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.
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.
"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
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.jackinnj said:
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...
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?
An externally hosted image should be here but it was not working when we last tested it.
That would upset quite a few people in the industry
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?Bas Horneman said:
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.
This place is $50 for assembly for 5-25 units:
http://www.flex1express.com/
The details are on the front page.
--
Brian
http://www.flex1express.com/
The details are on the front page.
--
Brian
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 !
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 !
Hi,
well, I'd say I'm in
But I'm not sure if I understand You right, Per-Anders: You are looking for beta testers?
That would mean you supply everything except shipping costs? I think I've got you wrong though
The reason why I'm asking: because I'm short of cash at the moment... But a project like this fascinates me, as I'm currently in the process of developing an LM3875 or OPA541/9 based GC in smd.
Sebastian.
---
My last smd project. Just because it's a rare opportunity to see smt stuff
It's a partially uncrowded board (finished yet) of a USB-DAC (PCM2902) entirely made with Eagle, manufacturer's Datasheets and information from this board
EDIT: And manufactured DIY with overhead slides, laserprinter, Gesichtsbräuner and etching tools on the kitchen table. That goes without saying
well, I'd say I'm in
But I'm not sure if I understand You right, Per-Anders: You are looking for beta testers?
That would mean you supply everything except shipping costs? I think I've got you wrong though
The reason why I'm asking: because I'm short of cash at the moment... But a project like this fascinates me, as I'm currently in the process of developing an LM3875 or OPA541/9 based GC in smd.
Sebastian.
---
My last smd project.
Just because it's a rare opportunity to see smt stuff An externally hosted image should be here but it was not working when we last tested it.
It's a partially uncrowded board (finished yet) of a USB-DAC (PCM2902) entirely made with Eagle, manufacturer's Datasheets and information from this board
EDIT: And manufactured DIY with overhead slides, laserprinter, Gesichtsbräuner and etching tools on the kitchen table. That goes without saying
sek said:
My last smd project.
EDIT: And manufactured DIY with overhead slides, laserprinter, Gesichtsbräuner and etching tools on the kitchen table. That goes without saying
I only do etching in the kitchen when the wife is out of the house. Not a good idea to etch on a gas stove, btw -- releases hydrogen gas !
This is low budget so you have to actually pay me, then after completed task will get rewarded. I know the nature of people so they must have some pressure to actually perform. Money is good for that purpose.sek said:But I'm not sure if I understand You right, Per-Anders: You are looking for beta testers?
That would mean you supply everything except shipping costs? I think I've got you wrong though
Experience from my QRP01 project tells me that some people are very fast in building and others are really slow (no result yet...). The purpose of the beta testers is to really get results in a give time.
At the moment my project is only food for thought and when it has come so far so it's time to build I will make up my mind exactly how the beta building will be organized.
First I would like to have opinions of the design or at least the specifications.
Konnichiwa,
While I like the SMD part, may I ask why not make something unusual, instead of just another 1/2 Channel Amp?
How about an active 2-Way bi-amplifier build around LM3875 with an inverting Highpass (3rd Order) and an Inverting Op-Amp as subtractive Filter for the LF. Then apropriate EQ networks in the NFB of the LF section (correction for usual rising MF in most moder "Bass/Mid" drivers) and possibly in the HF section for the high frequencies.
An option should/could be current drive for the speakers.
Fit a non Op-Amp (eg Diamon Transistor) Buffer for the input (BUF634 or BUF04?) and have the PCB designed to handle the PSU with seperate bridges (discrete diodes) and windings per Amplifier. This way 1,000uF (or even less) on the HF section can be used and 10,000uF (or whetever people like) on the LF section.
Scale the Filters and you can "activate" either any 2-Way speaker or make a 3-Way partially active by separating Woofer and Midrange/Treble.
I think that sort of thing would make a ton more sense.
The Example could have the EQ and X-Over set for the TPX cone Seas Coax driver in a nice slim column enclosure (TQWT) using it's < 40Hz resonance to good effect, making for a nice "beginners" project.
