| BrianGT |
I made this board for the gainclone this weekend, based on the components used in Peter Daniel's unit. It is in non-inverting configuration.
Any one interested in a group order of non-inverted LM3875 pc boards?
For resistors, Caddock MK132V resistors were used for the input, shunt and feedback resistors. A Riken 680 ohm resistor was used for the resistor setting the gain with the NFB resistor. The board is designed with these components in mind, so the group order could also include these components.
As far as power supply capacitors, the board has room and component pads for using the BlackGate 1000uF 50v caps, Panasonic FC 50v 1000uF caps and Panasonic FK SMD 1000uF capacitors (new product).
I am also looking at making a power supply board to go with this.
Is anyone interested in a group order of these boards, and possibly also interested in a group order of the components used on the boards if we can get a substantial discount over single unit quantities?
More info & to get on the list:
http://www.diyaudio.com/wiki/index....PCB+Group+Order
Order Form
-- Brian |
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| BrianGT |
Schematic used for layout:
(NFB resistor is to be soldered directly to the LM3875 pins.)
--
Brian |
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| jlh28 |
I am in on the boards and the other components as well. The PS board too if you design it. I guess that we can source our own caps as I am sure everyone will not want the same ones. I will probably be in for 20 or so channels worth. It looks like that would be 5 boards.
Thanks for taking the initiative. If you need any assistance along the way, let me know.
Jeff |
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| KevinLee |
Hello,
I would be in for a couple boards.
KevinLee |
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| elizard |
| Count me in for a board or two. Quite possibly for the resistor pack too if its available. |
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| hifi |
ill take a couple of boards and resistor kits
/ Micke |
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| roddyama |
Hi Brian,
You know me, if there are boards for sale, I'm in. I guess I would be interested in a couple.
BTW, to those thinking about getting boards, if you need parts, read on.
If you're a Cardas fan, the 2nd annual Cardas bulk purchase is well under way. If you're interested see this thread in the trading Post Forum and the WIKI Page for details.
I have already started to send order confirmation emails to those that already placed their orders.
I will be accepting requests for the price list up until Wednesday, the 25th at 12 midnight EST.
PS: I will delete this post after Wednesday. |
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| uvodee |
I prefer Peer peer connection and have made quite a few gc sets I would be interested in 2 boards provided all the right components can come with it.
Power supply pcb is not really essentials but, again, if they can come with the good stuff components, write me down for 4 of them !
Jean-Pierre |
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| leadbelly |
| Count me in for a couple of boards. Also possibly interested in component kits depending on what those look like finally. |
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| tiroth |
I'm in for a couple (8 amps); more if the price happens to go down as people pile in.
I think it is great to stock up as these make great little surround or multi-amp setups, and they are much faster than doing P2Ps. Instant amps when you want to try out a new project. ;) |
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| hifi |
"Instant amp just add solder"
;)
/ Micke |
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| moe29 |
i would be in for a couple of boards.
a resistor pack would be great!
actually a resistor/capacitor pack would be better! :)
PSU boards too. |
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| elizard |
| Pansonic FC caps can be had for $1.11 each from digikey in quantities of 100, or $0.65 for 1000! |
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| bsyyu |
I interest to buy and count me with 6pcs.
Packed with resister is great for me. |
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| elizard |
Well, I just did a quick calculation based on www.partsconnexion.com, and here's what I came up with:
Caddock 220R, CADDOCK- 62279, $3.55
Caddock 22K, CADDOCK- 51206, $3.55
Riken 680R, RIKEN- 62147, $3.20
Are these the right resistors btw?
That's $10.30 per channel for the 3 resistors (pricey little things, aren't they?), but there may be a discount. Also, if anyone else knows of a cheaper place to get resistors from, they should suggest it. (I'm sure there is).
If partsconnexion is in fact the cheapest, I would be more than willing to do the order from them, and re-ship it to everyone, as this would save a bit of money when it comes to customs (if someone from the statest orders it they'll for customs b/c of canadian origin), as well, it'll cut down on shipping (cheaper to ship it within canada originally, then separately to everywhere else.
The shipping then within canada would be around $2.50 for a standard bubble envelope, and like $3-$4 for US shipping.
Anyway, just something I came up with at work. If someone else knows of a cheaper place, please do recommend it. I would definitely be interested in a resistor + capacitor pack, and wouldn't mind organizing something. |
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| Peter Daniel |
| check percyaudio.com |
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| hifi |
I think you took the wrong riken this is the 0,5W variaty:
RIKEN- 62079 680R $2.40
But where there not also some Vishay resistors in PD:s schematic?
