Re: High-current connectors
Look at the BOM (bill of materials):
http://www.national.com/appinfo/audio/files/LM4780_BillofMaterials_Web.pdf
They are just standard banana jacks...
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Brian
tcpip said:
Look at the BOM (bill of materials):
http://www.national.com/appinfo/audio/files/LM4780_BillofMaterials_Web.pdf
They are just standard banana jacks...
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Brian
Attachments
mAJORD said:
Do you think this design would have anything on a pair of gainclones? 🙄
There is no telling, but for a bridged/parallel design, the LM4780 seems like a good chip. I am quite curious to see how it sounds, and this seems like the easiest way to try it out.
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Brian
I had a look at the National SIte and could not find the eval board price, there is loads o finfo but the board does not seem to be in the price list. The chips are priced but not the boards, have I missed something?
I hereby express an interest in any 3rd party PCB order that might arise 😉
I hereby express an interest in any 3rd party PCB order that might arise 😉
If an order is generated, here are some prices that I worked up, based on a quote from Advanced Circuits. The price is including tooling, shipping from vendor, and paypal charges.
25 boards - $27.75 each
50 boards - $17.50 each
100 boards - $12.25 each
I don't have time to setup a group order and mail stuff out, but I can help someone else set one up, assuming that there is enough interest.
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Brian
25 boards - $27.75 each
50 boards - $17.50 each
100 boards - $12.25 each
I don't have time to setup a group order and mail stuff out, but I can help someone else set one up, assuming that there is enough interest.
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Brian
wytco0 said:
BrianGT said:
I think National probably only gives away their eval boards via their sales engineers. In fact, I have two Boomer eval boards in front of me that came that way. I did ask about Overture boards and they just laughed at me...
I'd go in for a group order but I don't have time to run one.
Paul
Peter Daniel said:
I'm not big on P2Ping things with more prongs that a porcupine has quills - me peepers aren't that good any more.
So, I had ExpressPCB make a few boards to test my implementation of a parallelled 4780 amp. Here are six of them, panellized:
An externally hosted image should be here but it was not working when we last tested it.
If they work I'm debating a production run, especially if I can chain multiple boards together and parallel several 4780s with relative ease.
oO
😀 peter,Excellent P2P designs! Very compact!!!
what gain setting resistors do you use? 0.1 % is very difficult to look for.
I think gain setting resistors will be very great influence the parallel 4780 amps performance,even exceed the output resistors.
what gain setting resistors do you use? 0.1 % is very difficult to look for.
I think gain setting resistors will be very great influence the parallel 4780 amps performance,even exceed the output resistors.
I'm using Caddocks and Rikens, and I measured them so they matched pretty well. Those Vishays at the input are 0.01% accurate😉
Member
Joined 2002
Peter Daniel said:
Not sure of which capacitance you're referring to, but normally I use 2 1000uF + 2*10pF bypass capacitors, no input cap as the preamp already has a capacitor on the output that blocks the DC.
Almost all it's done in compliance with the datasheet.
It works very well, a little warm but nothing to worry about.
The circuit it's made in p2p with normal components (no smd or exotic parts) and the electrolitycs are panasonic FA series.
The supply is a +- 30V with 2 x 10000uF per rail filter.
bye!
I see peter doing some nice magic with the ICs there...how did they sound?? Especially since you used "good" quality resistors...I'm in for a pair of boards to play around with...so how many boards are we actually looking at here??
I wouldn't have any problem running the group buy for the boards. I already have an account with Advanced Circuits and run to the post office everyday to ship anyway. ;-)
Kevin Haskins said:
Sounds good to me. I created a Wiki here:
http://www.diyaudio.com/wiki/index.php?page=LM4780+Eval+PCB+Group+Order
This should gauge the interest in the order, and see how it will proceed.
I hope this goes through, as I want to try this chip out, without doing it p2p.
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Brian
Ok... thanks Brian. I'll set up a payment form in PayPal for this. I don't think we will have any problem getting at least 25 units.
I might play with the PCB layout a little and scale it down in size. Does anyone really want those banana connectors? I'd ideally also like the LM4780 flush mount against the heatsink and the extra board on that side is just getting in the way.
I might play with the PCB layout a little and scale it down in size. Does anyone really want those banana connectors? I'd ideally also like the LM4780 flush mount against the heatsink and the extra board on that side is just getting in the way.
Kevin Haskins said:
The board could be made quite a bit smaller, and regular pads used for the inputs and outputs. Do you have a way of importing gerber files, or are you redoing the layout? I was going to do my own version of the board, but I haven't had time yet, and I figured that the National design is pretty much guaranteed to work without any problems.
It would definately be nice to be able to flushmount the board against a heatsink without the extra board.
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Brian
Yep, I would agree here too, the board would be alot more usefull if the chips were close to the edge and there were pads ofr more conventional conectors rather than those of the evaluation boards.
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