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GB for DC coupled B1 buffer with shunt PSUs

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A

AndrewT

R.I.P.
Joined 2004
Any 3mm round LED will fit
5mm round LEDs only just fit.
Pin pitch is 0.1" , but 2.5mm will also fit.
Red is lowest voltage of the visible light LEDs and may also be the lowest noise.
Red LEDs do come in different Vf, but this can only be determined after you receive delivery and measure them.
I have had Vf vary from 1.6Vf to 1.9Vf at the same ~4mA current. But within a batch they are surprisingly close.
 
jean-paul

jean-paul

Disabled Account
Joined 2002
Salas said:
Blatant Chinese Mez clone. Finally I am namelessly famous in Taobao LOL

P.S. No its not the same board quality, its not even double sided, and it does not accept the same audio grade relays. The one in the DIYA shop is proper and much better quality. Plus the MOSFETS are not near the edges enough to sink them with anything more than small clip-on sinks. So no hot-rod ability.
Click to expand...

Is it really that important to have a double sided PCB for such a simple design ? I don't encourage copying but I think they could have done worse. Not everyone wants to hotrod. It would be nice to compare this board with an original one.

There are many very good relays with that footprint. Like Takamisawa (now Fujitsu) series that still can be found. For example RY-12W-K.

https://www.fujitsu.com/downloads/MICRO/fcai/relays/ry.pdf
 
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M

m0rten

Member
Joined 2006
I agree with Jean-Paul, and though having no Salas-PCB to compare with, I certainly look forward to listening to this board! If I mount the power FETs from underneath, that will also answer the concerns about sufficient heat-sinking. Except from a few 35 year old SK170 leftover from my first Monster 8W project, many of my components will be "cheap China". :)

[image]Image:Salas clone|none[/image]
 
jean-paul

jean-paul

Disabled Account
Joined 2002
With standard current you can even do without heatsinks but it is advisable to use 4 small ones directly on the MOSFETs (better safe than sorry). AndrewT is 100% right that you will damage this specific board when mounting the parts not as intended. Please use good parts and not cheap stuff as the DCB1 deserves it and part costs are low for this one. Chances are likely that if you keep to analog stuff this DCB1 is the last buffer you will build. With only a handfull of electrolytic caps one better buys Pana FC or the like. Saving on the wrong items really. Secondly you loose credibility and that is enough for some :D

BTW I think you are mistaking: the indicator LEDs are normally used mounted in the front cover to see what you are doing :)
 
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M

m0rten

Member
Joined 2006
Thank you both for good advice and also a very generous offer, Jean-Paul! I just ordered SK170-BL from the seller recommended higher up on this page, and I'll check my caps. I'm sure I can arrange sufficient cooling with top-mounted FETs as well :)
I'll give you my contact info concerning the relays, which I much appreciate!
 
P

polaron

Member
Joined 2013
Hi dear diyers!
I want to post a few links showing where to buy certain parts. These are items that we can't or shouldn't buy in online "boutiques". Online boutiques are great, better for certain products, but not all of them.
So I want, honestly, to know if all these items are the right ones to the buffer, before to order.
Please.
I think they are, but want to be sure. Also, I want to share it and hope that it will helps newcomers.

1) Just a suggestion of upgrading 10R resistor for Hot Rod
http://www.mouser.fr/Search/ProductDetail.aspx?R=MP930-10.0-1%25virtualkey68400000virtualkey684-MP930-10

BTW, when you order more than 50us, (I think it is 50us...), there are no shipping fees.

2) Relays, for 12Volts, when you use these 12V relays in DCB1, you must to solder a wire in the place of that 600ohm parallel resistors, TWO. Explained in the blue boom.
http://www.mouser.fr/Search/ProductDetail.aspx?R=TQ2-12Vvirtualkey66710000virtualkey769-TQ2-12V

3) 12 Volt regulator
http://www.mouser.fr/Search/Product...-DGvirtualkey51120000virtualkey511-L7812CV-DG

4) Mosfets IRF9240 and IRF240
http://www.mouser.fr/Search/Product...BFvirtualkey61370000virtualkey844-IRFP9240PBF

http://www.mouser.fr/Search/Product...PBFvirtualkey61370000virtualkey844-IRFP240PBF

5) 1N4001, near the Relay
http://www.mouser.fr/Search/Product...virtualkey61370000virtualkey625-1N4001E-E3/54



6) Transistors 560, 550 and 517
http://www.mouser.fr/Search/ProductDetail.aspx?R=BC560CTAvirtualkey51210000virtualkey512-BC560CTA

http://www.mouser.fr/Search/ProductDetail.aspx?R=BC550CBUvirtualkey51210000virtualkey512-BC550CBU

http://www.mouser.fr/Search/ProductDetail.aspx?R=BC517_D74Zvirtualkey51210000virtualkey512-BC517D74Z

These are just to help you with the research, I have 100% sure that they are the right parts.

