Thanks. Here's a version that would support an MPC resistor with 10mm lead spacing. It's based on the footprint of the TE Connectivty resistor
(HPR5RSR47J Product Details - TE).
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Hello everyone,
I am considering building this for my next power amp project. I have a recent thread on here detailing my ESP P3A build, which I am very happy with, but would like to try something more powerful this time. A few questions:
- Where can I buy PCBs from? Jim's Audio has supposedly "official" boards for sale and they seem to be of high quality. He seems to have get a bad rap here though. I have sent alex mm a message and await his reply.
- What is the best way to source matched output transistors? I can buy a roll each of 3281A/1302A and match them myself. But it is expensive to buy 50 transistors when I only require 20.
- Would two heatsinks (one per channel) be sufficient for this amplifier? Each heat sink is 300x75mm with 48mm deep fins and a thermal resistance of 0.37 C/W. I used only one of this same heatsink for stereo P3A build and it barely gets warm and normal volumes. If this is inadequate, would a 300x151mm and 0.25 C/W heat sink suffice?
- What transformer would you recommend? I was thinking of either 2x 300VA or 1x 500VA toroidal. I'll only be driving 4-8 ohm speakers and don't require 2 ohm stability. 200W @ 8 ohm or around 300W @ 4 ohm is my target.
- I see that each board has space for 2x 10,000uF / 100V filter caps (40,000uF in total). Is there any benefit to mounting the filter caps separately, or having a bank of "prefilter" caps as well?
I am considering building this for my next power amp project. I have a recent thread on here detailing my ESP P3A build, which I am very happy with, but would like to try something more powerful this time. A few questions:
- Where can I buy PCBs from? Jim's Audio has supposedly "official" boards for sale and they seem to be of high quality. He seems to have get a bad rap here though. I have sent alex mm a message and await his reply.
- What is the best way to source matched output transistors? I can buy a roll each of 3281A/1302A and match them myself. But it is expensive to buy 50 transistors when I only require 20.
- Would two heatsinks (one per channel) be sufficient for this amplifier? Each heat sink is 300x75mm with 48mm deep fins and a thermal resistance of 0.37 C/W. I used only one of this same heatsink for stereo P3A build and it barely gets warm and normal volumes. If this is inadequate, would a 300x151mm and 0.25 C/W heat sink suffice?
- What transformer would you recommend? I was thinking of either 2x 300VA or 1x 500VA toroidal. I'll only be driving 4-8 ohm speakers and don't require 2 ohm stability. 200W @ 8 ohm or around 300W @ 4 ohm is my target.
- I see that each board has space for 2x 10,000uF / 100V filter caps (40,000uF in total). Is there any benefit to mounting the filter caps separately, or having a bank of "prefilter" caps as well?
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Fitter maybe,me personal don't like those big caps direct on the boards due the charging currents,I could be wrong.
I do think Fabio Zimmer, from Brasil, has pcboards.
Also Juan Vargas from Puerto Rico.
But i am afraid to say we cannot give you guarantee the pcboards will arrive your place..some shipments fails and we do not trust into Brazil interface with UPS and other international systems.... even inside Brasil....from Brasil to Brasil, we are having troubles...so...i do blame Brazilian system first...but also UPS have failed twice.
From USA... from UPS.... a package of pcboards have arrived in Brasil, delayed 192 days.
So... we can guarantee we ship them...with pictures and documents...but we cannot guarantee the arrival as we will not go to travel to your place with the package in our hands.
I have lost three packages, one from Canada, other from Puerto Rico and one more from USA....so... we decide not to ship or to inform the guy that gonna order the risk will be for him, as we have no conditions to track and to give any kind of guarantee of arrival...we just can prove we have shipped with documents of shipment...anything more.
Meanman had pcboards...also Byron from USA... these ones have gerbers.
Fabio Zimmer has asked layout (not gerbers) to prepare a batch of boards to provide his close friends and himself..he have ordered 30 pcboards..i do imagine he may have 8 units left aproximatelly..as he ordered more than he needed to reduce cost of production of pcboards.
If you want to take the risk (to yourself) then go to:
Fábio Zimmer
imap.eletro@gmail.com
Juan Vargas Diaz
vargasmongo@yahoo.com
vargasmongo@gmail.com
If Alexmm agree, then i will provide you all (the ones post they want, using direct email adress) gerbers for you to order by yourself and provide to others without profit.....not allowed, no permission to sell them with profit... just include your personnal costs to produce test prototype, photolite master image, shipment cost, your gasoline spent for that purpose and all costs to obtain boards to share...of course you can have your set for free sharing this cost in between the group buy personnel.
I will make contact direct with the ones ask gerbers, a personal intervue to try to detect intentions... an effort to avoid this to go to pirate's hands.
carlos.eugenio1951@gmail.com
But this will happens, ONLY IF, Alexmm post, clear and without any doubts, he agree with that.
I would also love to listen what Meanman thinks about that.
regards,
Carlos
Also Juan Vargas from Puerto Rico.
But i am afraid to say we cannot give you guarantee the pcboards will arrive your place..some shipments fails and we do not trust into Brazil interface with UPS and other international systems.... even inside Brasil....from Brasil to Brasil, we are having troubles...so...i do blame Brazilian system first...but also UPS have failed twice.
From USA... from UPS.... a package of pcboards have arrived in Brasil, delayed 192 days.
So... we can guarantee we ship them...with pictures and documents...but we cannot guarantee the arrival as we will not go to travel to your place with the package in our hands.
I have lost three packages, one from Canada, other from Puerto Rico and one more from USA....so... we decide not to ship or to inform the guy that gonna order the risk will be for him, as we have no conditions to track and to give any kind of guarantee of arrival...we just can prove we have shipped with documents of shipment...anything more.
Meanman had pcboards...also Byron from USA... these ones have gerbers.
Fabio Zimmer has asked layout (not gerbers) to prepare a batch of boards to provide his close friends and himself..he have ordered 30 pcboards..i do imagine he may have 8 units left aproximatelly..as he ordered more than he needed to reduce cost of production of pcboards.
If you want to take the risk (to yourself) then go to:
Fábio Zimmer
imap.eletro@gmail.com
Juan Vargas Diaz
vargasmongo@yahoo.com
vargasmongo@gmail.com
If Alexmm agree, then i will provide you all (the ones post they want, using direct email adress) gerbers for you to order by yourself and provide to others without profit.....not allowed, no permission to sell them with profit... just include your personnal costs to produce test prototype, photolite master image, shipment cost, your gasoline spent for that purpose and all costs to obtain boards to share...of course you can have your set for free sharing this cost in between the group buy personnel.
I will make contact direct with the ones ask gerbers, a personal intervue to try to detect intentions... an effort to avoid this to go to pirate's hands.
carlos.eugenio1951@gmail.com
But this will happens, ONLY IF, Alexmm post, clear and without any doubts, he agree with that.
I would also love to listen what Meanman thinks about that.
regards,
Carlos
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