But then again PD might have specified a 1W Riken but it will not fit the PCB (lead spacing ~10mm)
/ Micke |
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| elizard |
percyaudio doesn't stock riken, as well partsconnexion is slightly cheaper.
partsconnexion is $0.05 cheaper than percy
also, with that other riken resistor, the total is $9.50 without any further discounts |
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| BrianGT |
Well, if a bulk order is made of a significant amount, ordering from individual vendors for the resistors shouldn't matter too much.
Peter, can 20k MK132 resistors be used? It will lower the gain a bit, but it already seems high enough.
from Mouser.com
1 $ 3.400
10 $ 2.720
25 $ 2.520
50 $ 2.380
100 $ 2.240
--
Brian |
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| Peter Daniel |
| I think it can be used, there shouldn't be any major difference here. |
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| elizard |
| One question - if you use a pot, you just connect the output from the pot to the "in" on the board without omitting any resistors? |
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| Peter Daniel |
| quote: | Originally posted by hifi
I think you took the wrong riken this is the 0,5W variaty:
RIKEN- 62079 680R $2.40
But where there not also some Vishay resistors in PD:s schematic?
But then again PD might have specified a 1W Riken but it will not fit the PCB (lead spacing ~10mm)
|
I'm using 0.5W Riken. Also, for series 220R resistor, you might not need it, depending on your system. I'm using it only to prevent any excessive DC offset jump.
Vishay S102 is good in this position, and it seems to be more neutral than Caddock, but some people may prefer some extra touch and Caddock seem to add that extra bit of speed and dimentionality, but it could also be interpreted as edginess. The choice is yours. |
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| Peter Daniel |
| quote: | Originally posted by elizard
One question - if you use a pot, you just connect the output from the pot to the "in" on the board without omitting any resistors? |
Yes, and because I'm using 50K pot, I need 22k shunt resistor to lower input impedance (from + to ground). But if your pot is around 20k in value, you don't need 22k shunt resistor. |
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| digi01 |
Hi,BrianGT.you do a good pcb work,the style of your PCB overall arrangement is very nice!!
Did you use Protel for that? |
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| elizard |
| quote: | Originally posted by Peter Daniel
Yes, and because I'm using 50K pot, I need 22k shunt resistor to lower input impedance (from + to ground). But if your pot is around 20k in value, you don't need 22k shunt resistor. |
no, it would be the 50k i got from you .. thank you :) |
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| BrianGT |
| quote: | Originally posted by digi01
Hi,BrianGT.you do a good pcb work,the style of your PCB overall arrangement is very nice!!
Did you use Protel for that? |
Yes. I used Protel for it.
--
Brian |
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| BrianGT |
| quote: | Originally posted by elizard
One question - if you use a pot, you just connect the output from the pot to the "in" on the board without omitting any resistors? |
| quote: | Originally posted by Peter Daniel
Yes, and because I'm using 50K pot, I need 22k shunt resistor to lower input impedance (from + to ground). But if your pot is around 20k in value, you don't need 22k shunt resistor. |
As Peter stated, if you are using a 20k pot, you do not need the shunt resistor to ground [R2]. You also might not need the 220 ohm series resistor on the input pin. I made the second pad on the R1 pad (series resistor) larger, so that the input wire can be wired directly into this pad if the 220 resistor is omitted.
--
Brian |
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| elizard |
Well, a little research done :)
www.alliedelec.com has cheap resistors! :)
$2.20 for the 20k in 100+ quantities (model#: 524-5575)
$1.58 for the 220R in 1+ quantity!!! (model#: 524-9996)
so that's $3.78 for these 2, plus the $2.40 for the riken .. not too bad, $6.18 for the 3 resistors ..
am i missing a resistor here? |
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| BrianGT |
| quote: | Originally posted by elizard
Well, a little research done :)
www.alliedelec.com has cheap resistors! :)
$2.20 for the 20k in 100+ quantities (model#: 524-5575)
$1.58 for the 220R in 1+ quantity!!! (model#: 524-9996)
so that's $3.78 for these 2, plus the $2.40 for the riken .. not too bad, $6.18 for the 3 resistors ..
am i missing a resistor here? |
Don't forget that you need a 20k for the negative feedback resistor, which mounts directly to the chip.
We are probably talking about $12 per board for resistors and Panasonic FC power caps, including the shipping of the components to me.
I have a prototype of the power supply board done, which is 2.5" x 1.5". 2 boards and the power supply board would make a single board that is 3.5" x 2.5".
