I guess you are referring to me, but sorry sir, I dont have that amp's schematic.
reg
Prasi
Hi Camelator,
Good to see you over here, like me, we both came from years of class D amplification using mostly TI's TPA311x series, while excellent sounding, cannot match the bass and dynamics of the nice class AB or class A designs around here.
For all 1% resistors, 2W/3W/5W/10W power resistors, most electrolytic caps, most small signal transistors (BC546, 2N5401, MPSA42/92, etc...) you are fine getting them a bag of 50 for $3 from Aliexpres (Ali). Get the complete assortment of 1% 1/4 resistors. Get a bunch of 47uF, 100uF, 220uF, 470uF, 1000uF 50V or 63V caps. Don't forget small bypass caps like 100nF 100V (orange drops) you use a lot of those, 330pF, 100pF, 4.7pF, 220pF, etc ceramic caps, then get some poly film caps for the audio signal input: 1uF, 2.2uF, 3.3uF, 4.7uF. The best deal on Ali are things like a box of 50 PCB mount multiturn trim pots for $5. Try getting that price on Mouser or Farnell. Also, heatsinks are a good thing to get from Ali, can't fake those. Can a pot be faked? Doesn't matter as long as the resistance is adjustable and stable. Even the medium power transistors like BD139/140 or TIP40/41, etc. are fine from Ali. Where you might run into trouble are output stages like 2SC5200 and 2SCA1943. I got shipped some fakes and they died after 10 seconds. Ali gave me a refund. Things like 5mm spacing terminal blocks, PCB spade conectors, 12v Zeners, 1n4148's are all good from Ali and it's pennies on the dollar. You must be willing to wait 3 weeks though. If its urgent, buy from local vendor. I have outfitted my parts supply cabinet for maybe 10% of cost to do so from Digikey/Mouser/Newark. Just got o Aliexpress and type in seach bar name of part like BD139, select free shipping filter, select sort low price to high. Choose and buy. I have stuff coming in everyday, it's kind of fun to see what surprises the post brings each day in the ubiquitous little yellow padded envelopes.
For PSU, you need big good caps. Look for 4700uF 50V Nichicons, Panasonics, Elna, etc. get at lest 4. Get some big high current diodes and make your rectifier bridge rather than a one piece bridge.
There are plenty of PSU designs around, I used Carlos' Dx PSU because it is simple. Like you, I wanted to use SMPS, but they are not very good for class AB or class A. Get a toroidal transformer (I know they are the big bux in this hobby) - I got an Avel Lindgergh 250VA, +/-25VAC one for $50 and it has served me well. Check out Antek for cost effective power trafos. I got a 300VA +/-32V one for $50 as well direct from Antek. They are US based so you will need to find a company in Europe to keep shipping costs down.
Good luck!
Regarding fakes: I measure all the stuff I get with an RLC meter or a transistor checker. Everything has been good except for that one order of the big Toshiba 2SC5200/2SCA1943's. 98% success rate, and 6 amps to prove it... 🙂
Good to see you over here, like me, we both came from years of class D amplification using mostly TI's TPA311x series, while excellent sounding, cannot match the bass and dynamics of the nice class AB or class A designs around here.
For all 1% resistors, 2W/3W/5W/10W power resistors, most electrolytic caps, most small signal transistors (BC546, 2N5401, MPSA42/92, etc...) you are fine getting them a bag of 50 for $3 from Aliexpres (Ali). Get the complete assortment of 1% 1/4 resistors. Get a bunch of 47uF, 100uF, 220uF, 470uF, 1000uF 50V or 63V caps. Don't forget small bypass caps like 100nF 100V (orange drops) you use a lot of those, 330pF, 100pF, 4.7pF, 220pF, etc ceramic caps, then get some poly film caps for the audio signal input: 1uF, 2.2uF, 3.3uF, 4.7uF. The best deal on Ali are things like a box of 50 PCB mount multiturn trim pots for $5. Try getting that price on Mouser or Farnell. Also, heatsinks are a good thing to get from Ali, can't fake those. Can a pot be faked? Doesn't matter as long as the resistance is adjustable and stable. Even the medium power transistors like BD139/140 or TIP40/41, etc. are fine from Ali. Where you might run into trouble are output stages like 2SC5200 and 2SCA1943. I got shipped some fakes and they died after 10 seconds. Ali gave me a refund. Things like 5mm spacing terminal blocks, PCB spade conectors, 12v Zeners, 1n4148's are all good from Ali and it's pennies on the dollar. You must be willing to wait 3 weeks though. If its urgent, buy from local vendor. I have outfitted my parts supply cabinet for maybe 10% of cost to do so from Digikey/Mouser/Newark. Just got o Aliexpress and type in seach bar name of part like BD139, select free shipping filter, select sort low price to high. Choose and buy. I have stuff coming in everyday, it's kind of fun to see what surprises the post brings each day in the ubiquitous little yellow padded envelopes.
