The only sonical difference i perceived between sym4 and sym5 is that sym5 sounds more relaxed. (less internal overshoot because of getting rid of the rc in 1st diffamp)
Chris, i also had no more time to do something about symasym. I kept the 22ma bias for now, but i am convinced that the 22ma are valid only for MJx0281/0302.
Mike
Chris, i also had no more time to do something about symasym. I kept the 22ma bias for now, but i am convinced that the 22ma are valid only for MJx0281/0302.
Mike
Hi Mike,
I agree with you with regard to the output transistors and bias setting. When I was testing these, I had the idea this would happen. I'd like to try some good Japanese driver transistors as well. Just for chuckles and grins. I do have the feeling that this would allow a lower bias setting. I think I have some hidding around somewhere.
Once I have finished testing this incarnation, I can start with the diff pair. I received my transistors from Linear Systems yesterday. Only one bipolar type and one fet type suitable for your amplifier. On Semi lost my order for 1/2 of the outputs.
Now I have to try and sort that one out.
-Chris
I agree with you with regard to the output transistors and bias setting. When I was testing these, I had the idea this would happen. I'd like to try some good Japanese driver transistors as well. Just for chuckles and grins. I do have the feeling that this would allow a lower bias setting. I think I have some hidding around somewhere.
Once I have finished testing this incarnation, I can start with the diff pair. I received my transistors from Linear Systems yesterday. Only one bipolar type and one fet type suitable for your amplifier. On Semi lost my order for 1/2 of the outputs.
Now I have to try and sort that one out.-Chris
MikeB said:
2SK117
another similiar Toshiba low-noise JFET, has got 50 Volt max VDS
Not big difference, but ..... any JFET volt is welcome!
Datsheeet:
http://www.semicon.toshiba.co.jp/docs/datasheet/en/Transistor/2SK117_en_datasheet_030325.pdf
Should not be impossible to buy, at least for a couple of more years
before become obsolete and go out of production replaced by all them surface mount things.
See for example here some prices ( Euro € ):
http://www.elfa.se/elfa-bin/dyndok.pl?lang=en&vat=0&dok=2424.htm
lineup
thinks discrete semiconductor market aint what it used to bein these modern Chip & SMD IC times
Hi Mike,
At a rating of 40V you will be fine. Ground reference will only be a couple volts added to 35 VDC at the most. Close, and here is your cigar!
I was thinking cascode anyway. Try for both the BJT and FET to be fair.
Hey lineup,
Thanks for looking. Nothing wrong with some headroom.
-Chris
At a rating of 40V you will be fine. Ground reference will only be a couple volts added to 35 VDC at the most. Close, and here is your cigar!
I was thinking cascode anyway. Try for both the BJT and FET to be fair.
Hey lineup,
Thanks for looking. Nothing wrong with some headroom.
-Chris
Circuit differences between model 4 and 5 are not so great
Sonic differences are not also too much big.
Making two channels, you can make one model 4 and other model 5 and compare them to make your choice.
To finally produce the one you prefer, will have to make very small modifications in the same printed board...or to solder the capacitor down the board.
They are both great amplifiers...let's say that one can receive 9,543 and other 9,503 if you not bother yourself, too much, related specs...just listening to them you perceive something....for me it is inside my personal threshold of differences perceived.
Ten is some amplifier that can make me feel listening alive music...so.....i will have to listen "alive" to give a 10.... as alive has no amplifier...10 is only theoreticall...not a real existance to me.
regards,
Carlos
Sonic differences are not also too much big.
Making two channels, you can make one model 4 and other model 5 and compare them to make your choice.
To finally produce the one you prefer, will have to make very small modifications in the same printed board...or to solder the capacitor down the board.
They are both great amplifiers...let's say that one can receive 9,543 and other 9,503 if you not bother yourself, too much, related specs...just listening to them you perceive something....for me it is inside my personal threshold of differences perceived.
Ten is some amplifier that can make me feel listening alive music...so.....i will have to listen "alive" to give a 10.... as alive has no amplifier...10 is only theoreticall...not a real existance to me.
regards,
Carlos
Hi MikeB,
I had just visited your website and there you've stated that symasym is designed to be driven directly from a CD/DVD-player, simply place a 22k poslog stereo pot between player and symasym, I want to build this amp and wanted to incorporate a tone control between this amp and player, is there any changes to be made? Or, I might need a tone control which suit its specification.
If you have available circuits for this tonecontrol, I am very interested.
Best regards,
bernhix
I had just visited your website and there you've stated that symasym is designed to be driven directly from a CD/DVD-player, simply place a 22k poslog stereo pot between player and symasym, I want to build this amp and wanted to incorporate a tone control between this amp and player, is there any changes to be made? Or, I might need a tone control which suit its specification.
If you have available circuits for this tonecontrol, I am very interested.
Best regards,
bernhix
Hi Mike,
Most tone controls have an insertion loss of approx 20 dB. It could be designed to have reduced range but you'd still want an active device. They used to be part of something called a "control amplifier".
You could always put it in the feedback loop <really ducking and running for cover!>
After listening for a while, how do you like the FET front end?
-Chris
Most tone controls have an insertion loss of approx 20 dB. It could be designed to have reduced range but you'd still want an active device. They used to be part of something called a "control amplifier".
You could always put it in the feedback loop <really ducking and running for cover!>
After listening for a while, how do you like the FET front end?