--
Brian |
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| elizard |
i knew i was forgetting a resistor ..
but at $12/board, that's still a damn good price! |
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| BrianGT |
| quote: | Originally posted by elizard
i knew i was forgetting a resistor ..
but at $12/board, that's still a damn good price! |
I am estimating $50 or less for all the parts, pcbs for 2 channels and the power supply (8 x MUR860 and 2 x 4.7uF caps), including packing and shipping. (this is for panasonic caps, not BG. I am considering omitting the BG caps from this order, since I can't seem to find good quantity discounts anyway. In addition, most of the interest for this order seems to be for the Panasonic FC caps.)
--
Brian |
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| BrianGT |
The newer Panasonic FK capacitors get cheaper if bought in discount: $102.25 for 125 of them, $0.82 each
--
Brian |
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| elizard |
| quote: | Originally posted by BrianGT
The newer Panasonic FK capacitors get cheaper if bought in discount: $102.25 for 125 of them, $0.82 each
--
Brian |
You said they're surface mount types, right?
I do not like those :( |
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| BrianGT |
| quote: | Originally posted by elizard
You said they're surface mount types, right?
I do not like those :( |
Well, the regular FC caps will work fine, and have proven to work fine, though the many gainclones built with them. I allowed for the option for trying the FK caps if anyone is interested.
Has anyone compared the different sized FC 1000uF 50v caps? They make 2 different sizes, 16mm x 25mm x 7.5mm or 12.5mm x 40mm x 5mm [ diameter x length x spacing ]. I have only used the 12.5mm x 40mm caps, which cost a bit more, and have a slightly lower ESR. Both will work on the PCB.
--
Brian |
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| jean-paul |
I am interested in 4 boards ( or more ) but I would like to have 3 mm mounting holes at both sides to support the board in the case.
The following comment is meant as positive input:
It seems the amp will be "hanging" at only one screw this way. The weight of the caps will cause mechanical stress at the solder joints possibly causing premature failure. Also the risk of short circuits with "loose" PCB's is higher than with well mounted boards. |
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| uvodee |
you did not put me in the wiki list ?
that's ok, i'll keep making them the way I am used to, however, too bad for me, I would have thought the thing would have gotten cheaper when as expressed in my earlier message I would have been on the list for 4 ....
J-P |
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| usekgb |
I'd be interested in a few boards, caps and resistors. What is the final price looking like?
Cheers,
Zach |
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| Variac |
Should't there be an option to actually also get the 3875s also, or is everyone going to use sampling?
UVODEE: I think you are supposed to put yourself on the wiki list.
That way your future is in your own hands!!! |
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| BrianGT |
| quote: | Originally posted by jean-paul
I am interested in 4 boards ( or more ) but I would like to have 3 mm mounting holes at both sides to support the board in the case. It seems the amp will be "hanging" at only one screw this way. The weight of the caps will cause mechanical stress at the solder joints possibly causing premature failure. |
What about a single hole in the middle of the board, to relieve stress on the solder joints? With the current positioning of the capacitors, and board dimensions, there is no easy way to put holes on the sides of the boards.
--
Brian |
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| BrianGT |
| quote: | Originally posted by uvodee
you did not put me in the wiki list ?
that's ok, i'll keep making them the way I am used to, however, too bad for me, I would have thought the thing would have gotten cheaper when as expressed in my earlier message I would have been on the list for 4 ....
J-P |
I posted a link to the WIKI list:
http://www.diyaudio.com/wiki/index....PCB+Group+Order
Please add your entry to the Wiki.
--
Brian |
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| BrianGT |
| quote: | Originally posted by BrianGT
I am estimating $50 or less for all the parts, pcbs for 2 channels and the power supply (8 x MUR860 and 2 x 4.7uF caps), including packing and shipping. (this is for panasonic caps, not BG. I am considering omitting the BG caps from this order, since I can't seem to find good quantity discounts anyway. In addition, most of the interest for this order seems to be for the Panasonic FC caps.)
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| quote: | Originally posted by usekgb
I'd be interested in a few boards, caps and resistors. What is the final price looking like?
|
See my above post. If you want to express interest in the group order, add your name to the Wiki, along with the amount of items that you want.
http://www.diyaudio.com/wiki/index....PCB+Group+Order
I will give it a few more days to generate interest, then I will work on getting some definate prices. One more addition to the above price list above, is the LM3875, which will add another $8-10 to the order if you don't already have some of these chips.
--
Brian |
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| BrianGT |
| quote: | Originally posted by Variac
Should't there be an option to actually also get the 3875s also, or is everyone going to use sampling?
UVODEE: I think you are supposed to put yourself on the wiki list.
