SyncTronX,
I can tell you I didn't learn much in that class. I had already built a digital clock back then that worked for close to 35 years before the elements burned out on the front of the clock. I was already messing with phone equipment and taking things apart for a long time before i took that class. I actually had to ring out all the wiring in that auditorium and figure out what had been done before me, no schematic existed and when I was done I didn't give them one either, I figured the next guy could do the same if it ever failed. I was already working on a real sound crew by high school setting up and tearing down speakers and all the rest.
OS,
I'm with you, I still don't have a smart phone, no problem using one but I figure when I'm out it is my chance to disconnect from the internet and constantly looking at email and such. As far as Sonos goes I turned down the opportunity to work there as I would have had to give up my personal IP, my speaker designs weren't going to end up with a company like that. No major company will spend the money to make a high quality speaker for consumer applications, it doesn't pencil out for them I was looking at a Fry's add this morning for a set of JBL speakers, 6 foot high column with 2- 6 1/2" speakers, a mid and two dome tweeter for $150.00 each on sale. There building the entire thing for about $20.00 in China with the enclosure, sound quality has nothing to do with what they are building, only price point.
I can tell you I didn't learn much in that class. I had already built a digital clock back then that worked for close to 35 years before the elements burned out on the front of the clock. I was already messing with phone equipment and taking things apart for a long time before i took that class. I actually had to ring out all the wiring in that auditorium and figure out what had been done before me, no schematic existed and when I was done I didn't give them one either, I figured the next guy could do the same if it ever failed. I was already working on a real sound crew by high school setting up and tearing down speakers and all the rest.
OS,
I'm with you, I still don't have a smart phone, no problem using one but I figure when I'm out it is my chance to disconnect from the internet and constantly looking at email and such. As far as Sonos goes I turned down the opportunity to work there as I would have had to give up my personal IP, my speaker designs weren't going to end up with a company like that. No major company will spend the money to make a high quality speaker for consumer applications, it doesn't pencil out for them I was looking at a Fry's add this morning for a set of JBL speakers, 6 foot high column with 2- 6 1/2" speakers, a mid and two dome tweeter for $150.00 each on sale. There building the entire thing for about $20.00 in China with the enclosure, sound quality has nothing to do with what they are building, only price point.
Wireless sucks !
The solar storm we had a few nights ago , (I saw the northern lights here !)
not only knocked out my sprint wireless internet , my verizon phones ...
but even my local wireless hub was dropping packets (seriously reduced
usability). ! 😱
If a minor solar storm can do that - whoa !!
Guess what still worked ... my local PC and the slewmaster.
I said "screw the internet" and listened to flac's through my wires instead.
Blue tooth uses a lossy AP2D , then there is APTX - and a slew of
other proprietary codecs. Sono's has their own codec , too.
I don't wan't another "Carrington event" to end my audio listening.
OS
The solar storm we had a few nights ago , (I saw the northern lights here !)
not only knocked out my sprint wireless internet , my verizon phones ...
but even my local wireless hub was dropping packets (seriously reduced
usability). ! 😱
If a minor solar storm can do that - whoa !!
Guess what still worked ... my local PC and the slewmaster.
I said "screw the internet" and listened to flac's through my wires instead.
Blue tooth uses a lossy AP2D , then there is APTX - and a slew of
other proprietary codecs. Sono's has their own codec , too.
I don't wan't another "Carrington event" to end my audio listening.
OS
Sonos can be wired as well. They have a 2 port switch built right into them. I don't like their proprietary network but I do like the way their software works. I installed 13 of them in the bosses house when we renovated it. You can run tunes all over his house from Ipads (and from my phone- might be a rude awakening at 3am sometime for him). He's pretty much useless when it come to electronics. I'm surprised he can turn the lights on some days. But he can work the Sonos like a champ.
If Runeplayer or some other App can work that simply and have good sound quality I'm all for it. The wives love it when they're in the kitchen or doing housework. No walking to the stereo to change stations/music.
