Originally posted by georgehifi
Hold on George...
I have nothing to do with the patent, for me it is just this much...
My circuit was taken away from a publishing establishment by someone and that person or his acquaintance claims it to be his. That is all the issue here.
And that fool did not even take the trouble of renaming it.
And if u have not read it properly, I repeat
'The LED/LDR combo was left out as it is not considered AUDIOPHILE and induces harmonic distortion.'
That keeps lightspeed away.
Gajanan Phadte
------------_--___-__-________---------
Hold on George...
I have nothing to do with the patent, for me it is just this much...
My circuit was taken away from a publishing establishment by someone and that person or his acquaintance claims it to be his. That is all the issue here.
And that fool did not even take the trouble of renaming it.
And if u have not read it properly, I repeat
'The LED/LDR combo was left out as it is not considered AUDIOPHILE and induces harmonic distortion.'
That keeps lightspeed away.
Gajanan Phadte
------------_--___-__-________---------
gmphadte said:
No No, hold on you!!!! I never pointed the finger at you at all, my statement about Dartzeel was just a fact, about someone giving themselves a pat on the back for someone else's IP that's all, and trying to patent it. It never made reference to you at all.
And your last paragraph obviously says to me you have never heard one in the right circumstances, otherwise it would never have been said.
Cheers George
Which was this phantomatic "publishing establishment"?
Can you explain how someone from another continent could have had "taken away" a not yet published document?
The name of the "incriminated" file is "bozzaswitchless". Please notice that "bozza" is the Italian for "draft":
http://it.wikipedia.org/wiki/Bozza
For an Italian that file name is quite an obvious one for the draft of a "switchless" front-end design.
On the other end, AFAIK that word is meaningless in English.
Thus, to me such a name is in itself a clear evidence that whoever had given that name to a file is likely an Italian, or at least a native Italian language speaker... and quite unlikely an Indian guy.
In the end, again: bring the evidences to prove your claims. Otherwise, the only possible conclusion is that if there is someone trying to steal someone's else design, that one is you.
P.S.: sorry for the OT.
Gentlemen, at diyAudio we fully support those who want to protect their IP. However, without evidence, there is no case, so until such evidence is posted, this discussion is over. Please get back to the topic at hand. Any further off topic posts on this subject may be removed without notice and/or further action taken against the poster. You have been warned.
I've put one of these together and am really happy with the results. I'm not using it as a passive though, but as an attenuator in a valve pre. Sound is very neutral and the treble especially is just so far ahead of something like a alps pot.
Highly recommended! (and mine is the earlier version with just 2 LDRs)
Fran
Highly recommended! (and mine is the earlier version with just 2 LDRs)
Fran
woodturner-fran said:
Good one Fran, in a tube amp you have the advantage of the impedance match being right, nine x out of ten, because most are usually 100k or more input.
Now you have the taste for the Lightspeed you should try the series shunt (4 LDR) arrangement, because what you will gain on top of what you already have, is more bass impact, extension and tightness with the series/shunt (4xLDR) arrangement.
Keep up the good work.
Cheers George
OK all,
I have built two of these LS attenuators and have finally hit paydirt.
I have just the standard LS as suggested from the beginning and but with a single pot, not dual. No fancy caps, or inductors, or anything like some of you have indicated...
Sounded fine with a Laptop Power supply, just needed a bit more gain to drive my Krell Clone/Magnepan MGIIIa speakers. I needed to crank the volume to 3/4 full at my listening level.
Next I tried two 9 volt batteries in series with an LM317 dropping the voltage to 12v on the LS. Much better clarity and presence, but still needed a bit more gain.
So here is what I did. I slapped together a JFET BOZ on the back end of the LS and powered both the LS and the JFET BOZ from the pair of 9V batteries in series.
This is it. Better than my M7 Clone Tube pre, my 12B4 tube pre, and a friends Melos SHA-Gold Reference I currently have.
All the gain I need. Sound is so crisp and delicate...
Listening to some Nora Jones right now and its bringing tears to my eyes.
Someone try it and confirm I am not crazy....
I have built two of these LS attenuators and have finally hit paydirt.
I have just the standard LS as suggested from the beginning and but with a single pot, not dual. No fancy caps, or inductors, or anything like some of you have indicated...
Sounded fine with a Laptop Power supply, just needed a bit more gain to drive my Krell Clone/Magnepan MGIIIa speakers. I needed to crank the volume to 3/4 full at my listening level.
Next I tried two 9 volt batteries in series with an LM317 dropping the voltage to 12v on the LS. Much better clarity and presence, but still needed a bit more gain.
So here is what I did. I slapped together a JFET BOZ on the back end of the LS and powered both the LS and the JFET BOZ from the pair of 9V batteries in series.
This is it. Better than my M7 Clone Tube pre, my 12B4 tube pre, and a friends Melos SHA-Gold Reference I currently have.
All the gain I need. Sound is so crisp and delicate...
Listening to some Nora Jones right now and its bringing tears to my eyes.
Someone try it and confirm I am not crazy....
Attachments
Great that you've seen the Light john65b, (I couldn't help that) the reason for your liking of the buffer after the Lightspeed is that the Krell has a low input impedance of around 22k, that would definitely load up a standard Lightspeed too much.