For PSU, you need big good caps. Look for 4700uF 50V Nichicons, Panasonics, Elna, etc. get at lest 4. Get some big high current diodes and make your rectifier bridge rather than a one piece bridge.
There are plenty of PSU designs around, I used Carlos' Dx PSU because it is simple. Like you, I wanted to use SMPS, but they are not very good for class AB or class A. Get a toroidal transformer (I know they are the big bux in this hobby) - I got an Avel Lindgergh 250VA, +/-25VAC one for $50 and it has served me well. Check out Antek for cost effective power trafos. I got a 300VA +/-32V one for $50 as well direct from Antek. They are US based so you will need to find a company in Europe to keep shipping costs down.
Good luck!
Regarding fakes: I measure all the stuff I get with an RLC meter or a transistor checker. Everything has been good except for that one order of the big Toshiba 2SC5200/2SCA1943's. 98% success rate, and 6 amps to prove it... 🙂
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Look at Tayda.com. Best price on genuine Renesas latfets and good prices on resistors and such.
Sorry, I typed that from bed on my tablet. Should have looked it up first. They have a warehouse in Colorado so a lot of their stuff ships quickly here in the states.
No worries, nice website! Thanks for the tip. I can see that it looks very good for the budget amp builder. I need some volume knobs and $0.49 is the right price 🙂
If you say the Renesas are genuine then $5 for the 2SK1058 or 2SJ162 is a very good price as well...
😀
you generally don't get 1/2W or 1W MFR(of various values) in India, Tayda is a good site! (for Indian DIYers), only i wish they expand to e24 series...
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HI XRK971, many thx for your support 🙂
as I am new here, I have to work hard to build this amp!
So by advance, excuse me for stupid question or repeated questions.
So, here is the results of my study and blocking points:
p { margin-bottom: 0.25cm; direction: ltr; line-height: 120%; text-align: left; }a:link { color: rgb(0, 0, 255); } 1/ Sprint File
I think this one is the most recent,
http://www.diyaudio.com/forums/soli...imate-fidelity-amplifier-652.html#post4641883
unfortunately, I think it is not updated,
I am very curious, what tool do you use for the design?
1/ BOMs :
Please, can someone confirm this is the right BOM :
http://www.diyaudio.com/forums/soli...imate-fidelity-amplifier-654.html#post4642711
T4 and T5 has been removed from v1.1 to v1.3 but I don't understand why… Is it a bug ? Or maybe is it because it was changed for 2SA1360 as suggested here
http://www.diyaudio.com/forums/soli...imate-fidelity-amplifier-654.html#post4642209
but unfortunately, 2SA1360/2SC3423 look hard to find,
is it really better than BD139/BD140 ? any other alternative for BD139/BD140 ?
2/ PCB
Here is my GERBER file, I ordred the boards at seed
http://www.diyaudio.com/forums/soli...imate-fidelity-amplifier-651.html#post4641450
PCB Thickness: 1.6mm
PCB Qty.: 10
PCB Color: Green
Surface Finish: Hasl
Do you think it is ok?
3/ Heatsink
I found this one, do you think is it suitable ?
( Offre spciale ) de haute qualit 150 x 60 x 25 mm radiateur dissipateurs en aluminium extrud dissipateur de chaleur profil pour dissipation de la chaleur lectronique dans Ventilateurs & refroidissement de Matriel informatique et logiciels sur A
4/ BIMO Mod
I red posts about BIMO mod, is it really better? Do I have to build this one instead the regular FX8?
5/ Capacitor improvements
I red here adding capacitors bring improvements,
http://www.diyaudio.com/forums/soli...imate-fidelity-amplifier-704.html#post4680132
Is it any recommandations for the choice of capacitors?
Well...
Any other comments are very welcome! 🙂
many thx everybody!
you can find these references "Reichelt Elektronik" renewed by "Inchange Semiconductor".
SA 1360: Transistor 2SA 1360, Si-P, 150V, 0.05A, 5W bei reichelt elektronik
SC 3423: Transistor 2SC 3423 NPN 150V 0,05A TO-126 bei reichelt elektronik
Camelator,
Yes, this is the file I sent off to fab the PCB at Seeedstudio.
