The ultimate integrated frugalphile gainclone

[yldouright]

I've been thinking about a full purpose best bang for the buck integrated amp based on the gainclone for a long time and would like to present some guidelines and a feature set:

Inverted "T" configuration with SuperSymmetry on amplifier section

JFET buffered to achieve maximum current/minimum phase error

unregulated power supply

1 digital input to a five channel DAC

2 general purpose inputs

2 tape (analog) inputs and outputs

1 tuner (analog) input

1 phono input with MM/MC circuits

1 headphone jack and amplifier

Does anyone here see why this project couldn't be completed for less than $250? I think this can all fit in standard 430mm form factor with plenty of room. Please feel free to critique the idea and point out some of the difficulties we are likely to encounter.

Thanks to Dave (planet10) for the use of "frugalphile"

[carlosfm]

Why do you need a 5-channel dac?
Is this a 5-channel amp?

[yldouright]

carlosfm
Actually, I am undecided. It would be a nice feature to implement with future DVD-A recorded material but it will add some complexity. I suspect, going from a two to five channel DAC will be less trouble than making five amps work well. I think I read that there are some high quality multichannel DAC chips available today but correct me if I'm wrong.

[carlosfm]

It depends of what you wanna do.
I don't know any "high-quality" integrated 6-channel (not five) dac.
High quality is single or two-channel dacs.

But this all depends what you want.
You'd better tweak a half-decent DVD-A player and forget about the multi-channel dac inside the amp.

Otherwise what you propose yourself to build is not possible for $250.
Don't forget (ideally) independent trafos and PSUs for everything.

[Steve Eddy]

Why complicate things? Get in tough with your frugalphile roots and just go mono.



Transformers by the way make great stereo-to-mono converters.

se

[carlosfm]

[Steve Eddy]

Originally posted by carlosfm

Don't laugh too hard. I'm not entirely joking.

se

[yldouright]

carlosfm
Let's go for the two channel DAC. I'm assuming that you're thinking of three separate power supplies (phono, DAC and integrated amp) but perhaps we can get away with two alone.

Steve Eddy
From your "mono" perspective, the whole thing can be run with a battery supply and a single source supply for recharge.

[Steve Eddy]

Originally posted by yldouright
Steve Eddy
From your "mono" perspective, the whole thing can be run with a battery supply and a single source supply for recharge.

Absolutely. Not to mention your speaker budget is cut in half. Or to look at it another way, for the same money, you could make one really mondo speaker.

Here's a sneak peek at my latest "chip" endeavor.

I've dubbed it the IPSGTCBPBICA, for Integrated Passive Signal Gain Transformer Coupled Battery Powered Buffered Inverting Chip Amplifier. Also known as the MABTYASTA, for My Acronym's Bigger Than Your Acronym So There Amplifier.

Not sure it can rightly be called a "chip amp" though seeing as I'm using the chip as a unity gain buffer. All of the signal (i.e. voltage) gain is accomplished passively using transformers.

Feel free to take any ideas from it if you like.



se

[yldouright]

Steve Eddy
That's quite an interesting twist on transformer volume control but I think that your project definitely requires a new thread since it is an active speaker concept
The more I think about battery supplies for the amp, phono and DAC section, the more I like it. The whole thing can be arranged with 4 cells but the case requirements will probably increase. The 3875 likes the 12V supply on 4ohm loads but some people may not like the power numbers generated with only 12V on the amp rails. I've heard a battery gainclone with a 12V supply driving a bi-wire 4ohm two way speaker and it sounded pretty good to me and plenty loud too. I suppose it depends on the sensitivity of the speakers used.