Hi Osscar,
seems I've overlooked this. Could you send it to me per mail???
V type for JFets is best suited?
Regs, Dirk
Looking forward to get your sound impressions...
seems I've overlooked this. Could you send it to me per mail???
V type for JFets is best suited?
Regs, Dirk
Looking forward to get your sound impressions...
hi,
Look again attached PDF file!
i will tell about the sound after few days- currently working with enclosure.
regards,
Oskars
Look again attached PDF file!
i will tell about the sound after few days- currently working with enclosure.
regards,
Oskars
JFet's grade
No, they aren't ! That strange idea was emitted on this thread because one thought it was a printing mistake between "Y" and "V" !! 😱
It is not.
"Y" grade does exist : i'have got some.
Their Idss is very low, so the closer grade is "GR". You will perhaps have to use a 200ohm trimpot in order to get a 1.2 - 1.5 mA current in the cascode.
You can find easily Toshiba 2SJ74GR/2SK170GR singled or matched on the web.
If you need some other info on trans for this amp, just let me know.
And don't forget the first class passive power supply !😉
Rgds
PYJ
No, they aren't ! That strange idea was emitted on this thread because one thought it was a printing mistake between "Y" and "V" !! 😱
It is not.
"Y" grade does exist : i'have got some.
Their Idss is very low, so the closer grade is "GR". You will perhaps have to use a 200ohm trimpot in order to get a 1.2 - 1.5 mA current in the cascode.
You can find easily Toshiba 2SJ74GR/2SK170GR singled or matched on the web.
If you need some other info on trans for this amp, just let me know.
And don't forget the first class passive power supply !😉
Rgds
PYJ
Today Just finished my Le monstre, pots still don't delivered to me, so i soldered instead of pot to fixed resistors - for one channel 2x680R - works fine - bias 0.7A DC offset - in range of 10mV. Other channel - 2x 100R -bias around 0.7A , DC offset - 150mV , i will solder pots when received them.
Supply voltage around 13.6V with load.
Now will be listening tests.
Thanks to all DIYers from this thread - Lineup, Gaborela, Nezoi , and others who create PCB and explain things. And also thank you Mr. Hiraga 🙂
Inform you about sound later 😉
Supply voltage around 13.6V with load.
Now will be listening tests.
Thanks to all DIYers from this thread - Lineup, Gaborela, Nezoi , and others who create PCB and explain things. And also thank you Mr. Hiraga 🙂
Inform you about sound later 😉
After a two-night listening, I can tell you something, compared with F5:
Monstre have more gain;
it is not as sharp as F5;
Detailed - like F5;
Bass - very good, but more rounded then in F5;
Microynamics - very good.
I really like the classical and instrumental music with this amp and it not so hot like F5.
Le monstre sounds good at very low levels also...
I am a bit confused - different they sounds, but at the same time the same in some way 🙂
I like electronic music with F5 and also Le monstre sounds very good.
In winter i will use F5 -in summer - Monstre 😀
Monstre have more gain;
it is not as sharp as F5;
Detailed - like F5;
Bass - very good, but more rounded then in F5;
Microynamics - very good.
I really like the classical and instrumental music with this amp and it not so hot like F5.
Le monstre sounds good at very low levels also...
I am a bit confused - different they sounds, but at the same time the same in some way 🙂
I like electronic music with F5 and also Le monstre sounds very good.
In winter i will use F5 -in summer - Monstre 😀
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Hiraga 8 Watt Pcb
My Friend Klaus did a very nice Pcb for me.
Look for the short signal traces!
Use a Silver Mica for feedback compensation, 1,5nF to 2nF, watch the scope.
You can tray to test Bulk Foil or Tantal-R or Riken Resistor in the feedback path, you can trimm the sound with the 220R resistor.
With kind regards
SAm
My Friend Klaus did a very nice Pcb for me.
Look for the short signal traces!
Use a Silver Mica for feedback compensation, 1,5nF to 2nF, watch the scope.
You can tray to test Bulk Foil or Tantal-R or Riken Resistor in the feedback path, you can trimm the sound with the 220R resistor.
With kind regards
SAm
That s fairly enough for domestic use provided the speakers
have at least 90db/W/1M efficency, although, it works best
in a triphonic scheme with a 20W amp for the basses..
Hi Colin,
I don't want to start a Cap discussion🙂
The 8Watt is a nice amp, where everybody can play with parts substitution.
Did you you compared the sound of the 8 Watt with several setups?
The 8 Watt is not expensive, so you can build 2 stereo sets for comparism.
In the moment we do a new design, where we add a current source to the inputstage.
Matching of the j-fet would be easier, and only four sound relevant resistors.
Regards
SAm
I don't want to start a Cap discussion🙂
The 8Watt is a nice amp, where everybody can play with parts substitution.
Did you you compared the sound of the 8 Watt with several setups?
The 8 Watt is not expensive, so you can build 2 stereo sets for comparism.
In the moment we do a new design, where we add a current source to the inputstage.
Matching of the j-fet would be easier, and only four sound relevant resistors.
Regards
SAm
Dear Sam
No compliant about the design none, but I have tried Silver Mica in filters and I was trying to avoid other having the same problem, and that is all.
Just due care to my fellows on this site.
Regards Colin
Colin,
I would use polystyrene or polypropylene. Maybe it´s not even needed. Have you built Le Monstre?
I would use polystyrene or polypropylene. Maybe it´s not even needed. Have you built Le Monstre?
@Wuyit
No polystyrene cap, polyprop is ok, but you have to try
You will need compensation cap over the 220R feedback resistor. There was always a peak on the squarewave signal.
With the 2SA1407/2SC3601 we could scale down to 1nF.
I have built more then 10 pairs of 8 Watt amps.
Regards
Sam
No polystyrene cap, polyprop is ok, but you have to try
You will need compensation cap over the 220R feedback resistor. There was always a peak on the squarewave signal.
With the 2SA1407/2SC3601 we could scale down to 1nF.
I have built more then 10 pairs of 8 Watt amps.
Regards
Sam
masag1,
I would try to avoid that capacitor, would rather reduce the resistor value from 220 to 100 Ohms (or more).
I would try to avoid that capacitor, would rather reduce the resistor value from 220 to 100 Ohms (or more).
Compared with LM1875 ?
After a two-night listening, I can tell you something, compared with F5:
Thanks for your comparison with the F5.
I was curious. Have you compared it against the LM1875 ? levels have to be matched . You can even use low voltage mains hum as a signal source and measure the levels on both amps with a DMM. Quick and dirty way of doing this. You have to make sure you don't clip the 1875.
Can you please try this and let us know ?
Thanks.
By the way your LM1875 implementation looks great !
Today Just finished my Le monstre, pots still don't delivered to me, so i soldered instead of pot to fixed resistors - for one channel 2x680R - works fine - bias 0.7A DC offset - in range of 10mV. Other channel - 2x 100R -bias around 0.7A , DC offset - 150mV , i will solder pots when received them.
Supply voltage around 13.6V with load.
Now will be listening tests.
Thanks to all DIYers from this thread - Lineup, Gaborela, Nezoi , and others who create PCB and explain things. And also thank you Mr. Hiraga 🙂
Inform you about sound later 😉
Very tidy job again Oscar ..... Scope pics ? ... 🙂
🙂
F5 is more than double the power i would have expected better dynamics , do you have anyway of testing your speakers impedance vs mag vs phase.
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