| DWong |
Peter,
Would you please let me know when will you ship out the kits for international orders?
Dennis |
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| Peter Daniel |
| I'll do that tomorrow. |
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| DWong |
| Many Thanks! Peter. |
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| Maurice |
Peter,
I am sorry to post this here. I had put an order for LM3875 kit on 28 Oct. I am just curious whether you are taking care of the order for the LM3875 kit as well as LM4780 kit.
If you are not, I would appreciate if you let me know who are. I've already sent an email to Mr. Bell without any reply so far. Thanks, |
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| m0tion |
| I'm very interested in hearing some outside reviews from these new LM4780 kit recipients, anyone completed their amp yet? |
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| Vuamp2 |
I got my LM4780 kits from Brian today when I got home. They look FANTASTIC!!!:smash:
To bad I can't work on them until this weekend :bawling:
Thanks Brian. |
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| Peter Daniel |
| quote: | Originally posted by Maurice
I had put an order for LM3875 kit on 28 Oct. I am just curious whether you are taking care of the order for the LM3875 kit as well as LM4780 kit.
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I sent out all the orders placed untill November 1st. It seems like the intererst with GC in South Korea increases, as I had at least 5 orders from there.
So, if you placed the order on Oct28, it's been shipped out already. |
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| DWong |
Peter,
I received your kit today and it looks great! But unfortunately I found one 10k mute resistor is missing (only one in the bag).
Dennis |
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| jmateus |
Hi Peter
I've been away from the forum for a while so I don't know anymore who sells the boards or who makes them.
But by reading the previous posts I take it that you have some
direct part in distributing these boards for the parallel 4780 amp.
If so, can I bother you to tell me how to order 2 of these boards
and who from?
I'd appreciate. |
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| BrianGT |
| quote: | Originally posted by jmateus
Hi Peter
I've been away from the forum for a while so I don't know anymore who sells the boards or who makes them.
But by reading the previous posts I take it that you have some
direct part in distributing these boards for the parallel 4780 amp.
If so, can I bother you to tell me how to order 2 of these boards
and who from?
I'd appreciate. |
Hello,
I am handling the US orders, and Peter is handling the International orders. I have more information and an order form on my website:
www.chipamp.com
Let me know if you have any more questions.
--
Brian |
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| Peter Daniel |
| quote: | Originally posted by DWong
Peter,
I received your kit today and it looks great! But unfortunately I found one 10k mute resistor is missing (only one in the bag).
Dennis |
Sorry about that. Do you want me to send you another one, or you can source it locally? |
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| Andypairo |
| quote: | Originally posted by BrianGT
Hello,
I am handling the US orders, and Peter is handling the International orders. I have more information and an order form on my website:
www.chipamp.com
Let me know if you have any more questions.
--
Brian |
Brian, did you get my emails?
Cheers
Andrea |
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| BrianGT |
| quote: | Originally posted by Andypairo
Brian, did you get my emails?
Cheers
Andrea |
Yes, I just sent a reply.
--
Brian |
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| x. onasis |
I have 4 toroids onhand. Two ea. of 18 and 25V, 250VA, and was planning on using the 18V for 3875kits.
Now as I'm ready to assemble the two 4780 kits I have, I'm wondering...
Should I use both rectifier boards with one 250V 25-25 tranny, or just one? Is there a difference?
What would be the benefit of dual mono compared to this? Is this something I should try and and share my results? Or is this obvious to you experts? |
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| ShieldJaguar |
| Sorry ignore, wrong thread :angel: |
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| jmateus |
Hello Brian
Thanks for the info.
I already pleced my order through the web site.
Thanks again |
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| Vuamp2 |
Hello All, :smash:
I just finish the LM4780 AMP using BrianGT kits. Just the gut for now (no chassis). They have been working for ~ 20 minutes now and they sound great. The temporary heatsink seem to be too small for this amp and seem to get hot very quick.
As you can see from picture, I only use half of the rectify board to drive one channel. How much will this impact the ovarall sound quality?
You can see picture at 
Thanks Brian. It only take me ~30 minutes to put one amp PCB together :D |
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| cdoggy81 |
x. onasis, good question.
