Hi, there is an "even" and a conditional "may" in there.
The problem is getting all six filters (or is it 8?) to let through the required passband.
With careful selection, it can be done, but the odds are stacked against the assembler if he/she is not also the builder/designer of all three compoments, source, pre and receiver.
High output impedance sources
I use a Pioneer TX-9100 tuner in both my systems. This old discrete output stage beast has a voltage divider on the output. The shunt is 22K and the series element is 15K. In my mind the output impedance is 15K. Maybe it is closer to 10K if you count the effect of the 22K to ground. There is a 10 ufd cap after the voltage divider.
Either way, the impedance is way higher than what SHOULD work with a 10K passive. But the combo works great! Slam, bass, and dynamics are fine. Maybe not as good as my 200 ohm disc player or 50 ohm phono stage, but more than adequate. The amps used are both 100K input.
I suspect the dac output will work just fine. The dac chips usually can handle 10K with no sweat.
Tried a Monica II dac for a while. It uses the dac as an output stage. But it went to the attic before trying the Lightspeed. I might dig it out to see how it interfaces.
George
I use a Pioneer TX-9100 tuner in both my systems. This old discrete output stage beast has a voltage divider on the output. The shunt is 22K and the series element is 15K. In my mind the output impedance is 15K. Maybe it is closer to 10K if you count the effect of the 22K to ground. There is a 10 ufd cap after the voltage divider.
Either way, the impedance is way higher than what SHOULD work with a 10K passive. But the combo works great! Slam, bass, and dynamics are fine. Maybe not as good as my 200 ohm disc player or 50 ohm phono stage, but more than adequate. The amps used are both 100K input.
I suspect the dac output will work just fine. The dac chips usually can handle 10K with no sweat.
Tried a Monica II dac for a while. It uses the dac as an output stage. But it went to the attic before trying the Lightspeed. I might dig it out to see how it interfaces.
George
Thanks, all.
My amp is an old, sorry vintage Accuphase E-406V from 1997.
It is an integrated with a nice option on the back, a switch to split the pre and the power. A seperate input and output do the rest.
After I made the bypass, I started to look at my set with new eyes. I used to respect it, now we've left those feelings behind us. It's love now. Accuphase has a distinct house sound, at least in my chain (Shigaraki -> anti-IC's -> Accuphase -> Dynaudio C1's). In active mode there is a lot of finesse there, if you compare it to the competition. But loud mids and loud hi's are not guaranteed stress free. And the transparancy and tonallity of the little passive, well, that's something else.
Like George says, you can spin discs for hours. You just zoom in on the mids and you stay there, as you would with unrecorded, unamplified music. Right in the center of the frequency spectrum, where most of the music happens. Notes are hit dead center, sounding pure and uncut. Changes in pitch, color, shape all come out in a very familiar and unelectronic way. High notes are compact but have real density and mass. There are these crazy contrasts, hardness and softness in one note, loudness and low level from one drum at the same time. Harmonics are very true, bowing and flexing over a piano, travelling endlessly through the room. In short, it's the old cliché of pulling out cd's you haven't pulled out for years.
Now, I've noticed three things about the dynamic behavior with the passive. Firstly, dynamics are not as overpowering as they can be with the active. Secondly, dynamics seem best with the attenuator at twelve o'clock, which is loud so perhaps the overall level masks dynamic shortfalls, not quite sure there. Thirdly, dynamics are best in the highest registers, less so in the mids, and perhaps weakest in the lows. Leanness however is not an issue, mass is very real. No Milanese catwalk around my speakers.
How do you explain all that? The input impedance of the power stage is a low 20kOhm. So on paper that's another nono. The high source impedance being the first.
Turning to AndrewT's explanation, it could be those unknown paramaters (that I am struggeling to get a grasp on, sorry Andrew). Perhaps it is simpler, though. The anti-IC's have a very thin lead wire that might be easy to drive for the passive. This, combined with the power on tap - the Accuphase delivers 340 Watts to 4 Ohm speakers - is helped by the dynamic character of the Dynaudio's. And they are dynamic, don't let their sensitivity of 85dB fool you.