That way your future is in your own hands!!! |
Mark,
Good point. I had forgotten about this item, because I initially didn't plan on an entire kit. I do NOT advise exploiting National Semiconductor's sample program for this project. ;) Especially since it is quite a reasonably priced chip.
--
Brian |
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| BrianGT |
Here is my initial layout of the power supply pcb. It is the same size as the gainclone pcb.
My current idea is to put 1 of these boards and 2 channels of the gainclone board one a single pcb.
--
Brian |
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| BrianGT |
schematic for power supply board.
--
Brian |
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| Variac |
Hey Brian, at this point why don't you make it a complete kit pleeeease?
Power Supply:
You could just lump the power supply items together
add the small supply cap to any of the cap choices, i.e. if the big caps are Panasonic they include a Panasonic small cap
If BG, then include a small BG
Maybe you really don't need 2 panasonic cap choices.
Maybe each resistor pack includes the amp chip.
This could be a record buy!!! |
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| Chris Marshall |
Hi Guys
I'm new at this diy thing and this looks a great way to get started.
Brian, are you happy to ship to the UK? If so I'll put my name down on the Wiki.
regards
Chris |
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| BrianGT |
I added a LM3875 category to the table, along with a category for your Geographic Location. I made the LM3875 category the same as the Rpack category. Please check over your information again, and add your Geographic location to the table.
--
Brian |
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| BrianGT |
| quote: | Originally posted by Variac
Hey Brian, at this point why don't you make it a complete kit pleeeease?
Power Supply:
You could just lump the power supply items together
add the small supply cap to any of the cap choices, i.e. if the big caps are Panasonic they include a Panasonic small cap
If BG, then include a small BG
Maybe you really don't need 2 panasonic cap choices.
Maybe each resistor pack includes the amp chip.
|
Mark,
I am getting close to lumping together everything as a kit. If I can't find a volume discount on the BG caps, I will not offer them as part of this order. I will give this order a week to see how the numbers work out, then I will work out pricing.
--
Brian |
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| KT |
I'd be interested in several of the boards. Enough to make a couple of 5 channel home theatre amps or so.
Best,
KT |
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| BrianGT |
Here is the link to the Wiki, for those missed it:
http://www.diyaudio.com/wiki/index....PCB+Group+Order
Please fill out the table. I attached the current view of the table.
Most likely, 2 channels will be combined with a single power supply board, on one pcb, so please keep # of channels to an even number.
Also, please fill in your geographical location, and verify the numbers listed in the sheet.
--
Brian |
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| jean-paul |
| quote: | Originally posted by BrianGT
What about a single hole in the middle of the board, to relieve stress on the solder joints? With the current positioning of the capacitors, and board dimensions, there is no easy way to put holes on the sides of the boards.
--
Brian |
A single hole is OK but when the board would be slightly wider there is room fo a 3 mm hole at the left and at the right.
Never mind, a single mounting hole is better than none at all.... |
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| BrianGT |
| quote: | Originally posted by jean-paul
A single hole is OK but when the board would be slightly wider there is room fo a 3 mm hole at the left and at the right.
Never mind, a single mounting hole is better than none at all.... |
What about placing the single hole here:
If not.. where would would you recommend placing it, with it not interfering with the layout.
The blue traces are the traces on the bottom of the pcb.
--
Brian |
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| tiroth |
| I just updated the totals. |
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| Peter Daniel |
| quote: | Originally posted by jean-paul
I am interested in 4 boards ( or more ) but I would like to have 3 mm mounting holes at both sides to support the board in the case.
The following comment is meant as positive input:
It seems the amp will be "hanging" at only one screw this way. The weight of the caps will cause mechanical stress at the solder joints possibly causing premature failure. Also the risk of short circuits with "loose" PCB's is higher than with well mounted boards. |
This is a very good observation and I also thought about it. Instead of using holes in the board for support, I'd rather use a block on the caps and atach it to the heatsink. This will provide enough support for everything. |
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| Peter Daniel |
| Black Gates can be ordered directly from Japan, with at least 30% discount. |
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| BrianGT |
| quote: | Originally posted by Peter Daniel
This is a very good observation and I also thought about it. Instead of using holes in the board for support, I'd rather use a block on the caps and atach it to the heatsink. This will provide enough support for everything. |
Sounds like a much better idea, but, do you know an easy way to get these manufactured? Would wood be fine for this, or is the white plastic stuff you used on your earlier amps better?
If someone wants to look into this, and get some made, they could be included in with the order if people are interested.