IIRC Peter did some dual mono designs & recommended them. |
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| m0tion |
| I don't think your webshots link works... |
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| yutty |
| How to do with mute resister ? Does it have to solder at copper side of PCB ? |
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| Vuamp2 |
| quote: | Originally posted by m0tion
I don't think your webshots link works... |
Try this  |
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| m0tion |
damn THAT heatsink gets hot? do you have more than one chip attached to it?
Correct me if I'm wrong, but that is a Leach Superamp in your webpics as well is it not? Very nice pcb, where did you get it? |
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| Evilsizer |
my thoughts exactly on cooling that chip seeing how i have two of those heatsinks. im going to add fans 80x80x25mm (40cfm 12vDC) @6v should give about 20 cfm and be really quite too.
edit:
@motion
that heatsink mayget warm but not sure how hot. dont know how to make out the c/w with out a fan but @ overclockers.com its rated at .45 c/w that is an older ver. of it though, in there tests. Its a P4 heatsink that comes with cpu's as fast as 2.8ghz. The fan is around 30cfm if i remember correctly. |
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| Vuamp2 |
| quote: | Originally posted by m0tion
damn THAT heatsink gets hot? do you have more than one chip attached to it?
Correct me if I'm wrong, but that is a Leach Superamp in your webpics as well is it not? Very nice pcb, where did you get it? |
There are two albums at this site. One is my Leach Super Amp and the other is LM4780 GainClone (BrianGT LM4780 kit).
My LM4780 GainClone get to 69 degree C after it ran for an hour. This is hot! I need to use a lager heatsink. :D
I have several extra Leach Super Amp PCBs. Email me if you interest. |
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| m0tion |
| I am actually, very, but I'm unable to e-mail you via this forum (it won't allow me to see your e-mail address). Please e-mail me at the address you would like me to reply to. You can find my e-mail address on my website (sig) on the front page under "contact", or simply click on my username on this forum. =) |
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| D_GR8_1 |
Hey Brian, Peter D.,
Is it possible for you to provide the Gerber files or PCB schematic for the LM4780 board.
I like making my own PCB's however I need the proper 1:1 scale when transfering the design to the copper board.
Also, can you indicate which software you used for designing those PCB's?
Thanks. |
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| D_GR8_1 |
Yeah, I've seen the pdf, but I cannot modify the board on the pdf.
Brian is using certain resistors & capacitors which a rarety "down-under", so I may need to change some footprints.
That's why I was asking for the actual PCB file. |
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| Peter Daniel |
I'd rather send you those rare resistors & capacitors, than release the actual gerber files ;)
Sorry |
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| D_GR8_1 |
So you release a pdf of a 1:1 scale of the schematic, however you wont release the software version?
Why? Its not a top secret NASA project. We know what the circuit looks like, what the schematic looks like, by releasing the Gerber files you will save me a couple of hours of actually going to Protel and replicating the PCB.
That's all.
By the way, can you at least tell me where can I find a SPICE model for the LM4780? Or which footprint you used to create the pinouts? |
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| D_GR8_1 |
National can release Gerber files of their LM4780 evaluation board and you cannot.:confused:
I am not asking you to send me a free PCB, I just need to change a few things.
Thats all.:smash: |
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| grege |
| quote: | Originally posted by D_GR8_1
National can release Gerber files of their LM4780 evaluation board.....
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Hey, the great one, I think you solved your own problem, start with National's. :D |
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| m0tion |
GR8_1:
I think fundamentally I understand and agree with what you're saying, but one's own property is one's own property. In the end it's the owner's perogative who should have possesion of it. |
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| peranders |
| quote: | Originally posted by D_GR8_1
National can release Gerber files of their LM4780 evaluation board and you cannot.:confused:
I am not asking you to send me a free PCB, I just need to change a few things.
Thats all.:smash: |
Notice that everyone here share as much as he wants to. The only thing you can do is ask nicely and a no is a no. |
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| peranders |
| quote: | Originally posted by D_GR8_1
Why? Its not a top secret NASA project. We know what the circuit looks like, what the schematic looks like, by releasing the Gerber files you will save me a couple of hours of actually going to Protel and replicating the PCB.
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I'll guess you have to sacrifice those hours it takes for this "simple" layout.