Sure, these are all explanations I can understand. But that doesn't mean they are wrong, does it?
My amp is an old, sorry vintage Accuphase E-406V from 1997.
It is an integrated with a nice option on the back, a switch to split the pre and the power. A seperate input and output do the rest.
After I made the bypass, I started to look at my set with new eyes. I used to respect it, now we've left those feelings behind us. It's love now. Accuphase has a distinct house sound, at least in my chain (Shigaraki -> anti-IC's -> Accuphase -> Dynaudio C1's). In active mode there is a lot of finesse there, if you compare it to the competition. But loud mids and loud hi's are not guaranteed stress free. And the transparancy and tonallity of the little passive, well, that's something else.
Like George says, you can spin discs for hours. You just zoom in on the mids and you stay there, as you would with unrecorded, unamplified music. Right in the center of the frequency spectrum, where most of the music happens. Notes are hit dead center, sounding pure and uncut. Changes in pitch, color, shape all come out in a very familiar and unelectronic way. High notes are compact but have real density and mass. There are these crazy contrasts, hardness and softness in one note, loudness and low level from one drum at the same time. Harmonics are very true, bowing and flexing over a piano, travelling endlessly through the room. In short, it's the old cliché of pulling out cd's you haven't pulled out for years.
Now, I've noticed three things about the dynamic behavior with the passive. Firstly, dynamics are not as overpowering as they can be with the active. Secondly, dynamics seem best with the attenuator at twelve o'clock, which is loud so perhaps the overall level masks dynamic shortfalls, not quite sure there. Thirdly, dynamics are best in the highest registers, less so in the mids, and perhaps weakest in the lows. Leanness however is not an issue, mass is very real. No Milanese catwalk around my speakers.
How do you explain all that? The input impedance of the power stage is a low 20kOhm. So on paper that's another nono. The high source impedance being the first.
Turning to AndrewT's explanation, it could be those unknown paramaters (that I am struggeling to get a grasp on, sorry Andrew). Perhaps it is simpler, though. The anti-IC's have a very thin lead wire that might be easy to drive for the passive. This, combined with the power on tap - the Accuphase delivers 340 Watts to 4 Ohm speakers - is helped by the dynamic character of the Dynaudio's. And they are dynamic, don't let their sensitivity of 85dB fool you.
Sure, these are all explanations I can understand. But that doesn't mean they are wrong, does it?
Re: UPDATE on my LIGHTSPEED
Mike just had a new Lightspeed Attenuator customer get back to me with his A/B comparison with a TVC S/B 102 MkIII with a few of his mates, and all agreed that (as you stated) the Lightspeed made the S/B sound confused and congested.
I think the fact that in the Lightspeed the signal goes in and back out with only a couple of centimetres travel, whereas the S/B TVC is more like a couple of hundred meters of very fine wire to go in and back out, there has to be loses.
Cheers George
mikelm said:
Mike just had a new Lightspeed Attenuator customer get back to me with his A/B comparison with a TVC S/B 102 MkIII with a few of his mates, and all agreed that (as you stated) the Lightspeed made the S/B sound confused and congested.
I think the fact that in the Lightspeed the signal goes in and back out with only a couple of centimetres travel, whereas the S/B TVC is more like a couple of hundred meters of very fine wire to go in and back out, there has to be loses.
Cheers George
Hey all,
Anybody want to find a good home for those surplus unmatched junk optos? Hey you know it makes sense they're just gonna sit in a drawer for years until you've forgotten what hey were for.
I have an idea to use unmatched optos:
Just use a vol pot (remote controlled) for gross vol adjustment and a second remote controlled pot for channel balance. EDIT: All can be done from the listening position.
I've also seen a post about using stepped attenuators with Rs matched to the opto it is being used with to give a matched output from both channels. A calibration step is needed to determine the values of these Rs
John
Anybody want to find a good home for those surplus unmatched junk optos? Hey you know it makes sense they're just gonna sit in a drawer for years until you've forgotten what hey were for.
