Bob Cordell’s BC-1 audio power amp

so the last normal modification of the working circuit will not be here?))
I posted my sim file in the first post

I have an old Pioneer SX-950, uses silver plated switches, every time I turn it on, it gets the silver plated contact wipe routine :) One day it will be serviced.
As far as speaker connectors go, in some cases it depends whats on the other end, what cabling you are using.
I went with ole reliable, two brass/nickel plated Keystone 7019, although the gold ones, 4108,4109 look nice as well.
Member zoji6645, decided he wanted one dual gold binding jack and drew up his .dxf for his back panel to be fab'd.
 
он наверное там был, просто даже просмотрел два листа, такого файла там нет.-)
просто любопытно, ли она сильно отличалась от моей версии.-))
 

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У вас есть основная идея, посмотрите последнюю версию sim-файла. Базовая пробка выглядит ужасно маленькой, 1206?
У вас есть это и работает?
Where's the google translator plug-in? I guess that goes along with the gerber viewer too.
 

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Hi Rich,

I anticipate ordering your board kit a few weeks from now and believe it's a good deal. There's intrinsic value in the boards themselves and the BOM. Furthermore, I fully appreciate the IP inherent in a proven layout and the effort required to realize it. Kudos!

My interest in a group buy is solely for the quantity discounts on the electronic parts. I have no experience with group buys; I would probably salvage an enclosure rather than opt for the hifi2000 Dissipante chassis. No doubt other members would prefer their own deviations from a uniform recipe. My son would say "Maybe the juice isn't worth the squeeze." ;)

Best regards,

Steve
 
Group buys are usually for blank pcbs or fully assembled, but can be anything depending on whats involved. Say if someone is wanting a group buy on a pcb blank, they get a list together, enough for say a batch of boards, get them ordered to one address, ask for $ to be sent, paypal? then that person sends them to each person on the list. Even though ebay charges an arm & a leg, the process is streamlined.

The pcbs were designed specifically for that chassis, if you deviate on the chassis, then you are now the MEng.
 
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Hi,

For me the mechanics is the hardest part ( I hope ).

So a group buy of a predrilled an tapped enclose might be a good idea. Problem might be to agree on what contacts to use.

I like balanced inputs which the bc1 doesn't have. And I like the neutrics speacon connectors. But that's me...
To start with I will use a Lundahl transformer to get balansed input, while planning for a more permanent solution.

/örjan
It would be fairly easy to build a small board and hang on the Neutric with an OP derived balanced to single ended converter IC. Not even necessary to design a board but do it on VERO if using DIP capsules. There is more or less esoteric ICs available.
THD is significantly better than a Lundahls but perhaps not to taste.
 
@rikkitikkitavi

Hi,

I probably should concentrate on getting the bc1 built as is.

Yes the lundahls are just planned to be a short time solution and I already have them.

If I was going for a really good cmrr I probably go for an that 120x or similar, but hang it on input of bc1 and run balanced cables as long as possible.

Or I could try out something like figure 30.4 in the second edition. Perhaps not as good cmrr but good enough for home use.

Then I have to check for noise. But at this point of time just ideas, I have to build the bc1 first ;)

/örjan


.
 
Have just ordered the Dissipante case and base plate for shipping from Italy to the UK. The cost of shipping is 33 Euros. I note that the copy of your invoice is $8.22 American (albeit on 14/01/2021). A significant difference..........so get yours ordered before the prices rise again!
 
That invoice was for buying the chassis for Bob from DIYAudio store, which includes the shipping cost, only for US customers or addresses as in this case. The additional shipping costs shown on the invoice are for the base plate addition to the order.
Since I live in Canada, DIYAudio would have charged me for chassis shipping costs, so I bought mine as you have done directly from hifi2000 where I paid substantially more, probably more than you have but I would have to look to see what it was at that time. It’s a heavy chassis and it’s big so costs are what they are.

Rick
 
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I agree everything has gone up from only a few years ago and the trend just continues. Also parts are being discontinued as well, so it’s dynamic in that regard.
Let me know how your parts sourcing is going since I know onsemi and nichicon has long leadtimes.
I just wanted to point out to you and others that the $8.22 was only for additional shipping cost of adding the base plate to the order from DIYAudio. I could or should have shown what I paid for my chassis directly from hifi2000 but the intent was to show what was ordered.
 
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I found my chassis receipt from May 17,2021,
Dissipante 03/300N 3U 10mm BLACK
Item# 1NPD03300N
€126.00 EUR1€126.00 EUR
Inner baseplate for Dissipante 300mm
Item# 1BASEPD300
€13.00 EUR1€13.00 EUR
Shipping, Handling, Discounts & Taxes€54.00 EUR1€54.00 EUR
Subtotal€193.00 EUR
Total€193.00 EUR
Payment€193.00 EUR
Funding Sources Used (Total) Additional balance$296.09 CAD Exchange rate: 1 CAD = 0.651819 EUR Converted From:$296.09 CAD Converted To:€193.00 EUR. This rate includes a currency conversion fee.

They have the bjt process down pat, most parts on a tape are within a mV or two of each other from what I have found, sounds like you are getting similar results
 
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With Vbe matching sorted, next question.

Snubbers in the PS card. Is it correct that only on of the set snubbers; c7.8, c13,14 ( over rectifiers ) or c1,c2, r1 and c18, c19, r6 ( parallel with secondaries ) are used. and not both?

If any of previous builders has used the snubbers parallel with secondaries, what was the component values? I plan to measure myself and understands it depends on the chosen transformer.

/örjan
 
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