--
Brian |
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| BrianGT |
| quote: | Originally posted by Peter Daniel
Black Gates can be ordered directly from Japan, with at least 30% discount. |
Sounds like a good idea, but how are the lead times? I once ordered a box of Elna capacitors, and it took me 2 months to get them.
--
Brian |
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| Peter Daniel |
It usually takes 2 weeks and is sent by air mail.
Mounting block can be made out of delrin. It's almost as easy to work with as MDF. If there is enough interest, I could produce them, as I already have experience with that;) |
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| johnm |
Hello there!
I'd be up for ordering six of the boards only if it's not too late?
Cheers!
- John. |
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| Peter Daniel |
| quote: | Originally posted by BrianGT
schematic for power supply board.
--
Brian |
C1 and C2 should be the other way around. |
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| BrianGT |
| quote: | Originally posted by johnm
Hello there!
I'd be up for ordering six of the boards only if it's not too late?
Cheers!
- John. |
Don't worry.. I just started this thread last night. I will give it a week to see how much interest there is in the order, then work out pricing and farther details.
Add your name to the Wiki, along with what you are interested in.
http://www.diyaudio.com/wiki/index....PCB+Group+Order
--
Brian |
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| BrianGT |
| quote: | Originally posted by Peter Daniel
C1 and C2 should be the other way around. |
I was initially planning on using non-polar BG N caps, so I overlooked this. There also is currently no polarity marked on the pcb for the capacitors..
Here is a revised schematic, and I will update the pcb as well with polarity markings in the correct way.
--
Brian |
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| Leo_Smith |
I would like to get in on this also, two boards and possibly a few sets of components.
thanks
L Smith |
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| chris ma |
Hi BrianGT,
Please confirm that with this group buy kit it is true that only the following items are buyer's own responsibility in order to build one channel of 50W classA/B.
1/ one 400VA 22-0-22 transformer
2/ one power switch rated 10A
3/ one RCA input jack
4/ one set of speaker binding posts
5/ one in-line 3A slow blow fuse and holdler
6/ one power cord
7/ one chassis of ones choice if not remote PSU
8/ one volumn pot; what value?
If this is true I will be interested in 5 or 8 channels
Regards,
Chris |
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| usekgb |
Hi Brian......I've added my name to the Wiki, but don't need the MUR860's. Will the total be less without them?
Cheers,
Zach |
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| Da5id4Vz |
| Any thougths of offering a generic "Brian-Box"? |
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| BrianGT |
| quote: | Originally posted by Leo_Smith
I would like to get in on this also, two boards and possibly a few sets of components.
thanks
L Smith |
Leo (and others interested in this group buy),
Put you name in the Wiki, along with what you are interested in for this order:
http://www.diyaudio.com/wiki/index....PCB+Group+Order
--
Brian |
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| BrianGT |
| quote: | Originally posted by usekgb
Hi Brian......I've added my name to the Wiki, but don't need the MUR860's. Will the total be less without them?
Cheers,
Zach |
I added an extra field to the Wiki sheet, where you can add stuff that you might not want... Yes, it will probably be a few dollars less without the diodes. I will sort out what exactly comes in the kit, in a few days, after I see how large the interest is for this order.
--
Brian |
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| roddyama |
To those thinking about getting boards, if you need hardware, read on.
If you're a Cardas fan, the 2nd annual Cardas bulk purchase is well under way. If you're interested see this thread in the trading Post Forum and the WIKI Page for details.
I have already started to send order confirmation emails to those that already placed their orders.
I will be accepting requests for the price list up until Wednesday, the 25th at 12 midnight EST.
PS: I will delete this post after Wednesday. |
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| BrianGT |
| quote: | Originally posted by Da5id4Vz
Any thougths of offering a generic "Brian-Box"? |
If you want a finished product, just buy one of Peter Daniel's great amps ;)
The goal of this order is to make it easier to build a gainclone with a simple pcb. If someone else wants to offer a chassis for this project, they can do so in another group order. I have no interest in making chassis for this, due to time that it would take to do so.
Listen to Rodd, if you want great chassis connectors, get in on the Cardas order while you can. You will not find a lower price for these connectors. Here is a picture of my chassis, running the same circuitry that these pcbs contain. I used Cardas copper binding posts and RCAs. I also used a stepped attenuator, which is offered in another thread on this forum.
(this is the amp that I helped my friend Eric build last week http://www.diyaudio.com/forums/show...&threadid=28048 )
--
Brian |
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| Sheldon |
I may be the dumbest one here, but I went to the wiki and couldn't figure out how to plug in my figures. I didn't want to mess up the table. I'm looking for four channels, as complete as possible.
