AudioSector-chip amp kits, dacs, chassis

[paulomartires]

Hi Peter,

I've finaly put your LM3875 Premium Kit in is final enclosure. But I'm having some problems: I can hear a radio station in my speakers. Any solution for this problem?

Thanks,

Paulo

 

[Peter Daniel]

That may be caused by some grounding issues. I posted my preferred grounding method here: http://www.diyaudio.com/forums/showthread.php?postid=787773#post787773

Also, you may try to install 300pF capacitor between positive and negative chip input, more info can be found here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=55300&highlight=

You may also see if installing Zobel components (Rz=2.7R, Cz=0.1uF) changes anything.

 

[paulomartires]

Thanks Peter, I'll try that 300pF capacitor. Just one question, by positive and negative chip input you mean in the rca's ou directly in the board? And the Zobel components won't have an impact in the sound?

Paulo

 

[Peter Daniel]

The 300pF cap mounts directly to chip pins 7 and 8, there is no separate footprint for it on the board.

More than likely, Zobel won't help here, but it won't hurt to try. And yes, it will affect the sound: you may like it or not

 

[paulomartires]

OK, just one more question: what kind of cap (ceramic, electro, any kind)? Sorry for the newbie questions...

And with monoblocs how do I apply your grounding, because I can't connect the OG's.


Thanks for all the help

Paulo

 

[Peter Daniel]

I'm using polystyrene caps here.

That grounding method was specifically for stereo amp. Monoblocks are much more forgiving to grounding errors and if you wire them in conventional method (4 wires from rect board to amp board) it should work fine too. You may experience problem though, if Earth ground is connected to chassis, in that case connect output ground to chassis instead (from negative speaker post) and Earth ground not connected (to chassis).

 

[poseidonsvoice]

Audiosector NOS dac completed!

Hi guys,

Finished the dac . Currently breaking in. I added a HagUSB board as well (modified with Lundahl pulse transformer, BG caps, Caddock resistors).

Enclosure is Michael Woods' 0908 enclosure from DIY enclosures

Check it out. Thanks for all your help

Comments, questions, advice...welcome! Other pics here on audiocircle:

Poseidons Voice NOS USB dac

Anand

 

[Peter Daniel]

Facing the competition from various group buy offers, I decided to introduce new version of LM4780 board. Since my cost is also lower now, I'm passing the savings to potential buyers. The board as you see in a picture is $20.

 

[Peter Daniel]

In other words you are getting two separate LM4780 PCBs at $10ea, as pictured below. Untill I do changes to my website, those prices will also include worldwide shipping. If you order larger quantities, further discount will apply. Just contact me directly through PM.

 

[Peter Daniel]

That offer also applies to LM3875 board, which is available in the same format.

 

[Peter Daniel]

The new LM4780 board is exactly the same as the Premium version that was described here: http://www.diyaudio.com/forums/showthread.php?postid=636565#post636565

Premium boards (clear mask, gold plating) are available as well and no discounts are available.

 

[Peter Daniel]

Re: Audiosector NOS dac completed!

Finished the dac . Currently breaking in. I added a HagUSB board as well (modified with Lundahl pulse transformer, BG caps, Caddock resistors).

Enclosure is Michael Woods' 0908 enclosure from DIY enclosures

Check it out. Thanks for all your help

Comments, questions, advice...welcome! Other pics here on audiocircle:

Poseidons Voice NOS USB dac

This is an incredibly well made piece of equipment, with a lot of attention to detail. If I can suggest anything, you may bapass the input coupling caps if your source or HagUSB board allows it.

Also, what is your primary source? If it's CD player, you may still simplify the way the inputs are wired.

 

[poseidonsvoice]

This is an incredibly well made piece of equipment, with a lot of attention to detail. If I can suggest anything, you may bapass the input coupling caps if your source or HagUSB board allows it.

Peter,

Thanks, that's a great compliment coming from you as your enclosures are really, really cool.

I was thinking about removing the polystyrene caps like you recommend. And I was also thinking about using some VH Audio or Mundorf Silver in Oil caps on the output but the unit sounds so good already...My source currently is a modified Philips 963SA as a transport. I'm moving up to a Squeezebox/Computer USB territory in the near future.

I'm sure your NOS design will complement it quite well.

Thanks for the design,

Anand.

 

[richyrich212t]

Peter,

Is your DAC kit available yet. If so how do I get one or Two ??

 

[Peter Daniel]

Peter,

Is your DAC kit available yet. If so how do I get one or Two ??

The DAC has been available for the last two years. The thing is, I don't really advertise it much and all sales have been generated by a small info entry in May18th Latest News on my site: http://www.audiosector.com/ and couple reviews from 6moons with the latest one posted here: http://www.6moons.com/audioreviews/audiozone5/system.html

Few months back, I redesigned the original board, since DIP version of CS8412 receiver is not available any longer in large quantities. The board now accepts only SMD receiver version, and the layout has been slightly improved. The current price is $230 for Premium kit. Hammond transformer is additional $30 (including PCB mount fuse and power entry module), Cardas dual RCA adds another $20. International shipping is $25 (with transformer), $12 without.

 

[Peter Daniel]

The PCB alone is $35.

 

[moe29]

Deal of the century!

(i haven't turned mine off in 2 years)

 

[karma]

my dac still works great, im sure its burned in by now

 

[jleaman]

The DAC has been available for the last two years. The thing is, I don't really advertise it much and all sales have been generated by a small info entry in May18th Latest News on my site: http://www.audiosector.com/ and couple reviews from 6moons with the latest one posted here: http://www.6moons.com/audioreviews/audiozone5/system.html

Few months back, I redesigned the original board, since DIP version of CS8412 receiver is not available any longer in large quantities. The board now accepts only SMD receiver version, and the layout has been slightly improved. The current price is $230 for Premium kit. Hammond transformer is additional $30 (including PCB mount fuse and power entry module), Cardas dual RCA adds another $20. International shipping is $25 (with transformer), $12 without.

I think this page needs some updating. Or at least some new information about the kits and other products.

J'

 

[JonE2435]

I had 2 questions about the LM4780. If i just run it in stereo mode with 8ohm what transformer should i get? I was thinking a 32 vct. Also, how should i implement volume control?