disco said:
Yes, it's in microseconds. Your inductance point is indeed also something to consider
. The smaller the better. As always, this property is contradictive to another: a low -3dB frequency....
SimontY said:
That puts things into perspective. You're right, our 'electro-mechanical transducers' cause much more trouble in the time-domain. I don't think this tiny delay will make much difference. Just something I came across during simulating.
Regards,
Ray.
Ray
Is the bass less or just the sound more even between high to lows?
Like turning up the tone control?
also how would the component impedance match between changing one component from tranny to fet?
allan
ps i just found a pair of mica caps labeled 162 j5
should be 1600pF 1n6 5%
must be old? being 1n(6)
I expected 1n2, 1n5, or 1n8?
Is the bass less or just the sound more even between high to lows?
Like turning up the tone control?
also how would the component impedance match between changing one component from tranny to fet?
allan
ps i just found a pair of mica caps labeled 162 j5
should be 1600pF 1n6 5%
must be old? being 1n(6)
I expected 1n2, 1n5, or 1n8?
awpagan said:
Hi Allan,
That's a good one. You get used to the sound you have so easily that you don't know which one is actually the 'right' one if you hear two differences. The bass is there, it just seems more 'loose'. It's a bit like my tubeamp: without the 6dB feedback I normally use, the bass becomes a bit sloppy because of the bad damping factor. Maybe it has to do with the lack of feedback, compared to the opamps.
Btw: 1n6 is a E-24 value, it's not that uncommon.
Regards,
Ray.
Ray
Just remembered something that Elso stated about 2sk389's and bias
might be relevent to 2sk170's in diff pair also
The sound can change with the amount of bias for the diff pairs.
improve bass or high's with the bias current
I already made my pcb with a multi turn pot "being R25 in your bc550 schematic" for testing this.
also helpful for changing between fet and tranny's or different types
allan
Just remembered something that Elso stated about 2sk389's and bias
might be relevent to 2sk170's in diff pair also
The sound can change with the amount of bias for the diff pairs.
improve bass or high's with the bias current
I already made my pcb with a multi turn pot "being R25 in your bc550 schematic" for testing this.
also helpful for changing between fet and tranny's or different types
allan
awpagan said:
I guess it won't hurt to increase the bias. I haven't got much experience with these FET's. In the HDAM circuit they are also used at a much higher current. You may want to lower the 4k7 and 820R resistors though, to maintain sufficient amplification. The whole thing is DC coupled, just about 10mA through the 1k8 output resistor is o.k.
Regards,
Ray.
Re: CD63 Transistor Output Stage
1 week Update on transistor stage sound:
Well... A week's past since I put this mod into the CD63... which to me... transformed it into a giant killer.
First of... those initial impressions that I first had.... well... over the next 4 days of running in, the sound got progressively "worse" .... but this has happened to me many times before.... a result of the components "running in" and there's lots of new components in the signal path. I left the player running on my Test & Burn in CD over the last week.
Finally this weekend, I sat down to have another proper listen, and it had indeed gotten better.... that low frequency energy was back... and the soundstage had more depth. One of the things that is very noticable now is the amount of "intelligibility" in each recording.... boy it's clean!! Also, over the week... things weren't sounding too musical, but after around the 100 hr mark... it all started gelling again. The pace, rhythm and timing is back.... but my CD player still lacks that ultimate transparency I had before the change-over.
I'm sure this is due to the crummy polyester 3.3 uF coupling caps I'm using at the moment.
After looking through the discussion last week re. coupling caps (thanks Disco and Ray... for enlightening me further)... I've bit the bullet and ordered some 10uF Ampohm polyprops from RS Components and the Vishay 1837s to bypass them with. Fitting these would be interesting indeed, given they are 70mm long!!! I'll try and mount them over the HDAM copper covers and run the output wire directly to the RCAs.
So overall... after one week of running in, the initial impressions still stand. I've noticed the "true character" of the transistor output stage emerging... and it's very clean (intelligible) with very good lows and a wonderful midrange. Ray's right... the opamps sounded a bit "fake" in comparrision. I like the transistor stage sound a lot better... to me at least... it sounds more "real".
Just one final comment..... the CD player (after fitting the transistor stage) now has a constant hum when the preamp volume is turned all the way up (not white noise...but like 50 hz hum) and when no CDs are playing. It's definitely comming from the player... when the power's on (in stop, pause etc.) When it's playing music, I guess it's still there, but the music takes over and I don't notice it. It is otherwise not noticable, but the fact that it's still above the noise floor concerns me. I wonder if this is the noise of the DACs being amplified?? Anyone? Could this be a noisy ground or digital noise seeping through my shoddy workmanship? How can I get rid of this, or is it a known side effect of having such a great sounding passive filter + output stage? Your thoughts would be appreciated!
