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-   -   Industrial SMD Gainclone - group buy (http://www.diyaudio.com/forums/group-buys/37434-industrial-smd-gainclone-group-buy.html)

peranders 8th July 2004 01:16 PM

Industrial SMD Gainclone - group buy
 
What do you say about a SMD Gainclone project in August, September?

Project name is "Industrial Gainclone", QRP02

For this I would like a few beta testers which of course will be rewarded.

Specifications:

* 50 um pcb with groundplane

* Rectifier diodes, TO247 and option for TO220

* 4700 uF/50V max, 10 mm snap-in and regular ones too.

* LM3886, inverting, 1k+18k, properly decoupled

* Mute

* Output filter, 1.5 mm wire, 5 mohms

* Zobel network

* DC-servo, AD8620, properly decoupled (possible not to use it)

* Input buffer, non-inverting, 220 kohms input impedance, AD8620, properly decoupled.

* 7812, 7912, TO220, maybe SO08, maybe LM317/337 in SOT223 (not desided yet)

* All elctrolytic caps hole mounted

* SMD caps PPS types and ceramics, 0805

* SMD resistors, 0805

* Lug connectors with option for 1.5 mm2 wires

* Fuses 5 x 20 mm

The goal is a complete product, just add two windings with AC, signal in and speaker out and a cute small pcb.

I'm going to vacation now and after my vacation I will start a wiki to see how the interst is. This first list doesn't mean any commitments. It just to see the interest. I think i will have at least 50 pcb's in order for moving further.

This project is only for persons that are rather handy with soldering iron so if you think my other SMD projects are too hard to build, this one is equally hard. Personally I think it is going to be rather easy, just 0805, and SO08 parts.

jackinnj 8th July 2004 01:32 PM

"QRP" in the lingua franca of ham radio means "small signal" --

with respect to "onboard" regulators -- as long as this is going to be surface mount you might want to specify some of the low noise variety from Linear Tech (LT1763, LT1964 instead of the garden variety 78L12 79L12. )

have a nice vacation -- stay away from the internet

li_gangyi 8th July 2004 02:35 PM

I;m interested...but it would mean I'm gonna spend a bit shipping them over...gotta get a new iron for that too...tips at least...

peranders 8th July 2004 03:46 PM

Quote:

Originally posted by jackinnj
"QRP" in the lingua franca of ham radio means "small signal" --

with respect to "onboard" regulators -- as long as this is going to be surface mount you might want to specify some of the low noise variety from Linear Tech (LT1763, LT1964 instead of the garden variety 78L12 79L12. )

have a nice vacation -- stay away from the internet

One of my design rules is to use normal parts. If other (better?) parts fits, used those by all means.

Due to very good PSRR I don't think very low noise is essential especially when the gain is only 2.

Those regualtors you mention can only take 20 volts in which is a bit low and the output voltage is only 5 volt max.

... haven't started the vacation yet...

Bas Horneman 8th July 2004 04:04 PM

Quote:

What do you say about a SMD Gainclone project
How about a groupbuy of the complete module ASSEMBLED and all.

Here is a board by Raleigh Audio and K&K...it retails for 249$ as you see it pictured (one 18$ transformer included)...

Must have cost around 50$ to get it manufactured? Maybe this proposed gainclone...could be in that price range for 2 channels?

http://www.raleighaudio.com/rakk_dac.jpg

That would upset quite a few people in the industry :-)

peranders 8th July 2004 06:32 PM

Quote:

Originally posted by Bas Horneman
Must have cost around 50$ to get it manufactured? Maybe this proposed gainclone...could be in that price range for 2 channels?

It's only a matter of quantity. I'd say it must be over 500 units to get attractive prices. We have also the question: Do you want to build or do you only want the end result and also pay for it?

At the moment I have no desire to manage 500 units = 25000 USD for non-profit.

I'd say that people put themselves on the coming list in order to get a picture of the interest. At the moment people seems to prefer Caddock and Riken resistors more than SMD and no input buffer so I expect that only 10-30 people will be interested in this totally different Gainclone. My QRP01 has been very well recieved so I have no doubts that this also will be quite alright.

BrianGT 8th July 2004 06:40 PM

This place is $50 for assembly for 5-25 units:
http://www.flex1express.com/
The details are on the front page.

--
Brian

peranders 8th July 2004 06:46 PM

Quote:

Originally posted by BrianGT
This place is $50 for assembly for 5-25 units:
http://www.flex1express.com/
The details are on the front page.

--
Brian

Looks interesting but there is always one catch. Here it is max 5 hole mounted parts. In my case it will be more than that. Since it's in USA I must also add freight costs and actually buy the parts.

jackinnj 8th July 2004 07:02 PM

www.screamingcircuits.com has a Proto program in which you can combine SMT's BGA's, Finepitch, and "through-hole" -- parts can be on cuttape instead of reel -- but it's probably about $20/board.
http://www.screamingcircuits.com/order/quote.aspx
one of the proto-houses in the US will take your shipment directly from Digikey !

i have no intention of buying a "pick n place" machine !

peranders 8th July 2004 07:27 PM

Enlighten me please, but what is "cuttape"?


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