I have an idea to use unmatched optos:
Just use a vol pot (remote controlled) for gross vol adjustment and a second remote controlled pot for channel balance. EDIT: All can be done from the listening position.
I've also seen a post about using stepped attenuators with Rs matched to the opto it is being used with to give a matched output from both channels. A calibration step is needed to determine the values of these Rs
John
I've only read the first 8 pages of this thread, so I have an excuse, if this answer has come up already.....
How about building a digital circuit to control these puppies? In that way, enough steps can be used to keep things under 'fine control', and linearity is not a problem. Correction curves can be fitted easily. Any LED can be used at that point, no matter what linearity or non linearity any given one may have. Simply add in the correction curve, and presto!, done.
Assembly/time/selection problems go the way of the Do-Do bird. Repair becomes quite easy too.
Single display, multiple volumes and balances, individually addressed, or ganged, via the software, and then a 'curve fitting' function for 'repairs'. (curve entry).
Not that common for the forum in general, but not all that difficult for many of us. This is slightly out of my current capacities, but I did take this sort of stuff (digital control systems) in school. Many of us here, have done so as well, and many still do, or are working in that field.
This would be the wickedest outboard volume control box known to mankind. All you Digital crossover dudes, aka..the DCX24/96...start drooling..now. Methinks I just had a brain fart.
How about building a digital circuit to control these puppies? In that way, enough steps can be used to keep things under 'fine control', and linearity is not a problem. Correction curves can be fitted easily. Any LED can be used at that point, no matter what linearity or non linearity any given one may have. Simply add in the correction curve, and presto!, done.
Assembly/time/selection problems go the way of the Do-Do bird. Repair becomes quite easy too.
Single display, multiple volumes and balances, individually addressed, or ganged, via the software, and then a 'curve fitting' function for 'repairs'. (curve entry).
Not that common for the forum in general, but not all that difficult for many of us. This is slightly out of my current capacities, but I did take this sort of stuff (digital control systems) in school. Many of us here, have done so as well, and many still do, or are working in that field.
This would be the wickedest outboard volume control box known to mankind. All you Digital crossover dudes, aka..the DCX24/96...start drooling..now. Methinks I just had a brain fart.
Hey All,
I'm serious about your surplus unmatched NSL-32SRS optos - I will buy or trade with you - I don't want to be gouged by RS UK at £1.60 per pop + £10 shipping or to order from Allied in US.
I have emailed both of them asking if they will supply parts with the same grade letter and received no reply. I also emailed Silonex asking the same question but got no reply. Obviously, not interested unless I am buying 100s or 1000s of these parts.
My contention is that if the products are termed "sorted" (and they charge a higher price for the sorted product) & they are intended for use in audio (Audiohm) then it should be possible to buy two and use them as matched parts. As I pointed out to Silonex Supply Chain Manager (who should understand the value of the customer) - having to buy 10 to get two matched pairs is good for Silonex but not for their customers (maybe that's why I got no reply). Otherwise they are being sold not fit for the purpose to which they are intended. </Rant Over>
So guys I'm turning to the forum members - anybody?
John
I'm serious about your surplus unmatched NSL-32SRS optos - I will buy or trade with you - I don't want to be gouged by RS UK at £1.60 per pop + £10 shipping or to order from Allied in US.
I have emailed both of them asking if they will supply parts with the same grade letter and received no reply. I also emailed Silonex asking the same question but got no reply. Obviously, not interested unless I am buying 100s or 1000s of these parts.
My contention is that if the products are termed "sorted" (and they charge a higher price for the sorted product) & they are intended for use in audio (Audiohm) then it should be possible to buy two and use them as matched parts. As I pointed out to Silonex Supply Chain Manager (who should understand the value of the customer) - having to buy 10 to get two matched pairs is good for Silonex but not for their customers (maybe that's why I got no reply). Otherwise they are being sold not fit for the purpose to which they are intended. </Rant Over>
So guys I'm turning to the forum members - anybody?
John
Sorted, not matched
John,
Reading the spec sheet, htey are doing a one point match or sort. They do seem to follow this.
