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AudioSector-chip amp kits, dacs, chassis

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Hi Peter

I've placed an order for a new front panel. Thanks for getting the chassis back into production. For anyone who is contemplating it, I have the mk1 chassis and it is a high quality bit of kit (the front panel scratch on my original was my fault - don't bounce bolts off it from a height).

BTW, I notice on your site you have links to a digital amp kit manufacturer. Have you compared a digital amp to the gainclone?

Colin
 
Hi Peter,
finally finished my version of the DAC this week. Thanks a lot for this, sound awesome! Also, i really liked the design of yours, so it looks like a copy...smal differences, just to match my GC amp;)
 

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sdedalus said:
what transformers would you recommend for the buffers? Are a pair of the amveco 12V 25VA trannies sufficient, or should I look into something with a little more juice?

12V may be a little low. The voltage before regulators in Levinson implementation was 24V DC so I wouold think that at least 15V AC would be required from the trafo.


Colin said:
Hi Peter

I've placed an order for a new front panel. Thanks for getting the chassis back into production. For anyone who is contemplating it, I have the mk1 chassis and it is a high quality bit of kit (the front panel scratch on my original was my fault - don't bounce bolts off it from a height).

BTW, I notice on your site you have links to a digital amp kit manufacturer. Have you compared a digital amp to the gainclone?


The front panel has been shipped already, this time chassis is even better as everything is milled out of plates and top and bottom panels are thicker (0.25").

I have link to LC Audio site as I like what they do, although I didn't try their digital amps. I only tried Nuforce and Hypex, and although quite impressive initially, they were not satysfying enough in a long run.

There was a discussion on one of the forums and somebody compared the silence between the notes to a vacuum, an empty space that is quite annoying.
 
Hi,
from my experiments lowering gain decrease sound quality .
Peter Daniel have written he preferred battery supply.And how now with Plitron toroyds and BG N+std capacitors?& have battery powered gaincone (10 uF BG-N on supply pins).Is that enough or better change to 100,0 BG-N.
What is better with transformer-1000,0 BG-n or 1000,0 std plus 100,0 BG-N?
Thanks for answer.
 
Ok, which method is the best for lowering the volume:

1. Lower gain from 33 dB to 23 dB (Ri = 22 kohm > 15 kohm)
2. Lower gain from 33 dB to 23 dB (Rf = 680 ohm > 1 kohm)
3. Changing 10 kohm stepped attenuator (series type) into shunt type with 32 kohm input resistor (Ri/o) > 10 dB more attenuation
4. Adding 22 kohm resistor to attenuator input > 10 dB more attenuation.
 
Re: newbie question

DIAR said:
Are those DAC and buffer kits still available?

Edit: I guess they are, but not on the website.

Both kits are available, e-mail me for more info. The All-in-one board has been redesigned, with slightly improved layout, is not inverting any longer and accepting only SMD version of CS8412.


dariusku said:
Hi,
from my experiments lowering gain decrease sound quality .
Peter Daniel have written he preferred battery supply.And how now with Plitron toroyds and BG N+std capacitors?& have battery powered gaincone (10 uF BG-N on supply pins).Is that enough or better change to 100,0 BG-N.
What is better with transformer-1000,0 BG-n or 1000,0 std plus 100,0 BG-N?

Lowering the gain will affect sound of the amp, to what degree, will depend on a listener and on the system. From my previous experiments I preferred the higher gain, but again, I'm not a fan of laidback soothing music, I like more intense presentation ;)

I was using the batteries for almost a year, but when I tried 100uF BG N caps with quality toroids there was no coming back to batteries. A battery has similar effect as large capacitors bank and achieving immediacy and transparency is not really possible.

I never like 1000uF BG N caps directly at the chip. They sound smooth and nice, but lack the bite and transparency. They make the sound too fat.

The BG N 100uF is much better soultion, especially if you only use those small caps, nothing else. But in real life, such configuration will usually lack in proper bass foundation (although everything else is almost perfect) so I'm adding 1000uF BG STD at the bridges: to avoid the hum and get improvement at lower frequencies. I'm not using any other bypass caps anywhere.

1000uF BG STD directly at the chip will also work well, and some people may prefer such arrangement: the sound is more forward, with good transparency and resolution, maybe a bit colder sounding though. With those caps I use 4.7uF BG N on negative rail only, at the bridges.


DIAR said:
Ok, which method is the best for lowering the volume:

1. Lower gain from 33 dB to 23 dB (Ri = 22 kohm > 15 kohm)
2. Lower gain from 33 dB to 23 dB (Rf = 680 ohm > 1 kohm)
3. Changing 10 kohm stepped attenuator (series type) into shunt type with 32 kohm input resistor (Ri/o) > 10 dB more attenuation
4. Adding 22 kohm resistor to attenuator input > 10 dB more attenuation.

I would say the option 3 would be probably most effective. Normally to reduce the gain you would adjust 680R resistor to higher value. You may try that, but also compare what it does to the sound of the amp.

I also like to use shunt type attenuator, with 10k fixed series resistor and shunt resistors switchable for proper attenuation. Having too much gain is never a problem really. The shunt resistors affect the sound the same way as series resistors, and here I find Caddock MK132 working really well (better than Vishay).


lwjnbtx said:
Hi Peter,

I've got a plitron va300 2x18VAC transformer. Can I use this? I am thinking of ordering only the boards, since I have several 3875s lying around. Am I able to order all other parts through digi-key?

Thanks,
Lee

That transormer will work fine. You can order the rest of the parts from Digi Key, but getting them directly from me will be probably cheaper and more convenient.
 
DAC RCA Output

I forgot to order the dual RCA output with my Greenboard DAC kit from Peter :yell: - i have a dual cardas but it doesnt fit the greenboard layout.
i did remember to order the input socket & it fits neatly into the board.
anyone know if i can find a board mounted dual output rca in the UK that fits the greenboard ? i wanted to go enclosure-less, so it is much neater if i can manage this.
i have searched the thread and can see some home made ones, but i didnt fancy that.
thxs
 
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