Good point Nfsgame.
The BC550/560 are rated 50Vdc so with the cascode input stage should be quite correct.
I will update the manual accordingly, thanks for your comment.
Fab
The BC550/560 are rated 50Vdc so with the cascode input stage should be quite correct.
I will update the manual accordingly, thanks for your comment.
Fab
Thank you.
Also you got the 10 Ohms resistors (R13, R14 + R15, R16) two times in the BOM. Same CMF55 - one pair with 50ppm/°C, the other with 100ppm/°C (FHEB/FKEB). Is this a mistake?
Also you got the 10 Ohms resistors (R13, R14 + R15, R16) two times in the BOM. Same CMF55 - one pair with 50ppm/°C, the other with 100ppm/°C (FHEB/FKEB). Is this a mistake?
R13/R14 are 1/2W (CMF55) and R15/R16 can be only 1/4W (CMF50). You can also use 1/2W for both resistors pairs. 50ppm or 100ppm does not do much difference in that case.
Fab
Fab
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Hi Anthony,
We just open up, so the machinist is working on it now, will post some pics when i got them back.
BOM
It is also possible to use MP915-330 instead of MP930-330 for the power feedback resistors R7/R8. With the suggested heatsink it will be fine.
Fab
It is also possible to use MP915-330 instead of MP930-330 for the power feedback resistors R7/R8. With the suggested heatsink it will be fine.
Fab
Also ztx 795 695the top and bottom one..pass transistor
Can replace with Bc639 640 with different pinout its a small version of 139 140..
Vbe one use low noise bc 54x/55x will work as well to replace ztx 795
If you can get.. Get the nos Philips silver head.. They sound marvelous
Meanie.. Stay safe! Yes audio porn pls
Can replace with Bc639 640 with different pinout its a small version of 139 140..
Vbe one use low noise bc 54x/55x will work as well to replace ztx 795
If you can get.. Get the nos Philips silver head.. They sound marvelous
Meanie.. Stay safe! Yes audio porn pls
Carbon takman for feedback 22r 22k
And gate of final transistor
and signal.. 2.2k 100k
I use all takman carbon.. That definely will work very well, more H2 and bass
That is if you can get them matched.. It will sound even better.
And gate of final transistor
and signal.. 2.2k 100k
I use all takman carbon.. That definely will work very well, more H2 and bass
That is if you can get them matched.. It will sound even better.
Does someone has already any specifications for FSSA-1 and 2?
Is it a good idea to use an SMPS to power the FSSA?
If it is, what should be the SMPS power and Vdc range?
I have a meanwell se-600-36, is it suitable?
Thanks
Is it a good idea to use an SMPS to power the FSSA?
If it is, what should be the SMPS power and Vdc range?
I have a meanwell se-600-36, is it suitable?
Thanks
Now I got spare money spending on acoustic instead of searching for the best amplifier to build .
YouTube
Vocal/ acoustic
YouTube
Drum
You might hear what I actually boasted about now it's clearer to record after the system receive a spa treatment ..
Time for a little rant and some thoughts
There is alot of very experienced audio people forum, YouTube , people I know saying things like interconnects , power cable, hi end is all just toys .oh my 100 usd mogami cable can perform as good as 10,000usd ones ..it's not true ! I wonder if the guy actually own one , the answer is not and just a poor excuse ..
I use very expensive power conditioner , power cables , interconnects.. which I slowly collect over the years .I'm not cheapo when buying such things cause I heard it and I know how good it is .
Acoustic / mechanical isolation good power bar is important ..
It's recorded only with Samsung a50 .only a decent system setting can be recorded with that clarity using a mic ..a funny guy in YouTube say oh buddy 300k system wow him ..but there is distortion recording oh so sorry ..rolleyes lolol . No wonder not much people dare to review and record .. mic pickup noise ear cannot hear ...even from 300k system.. the owner don't know what he is doing ..
I'm lying down and recording .using a phone no stand or special setup.no big fuss for me..
So ...the expectation I give you is ..
Thats at least how good fssa , usspa can hit ..thanks to the hard work of Fab , but I also give a word of disclaimer .. system integration applies .
It can be your last amplifier and preamp..spend whatever money u save in future on something else. And I'm near the very end of to do list ..it's a peaceful feeling.
Have good weekend
YouTube
Vocal/ acoustic
YouTube
Drum
You might hear what I actually boasted about now it's clearer to record after the system receive a spa treatment ..
Time for a little rant and some thoughts
There is alot of very experienced audio people forum, YouTube , people I know saying things like interconnects , power cable, hi end is all just toys .oh my 100 usd mogami cable can perform as good as 10,000usd ones ..it's not true ! I wonder if the guy actually own one , the answer is not and just a poor excuse ..