-Chris
humorous humor makes me happy, but...
Gosh... Such violence...
I have thought about tone controls in the feedback loop but it's just one of those feelings that something will work, it just won't work good enough (not always good to go with instinct, though, right?). Besides, I'm not experienced enough to do any feedback stuff anyways. Anyone know of a tone control circuit using at most two POT's and a some resistorsand capacitors? I want it to have low volume penalty (why not?). Is human hearing response logarithmic to frequency? I want to know this so that I know whether to make a redneck log pot or not.
redneck log pot refering to
http://sound.westhost.com/pots.htm#chg-law
Gosh... Such violence...
I have thought about tone controls in the feedback loop but it's just one of those feelings that something will work, it just won't work good enough (not always good to go with instinct, though, right?). Besides, I'm not experienced enough to do any feedback stuff anyways. Anyone know of a tone control circuit using at most two POT's and a some resistorsand capacitors? I want it to have low volume penalty (why not?). Is human hearing response logarithmic to frequency? I want to know this so that I know whether to make a redneck log pot or not.
redneck log pot refering to
http://sound.westhost.com/pots.htm#chg-law
Hi keantoken,
I think Mike is now lying on his back, planning to take back every Symasym ever built due to that comment!
Tone controls in the feedback network does horrible things to the phase margins and stability as a result. Never mind the fact you are now running the feedback signal all over the world.
I think National made a tone control / volume control chip. It only has about 0.5% THD. Run the input signal through that first.
Really, build a proper preamp if you want tone controls.
-Chris
I think Mike is now lying on his back, planning to take back every Symasym ever built due to that comment!
Tone controls in the feedback network does horrible things to the phase margins and stability as a result. Never mind the fact you are now running the feedback signal all over the world.
I think National made a tone control / volume control chip. It only has about 0.5% THD. Run the input signal through that first.
Really, build a proper preamp if you want tone controls.
-Chris
esp project97 preamplifier with tone control
bernhix
if you put a tone control between, symasym is no longer driven directly from CD
and this is one of the merits:
to be able to get the signal as direct as possible.
And hopefully the signal is not destroyed of several circuits
and even circuits with worse performance than SymaSym.
It is within an audio chain, as with real chains:
Chain is no stronger than weakest link.
What sound you will be able to hear is probably most of it produced and coloured by this the weakest spot.
It is like doing listening test of a HIFI amplifier with 0.01% distortion
using a preamplifier with 0.50% distortion.
Not very good test, is it?
--------
keantoken
Rod Elliott have, if not the ultimate audiophile high end stuff,
very good standard circuits for most anything we would need.
You name it - he's got it
Project97 Hi-Fi Preamplifier by Rod Elliott (ESP) .. [ December 2002 ]
has got tone controls and balance, if you want use this part of preamp.
Link:
http://sound.westhost.com/project97.htm
Tone control circuit uses 2 potentiometers, some resistors, capacitors and op-amps.
You can also get PCB for this HIFI Preamp from him. For a small price.
The Circuit is here:
http://sound.westhost.com/p97-f1.gif
lineup audio projects at
>> lineup.awardspace.com <<
bernhix said:
keantoken said:
bernhix
if you put a tone control between, symasym is no longer driven directly from CD
and this is one of the merits:
to be able to get the signal as direct as possible.
And hopefully the signal is not destroyed of several circuits
and even circuits with worse performance than SymaSym.
It is within an audio chain, as with real chains:
Chain is no stronger than weakest link.
What sound you will be able to hear is probably most of it produced and coloured by this the weakest spot.
It is like doing listening test of a HIFI amplifier with 0.01% distortion
using a preamplifier with 0.50% distortion.
Not very good test, is it?
--------
keantoken
Rod Elliott have, if not the ultimate audiophile high end stuff,
very good standard circuits for most anything we would need.
You name it - he's got it
Project97 Hi-Fi Preamplifier by Rod Elliott (ESP) .. [ December 2002 ]
has got tone controls and balance, if you want use this part of preamp.
Link:
http://sound.westhost.com/project97.htm
Tone control circuit uses 2 potentiometers, some resistors, capacitors and op-amps.
You can also get PCB for this HIFI Preamp from him. For a small price.
The Circuit is here:
http://sound.westhost.com/p97-f1.gif
lineup audio projects at
>> lineup.awardspace.com <<
I would definitely LOVE to be able to build one of these, but the problem is that I can't buy TLO72 and other IC's as easily as everybody else because mainly I don't have the money, I don't have a basement to work in, (I am living in a 3 bedroom house 
) and I just don't want to give away my address to buisinessmen. Anyone know of a good preamp with discrete components?
Are you talking about the line with the smilie at the end or are you mistaking me for saying that I think that tone controls in the feedback is a good idea (I was meaning the opposite).
I communicate with people on another level, in a slightly different way, and it's not exactly a personality aspect either (if you know what I mean). I am sure that there are other people on this forum with the same problem. Sorry!
) and I just don't want to give away my address to buisinessmen. Anyone know of a good preamp with discrete components? Are you talking about the line with the smilie at the end or are you mistaking me for saying that I think that tone controls in the feedback is a good idea (I was meaning the opposite).
I communicate with people on another level, in a slightly different way, and it's not exactly a personality aspect either (if you know what I mean). I am sure that there are other people on this forum with the same problem. Sorry!
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