Sheldon |
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| BrianGT |
| quote: | Originally posted by Sheldon
I may be the dumbest one here, but I went to the wiki and couldn't figure out how to plug in my figures. I didn't want to mess up the table. I'm looking for four channels, as complete as possible.
Sheldon |
I added you on there. If it is incorrect, what I added, drop me an e-mail and I will fix it.
--
Brian |
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| Sheldon |
| quote: | Originally posted by BrianGT
I added you on there. If it is incorrect, what I added, drop me an e-mail and I will fix it.
--
Brian |
Looks good. This will be my first shot, so if it's worth trying a couple of the BG caps, I could go 2 and 2 with Panasonic. I'm flexible, whatever is available from those listed, I'll take.
Sheldon |
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| elizard |
brian: are you going to order lm3875t (non-insulated) only? Or is there an option to purchase the lm3875tf?
I would personally be only interested in the insulated version.
btw, this thing is picking up momentum fast :) |
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| jlh28 |
| Brian, where were you able to order these from. I have as of yet been unsuccessful in locating the post were they were mentioned. Too much more searching at work and the IT guys will come down and ask me to actually do something today :D |
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| jean-paul |
| quote: | Originally posted by Peter Daniel
It usually takes 2 weeks and is sent by air mail.
Mounting block can be made out of delrin. It's almost as easy to work with as MDF. If there is enough interest, I could produce them, as I already have experience with that;) |
Hi Peter, technically a very good and sonically probably the best solution but it depends if you want to make those otherwise I think simple mounting holes are more convenient ( DIY-friendly that is ).
Brian, glad to see you edited the board. There is no other solution than the one you proposed or the one with the holes at the left and right side. I think it won't be easy to put a screw in at that place with the resistor soldered in though but I won't ask for more ;) |
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| Lee35210 |
I'm in for 2 boards(8 amps). Also interested in Black Gate's and PS bd.
Thanx,
Lee |
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| BrianGT |
| quote: | Originally posted by elizard
brian: are you going to order lm3875t (non-insulated) only? Or is there an option to purchase the lm3875tf?
I would personally be only interested in the insulated version.
btw, this thing is picking up momentum fast :) |
If you want the uninsulated version, put it in the Comments field, and I will see what I can do later. It might cost a few dollars more.
| quote: | Originally posted by jlh28
Brian, where were you able to order these from. I have as of yet been unsuccessful in locating the post were they were mentioned. Too much more searching at work and the IT guys will come down and ask me to actually do something today :D |
I started this group order less than 24 hours ago, and it has gotten big quite fast. I am going to wait a few more days, and see how large the demand gets for this. I haven't decided where I am going to source the parts from, as it will be determined by the quantity. I will work out the details of this, hopefully by the end of the week.
The Wiki is currently only a preliminary interest survey, and I will use this to look at the demand, and put together a kit and pricing structure.
Once the pricing and details are worked out, I will put together a shopping cart system on my website. I will be accepting money via paypal, once I work this whole thing out.
I can get some help from local friends in putting this thing together, as it seems like it will get larger than I imagined.
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Brian |
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| Anorgan |
So what is there to order besides LM and resistors?
I'm interested in some binding posts (speaker and RCA), 5KOhm stereo pot. |
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| BrianGT |
| quote: | Originally posted by roddyama
To those thinking about getting boards, if you need hardware, read on.
If you're a Cardas fan, the 2nd annual Cardas bulk purchase is well under way. If you're interested see this thread in the trading Post Forum and the WIKI Page for details.
I have already started to send order confirmation emails to those that already placed their orders.
I will be accepting requests for the price list up until Wednesday, the 25th at 12 midnight EST.
PS: I will delete this post after Wednesday. |
| quote: | Originally posted by Anorgan
So what is there to order besides LM and resistors?
I'm interested in some binding posts (speaker and RCA), 5KOhm stereo pot. |
See the above quote from Rodd for the binding posts and rca jacks. I am not going to include them in my kit order.
As for the potentiometer/attenuator, if anyone finds a decent deal on one, I will consider adding it to this order. I am looking to see if I can get some 20k stepped attenuators for mine, like the one in the picture that i posted a few posts back.
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Brian |
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| idex |
Brian,
Can you edit your 1st post to include the wiki? I think that help those who are new to the thread.
Matt |
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| JCoffey |
| OK, I put in my order. |
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| jlh28 |
| quote: | Originally posted by BrianGT
If you want the uninsulated version, put it in the Comments field, and I will see what I can do later. It might cost a few dollars more.
I started this group order less than 24 hours ago, and it has gotten big quite fast. I am going to wait a few more days, and see how large the demand gets for this. I haven't decided where I am going to source the parts from, as it will be determined by the quantity. I will work out the details of this, hopefully by the end of the week.