I use very expensive power conditioner , power cables , interconnects.. which I slowly collect over the years .I'm not cheapo when buying such things cause I heard it and I know how good it is .
Acoustic / mechanical isolation good power bar is important ..
It's recorded only with Samsung a50 .only a decent system setting can be recorded with that clarity using a mic ..a funny guy in YouTube say oh buddy 300k system wow him ..but there is distortion recording oh so sorry ..rolleyes lolol . No wonder not much people dare to review and record .. mic pickup noise ear cannot hear ...even from 300k system.. the owner don't know what he is doing ..
I'm lying down and recording .using a phone no stand or special setup.no big fuss for me..
So ...the expectation I give you is ..
Thats at least how good fssa , usspa can hit ..thanks to the hard work of Fab , but I also give a word of disclaimer .. system integration applies .
It can be your last amplifier and preamp..spend whatever money u save in future on something else. And I'm near the very end of to do list ..it's a peaceful feeling.
Have good weekend
You must have a good reason needing to go smps route . Linear is better , sound wise , you get more texture , softer vocaland lower bass weight . Advantage is weight , and it sound more speedy and snappy . But I never see a complete sound with smps based amp or preamp but somehow it can work with dac .
Phinnochio did mention cresnet smps sounds very good ..
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I will be using smps for the first time.
This is dual rail, from Cresnet.
You can contact him directly in this forum, his name is Sami.
meanie,
If it is +/- 55Vdc, then my understanding is that you will require another power supply to drive the front end, (probably also implied in strechneck's post and question).
You have any solution in mind? I also have SMPS from Cresnet with +/- 55Vdc.
If it is +/- 55Vdc, then my understanding is that you will require another power supply to drive the front end, (probably also implied in strechneck's post and question).
You have any solution in mind? I also have SMPS from Cresnet with +/- 55Vdc.
Oh i just look into the manual, it says max voltage for front end should be +/- 50Vdc.
I may still go ahead with just a common PS first using only the smps.
Later on i might cannibalise my electrocompaient AW60 for its power supply unit.
It has 2 banks of dual +/- 45 and +/- 53 i think.
I wonder if using separate front end ps will enhance the SQ that much, maybe Fab can enlighten us?
I may still go ahead with just a common PS first using only the smps.
Later on i might cannibalise my electrocompaient AW60 for its power supply unit.
It has 2 banks of dual +/- 45 and +/- 53 i think.
I wonder if using separate front end ps will enhance the SQ that much, maybe Fab can enlighten us?
Hi guys
I will need some extras for my FSSA2:
- A Soft start
- A DC loudspeaker protection with turn on delay
What would you recommend for these?
I have seen some boards in the store but unsure if these are the most suitable options or if other options are perhaps around, be it DIY or ready built (doesn't matter)
Many thanks for your kind help!
Claude
I will need some extras for my FSSA2:
- A Soft start
- A DC loudspeaker protection with turn on delay
What would you recommend for these?
I have seen some boards in the store but unsure if these are the most suitable options or if other options are perhaps around, be it DIY or ready built (doesn't matter)
Many thanks for your kind help!
Claude
Input stage heatsink
Regarding the max voltage of the power supply it is for input stage transistors power dissipation concern as specified in section 9 of the manual. It is depending on ID of the jfet which is about 70% of IDSS which sets the input stage current for J1/J2/Q1/Q2. As suggested when having IDSS >= 10ma, one should use very small heatsink (having thermal tape) on top of J1/J2 and Q1/Q2.
Thus having IDSS < 9ma allows to have a higher PSU voltage for the same power dissipation in input transistors. Since J74 has a max voltage of 25Vdc the D7/D8 zener voltage should be 24Vdc max thus the cascode Q1/Q2 will see the rest of the voltage thus will require small heatsink accordingly.
Fab
Regarding the max voltage of the power supply it is for input stage transistors power dissipation concern as specified in section 9 of the manual. It is depending on ID of the jfet which is about 70% of IDSS which sets the input stage current for J1/J2/Q1/Q2. As suggested when having IDSS >= 10ma, one should use very small heatsink (having thermal tape) on top of J1/J2 and Q1/Q2.
Thus having IDSS < 9ma allows to have a higher PSU voltage for the same power dissipation in input transistors. Since J74 has a max voltage of 25Vdc the D7/D8 zener voltage should be 24Vdc max thus the cascode Q1/Q2 will see the rest of the voltage thus will require small heatsink accordingly.
Fab
Attachments
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ClaudeG,
You can check these out:
Soft as a Feather Pillow (SFP) SSR Soft Start Circuit GB
Ready-to-Run (RTR) SSR DC Speaker Protection and Delay GB
You can check these out:
Soft as a Feather Pillow (SFP) SSR Soft Start Circuit GB
Ready-to-Run (RTR) SSR DC Speaker Protection and Delay GB