wputera said:
Hi, MJE15030/1 will work together with Toshiba SC5200/SA1943.
Possible subtitutes for example are:
2sc5171/2sa1930 Toshiba ft=200
2sc2344/2sa1011 Sanyo ft=100
2sc3298/2sa1306 Toshiba ft=100
2SA1943 is the complementary to 2SC5200.
Mike
Thank you MikeB. Is it possible if i parallel the output with two or more pairs of 2sc5200 and 2sa1943? What is the effects?
As long as you do not intend to drive very low impedances or increase voltage supply, it's better to stay with one pair.
Symasym is happy driving 4ohms from a 36v supply with a single pair.
Using more pairs can degrade quality and produce more heat as each pair need it's own bias.
Mike
Symasym is happy driving 4ohms from a 36v supply with a single pair.
Using more pairs can degrade quality and produce more heat as each pair need it's own bias.
Mike
Hi !!
Mike, I bought 330pF and 100pF of Styroflex (0,4USD) and the 10pF is Mica (2USD). 😀
If I put ceramic capacitors instead these Styroflex, would it perform bad?
I'm waiting my order from farnell, as soon as I start to build it, I'll post pictures ! 😉
Cheers !
Mike, I bought 330pF and 100pF of Styroflex (0,4USD) and the 10pF is Mica (2USD). 😀
If I put ceramic capacitors instead these Styroflex, would it perform bad?
I'm waiting my order from farnell, as soon as I start to build it, I'll post pictures ! 😉
Cheers !
Oh, I forgot,
I received the Beyma drivers, 10BR60 and T2010. They are just beautiful, I can't wait to hear it singing with Symassym ! 😀 😀
I received the Beyma drivers, 10BR60 and T2010. They are just beautiful, I can't wait to hear it singing with Symassym ! 😀 😀
-_nando-_ said:
Not sure if MikeB's still awake, so:
I believe Mike has advised against using ceramics, a sentiment many others echo. It's somewhere in the thread...
Cheers!
Hi Clem,
Correct sir.
If you have to use a ceramic, make sure it's an NPO / COG type. Still, they are best avoided. Mica and Polystyrene seem to work really well. I'll take any plastic (almost) over tantalum, electrolytic or ceramic.
-Chris 😉
Correct sir.
If you have to use a ceramic, make sure it's an NPO / COG type. Still, they are best avoided. Mica and Polystyrene seem to work really well. I'll take any plastic (almost) over tantalum, electrolytic or ceramic.
-Chris 😉
Hi all,
What does the group think re ideal PS filter capacitance? Stereo symasym driving 4 ohm speakers. I have two 200VA toroids, with dual 27.5V secondaries. Too large a capacitance in the filters would just increase the 'spike' charging currents beyond what the transformer would manage, wouldn't it?
Oh, I do recall seeing someting like 10,000uF for 100W as a 'rule of thumb'... I'd expect though that the speaker impedance would be a factor...
Cheers!
What does the group think re ideal PS filter capacitance? Stereo symasym driving 4 ohm speakers. I have two 200VA toroids, with dual 27.5V secondaries. Too large a capacitance in the filters would just increase the 'spike' charging currents beyond what the transformer would manage, wouldn't it?
Oh, I do recall seeing someting like 10,000uF for 100W as a 'rule of thumb'... I'd expect though that the speaker impedance would be a factor...
Cheers!
Clem_o, sorry, i somehow missed your questions...
Symasym will not sound "bad" with the ceramics. It's just you will hear an improvement with better caps. If you don't want to wait, use the ceramics. My prototype used ceramics all over.
About the PSU-caps, if i remember correct, they do not really scale with power, just with outputimpedance. They form a RC with the outputimpedance. The outputstage bias also forms some impedance seen by the caps, with 100ma at 36v that would be ~360ohms, negligible here.
I have 2x22.000uf feeding 2 channels into 4ohms and can't complain.
I guess you would be fine with 2x10.000uf for each channel.
Mike
Symasym will not sound "bad" with the ceramics. It's just you will hear an improvement with better caps. If you don't want to wait, use the ceramics. My prototype used ceramics all over.