Those litle 0,1uF rectangular film caps near the regulator
http://www.mouser.fr/Search/Product...rtualkey59250000virtualkey871-B32529C1104J189

Now, I've been spending to much money in the past, with fancy parts that don't make a difference. I am learning about it. For example, the 220R resistors, for those who don't know it, are very important and if you put your monrey here, you will be not disappointed. For ex, I bought Vishay nacked foils, in hificollective. But, you can use some resistors that are not expensive at all, resistors that will reward you. They are so cheap, compared to some others, that you can buy them to populate the all board. If you buy those nackeds for signal, it will be better, but if you are in a budjet, you will not be disappointed. I know that you can use them for ex in very good volume attenuators. Sometimes in hifi, you don't need to buy expensive parts for certain needs, and sometimes, where you should put your momey, there are some cheap part that you can use. I am talking about Vishay RN55C or RLR07 types.
In MOUSER website, you can easily find the values you want, with the best prices and you don't have to buy 5000 or 1000 of each item. The links above are just examples. They cost cents!! Well, this is only my point of view, and I'm allways changing.

http://www.mouser.fr/Search/Product...FB14virtualkey61300000virtualkey71-RN55C2213F

http://www.mouser.fr/Search/Product...14virtualkey61300000virtualkey71-RN55C-F-1.0M

http://www.mouser.fr/Search/Product...E6virtualkey61300000virtualkey71-RN55C2203F/R

I hope it helps at least one person and I wait some confirmation, to be sure that I can order. Thank you!

BTW, it you order more than (I think...), 50 us dol, there are not shipping fees.
 
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A

AndrewT

R.I.P.
Joined 2004
polaron said:
Hi dear diyers!
I want to post a few links showing where to buy certain parts. These are items that we can't or shouldn't buy in online "boutiques". Online boutiques are great, better for certain products, but not all of them.
So I want, honestly, to know if all these items are the right ones to the buffer, before to order.
Please.
I think they are, but want to be sure. Also, I want to share it and hope that it will helps newcomers.

1) Just a suggestion of upgrading 10R resistor for Hot Rod
http://www.mouser.fr/Search/ProductDetail.aspx?R=MP930-10.0-1%25virtualkey68400000virtualkey684-MP930-10
Click to expand...
Complete waste of your money. Buy an in specification Metal film 1% 50ppm/C
BTW, when you order more than 50us, (I think it is 50us...), there are no shipping fees.

2) Relays, for 12Volts, when you use these 12V relays in DCB1, you must to solder a wire in the place of that 600ohm parallel resistors, TWO. Explained in the blue boom.
http://www.mouser.fr/Search/ProductDetail.aspx?R=TQ2-12Vvirtualkey66710000virtualkey769-TQ2-12V
Click to expand...
OK.
3) 12 Volt regulator
http://www.mouser.fr/Search/Product...-DGvirtualkey51120000virtualkey511-L7812CV-DG
Click to expand...
OK.
4) Mosfets IRF9240 and IRF240
http://www.mouser.fr/Search/Product...BFvirtualkey61370000virtualkey844-IRFP9240PBF

http://www.mouser.fr/Search/Product...PBFvirtualkey61370000virtualkey844-IRFP240PBF

5) 1N4001, near the Relay
http://www.mouser.fr/Search/Product...virtualkey61370000virtualkey625-1N4001E-E3/54
Click to expand...
OK. but better to use 1n4148 and better still to use 1n4148+Zener
6) Transistors 560, 550 and 517
http://www.mouser.fr/Search/ProductDetail.aspx?R=BC560CTAvirtualkey51210000virtualkey512-BC560CTA

http://www.mouser.fr/Search/ProductDetail.aspx?R=BC550CBUvirtualkey51210000virtualkey512-BC550CBU

http://www.mouser.fr/Search/ProductDetail.aspx?R=BC517_D74Zvirtualkey51210000virtualkey512-BC517D74Z
Click to expand...
OK.
These are just to help you with the research, I have 100% sure that they are the right parts.

Those litle 0,1uF rectangular film caps near the regulator
http://www.mouser.fr/Search/Product...rtualkey59250000virtualkey871-B32529C1104J189
Click to expand...
OK.
Now, I've been spending to much money in the past, with fancy parts that don't make a difference. I am learning about it. For example, the 220R resistors, for those who don't know it, are very important and if you put your monrey here, you will be not disappointed. For ex, I bought Vishay nacked foils, in hificollective. But, you can use some resistors that are not expensive at all, resistors that will reward you. They are so cheap, compared to some others, that you can buy them to populate the all board. If you buy those nackeds for signal, it will be better, but if you are in a budjet, you will not be disappointed. I know that you can use them for ex in very good volume attenuators. Sometimes in hifi, you don't need to buy expensive parts for certain needs, and sometimes, where you should put your momey, there are some cheap part that you can use. I am talking about Vishay RN55C or RLR07 types.
In MOUSER website, you can easily find the values you want, with the best prices and you don't have to buy 5000 or 1000 of each item. The links above are just examples. They cost cents!! Well, this is only my point of view, and I'm allways changing.