When plotting the batch purchased from Allied, the result looked like an exponetial decay. Low current levels is where than really drifted apart.
Purchasing four to make up a control most likely would not work out. Even 10 is not a guarantee. But from two batches measured, 10 should yield two or three usable pairs.
George
jkeny said:
John,
Reading the spec sheet, htey are doing a one point match or sort. They do seem to follow this.
When plotting the batch purchased from Allied, the result looked like an exponetial decay. Low current levels is where than really drifted apart.
Purchasing four to make up a control most likely would not work out. Even 10 is not a guarantee. But from two batches measured, 10 should yield two or three usable pairs.
George
Hi George,
Were all your parts from the same grade letter - I believe this is printed on the part?
If they charge extra for sorted then why do they have grading parts within the sort & not supply all from the one grade as the sorted parts? Do you see what I'm saying? It's like saying there's sorted but then there's "Sorted". Remember these are designed for audio so matching accross channels would seem to be important.
Anyway, what does anybody think of going with unmatched parts in a shunt configuration and just using two pots - one for gross vol control & other for fine interchannel balance?
Were all your parts from the same grade letter - I believe this is printed on the part?
If they charge extra for sorted then why do they have grading parts within the sort & not supply all from the one grade as the sorted parts? Do you see what I'm saying? It's like saying there's sorted but then there's "Sorted". Remember these are designed for audio so matching accross channels would seem to be important.
Anyway, what does anybody think of going with unmatched parts in a shunt configuration and just using two pots - one for gross vol control & other for fine interchannel balance?
look here for circuit diagram with balance control....
http://www.diyaudio.com/forums/showthread.php?postid=1174453#post1174453
easy to implement but after some use u may end up wishing u had organised matched pairs.
http://www.diyaudio.com/forums/showthread.php?postid=1174453#post1174453
easy to implement but after some use u may end up wishing u had organised matched pairs.
I would love to see a full preamp substitute with a remote controlled volume and selector system. Then I can trade up from my Tvc.
Would it be possible to build an input selector 'switch' with a clear signal path to match the 'Lightspeed'? i.e. no diodes or contacts in the device's circuit.
or perhaps the use of a selector before the 'lightspeed's' input could have its assosciated losses 'tuned out' to some degree?
Would it be possible to build an input selector 'switch' with a clear signal path to match the 'Lightspeed'? i.e. no diodes or contacts in the device's circuit.
or perhaps the use of a selector before the 'lightspeed's' input could have its assosciated losses 'tuned out' to some degree?
[QUOTE How can switching be done in a contactless manner? What is the least sonically intrusive switching system? /B][/QUOTE]
Wetted mercury relays would be the best for source switching, but my own Lightspeed prototype now five years old has a 10amp gold contact source switch on it for two inputs, when I test the production Lightspeed Attenuators models for a day before they are shipped to customers, I clearly hear that they are just a bit more transparent than my prototype, the only difference being they have no source switch. So maybe even a mercury wetted relay can also be heard.
Cheers George
Wetted mercury relays would be the best for source switching, but my own Lightspeed prototype now five years old has a 10amp gold contact source switch on it for two inputs, when I test the production Lightspeed Attenuators models for a day before they are shipped to customers, I clearly hear that they are just a bit more transparent than my prototype, the only difference being they have no source switch. So maybe even a mercury wetted relay can also be heard.
Cheers George
Hi George,
Try removing both your in & out female RCA. Instead solder one end of your IC cable directly to the attenuator. You should hear improvement with less contact parts.
BTW... about the power supply for lightspeed. I am aware that you are using 5V supply but what is the ideal Amper? Is 200mA too much? Well I found a nice regulater power supply pcb O11 (signma 11) by AMB.
http://www.amb.org/audio/sigma11/
Try removing both your in & out female RCA. Instead solder one end of your IC cable directly to the attenuator. You should hear improvement with less contact parts.
BTW... about the power supply for lightspeed. I am aware that you are using 5V supply but what is the ideal Amper? Is 200mA too much? Well I found a nice regulater power supply pcb O11 (signma 11) by AMB.
http://www.amb.org/audio/sigma11/