Sometimes (often) people don't realize how much time it takes for a layout. You don't really see problems when they are solved, not matter how complicated or simple the layout was. |
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| Peter Daniel |
I wouldn't have a problem with releasing Gerber files, if this was completely diy effort. However, the board is actually a commercial product of chipamp.com and releasing such files negates the commercial nature of the product. This should be pretty obvious.
If you have any experience with Protel, or any other PCB software, coming up with a similar layout shouldn't present a problem, especially when pictures of the layout were posted and PDF files are available. Even if you have to spend couple hours doing that, it's still nothing compared to countless hours Brian and me dedicated to optimize that layout.
Please contact Brian directly for LM4780 pinout, as he was developing all the footprints. |
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| BrianGT |
| quote: | Originally posted by Peter Daniel
I wouldn't have a problem with releasing Gerber files, if this was completely diy effort. However, the board is actually a commercial product of chipamp.com and releasing such files negates the commercial nature of the product. This should be pretty obvious.
If you have any experience with Protel, or any other PCB software, coming up with a similar layout shouldn't present a problem, especially when pictures of the layout were posted and PDF files are available. Even if you have to spend couple hours doing that, it's still nothing compared to countless hours Brian and me dedicated to optimize that layout.
Please contact Brian directly for LM4780 pinout, as he was developing all the footprints. |
I agree with this post. I am willing to share the footprint libraries that I made for this project for the LM4780 if you need them, but don't feel that I can provide the full layout. Drop me an e-mail.
--
Brian |
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| D_GR8_1 |
| quote: | | I wouldn't have a problem with releasing Gerber files, if this was completely diy effort. However, the board is actually a commercial product of chipamp.com and releasing such files negates the commercial nature of the product. This should be pretty obvious. |
That's right, this little detail actually slipped my mind.
Sorry bout that.
:) |
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| SheldonD |
Insulators for lm4780
Peter/Brian
Were you ever able to source insulator pads for LM4780? |
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| Peter Daniel |
We never really came to any final conclusion with regards to that.
There are two choices, I see at the moment. One can use two aluminum oxide pads (TO-247 package), but wen you put them side by side (as that's required to match chip surface) the hole spacing is more than on a chip, so additional press bar on top of the chip is required (with two screws).
Another option are the insulated sheets, that had to be cut to size and holes made (as Upopa suggested with a nail ;)). If somebody, who ordered kits from me, has a problem with sourcing those, drop me an email and I'll send you this insulator material. |
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| jajabin |
Hi Peter & Brian,
Sorry to ask one more time.
Is the bridging board project for 4780 still under construction?
Haven't heard you guys talk about it for a while....
Not rushing, just wonder.
Thanks
Wing |
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| Peter Daniel |
The bridging board is definitely in the plans, but I didn't have much time recently to play with it. I received today a transformer that could be used for splitting single ended signal into balanced and will see how this works: http://www.edcorusa.com/transformer.../wsm10k-10k.htm
I will be not pursuing DVR134 option, as this has been already taken care of by digi01. His little boards are cute and present good value.
I will try to come up with some other solution, which is more of a challenge ;) |
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| tiroth |
I am afraid that the Edcor transformers are, well, not very exciting. Note however that only the Talema and Edcor results are from my testing; the Cinemag and Jensen are from the datasheets. But I will probably buy some Cinemags in the near future.
As you can see I had significantly better LF performance from the Talema at roughly the same cost. |
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| m0tion |
| I'm sorry, I'm a bit slow. Is a balanced line driver related to the bridging board project? What would the transformers you guys are talking about be used for? |
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| lgreen |
Maybe I'm also a bit slow, but I dont see a schematic for the boards? I see the layout, but is there a schematic showing the full circuit with labels corresponding to the layout and silk screen?
It would be really helpful if there were.
Also, I see the parts list on chipamp.com and some values don't match up to the National data sheet. Trying to figure out which parts to use where is a little tricky w/o a schematic. Maybe I missed the schematic after browsing page after page of this thread? |
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| Peter Daniel |
Brian is coming up with a manual. In the meantime I posted the National's schematic here : http://www.diyaudio.com/forums/show...1639#post501639
and the description of parts we supply with a kit. I believe the only difference is 680ohm gain setting resistor (National recommends 1K). We decided on 680R, similarly as with a previous kit, to get more gain from the amp. |
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| TPM |
In order to save some time for others a road map follows.
