced signal into balanced.

He's actually using my boards in a pic here: bpa-200-2.jpg (image) so I guess that design is possible with my boards.

[shortwave]

Originally Posted by Martin Prothero

Some pics of the completed integrated LM3875 and premium NOS DAC. Pretty much identical to Peter's. I wanted to know what it sounded like. I made the chassis from scratch as it would have cost too much to post to the UK (would have been so much easier to have paid the money!)

Attachment 170420

Attachment 170421

Attachment 170422

Sound? I have had it running non stop for week to settle. Recently bought a Squeezebox Duet to stream WAVs to the integrated. This replaces a £1000 CDP with valve output and a SET I built specifically for my single driver speakers.

The Audio0Sector 3875/DAC is stunning. Actually it is the best sounding hifi that I have ever heard at any price! Effortless, open, deep but for me most importantly I have stopped analysing the sound. It sounds so natural and tangible that with the lights out I can be there. The walls and floor disappear.

Thanks and all credit goes to Peter for his superb design and professional helpful manner.

I am one happy customer!

Really nice job Martin!

[moe29]

Peter,

Just a quick note to let you know my LM3875 kit with the Case you offered is still going
strong since April of 2004! along with the NOS DAC from April of 2005.

They both get every day use in the media room driving my B&W 805's.

Excellent sound and very durable! Thanks for all of your excellent work and sharing your
expertise with all of us over the years.

(now i need to order a USB DAC!)


-m.

[Hanzwillem]

Originally Posted by moe29

Peter,

Just a quick note to let you know my LM3875 kit with the Case you offered is still going
strong since April of 2004! along with the NOS DAC from April of 2005.

They both get every day use in the media room driving my B&W 805's.

Excellent sound and very durable! Thanks for all of your excellent work and sharing your
expertise with all of us over the years.

I can definately agree to that! My INT-1 amp is on every day and sounds beautiful with my Focal Micro Utopia Be. The NOS DAC is not used that much since I use the Linn Majik DS dynamic. I like the sound of that device more.

Still.. the Integrated-amp is sounding great and never had a problem!
I think I have it since 2007, and only unplugged during some holidays when I am out of the country.

Thanks!