Champi
pantera6 said:No more opamps!!!
.....
Compared to the Opamps, the “mostly” transistor stage (I’m using FETS in the T4 position) simply blows it away in terms of “rightness”
Ray, this passive output stage and transistor stage that you’ve put together turns the humble CD63 into a giant killer!!!
Once again, Thanks Raymond!!A very highly recommended mod!
Champi (Counting the minutes to get back home and see how much the output stage has "run in")
1 week Update on transistor stage sound:
Well... A week's past since I put this mod into the CD63... which to me... transformed it into a giant killer.
First of... those initial impressions that I first had.... well... over the next 4 days of running in, the sound got progressively "worse"
.... but this has happened to me many times before.... a result of the components "running in" and there's lots of new components in the signal path. I left the player running on my Test & Burn in CD over the last week.Finally this weekend, I sat down to have another proper listen, and it had indeed gotten better.... that low frequency energy was back... and the soundstage had more depth. One of the things that is very noticable now is the amount of "intelligibility" in each recording.... boy it's clean!! Also, over the week... things weren't sounding too musical, but after around the 100 hr mark... it all started gelling again. The pace, rhythm and timing is back.... but my CD player still lacks that ultimate transparency I had before the change-over.
I'm sure this is due to the crummy polyester 3.3 uF coupling caps I'm using at the moment. After looking through the discussion last week re. coupling caps (thanks Disco and Ray... for enlightening me further)... I've bit the bullet and ordered some 10uF Ampohm polyprops from RS Components and the Vishay 1837s to bypass them with. Fitting these would be interesting indeed, given they are 70mm long!!! I'll try and mount them over the HDAM copper covers and run the output wire directly to the RCAs.
So overall... after one week of running in, the initial impressions still stand. I've noticed the "true character" of the transistor output stage emerging... and it's very clean (intelligible) with very good lows and a wonderful midrange. Ray's right... the opamps sounded a bit "fake" in comparrision. I like the transistor stage sound a lot better... to me at least... it sounds more "real".
Just one final comment..... the CD player (after fitting the transistor stage) now has a constant hum when the preamp volume is turned all the way up (not white noise...but like 50 hz hum) and when no CDs are playing. It's definitely comming from the player... when the power's on (in stop, pause etc.) When it's playing music, I guess it's still there, but the music takes over and I don't notice it. It is otherwise not noticable, but the fact that it's still above the noise floor concerns me. I wonder if this is the noise of the DACs being amplified?? Anyone? Could this be a noisy ground or digital noise seeping through my shoddy workmanship? How can I get rid of this, or is it a known side effect of having such a great sounding passive filter + output stage? Your thoughts would be appreciated!
Champi
Re: Re: CD63 Transistor Output Stage
My transistor stage didn't have any noise on output.
50hz? check your earthing.
allan
ps those precision clock you gave link to.
how much are they?
pantera6 said:
1 week Update on transistor stage sound:
Well... A week's past since I put this mod into the CD63... which to me... transformed it into a giant killer.
First of... those initial impressions that I first had.... well... over the next 4 days of running in, the sound got progressively "worse"
Finally this weekend, I sat down to have another proper listen, and it had indeed gotten better.... that low frequency energy was back... and the soundstage had more depth. One of the things that is very noticable now is the amount of "intelligibility" in each recording.... boy it's clean!! Also, over the week... things weren't sounding too musical, but after around the 100 hr mark... it all started gelling again. The pace, rhythm and timing is back.... but my CD player still lacks that ultimate transparency I had before the change-over.
After looking through the discussion last week re. coupling caps (thanks Disco and Ray... for enlightening me further)... I've bit the bullet and ordered some 10uF Ampohm polyprops from RS Components and the Vishay 1837s to bypass them with. Fitting these would be interesting indeed, given they are 70mm long!!! I'll try and mount them over the HDAM copper covers and run the output wire directly to the RCAs.
So overall... after one week of running in, the initial impressions still stand. I've noticed the "true character" of the transistor output stage emerging... and it's very clean (intelligible) with very good lows and a wonderful midrange. Ray's right... the opamps sounded a bit "fake" in comparrision. I like the transistor stage sound a lot better... to me at least... it sounds more "real".
Just one final comment..... the CD player (after fitting the transistor stage) now has a constant hum when the preamp volume is turned all the way up (not white noise...but like 50 hz hum) and when no CDs are playing. It's definitely comming from the player... when the power's on (in stop, pause etc.) When it's playing music, I guess it's still there, but the music takes over and I don't notice it. It is otherwise not noticable, but the fact that it's still above the noise floor concerns me. I wonder if this is the noise of the DACs being amplified?? Anyone? Could this be a noisy ground or digital noise seeping through my shoddy workmanship? How can I get rid of this, or is it a known side effect of having such a great sounding passive filter + output stage? Your thoughts would be appreciated!