PCB National schematic Value
R1 RF1 22k
R2 RF2 22k
R3 Ri1 680
R4 Rin 22K
R5 Ri2 680
R6 Rb1 1k supplied parts list indicates 2k.
R7 Rb2 1k see above
R8 Rout1 0.1
R9 Rout2 0.1
My kits only came with one 10k muting resistor which is through hole, I'm sure I have a few in the parts bin so should be OK. There seems to be only a provision on the board for an SMD muting resistor. I'm assuming that I'll attach the 10k directly to the pins of the LM 4780 or would one be able to tack it to the SMD pads?:confused:
For those of us who will use the Zobel, it appears as though we need to connect the capacitor to ground via a piece of hook up wire running on the bottom of the PCB. I'm assuming og.
I hope someone will confirm the correct road map above is correct, I'd hate to steer people wrong, and hope someone can confirm my assumptions as well.
Thanks
T:clown: |
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| SheldonD |
the zobel circuit does not matter which is resistor or cap to ground
I found circiuit is fine no jumper needed, tho momentary confusion about extra hole for cap but extra hole must be for longer lead span on different size cap.
I applied 2 pads with solder, then bent the leads tight on muting resistor and then bent lead to make 2 "knees". One touch on the solder pad and it sucked lead on, almost like smd. They are barely off the board.
I also found it convenient to use the solder side for zobel resistor
the leads can be much shorter. |
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| TPM |
Thanks Sheldon I see how the zobel cct is laid out. I hadn't traced it out right:smash:
T |
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| yldouright |
| I have the original Aleph-X circuit boards from "hi-fi Zen". I am looking to trade them for a set of the latest rev BrianGT LM3875 Gainclone boards so contact me if you have them and are interested in trading. |
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| brentw |
Speaking of heatsinks for the L4780... I like this little guy.
http://www.coolermaster.com/index.p...-01CPU%20Cooler
Most local computer shops will stock this CPU heatsink and it is less then $10 US with the fan. If you run the fan at a slow enough speed you don't hear it. I power the fan from an old wall adapter from an external modem. Resister in series to slow it down.
Notice the copper at the bottom of the heat sink. It is actually pretty beefy. It is 50mm x 45mm and 4mm thick. It is screwed on with 4 screws. The spacing of the screws is 1mm short of the spacing between the two screws for a L4780 chip. To solve that you take a metal hacksaw blade and cut into the chip by 1mm. Put a little paint on the now exposed metal where you hacksawed. Two L4780 chips fit on the heatsink. There you have it, a nice little, inexpensive heatsink. No drilling or hole tapping required. To bad about the sawing, but that is minor.
If you want to insulate the chip from the heatsink then I suggest you put your insulating materal between the copper and the heatsink. If you use an old computer power supply case like I do in the picture below then all you have to do is drill 4 holes in the case and screw it on. The case is thin enough to transfer the heat through the case. The chunk of copper directly attached/touching the L4780 chips provides a nice heat buffer/transfer to the rest of the heatsink/case.
Most of my amps are not in cases, because I am still messing with them. Using this small heatsink makes it easy to handle them and use them without a case.
If you try it, let me know how you like it.
 |
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| rabstg |
Hi brentw-
That looks nice.
If you rotate the heat sink 90* so the fins are vertical, convection cooling will continue even if the fan fails. |
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| digi01 |
Hi Brian,I got these boards today,thank you.
rgds
digi |
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| Andypairo |
After a long wait at last my boards arrived... thank you Brian!
Cheers
Andrea
PS Did you get the chips I sent you? |
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| Russ White |
Brian, Anyone, Will you be selling these PCBs any more. I need a few. :) I will probably build Pavel's PA03 to get my fix. :D
Thanks,
Russ |
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| BrianGT |
I will begin selling boards again soon. I will post details soon, hopefully by the end of the week. I am also going to get some boards made for the LM3886 layout I did a while back.
--
Brian |
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| UrSv |
Good news.
I'll definitely get a couple of LM3886 boards. |
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| rabstg |
| quote: | Originally posted by BrianGT
I am also going to get some boards made for the LM3886 layout I did a while back.
--
Brian |
Please share some pictures or planned PCB with us! |
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