http://www.mouser.fr/Search/Product...FB14virtualkey61300000virtualkey71-RN55C2213F

http://www.mouser.fr/Search/Product...14virtualkey61300000virtualkey71-RN55C-F-1.0M

http://www.mouser.fr/Search/Product...E6virtualkey61300000virtualkey71-RN55C2203F/R
Click to expand...
OK, but cheaper to buy in specification metal film 250mW, or 400mW, or 500mW, or 600mW 1% 50ppm/C @ £3/per hundred.
I hope it helps at least one person and I wait some confirmation, to be sure that I can order. Thank you!

BTW, it you order more than (I think...), 50 us dol, there are not shipping fees.
Click to expand...
 
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P

polaron

Member
Joined 2013
AndrewT,
Thanks for the confirmation and new tips.
I'll not buy the caddocks, if you say it's a complete waste of money.

Can't find Metal film 1% 50ppm/C with 5Watts. I tryed several times with filters and nada!
I'll try later. I can't believe that Mouser hasn't them. Was that in Mouser website? May be the UK website, I'll try to find it.
Also, I can't find an option for that option,
"OK, but cheaper to buy in specification metal film 250mW, or 400mW, or 500mW, or 600mW 1% 50ppm/C @ £3/per hundred"
 
A

AndrewT

R.I.P.
Joined 2004
Rapidonline and Farnell sell 600mW 1% 50ppm/C metal film leaded @ ~ £3/per hundred.
Rapidonline recently put up their prices, they were £1.60 per hundred. They have not answered my enquiry about why?

But not metal film 5W.
5W are more likely to be metal wound, or metal oxide, used for source resistors, or heavy loads.

BTW,
three 30r in parallel give the equivalent to 1.8W 10r for ~10pence, or 14cents. Far better stability and accuracy than a mox, or big wirewound.
The Mez PCB has space for three 600mW on the top side and another three on the bottom side for a total 3.6W of Pmax.
 
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P

polaron

Member
Joined 2013
AndrewT said:
Rapidonline and Farnell sell 600mW 1% 50ppm/C metal film leaded @ ~ £3/per hundred.
Rapidonline recently put up their prices, they were £1.60 per hundred. They have not answered my enquiry about why?

But not metal film 5W.
5W are more likely to be metal wound, or metal oxide, used for source resistors, or heavy loads.

BTW,
three 30r in parallel give the equivalent to 1.8W 10r for ~10pence, or 14cents. Far better stability and accuracy than a mox, or big wirewound.
The Mez PCB has space for three 600mW on the top side and another three on the bottom side for a total 3.6W of Pmax.
Click to expand...

Very good tip! I'll check rapidonline and farnel, thanks again.

This is very important, now it is hard and meticulous work, but it gets easy after some practice. This will help me a lot for future orders. So far I was used to buy in fancy boutique web shops and this is a new world for me. I have loooots of projects and this will help a lot. Still like boutique shops, but just when it is necessary. I am very interested in learning where and in what situatuions it is worth to use expensive parts, this is very valuable knowledge. I know that in signal path is allways important. but other than that, it's not obvious. Is there a website for that? Sorry if this goes a litle behond this forum theme, I'll get to the dcb1 context now.
 
A

AndrewT

R.I.P.
Joined 2004
with space for upto 6 dropper resistors on the Mez PCB, you can very easily experiment with a gradual homing in on a hotrodded version.
Fit one 30r and measure/listen.
Add one to give a net 15r, measure and listen
Add another for 10r, measure and listen
Add another for 7r5, measure and listen and check temepratures !
Add another for 6r, measure and listen
Add another for 5r, measure and listen. It will be b....y hot by now.
Each experiment only costs you two more 3p resistors.
If you want to go back a stage because it's too hot or no improvement in sound, then just snip off the two 3p components and bin the refuse.
You still have stock of 90 more.
 
P

polaron

Member
Joined 2013
AndrewT said:
with space for upto 6 dropper resistors on the Mez PCB, you can very easily experiment with a gradual homing in on a hotrodded version.
Fit one 30r and measure/listen.
Add one to give a net 15r, measure and listen
Add another for 10r, measure and listen
Add another for 7r5, measure and listen and check temepratures !
Add another for 6r, measure and listen
Add another for 5r, measure and listen. It will be b....y hot by now.
Each experiment only costs you two more 3p resistors.
If you want to go back a stage because it's too hot or no improvement in sound, then just snip off the two 3p components and bin the refuse.
You still have stock of 90 more.
Click to expand...

AndrewT,
You mean I solder just one 30r, mes/listen, then one by one I add those you mentioned , mes/ and listen? I'll do that.
 
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