It would be nice if you could change that 22k input loading resistor to say 100k, (but never turn it on without the Lightspeed attached), then you could get rid of the buffer after the Lightspeed and get an even better sound.
After that and all is well, it would also be better to then change the input filter cap to ground from 470pf to 220pf when using the Lightspeed, this then will maintain a nice fast/transparent top end.
Cheers George
It would be nice if you could change that 22k input loading resistor to say 100k, (but never turn it on without the Lightspeed attached), then you could get rid of the buffer after the Lightspeed and get an even better sound.
After that and all is well, it would also be better to then change the input filter cap to ground from 470pf to 220pf when using the Lightspeed, this then will maintain a nice fast/transparent top end.
Cheers George
Fet Buffers
Hi John65B,
Fets have intrinsically very low intermodulation distortion which will allow simple circuitry with high musical transparency. I have used them for a variety of circuit functions for around 38 years and so far I have to say that I haven't found an op amp that would convert me. Sometimes a valve can do it better, sometimes not. They do require decent power supplies for their best performance as the power supply rejection, like simple valve circuits, is not great. The 2SK170 is designed for high gain low noise preamp input stages and may display more gain than you need. A lower GM fet may give a more linear result at the higher signal levels the line level stage sees. As George says part of their attraction is good impedance matching. They are a lot more user friendly than valves for DIY as they are cheaper to implement, the power supplies are simpler, and circuit voltages generally won't toast you if your finger strays towards the supply rail.
At the moment I am using a series resistor/shunt LDR configuration for my volume control. The LEDs are driven by infra red remotely controlled voltage controlled current sources and the LDR is buffered by either a simple fet circuit or a 300B valve, depending on my mood, which is then followed by a source follower MOSFET driving the loudspeakers. I don't need much gain as the loudspeakers give 105 dB for 1 watt of power with hardly any voltage swing required. The whole lot is very simple, very transparent and very musical.
Regards
Paul
Hi John65B,
Fets have intrinsically very low intermodulation distortion which will allow simple circuitry with high musical transparency. I have used them for a variety of circuit functions for around 38 years and so far I have to say that I haven't found an op amp that would convert me. Sometimes a valve can do it better, sometimes not. They do require decent power supplies for their best performance as the power supply rejection, like simple valve circuits, is not great. The 2SK170 is designed for high gain low noise preamp input stages and may display more gain than you need. A lower GM fet may give a more linear result at the higher signal levels the line level stage sees. As George says part of their attraction is good impedance matching. They are a lot more user friendly than valves for DIY as they are cheaper to implement, the power supplies are simpler, and circuit voltages generally won't toast you if your finger strays towards the supply rail.
At the moment I am using a series resistor/shunt LDR configuration for my volume control. The LEDs are driven by infra red remotely controlled voltage controlled current sources and the LDR is buffered by either a simple fet circuit or a 300B valve, depending on my mood, which is then followed by a source follower MOSFET driving the loudspeakers. I don't need much gain as the loudspeakers give 105 dB for 1 watt of power with hardly any voltage swing required. The whole lot is very simple, very transparent and very musical.
Regards
Paul
George and Maximus,
Thanks for your replies.
I would change a few things on my Krell Clone as you detailed out in your post, but may just leave it as it stands. This way I can try the LS/JFET BOZ pre on other amps (Aleph 60 and a ZEN amp) when I finish them.
I always felt the low impedance of the Krell was keeping the LS from really shining, but was confused by it sounding very good on one of my equally low impedance (22k) Gainclones.
Anyway, this LS/JFET BOZ combo is really nice and a keeper as far as I can tell. I am having a friend with "better ears" come by tonight to give me his impressions on it vs the Melos/M7/12B4 I have. He has some pretty impressive (read EXPENSIVE) gear compared to my DIY stuff.
Its always nice to see these guys with deep pockets squirm over my "cheap hobby stuff"...
Thanks for your replies.
I would change a few things on my Krell Clone as you detailed out in your post, but may just leave it as it stands. This way I can try the LS/JFET BOZ pre on other amps (Aleph 60 and a ZEN amp) when I finish them.
I always felt the low impedance of the Krell was keeping the LS from really shining, but was confused by it sounding very good on one of my equally low impedance (22k) Gainclones.
Anyway, this LS/JFET BOZ combo is really nice and a keeper as far as I can tell. I am having a friend with "better ears" come by tonight to give me his impressions on it vs the Melos/M7/12B4 I have. He has some pretty impressive (read EXPENSIVE) gear compared to my DIY stuff.
Its always nice to see these guys with deep pockets squirm over my "cheap hobby stuff"...
MikeHunt79 said:
If you were building your own optoisolators, from discrete LEDs and LDRs, I guess you could either match both the LDRs and the LEDs, OR, find an LED/LDR pair that created a matching R vs I characteristic with another LED/LDR pair, whether or not the LEDs and LDRs matched their own kind.
But what is typically used is an LED/LDR "combo" device, i.e. with an LED and LDR that are already encapsulated in a single four-lead part, such as the Silonex NSL-32SR2S. In that case, you 'only' need to match the R(LDR) vs I(LED) curves, between parts.
And you probably only need to match them in the sense of finding the most-parallel R vs I curves, since an offset can probably be trimmed out.
Alliedelec.com carries the Silonex parts that are used in George's Lightspeed attenuator, as well as the Perkin-Elmer/Vactec 'Vactrol' types.