If Runeplayer or some other App can work that simply and have good sound quality I'm all for it. The wives love it when they're in the kitchen or doing housework. No walking to the stereo to change stations/music.
JW,
I do see the utility of Bluetooth for the reason that you just stated of people with their music on their phones or other portable devices. I realize that it may not be the best audio signal but it is so generally used it is hard to ignore. I wouldn't think about WiFi, but Bluetooth yes. I just keep thinking about how you need to do that, you need to have a master slave setup or two identical setups that know which channel to play. The same goes for USB, an output from so many devices could be used with that, but then you need to convert the digital signal to analog with a DAC and I don't know what else. All of this is definitely above my pay grade, I would need major help to implement any of these things at a high level.
I do see the utility of Bluetooth for the reason that you just stated of people with their music on their phones or other portable devices. I realize that it may not be the best audio signal but it is so generally used it is hard to ignore. I wouldn't think about WiFi, but Bluetooth yes. I just keep thinking about how you need to do that, you need to have a master slave setup or two identical setups that know which channel to play. The same goes for USB, an output from so many devices could be used with that, but then you need to convert the digital signal to analog with a DAC and I don't know what else. All of this is definitely above my pay grade, I would need major help to implement any of these things at a high level.
The bluetooth audio codec is similar to S/Pdif - All the channel info is
digital , all the audio is digital. A "reverse" firmware codec sets appropriate
channels and the core audio bandwidth is decoded by the correct dac for
that channel.
A 30$ "pocket DAC" does the same thing with a direct usb/optical signal
instead of a wireless one.
OS
Thanks OS. Now how does a $30 DAC sound would be the next question? I guess they can get really small as they were talking about the dac in the Pono player and Scott Wurser said they used the same one that was in a bunch of cell phones.
"Pocket DAC" -
30$ ones can do -90db noise.
50-70$ ones can do -105 - -110db noise and
match most CD players. (ESS 24bit or even 32bit).
All do 20hz - 20K + ...
In ebay kit form ,ESS 24bit dacs are <50$
The limiting factor is not the DAC's , but the wireless codec
that feeds the digital info.
Bluetooths new "APT-X" codec is being changed/updated/altered
by every "audiophile" wireless vendor out there now.
Wireless "ultra hi-fi" audio transmission is in it's early days now. They
are still "hashing" out the standards (getting out the bugs).
Edit - Yup ... they are already into the bluetooth capable pocket DAC's
(for 150$+) can accept optical / coax , or bluetooth data - standard RCA out.
OS
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I wonder if this is the same APT-X codec that was licensed by DTS some 20 years ago. I'd bet that it is.
I have an off the wall question. I have a working Parasound HCA1200 amplifier rated at I think 200 watts per channel. I don't think it sounds very nice and I'm wondering if I could gut the amp and use the chassis and the power supply to build a Slewmaster inside of it. Do you think the power supply would be okay for this use or should I just start from scratch and get a new transformer and caps?
OS,
I actually think that the junky H/K integrated 60 watt amp sounds much better than this Parasound,
Are we talking about a unit like this to do the Bluetooth plus a dac. Not saying that model but something like this?
http://kcwirefree.com/kc6112.html
OS,
I actually think that the junky H/K integrated 60 watt amp sounds much better than this Parasound,
Are we talking about a unit like this to do the Bluetooth plus a dac. Not saying that model but something like this?
http://kcwirefree.com/kc6112.html
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No I haven't Christophe,
but even new it wasn't that nice sounding of an amp. Perhaps it could be improved from how it came originally.
but even new it wasn't that nice sounding of an amp. Perhaps it could be improved from how it came originally.
HCA1200 looks like a good amp. A "Badger" would fit it nice. The
"skived" heatsinks would not accept a slewmaster.
The slewmaster is more like H/K than anything else , just bigger
and quieter.
That bluetooth module is similar to what I discussed. It has
-95db noise / .01% THD , I'm sure there is better out there.