About the PSU-caps, if i remember correct, they do not really scale with power, just with outputimpedance. They form a RC with the outputimpedance. The outputstage bias also forms some impedance seen by the caps, with 100ma at 36v that would be ~360ohms, negligible here.
I have 2x22.000uf feeding 2 channels into 4ohms and can't complain.
I guess you would be fine with 2x10.000uf for each channel.
Mike
Having used ceramics to start, then upgraded to polystyrene and mica, I agree. Change them out as soon as you can.
As for PSU caps, I'm running dual mono, with three 6800uF per rail and that works well.
As for PSU caps, I'm running dual mono, with three 6800uF per rail and that works well.
MikeB and pinkmouse -
Many thanks for the prompt reply re PS capacitors. Time to start putting this thing together - seriously!! 🙂
Cheers
Clem
ps: MikeB, you didn't miss any of my questions - the ceramic cap question was from nando...
Many thanks for the prompt reply re PS capacitors. Time to start putting this thing together - seriously!! 🙂
Cheers
Clem
ps: MikeB, you didn't miss any of my questions - the ceramic cap question was from nando...
Hi Nando,
Prepare to be a happy fella!
Mike,
I'm not pushing my amps very hard, so 8,200 uF per rail will be fine. I think bypassing them will make more of a difference, and you provided for that. I believe your supply isolation comes into play as well. Using CCS's will make it far more forgiving to supply ripple. Don't forget you will see an audio signal on your B+ also. That's why I will experiment with a regulated supply for the voltage amp stages.
-Chris
Prepare to be a happy fella!
Mike,
I'm not pushing my amps very hard, so 8,200 uF per rail will be fine. I think bypassing them will make more of a difference, and you provided for that. I believe your supply isolation comes into play as well. Using CCS's will make it far more forgiving to supply ripple. Don't forget you will see an audio signal on your B+ also. That's why I will experiment with a regulated supply for the voltage amp stages.
-Chris
Hi !!
The 4.7uF Wima MKS2 costs 5USD at farnell
I have a Polyester 4,7uF here that is "generic", and looks ugly. Can I use a smaller Wima cap ? Like 2.2uF ?
I have here wire .18, Can I use it instead the 0,6mm wire for the output coil ? I'd say it is 0,5mm...
Cheers !
The 4.7uF Wima MKS2 costs 5USD at farnell
I have a Polyester 4,7uF here that is "generic", and looks ugly. Can I use a smaller Wima cap ? Like 2.2uF ?
I have here wire .18, Can I use it instead the 0,6mm wire for the output coil ? I'd say it is 0,5mm...
Cheers !
Nando, looky here: http://v-cap.com/tefloncapacitors.html 
Do you still believe that 5USD for 4.7µF film cap is ?
Be glad that you can get Wima MKS2...
Kidding...
I am not sure if 2.2µF is enough, the mathematics say yes.
According to f = 1/(2*pi*R*C), 2.2µF would give cutoff frequency of 3.3Hz.
If you lower it, you should consider also lowering C19, (for better AC-balance) like maybe 100µF.
0.18 ? I guess that's inch ? 0.018 inch would translate to ~0.45mm, that should be ok for the coil.
Mike
Do you still believe that 5USD for 4.7µF film cap is
?Be glad that you can get Wima MKS2...
Kidding...
I am not sure if 2.2µF is enough, the mathematics say yes.
According to f = 1/(2*pi*R*C), 2.2µF would give cutoff frequency of 3.3Hz.
If you lower it, you should consider also lowering C19, (for better AC-balance) like maybe 100µF.
0.18 ? I guess that's inch ? 0.018 inch would translate to ~0.45mm, that should be ok for the coil.
Mike
Hi Mike,
I'm using 1 uF on one amp.
Until I do tests. I can't hear any difference with music.
-Chris
I'm using 1 uF on one amp.
Until I do tests. I can't hear any difference with music.-Chris
anatech said:Hi Mike,
I'm using 1 uF on one amp.
-Chris
If you can't hear difference, it's allright !
My Prototype had 10uF inputcap and 220uf for c19, it had more slam in the bass. I am not sure why...
Mike