AudioSector-chip amp kits, dacs, chassis

[tangen]

Parallelling LM3875

I'm enjoying my LM3875 kit I ordered from Peter Daniel (very nice guy to do business with). The resulting amplifier was really astonishing. But, it would have been nice with some more power. Have anyone tried to parallell LM3875? What kind of resistors were used? And how did it sound?

Best regards
Jan Ove Tangen
Norway

 

[rdf]

Thank again! Actually, your description suits my needs very well. For me the hardest part of tuning a SET is cleaning up the top end. One of the LM3875 kits sounds like just the ticket for an alternate reference, to go with the other two tube amps and five pairs of speakers cluttering the place that is.

 

[Peter Daniel]

Thanks to the courtesy of a forum member, here's the detailed schematic of LM4780 rectifier's board.

C1/C2 as supplied are 10uF Panasonics FC, but you can experiment with different values as well. Recently some people tried 100/50 BG N caps here (with Panasoncs 1500/50 FC on the amps board) and the results were very good. You might also choose to not install those caps at all.


R1/R2 and C3/C4 are snubber components as suggested by Carlosfm. I'm not a fan of snubbers and I'm not using them. The current values can be found here: http://www.diyaudio.com/forums/showthread.php?postid=748529#post748529 There are additional holes on the board, where a cap up to 10,000uF can be installed when snubber is used (that cap would be on schematic in place of C1/C2 and the small 10u caps are not being installed then.

R3 is used to limit the current through the LED and for a small Panasonic red LED, I'm using 68K resistor.

I will be soon posting similar schematic showing the amp board.

Thanks Todd

 

[Peter Daniel]

OK, here it is, a proper schematic for LM4780 amp board: two options available, bridged configuration is the same as stereo (a balanced signal needs to be supplied to the amps input). The connections diagram also matches the board's layout (nice touch, Todd)

Resistors values are as follows:

R1/R2 = 22K
R3/R5 = 680R
R0/R4 = 22K
R6/R7 = 270R
R8/R9 = .1R
Rm = 10K
Rz = 2.7R
Cz = .1 uF

The (red) jumper for parallel config mounts like that: http://www.diyaudio.com/forums/attachment.php?s=&postid=636571&stamp=1115409304

CHG can be used for connecting circuit ground to the chassis. I'm using 10R resistor when doing that. Please also note that currently 270R series resistors are being used (instead of 1K).

 

[adolphe]

Very nice. I just finished soldering in the jumpers for my bridged boards yesterday. I'm waiting on my transformers before wiring up the inputs and outputs. These schematics will make things a lot easier.

Thanks!

 

[Anthony Dockril]

Phone Stage

Hi Peter,

How is the phone stage coming along? And hey will it invert phase? As this would mate well with your DAC.

Cheers,
Anthony

 

[Peter Daniel]

It's not gonna happen before NewYear. I'm presently extremally busy with amps building.

The DAC phase can be corrected (to non reversing). You simply need to reverse the connection of two traces from input buffer chip to the receiver. The next board version will have it corrected, I'm also working on optional USB interface.

 

[Anthony Dockril]

Phone and Dac

Hi Peter,

OK about the Phone stage - keep us posted.

RE: A couple questions about the DAC kit.

With the Dac when will the new boards be ready and how much for the Premium?

Cheers,

Anthony

 

[lohk]

Thanks for the phase reversal correction hint - it is just that simple, very good!

Will you use the PCM2704 for the forthcoming USB DAC input?


I listen to the DAC everyday with pleasure, and already - as it seems to be always - there are friends lining up for one to be made for them...

all the best
Klaus

 

[Peter Daniel]

I'm still not into using computer as a music source ( I have 3 decent transports: ML31.5, ML37 and Technics ZL-1000, all of them modified), but on suggestion from a forum member, I decided to give it a shot. USB interface will be based on PCM2707, but I'm still not into details here yet.

I have left ony 3 of the gold plated all-in-one boards, so I will be ordering new batch pretty soon. There won't be much difference, mostly fine tuning of some traces.

 

[jleaman]

I'm still not into using computer as a music source ( I have 3 decent transports: ML31.5, ML37 and Technics ZL-1000, all of them modified), but on suggestion from a forum member, I decided to give it a shot. USB interface will be based on PCM2707, but I'm still not into details here yet.