OS
Possibly it had a defect from new that slipped past QC? I repaired a buddies NAD amp a few years ago that blew a set of output devices. I noticed on the undamaged channel that there was a trace on the board that had been undermined when they etched it and was open circuit. As it was it would have never had any bias across the output devices, so on one channel he had been listening to horrible crossover distortion from new and he never realized it. It makes you wonder how the set bias on it from factory?
JW,
No I have two of those amps and they both sounded the same, lots of power but not great sounding. Yes, JC may have had his hand in this amplifier design but I don't think it was really anything special, it is not a John Curl signature model from Parasound, those were much more expensive and would have had more of his efforts.
No I have two of those amps and they both sounded the same, lots of power but not great sounding. Yes, JC may have had his hand in this amplifier design but I don't think it was really anything special, it is not a John Curl signature model from Parasound, those were much more expensive and would have had more of his efforts.
OS,
I just showed that module to give an example of what I thought you were talking about. CSR company seems to do a lot of this work and owns the licensing for BlueTooth I think. I get updates from them all the time about all kinds of weird document changes. They write the drivers and software and have integrated chip solutions.
Here is something that Bob Cordell just posted on the Blowtorch thread, thought that you may want to read it.
Hi Jan,
I think Esperado is correct in his comments on servos. However, as I pointed out in my book, the dc servo IS effectively in the signal path, so we must not be complacent about its design quality. I believe it should be designed with audiophile quality in mind. I personally would never use a TL072 in a DC servo in a high-end amplifier. I think a reasonably audio-grade op amp should be used. I usually use something like an OPA604.
Indeed, I actually prefer a servo that uses 2 op amps - one an inverting servo and one that inverts. This means that only one capacitor needs to be used, as opposed to the necessary 2 capacitors in the non-inverting servo many like to use. A dual op amp is not significantly more expansive than a single. I also beieve that the integrator capacitor should be of good quality - I always use a 1uF polypropylene.
Servo noise injected into the signal path is not a problem as long as it is kept in mind in the design. Attention to detail matters in the high end, and this includes the servo. I discuss this in my book.
Your point about the limited open-loop gain of the op amp letting some stuff through at high frequencies is interesting, but not likely a problem. One only needs to do the numbers or a simulation to see this. A decent FET op amp will have unity gain bandwidth as an integrator up to the 10MHz range. One also must recognize that the amount of signal current being injected into the integrator input is very small, as the integrator resistor is often 1M. I sometimes put a little bit of passive LPF after the integrator to further reduce noise, and this will also kill any HF feedthrough that might get through the integrator. Any such added LPF must be placed at a frequency where it does not create any ringing or instability in the servo. Putting in some such added filtering is easy in the two-op-amp servo. Of course, if desired to avoid two net poles, one can add a zero to the integrator with a small resistor that is placed in series with the integrating capacitor to cancel the subsequent passive pole, yielding a first-order servo, but with the higher-frequency part of the roll-off done passively. This is all probably guilding the lilly.
One must also make sure the servo never clips and has the right amount of authority. High-amplitude LF signals at the output of the amplifier can generate significant signal level at the output of the servo integrator. The servo should be designed not to clip with a full-power 10Hz signal at the output of the amplifier, AT MINIMUM.
Cheers,
Bob
I just showed that module to give an example of what I thought you were talking about. CSR company seems to do a lot of this work and owns the licensing for BlueTooth I think. I get updates from them all the time about all kinds of weird document changes. They write the drivers and software and have integrated chip solutions.
Here is something that Bob Cordell just posted on the Blowtorch thread, thought that you may want to read it.
Hi Jan,
I think Esperado is correct in his comments on servos. However, as I pointed out in my book, the dc servo IS effectively in the signal path, so we must not be complacent about its design quality. I believe it should be designed with audiophile quality in mind. I personally would never use a TL072 in a DC servo in a high-end amplifier. I think a reasonably audio-grade op amp should be used. I usually use something like an OPA604.
Indeed, I actually prefer a servo that uses 2 op amps - one an inverting servo and one that inverts. This means that only one capacitor needs to be used, as opposed to the necessary 2 capacitors in the non-inverting servo many like to use. A dual op amp is not significantly more expansive than a single. I also beieve that the integrator capacitor should be of good quality - I always use a 1uF polypropylene.