The Wiki is currently only a preliminary interest survey, and I will use this to look at the demand, and put together a kit and pricing structure.
Once the pricing and details are worked out, I will put together a shopping cart system on my website. I will be accepting money via paypal, once I work this whole thing out.
I can get some help from local friends in putting this thing together, as it seems like it will get larger than I imagined.
--
Brian |
Sorry, I was referring to the stepped attenuator that you used on the gainclone that you posted. |
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| moe29 |
Brian,
I hate to add another part, but a heat pad would be nice to have
in the package for the LM3875.
What do you think of this Digi-Key Part?
BER180-ND Bergquist Heat Sink Pads.
I've used the Sil-Pad 900-S material with MOSFETS in other amps
and it works well. The above part seems to fit the dimensions of
the LM3875. A quantity of 100 would make them 0.59 cents a piece.
I was thinking for addional parts like this, if they weren't included
in the buy, we could make up a reccomended parts list for buyers
to obtain on their own.
Like that On/Off switch that incorporates the AC Inlet (and fuse?),
one of those would be nice to have too! :) |
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| Variac |
Brian, OK I know this could become a PITA for you, and the amount of money maybe a hassle, but when you get these bulk rates of over a hundred, you can include parts that some people might not prefer, but they wil be so cheap that it really doesn't affect the bottom line much.
I suggest that you don't try to satisfy everyone. If they want a parts kit they can order one or two variations, A standard model and a deluxe. If they end up with a few parts they don't want, it only costs them a couple of dollars more and they have some extra stuff in their parts boxes.
I'd much prefer a very complete kit, and end up with a few parts I decide not to use, than to have to order a few parts separately.
If you only have 2 kits then making up the packs would be a lot easier. 5 variations will make you insane, but people will try too make you do it!!!
The total cost will still be a lot lower than ordering a small quantity of all the parts at the low quantity rates and paying shipping..
The only pieces that is probably not a good idea to include are the transformers, heatsinks, probably the pots are a problem too- mono?, stereo? high quality? , low? stepped?
also- don't need silpads if it is the insulated version.
Mark |
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| BrianGT |
| quote: | Originally posted by moe29
Brian,
I hate to add another part, but a heat pad would be nice to have
in the package for the LM3875.
What do you think of this Digi-Key Part?
BER180-ND Bergquist Heat Sink Pads.
I've used the Sil-Pad 900-S material with MOSFETS in other amps
and it works well. The above part seems to fit the dimensions of
the LM3875. A quantity of 100 would make them 0.59 cents a piece.
I was thinking for addional parts like this, if they weren't included
in the buy, we could make up a reccomended parts list for buyers
to obtain on their own.
Like that On/Off switch that incorporates the AC Inlet (and fuse?),
one of those would be nice to have too! :) |
The insulators would probably be a good idea to include with the order. I will consider this, when I finalize the order. I don't think that the Corcom power entry module should be included in the order, since it is rather expensive ($15 for one, $11 each for 25, $10 each for 50).
My goal is to get the cost at around $50 for the pcbs and for all the parts for the pcb and power supply pcb. This would be for 2 channels. I want to get 2 channels and one power supply board on a single 3" x 2.5" pcb, that is scored for easily breaking it apart.
I am trying to set realistic goals, and minimize the parts count for the boards, as I don't want to overwhelm myself, having to stuff 20+ different kinds of kits for 100+ different people would not be fun.
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Brian |
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| chris ma |
| quote: | Originally posted by Variac
Brian, OK I know this could become a PITA for you, and the amount of money maybe a hassle, but when you get these bulk rates of over a hundred, you can include parts that some people might not prefer, but they wil be so cheap that it really doesn't affect the bottom line much.
I suggest that you don't try to satisfy everyone. If they want a parts kit they can order one or two variations, A standard model and a deluxe. If they end up with a few parts they don't want, it only costs them a couple of dollars more and they have some extra stuff in their parts boxes.
I'd much prefer a very complete kit, and end up with a few parts I decide not to use, than to have to order a few parts separately.
If you only have 2 kits then making up the packs would be a lot easier. 5 variations will make you insane, but people will try too make you do it!!!
The total cost will still be a lot lower than ordering a small quantity of all the parts at the low quantity rates and paying shipping..
The only pieces that is probably not a good idea to include are the transformers, heatsinks, probably the pots are a problem too- mono?, stereo? high quality? , low? stepped?
also- don't need silpads if it is the insulated version.