The BOMs provided by Benz2 are good - go with the latest, but the electrolytic caps are a bit flexible. I use dual 47uF 63v on the power rails. The board calls for 100uF on the feedback reservoir (in lower middle of board), but notes by Prasi says to use bigger 1000uF low voltage like 6.3v. Personally, I am using Panasonic 330uF SEPF OSCON plus 1000uF 16v here and think the low ESR helps.
BD139/140 are the easiest to find, and here, I think an MPSA92/42 can also work (I tried it in TINA sim and it worked theoretically) but check the pin orientation as it is a TO92 case.
Yes, that is what I ordered at Seeedstudio.
Yes, that is the same heatsink I use - works well and is easy to drill and tap. You can even use for a bigger class A amp with addition of a $1 50mm PC CPU fan.
In theory (simulations) this Bimo edition board is better than the previous one, and I have these on order and should be arriving soon. They are bigger so cost more than $10. 🙂 But the fuse feature and other upgrades are probably worth it.
I mentioned using 330uF 25v SEPF OSCON for feedback reservoir cap. 47uf pairs seem adequate on rails but if you can fit 100uF or 220uF, even better. More is always better on rails.
On input cap, I am using 3.3uF film cap. I also found using 10uF electrolytic quite suitable and SQ with film cap is probably more of a placebo effect. If you can find a 4.7uF film cap like a Wima, that would be the ideal unit to put here.
Good luck!
Yes, this is the file I sent off to fab the PCB at Seeedstudio.
The BOMs provided by Benz2 are good - go with the latest, but the electrolytic caps are a bit flexible. I use dual 47uF 63v on the power rails. The board calls for 100uF on the feedback reservoir (in lower middle of board), but notes by Prasi says to use bigger 1000uF low voltage like 6.3v. Personally, I am using Panasonic 330uF SEPF OSCON plus 1000uF 16v here and think the low ESR helps.
BD139/140 are the easiest to find, and here, I think an MPSA92/42 can also work (I tried it in TINA sim and it worked theoretically) but check the pin orientation as it is a TO92 case.
Yes, that is what I ordered at Seeedstudio.
Yes, that is the same heatsink I use - works well and is easy to drill and tap. You can even use for a bigger class A amp with addition of a $1 50mm PC CPU fan.
In theory (simulations) this Bimo edition board is better than the previous one, and I have these on order and should be arriving soon. They are bigger so cost more than $10. 🙂 But the fuse feature and other upgrades are probably worth it.
I mentioned using 330uF 25v SEPF OSCON for feedback reservoir cap. 47uf pairs seem adequate on rails but if you can fit 100uF or 220uF, even better. More is always better on rails.
On input cap, I am using 3.3uF film cap. I also found using 10uF electrolytic quite suitable and SQ with film cap is probably more of a placebo effect. If you can find a 4.7uF film cap like a Wima, that would be the ideal unit to put here.
Good luck!
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Nice layout Prasi. Just a question on the philosphy behind removal of the CSS for FX8? Is that not a step backwards as the CSS helps reduce distortion?
One comment, can you move the 1000uF cap and the GND spade to the right a bit so that the signal input screw terminal can be rotated 90deg to face the front rather than sideways input? Otherwise looks great - I like that the VAS BD139/140 are now moved up to mount on the same heatsink.
One comment, can you move the 1000uF cap and the GND spade to the right a bit so that the signal input screw terminal can be rotated 90deg to face the front rather than sideways input? Otherwise looks great - I like that the VAS BD139/140 are now moved up to mount on the same heatsink.
BD on main heat sink was my original layout of FX-8. I just modified that layout slightly to make a layout for FX-7. Regarding CCS, Mr. Miles can answer better, but some are happy without it and plus 1 active device less🙂. If you are interested in 50mmx 50mm layout, may be Sonal can make it.
reg
Prasi
Attachments
Prasi,
Thanks for moving stuff around - looks perfect. I don't mind slightly larger format as the BD's get heatsink space and larger caps can be used. My Dx amp does not have CCS and it sounds fine - I agree sometimes do not really need it and simpler is sometimes better. I wonder if using LEDs to form bias setting voltage may be something we should try.
Thanks for moving stuff around - looks perfect. I don't mind slightly larger format as the BD's get heatsink space and larger caps can be used. My Dx amp does not have CCS and it sounds fine - I agree sometimes do not really need it and simpler is sometimes better. I wonder if using LEDs to form bias setting voltage may be something we should try.
One more thing here, you can use BC640/639 as per the sch. Just turn by 180 deg. Only thing is, if it gets too hot, one may have to use to-92 clip-on heat sinks I had seen somewhere and then monitor the temp. something like this...
Aavid Thermalloy 92FG Heat Sink TO92 Brass 36.1°C/W | Rapid Online
reg
Prasi