Servo noise injected into the signal path is not a problem as long as it is kept in mind in the design. Attention to detail matters in the high end, and this includes the servo. I discuss this in my book.
Your point about the limited open-loop gain of the op amp letting some stuff through at high frequencies is interesting, but not likely a problem. One only needs to do the numbers or a simulation to see this. A decent FET op amp will have unity gain bandwidth as an integrator up to the 10MHz range. One also must recognize that the amount of signal current being injected into the integrator input is very small, as the integrator resistor is often 1M. I sometimes put a little bit of passive LPF after the integrator to further reduce noise, and this will also kill any HF feedthrough that might get through the integrator. Any such added LPF must be placed at a frequency where it does not create any ringing or instability in the servo. Putting in some such added filtering is easy in the two-op-amp servo. Of course, if desired to avoid two net poles, one can add a zero to the integrator with a small resistor that is placed in series with the integrating capacitor to cancel the subsequent passive pole, yielding a first-order servo, but with the higher-frequency part of the roll-off done passively. This is all probably guilding the lilly.
One must also make sure the servo never clips and has the right amount of authority. High-amplitude LF signals at the output of the amplifier can generate significant signal level at the output of the servo integrator. The servo should be designed not to clip with a full-power 10Hz signal at the output of the amplifier, AT MINIMUM.
Cheers,
Bob
Even my wealthy neighbor "could not believe it" , my slewmaster beats
his Parasound - one that had the "JC" signature on it - HAH ! 😎
Badger could even give them a run in SQ.
Very nice amps - those parasound/ pass labs AB's , besides the brand ..
I still don't think 4-10K$ is justfied.
The H/K 's are the "poor man's" audiophile offering , at least most are in
3 digit territory (<1K$).
OS
Krypton-C rev 2, 3/2/15
are these the board with the lowest noise, lowest THD and the
highest slewrate that y'all have measured with SIM?
Sometime soon I'm going to be submitting the gerber files
to have boards made.
Who's interested in having them?
Also who's got the boards for the other projects associated
with this to make it work?
For you guys who've made this stuff, do you have your residual
incomplete BOMs? If you can send them to me at my email
address (it's here under handle Sync) hopefully as an excel spreadsheet.
Even if it's the new version I can open it, compile them all and
then reduce them down to one based on the part location.
I would need the file names like this to manage it:
boardname BOM# Yourname/handle.
That way I can manage it.
After I compile and reduce it I'll save it as the old year '97
excel so everyone can open it, review it and if you notice
a screw up let me know and I'll make the change.
There are some shortcuts that I know doing this stuff
as for contract I had having to manage the certifications
and recertify 18,000 employees of an aircraft manufacturer
after some Bozo or Bozetta pulled the emergency egress
(ejection seat) in the plant.
Yes, they are live when building the aircraft.
It shouldn't be a problem to do, as long as my hands hold up,
the joys of growing old.
are these the board with the lowest noise, lowest THD and the
highest slewrate that y'all have measured with SIM?
Sometime soon I'm going to be submitting the gerber files
to have boards made.
Who's interested in having them?
Also who's got the boards for the other projects associated
with this to make it work?
For you guys who've made this stuff, do you have your residual
incomplete BOMs? If you can send them to me at my email
address (it's here under handle Sync) hopefully as an excel spreadsheet.
Even if it's the new version I can open it, compile them all and
then reduce them down to one based on the part location.
I would need the file names like this to manage it:
boardname BOM# Yourname/handle.
That way I can manage it.
After I compile and reduce it I'll save it as the old year '97
excel so everyone can open it, review it and if you notice
a screw up let me know and I'll make the change.
There are some shortcuts that I know doing this stuff
as for contract I had having to manage the certifications
and recertify 18,000 employees of an aircraft manufacturer
after some Bozo or Bozetta pulled the emergency egress
(ejection seat) in the plant.
Yes, they are live when building the aircraft.
It shouldn't be a problem to do, as long as my hands hold up,
the joys of growing old.