Champi
My transistor stage didn't have any noise on output.
50hz? check your earthing.
allan
ps those precision clock you gave link to.
how much are they?
Re: Re: Re: CD63 Transistor Output Stage
Yea, could be a possibility. I've got the CD63 earthed and it's the only component in my system that's earthed... but... I'm not saying it's 50hz hum.... sound like it's a distinct frequency (not sure what), definitely not white noise. If it's from the DAC, would it be "white noise"?
Any more ideas guys.... would be appreciated..... I'll investigate them all! Thanks in advance!
You mean this one: www.rakon.co.nz ? If that's what you're refering to, I paid NZ$29.95 + GST -> approx NZ$ 35.00
The specs I used to place the order were as follows:
General Purpose Communications Crystal
* Model: UM-1S
* Fundamental Frequency: 16.9344 MHz
* Operating Temp: 0 to +50 C
* Calibration Tolerance: +/-5 PPM
* Frequency Stability: +/-3 PPM
* Circuit Conditions: 18 pF - parallel resonance mode -> I calculated this value taking into account the 2 x 10pF caps plus trace capacitance
* Ageing per year: +/- 0.5 PPM
* Frequency Perturbation: 0.1 PPM
* Package Style: Through-hole
Took 3 weeks to get it, but the crystal dropped right in and worked perfectly.
Hope this helps!
Cheers,
Champi
awpagan said:
Yea, could be a possibility. I've got the CD63 earthed and it's the only component in my system that's earthed... but... I'm not saying it's 50hz hum.... sound like it's a distinct frequency (not sure what), definitely not white noise. If it's from the DAC, would it be "white noise"?
Any more ideas guys.... would be appreciated..... I'll investigate them all! Thanks in advance!
awpagan said:
You mean this one: www.rakon.co.nz ? If that's what you're refering to, I paid NZ$29.95 + GST -> approx NZ$ 35.00
The specs I used to place the order were as follows:
General Purpose Communications Crystal
* Model: UM-1S
* Fundamental Frequency: 16.9344 MHz
* Operating Temp: 0 to +50 C
* Calibration Tolerance: +/-5 PPM
* Frequency Stability: +/-3 PPM
* Circuit Conditions: 18 pF - parallel resonance mode -> I calculated this value taking into account the 2 x 10pF caps plus trace capacitance
* Ageing per year: +/- 0.5 PPM
* Frequency Perturbation: 0.1 PPM
* Package Style: Through-hole
Took 3 weeks to get it, but the crystal dropped right in and worked perfectly.
Hope this helps!
Cheers,
Champi
Re: Re: Re: Re: CD63 Transistor Output Stage
pantera6 said:
Yea, could be a possibility. I've got the CD63 earthed and it's the only component in my system that's earthed... but... I'm not saying it's 50hz hum.... sound like it's a distinct frequency (not sure what), definitely not white noise. If it's from the DAC, would it be "white noise"?
Any more ideas guys.... would be appreciated..... I'll investigate them all! Thanks in advance!
Your amp is not earthed?
you have the grd on the output of the buffer connected to left/right rca grd?
and this grd can go to star grd.
allan
ps that the clock thank's
going to give it a try for another cdplayer
I've just been looking at Black Gate caps and the ones that seemed to be used in high end equipment or mods is the NX-Hi Q type.
Where I get mine from the lowest value ones are 22uF!
I can get the N type in 4.7uF but ideally the Nx-Hi Q are the ones to use.
I also looked at the AC type which is designed for xovers.
Has anyone tried these BG?
http://www.hificollective.co.uk/components/black_gate_caps.html
Brent
Where I get mine from the lowest value ones are 22uF!
I can get the N type in 4.7uF but ideally the Nx-Hi Q are the ones to use.
I also looked at the AC type which is designed for xovers.
Has anyone tried these BG?
http://www.hificollective.co.uk/components/black_gate_caps.html
Brent
rowemeister said:
I thought audio coupling was there major advantage
thought, i don't use them, always preferred dc coupling
no old small BG's being used somewhere else that can be changed for a FC or similar
allan
ps N should be ok just NX-Hi-Q are better.
pps they are non polar caps line
awpagan said:
I thought audio coupling was there major advantage
thought, i don't use them, always preferred dc coupling
no old small BG's being used somewhere else that can be changed for a FC or similar
allan
ps N should be ok just NX-Hi-Q are better.
pps they are non polar caps line
Yeah they are non polar.
They are cheap enough and may just buy them to test.
Brent