I have left ony 3 of the gold plated all-in-one boards, so I will be ordering new batch pretty soon. There won't be much difference, mostly fine tuning of some traces.

You were talking to Brent Welke..

 

[ozone_stink]

*insert self-depricating noob comment here*

Whew, now that's over with, I almost sent you Paypal staight away last night for one of your premium DACs. However, I would like somebody to help me with the following question:

I've got a Marantz 2285b Receiver/Amp & Rotel RCD-02. -Am I just wasting money or should I be able to realize an improvement given that I don't have any ML or other Über kit.

My speakers are homemade with Solen X-overs and Scan Speak drivers, though. (when in Montreal...)

Thanks for your help!!

 

[Peter Daniel]

The DAC plays well (and brings improvement) with any transport.

The better the transport, however, the better overall results. I also have Marantz CD-94 and use it with a DAC.

 

[jleaman]

The DAC plays well (and brings improvement) with any transport.

The better the transport, however, the better overall results. I also have Marantz CD-94 and use it with a DAC.

Well i use a external dac too. Froma lg dvd-player to athe dac .. ihave on many ocasions connected one channel back to the dvd player to hear the diference between each channels and TOTAL diference. the dac wins hands down. NOW to get a better transport/ cdplaywer with digital out..

 

[Thomas B]

Usb Dac

I'm still not into using computer as a music source ( I have 3 decent transports: ML31.5, ML37 and Technics ZL-1000, all of them modified), but on suggestion from a forum member, I decided to give it a shot. USB interface will be based on PCM2707, but I'm still not into details here yet.

Hi Peter,

Go for it! Biggest problem with current computer audio is that the initiative mostly comes from the computer community itself - them being mainly non audiophiles. Sign of hope is although at the horizon; cpu:s need to be dead quiet: passive cooling is underway with heatpipes connected to large heatsinks; graphics cards also need to be dead silent: same progression as with cpu's; hard drives need to be dead silent: they need to be exchanged with silent solid state drives. One barrier left though - D/A conversion. Peter, please make a high quality USB DAC that's up to the task of unleashing the promising sound quality waiting upstream...

Best Regards,
Thomas B (who once purhased your very first gainclone)

 

[planet10]

Re: Usb Dac

cpu:s need to be dead quiet

The MacMini satisfies most of your requirements....

An externally hosted image should be here but it was not working when we last tested it.

dave

 

[Thomas B]

Yes, Dave, you're right. So why don't I get excited? Mainly because the Mac Mini is a closed architecture. I want a modular design approach. I want to be able to change the motherboard, add some hard disks or SSD drives, etc; yes I know there are add on boxes to the Mac Mini. But being a diy-fanatic means you want to try it out for yourself, right? The uniqueness of Peter Daniel IMHO is that he actually has been listening to all the things he create, he's altering any component based on listening experiences only. Sound quality rules. I like that. The open modular approach, I think, is the way to go. Scrutinize every detail regardless of what the crowd says. Way to go, especially in dire straits like computer audio.

Best Regards,
Thomas B

 

[karma]

i allready have somthing in the works that im sure you will like
but its a winter project, it will fill my pc to dac gap and still look like just another piece of audio.

it will built around the asus a1 series a8v mainboard


cheers.

 

[planet10]

Mainly because the Mac Mini is a closed architecture. I want a modular design approach.

You are only looking at half the equation. The hardware may be closed but the software is open (Darwin kernal is open-source) as opposed to PC where (if you use windows) it is the opposite. Besides what more is needed in terms of expansion than a USB & Firewire port?

And i haven't seen anything better than iTunes (admittedly available for Windows too) for a UI (i used Brent's choice of best for windows and it was VERY dissapointing....)

dave

 

[Thomas B]

Hi Karma, you're saying A but not B. Please elaborate. You got me really curious.

Hi Dave, right, software is wide open. But I am mostly talking about physical components. Mobo, cpu, storage, casework. Mac Mini is wide shut. You have to break it open with a knife. Make no mistake, I own Quicksilver Mac, Cinema Display, PowerBook. iBook, iPod, iShuffle, etc, I love Macs. But for computer audio I think the PC camp is leading the way right now. People who's been comparing Mac to PC's agree, PC's are holding an edge in terms of sound quality. That can rapidly change, of course. Mac software still need to be more adapted to high end audio applications though.

/Thomas B