Sayonara
peranders said:
While I like the SMD part, may I ask why not make something unusual, instead of just another 1/2 Channel Amp?
How about an active 2-Way bi-amplifier build around LM3875 with an inverting Highpass (3rd Order) and an Inverting Op-Amp as subtractive Filter for the LF. Then apropriate EQ networks in the NFB of the LF section (correction for usual rising MF in most moder "Bass/Mid" drivers) and possibly in the HF section for the high frequencies.
An option should/could be current drive for the speakers.
Fit a non Op-Amp (eg Diamon Transistor) Buffer for the input (BUF634 or BUF04?) and have the PCB designed to handle the PSU with seperate bridges (discrete diodes) and windings per Amplifier. This way 1,000uF (or even less) on the HF section can be used and 10,000uF (or whetever people like) on the LF section.
Scale the Filters and you can "activate" either any 2-Way speaker or make a 3-Way partially active by separating Woofer and Midrange/Treble.
I think that sort of thing would make a ton more sense.
The Example could have the EQ and X-Over set for the TPX cone Seas Coax driver in a nice slim column enclosure (TQWT) using it's < 40Hz resonance to good effect, making for a nice "beginners" project.
Sayonara
Re: Re: Industrial SMD Gainclone - group buy
I worked out the PCB design for the above -- enough op-amp power for the buffer, cascaded LR (1) XO and a phase correction circuit (2). As I read more I decided that it would be a lot more than a beginner/kit project, and if not implemented carefully would lead to "the weaping and gnashing of teeth !", i.e. unhappy customeres.
The idea was to prepopulate the board with the no-brainer bypass and decoupling caps (0805), localized regulators, and decent low-noise opamps, and allow the DIY builder to use through-hole devices for the filter resistors and capacitors.
Without some method of measuring the output -- both magnitude and phase (not everyone has a portable PC with a sound card, or an FFT analyzer) it just looked to me as a project which would frustrate more than help. So, perhaps there is demand for a score of boards, but not for hundreds.
Further, in DIY there is an attitude that "more is better" -- not necessarily the case when it comes to crossovers, indeed, just the opposite can be true.
The good thing which came out of the above was an easy-to-build phase meter PCB, as I thought that DIYr's would find this a necessity to properly set the phase of the HI and LO filters. It is cobbled from an Intersil application note. Unfortunately Intersil seems to have stopped making the transistor array, so a new design is underway with an off-the-shelf comparator.
(1) With TI's "Filter Pro" software any permutation is possible, but the adjustable F(3) and Q option are most helpful.
(2) Ballard, R. "An Active Crossover with Phase Correctors, II", Speaker Builder 4/82.
Kuei Yang Wang said:
I worked out the PCB design for the above -- enough op-amp power for the buffer, cascaded LR (1) XO and a phase correction circuit (2). As I read more I decided that it would be a lot more than a beginner/kit project, and if not implemented carefully would lead to "the weaping and gnashing of teeth !", i.e. unhappy customeres.
The idea was to prepopulate the board with the no-brainer bypass and decoupling caps (0805), localized regulators, and decent low-noise opamps, and allow the DIY builder to use through-hole devices for the filter resistors and capacitors.
Without some method of measuring the output -- both magnitude and phase (not everyone has a portable PC with a sound card, or an FFT analyzer) it just looked to me as a project which would frustrate more than help. So, perhaps there is demand for a score of boards, but not for hundreds.
Further, in DIY there is an attitude that "more is better" -- not necessarily the case when it comes to crossovers, indeed, just the opposite can be true.
The good thing which came out of the above was an easy-to-build phase meter PCB, as I thought that DIYr's would find this a necessity to properly set the phase of the HI and LO filters. It is cobbled from an Intersil application note. Unfortunately Intersil seems to have stopped making the transistor array, so a new design is underway with an off-the-shelf comparator.
(1) With TI's "Filter Pro" software any permutation is possible, but the adjustable F(3) and Q option are most helpful.
(2) Ballard, R. "An Active Crossover with Phase Correctors, II", Speaker Builder 4/82.
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