Mark |
The idea is not to hunt for parts from different supplier. Once the package arrive I can light up my soldering iron
:D
Keep the kit generic and make it easy on yourself, you already do us a big favour on the PCB.
Chris |
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| BrianGT |
| quote: | Originally posted by chris ma
The idea is not to hunt for parts from different supplier. Once the package arrive I can light up my soldering iron
:D
Keep the kit generic and make it easy on yourself, you already do us a big favour on the PCB.
Chris |
I am looking forward to having this amplifier in kit form for myself as well. I have several friends wanting their own gainclone amplifiers. I love an amplifier that you can build in several hours.
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Brian |
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| Variac |
| quote: | | I love an amplifier that you can build in several hours. |
That should be the motto and driving philosophy:o :o |
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| Peter Daniel |
| I'm not completely sure about it, but my today's experiments indicate that insulated case (plastic encased) sounds probably better;) |
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| elizard |
| quote: | Originally posted by Peter Daniel
I'm not completely sure about it, but my today's experiments indicate that insulated case (plastic encased) sounds probably better;) |
As always I respect your opinion. Plus it is a lot easier dealing with the insulated cases when you have the option to. As well, seeing the chip doesn't require some amazing heatsinking needs, using an insulated vs. non-insulated chip isn't much of a problem. |
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| net-david |
Brian,
What about the possibility of getting a transformer from Victoria Magnetics. Special deal on a volume purchase?
David |
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| moe29 |
from reading posts in the past, it seems the VM sells at the lowest
cost already - group purchases don't bring the cost down. The
guy has to make a living! :)
They could maybe arrange a special order# so that they know
exactly what transformer to make, and it could cut down on the
lead time - meaning we might get them a little bit faster.
Brian has had lots of dealings with them, so he'd know for sure. |
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| moe29 |
Even with an insulated case, don't you still need a heat pad, just
for better heat transfer between the chip and the heat sink? |
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| Sheldon |
| quote: | Originally posted by Variac
.
I suggest that you don't try to satisfy everyone. If they want a parts kit they can order one or two variations, A standard model and a deluxe. If they end up with a few parts they don't want, it only costs them a couple of dollars more and they have some extra stuff in their parts boxes.
I'd much prefer a very complete kit, and end up with a few parts I decide not to use, than to have to order a few parts separately.
If you only have 2 kits then making up the packs would be a lot easier. 5 variations will make you insane, but people will try too make you do it!!!
Mark |
I like this approach too, if you're game. The cost is not so much an issue for me, as is convenience. After all, these have a very high cost/performance ratio as is. I don't mind paying extra for the convenience(I'd go for the corcom). Prepay is fine too, so you're not financing us and I don't have any problems with you cooking in some profit for your efforts.
Sheldon |
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| Variac |
Hey Moe 29,
all you need is some heatsink grease no heat pad reqd. In fact the heatpad adds more heat resistance, so is more likely to cook the chip. |
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| BrianGT |
| quote: | Originally posted by moe29
from reading posts in the past, it seems the VM sells at the lowest
cost already - group purchases don't bring the cost down. The
guy has to make a living! :)
They could maybe arrange a special order# so that they know
exactly what transformer to make, and it could cut down on the
lead time - meaning we might get them a little bit faster.
Brian has had lots of dealings with them, so he'd know for sure. |
If people want a common transformer, I can call John and nail down the specifications, and it can be referred to the "Gainclone transformer that Brian ordered".
| quote: | Originally posted by moe29
Even with an insulated case, don't you still need a heat pad, just
for better heat transfer between the chip and the heat sink? |
No, you do not need a heat pad between the 2 surfaces for the insulated chips, but I did use some heatsink compound when I used the insulated chips. I did read that the non-insulated chips have better heat transfer characteristics, so I will stick to these for now.
| quote: | Originally posted by Sheldon
I like this approach too, if you're game. The cost is not so much an issue for me, as is convenience. After all, these have a very high cost/performance ratio as is. I don't mind paying extra for the convenience(I'd go for the corcom). Prepay is fine too, so you're not financing us and I don't have any problems with you cooking in some profit for your efforts.
Sheldon |
I will work out some kits and pricing at the end of the week. I looked into getting pcbs made today, and I am going to go for a 1-week production time frame. As for the prepay, this would work best, due to the large amount of money that I would have to put on my credit card, which would probably max it out.
Does anyone have any numbers for the cost on international shipping? I am willing to do this, as it is paid for. I have filled out custom forms for mailing stuff to Canada and the UK before.
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Brian |
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| PHR |
Thanks for the effort
I am for 6 Kits (added to the wiki page)
Thanks
PHR |
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