AudioSector-chip amp kits, dacs, chassis

[rjkdivin]

Dual RCAs for Greenboard

Following Peter's example from earlier posts, I fabricated a dual RCA by soldering 2 high quality RCA's together with 12ga copper wire that is bent at the ends, threaded through the two holes in the PCB, and soldered to the pads on the back of the pcb. You cannot use cheap RCAs because the plastic insulators will melt when you solder them:

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

 

[Sangram]

Hi Peter

Quick question, my chassis are on order (not your chassis) and I wanted to know if I could eliminate the jacks altogether and wire the DAC up inside another case. This case will house input selection, stepped attenuator and balance circuit (DRV134 and 15 volt Zeners + filtercaps - to start with) and if you give your blessings, the DAC as well.

Would like to know advantages and disadvantages of such an approach. I like to call it 'integrated preamp'.

Also in such a case would toroid be better or EI? The case is huge, 320 mm deep by 85 mm tall and 430 mm wide to fit in standard rack.

Thanks

Sangram

 

[paulomartires]

Hi Peter,

I’ve just finished assembling your kit and I was amazed with the simplicity and quality of the boards and components. I had no problems soldering it (this was my first adventure in soldering components on a pcb) and I think the populated boards look beautiful.
And now some questions. For dual mono, in your opinion, what’s the best solution? One 300va toroide or two smaller ones, one for each channel? One or two rectifier boards? Have ever used capsuled toroides like the one in the photo? Are they any good? Can I put the two power supplies in the same enclosure with the amp, or is it better to separate them?

Well, that’s all for now. Thanks for your time Peter.


Paulo

 

[Peter Daniel]

300VA toroids can be still regarded as small, so I would recommend them for monoblocks as well. The best approach would be using separate transformer per amp, if not a single transformer for two channels (300-400VA) with shared rectifiers board. I only use toroids with those amps, the quality of sound depends on transformer as well, I like Plitrons.

Quick question, my chassis are on order (not your chassis) and I wanted to know if I could eliminate the jacks altogether and wire the DAC up inside another case. This case will house input selection, stepped attenuator and balance circuit (DRV134 and 15 volt Zeners + filtercaps - to start with) and if you give your blessings, the DAC as well.

Would like to know advantages and disadvantages of such an approach. I like to call it 'integrated preamp'.

Also in such a case would toroid be better or EI? The case is huge, 320 mm deep by 85 mm tall and 430 mm wide to fit in standard rack.

There will be advantage to installing the DAC in a same chassis as amp as the connectors and interconnects are eliminated. If you lay it out properly I wouldn't expect any disadvantages.

Toroid would be good to use with amp, as to the DAC, a separate transformer would be recommended, either toroid or EI (the preference here would depend on subjective comparison as the quality of both types ca vary and affect sound to even greater degree)

 

[Peter Daniel]

There is a review of AMP-1 in June issue of Hi-Fi World. The amp is basically a Premium kit, with the exception of p2p wiring and Noble pots. If you want a copy of the review, e-mail me (2 Meg file).

The review also shows some measurements and basically the conclusion comes to:

"the sound was never less than engaging, richly textured and unconstraind...."

 

[paulomartires]

Thanks Peter,

i forgot to attach the photo of the toroids I was asking for. Did you ever used one of these? Btw, how much for the Piltrons you use?

Paulo

 

[Peter Daniel]

The Plitrons are $80, but shipping will be very expensive from Kanada. However, there may be a beter solution to that, as I found a small factory in Poland that can produce transformer that rival Plitrons. If you are interested in getting them directly, here's the website: http://toroidy.pl/ and the actual product description:

TS300VA SEC:2x22V w wykonaniu AUDIO z rdzeniem z taœmy izopermowej,
- uzwojenie wtórne przy rdzeniu,
- 50% wiêkszy przekrój drutu, drut pojedynczy (1,8mm)

Those transformers have amorphous core and I used them in this amp: http://www.diyaudio.com/forums/showthread.php?s=&threadid=76609&highlight=

I'm not familiar with transformers in your picture though.

 

[karma]

There is a review of AMP-1 in June issue of Hi-Fi World. The amp is basically a Premium kit, with the exception of p2p wiring and Noble pots. If you want a copy of the review, e-mail me (2 Meg file).

The review also shows some measurements and basically the conclusion comes to:

"the sound was never less than engaging, richly textured and unconstraind...."

peter could i have a copy of that review? you should still have my e-mail


cheers

 

[Peter Daniel]

I sent it but it bounced back, 2 Meg space needed.

 

[karma]

ok i have a idea ill e-mail it to you

thanks

 

[Vikash]

You can email it to me if you want it hosted on your site Peter.

 

[karma]

or i can get it on your webpage



cheers

 

[motherone]

Peter,

I'd like a copy of the review if you can find a minute to send it my way.

Thanks!

Mike

 

[karma]

peters review can be picked up here


ftp://70.27.68.151


its anonymous



cheers

 

[Destroyer OS]

Hey Peter what speakers do you use with your personal GC amplifiers?

Do you think a really large input buffer could be put in to restrict a GC to 2wRMS total? You know, so adjust the volume will cap out at 2wRMS? I am just curious about the versatility of the GC.

I got the BG capacitors today, thanks!

 

[Sangram]

There will be advantage to installing the DAC in a same chassis as amp as the connectors and interconnects are eliminated. If you lay it out properly I wouldn't expect any disadvantages.

Toroid would be good to use with amp, as to the DAC, a separate transformer would be recommended, either toroid or EI (the preference here would depend on subjective comparison as the quality of both types ca vary and affect sound to even greater degree)

Thanks for the advice Peter.

Actually it's the DAC/preamp that's combined, as there isn't enough room in amp chassis for anything more than the amps.

All units have their own transformers. The balance circuit area will have a special transformer or two with the ability to power the BOSOZ preamps if required (+- 60 volt supplies) and a voltage tap to drive opamp based circuits at a lower voltage, and the DAC will have its own transformer.

The amp already has 440 VA EIs for each channel, in a totally separate case.

I have yet to find a good toroid supplier but my EI transformers can be custom-wound, are there any specifications and directions anyone can give me to pass on. I already ask for overrated secondary wire, shielding between windings, and for larger transformers a copper shield on the outside of the transformer.

Thanks

Sangram

 

[Peter Daniel]

Hey Peter what speakers do you use with your personal GC amplifiers?

I'm presently using FAL drivers: http://www.diyaudio.com/forums/showthread.php?s=&threadid=69176&highlight= but will be soon switching to Fertins: http://www.diyaudio.com/forums/showthread.php?postid=880080#post880080

If you want to restrict GC to lower power, you may use fixed attenuator at the input reducing input signal.

 

[Vikash]

Reviews recompressed and downloadable in PDF format from Peter's site:

Hifi Choice
http://www.audiosector.com/downloads/review_hifi_choice.pdf

Hifi World
http://www.audiosector.com/downloads/review_hifi_world.pdf

 

[karma]

thank you vikash. the ftp was going nuts, good review there peter.


cheers

 

[Peter Daniel]

All the reviews have been organized now in one place, thanks to Vikash:

http://www.audiosector.com/reviews.shtml