Thanks SyncTronX,
It's starting to cool off a bit and later this week it should be back down to 22 deg C. This is comfortable. Weather is unpredictable up here. It has been known to snow in August.
This morning it was snowing potash. Still is.
A lot of work but mostly fun and yes there were moments I was ready to pack it in.
Never accept defeat.
Cheers,
got Ice and a Fan?
Here is what the natives (American Indians) do --- they get a big cube/block of ice and put a fan behind it.... instant cool air.
I was told when I was in Turkey that in the summer the Mediterranean rim countries reach 130 degrees F. You loose about 1 quart of water per hour. I got dehydrated fast.
But in Bangkok, it will be raining while the temp is in the high 90's... a steam bath. Last month Lisa and I were on Phuket island and it started to rain.... caught without an umbrella.... but we decided to just walk in the rain... because it was warm and as soon as it stopped we would get dried out in 15 minutes.
There are some truely miserable places to live. Like the Arab countries... for heat and bleakness. But just across the border in western Canada isnt one of them. It's beautiful there. Still too cold for me in the winter, though. Lots of Canadian (snow birds) head south in winter to the warm Mexico beaches.
-Richard Marsh
Here is what the natives (American Indians) do --- they get a big cube/block of ice and put a fan behind it.... instant cool air.
I was told when I was in Turkey that in the summer the Mediterranean rim countries reach 130 degrees F. You loose about 1 quart of water per hour. I got dehydrated fast.
But in Bangkok, it will be raining while the temp is in the high 90's... a steam bath. Last month Lisa and I were on Phuket island and it started to rain.... caught without an umbrella.... but we decided to just walk in the rain... because it was warm and as soon as it stopped we would get dried out in 15 minutes.
There are some truely miserable places to live. Like the Arab countries... for heat and bleakness. But just across the border in western Canada isnt one of them. It's beautiful there. Still too cold for me in the winter, though. Lots of Canadian (snow birds) head south in winter to the warm Mexico beaches.
-Richard Marsh
Last edited:
@SyncTronX -- RE quad amps -- I can't even remember now what I have, but I think there are different ones waiting to go in the sockets I have yet to put in. My hesitation mainly has been just how inconvenient the 339 is to work on. I know I've got some LM part, and a Moto device, and a few others. We'll see how far I get when it starts to turn cold.
If you stick a spectrum analyzer on the 339 output, you'll see, for example, that when you switch in any of the filters, even though the meter reading goes down, the broadband npoise at the output goes way up -- really crummy amp for the filters, and the circuit topology doesn't help either -- Sallen-Key filters and the like are not optimized for low noise or low distortion.
If you stick a spectrum analyzer on the 339 output, you'll see, for example, that when you switch in any of the filters, even though the meter reading goes down, the broadband npoise at the output goes way up -- really crummy amp for the filters, and the circuit topology doesn't help either -- Sallen-Key filters and the like are not optimized for low noise or low distortion.
Needs an adapter but may be the best available quad opamp for this application: LME49740 | Audio Operational Amplifier | Audio | Description & parametrics A quick survey turned up nothing else similar.
Auto Tune notch filter ?
Some ideas regarding variable freq notch filters and auto tune notch filter.... just the tip of the ice-berg though...
View attachment 25404-notch_filter_autotunes_for_audio_applications_pdf.pdf
For use with a variable freq oscillator/generator and a sound card/QA400 to make a complete distortion test set for any audio frequency.
THx-RNMarsh
Some ideas regarding variable freq notch filters and auto tune notch filter.... just the tip of the ice-berg though...
View attachment 25404-notch_filter_autotunes_for_audio_applications_pdf.pdf
For use with a variable freq oscillator/generator and a sound card/QA400 to make a complete distortion test set for any audio frequency.
THx-RNMarsh
Last edited:
The biggest thing in auto tuning is how to measure what needs to be measured to do the tuning. We already know what needs to be tuned.
For a TT they have to be balanced as well as frequency tuned. The frequency is the easy part. The measurement must not be intrusive. What are the tuned phases at the two T's?
How do the phase very with balance?
Maybe See this and the original --
http://www.williamsonic.com/statevariable/article.html or Google williamsonic.com
he uses this approach:
THx-RNMarsh
Last edited:
dead link.
I think you mean this.
http://www.williamsonic.com/AudioOsc/index.html
Or perhaps this.
http://www.williamsonic.com/StateVariable/index.html
Last edited:
I thought they were referring to the HP 339A not the LM339.
The quad op amps in the 339A are LM348, quad 741. The pin out is the same as the LME69740 quad. Besides why replace a LM339 open collector comparator with a high performance audio op amp?
Okay,
I found it with your link, thanks Demian. I should get the 14 pin dip
and a socket for it. Now sure what board it needs, hmmm.
This is an example: Empty PCB for SOIC14 SOIC 14 SOIC 14 to DIP14 DIP 14 DIP 14 Plus Pin Headers | eBay
There probably are better options on ebay if you look.
There probably are better options on ebay if you look.