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Old 24th December 2012, 03:33 AM   #1291
benb is offline benb  United States
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I saw some Tek DUAL BEAM scope (dunno the model number) at a hamfest earlier this year. I don't know enough about old Tek scopes to fix these things (despite having a couple of carcases lying around), and the sheer number of toobs scares me, but I know the difference between that and the usual "dual trace" feature that all other analog scopes have. I kinda sorta think I shudda got it, or at least asked the price. I've heard of a Tek yahoo group, but do I want to learn such a skill? I read where Jim Williams fixed/revived/rebuilt these things as a hobby - I wish he had written a book on it.

I can't imagine what a NEW analog oscilloscope would cost.
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Old 24th December 2012, 06:10 AM   #1292
1audio is offline 1audio  United States
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Quote:
Originally Posted by guido View Post
Mmm,

Some samplers, a 7L5 and many more

I agree that these things are very handy. They are common over here, just not as much as in the us. And much more $$$ if it's a better mainframe or non standard plugins.

What's in the 3 plugin mainframe on the bench, a digitiser?
There are 2 7L5's, the one in the cabinet has a tracking generator. The 3 bay box is a Wavetek/Rockland fft thing. It goes to 100 KHz but is only 8 bits. Fine for the output of the distortion analyzer however. It has been very useful. And there is both a TDR and a sampler/timebase (and a handful of plugins for those). This all started when I decided I could not trust what I hear or what the BS merchants of audio passed on. Then I could not trust the meters etc. (The calibration setup is in another part of the shop.) Its a slippery slope. Just get a QA400 and be happy. . .
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Old 24th December 2012, 06:17 AM   #1293
1audio is offline 1audio  United States
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Quote:
Originally Posted by benb View Post
I saw some Tek DUAL BEAM scope (dunno the model number) at a hamfest earlier this year. I don't know enough about old Tek scopes to fix these things (despite having a couple of carcases lying around), and the sheer number of toobs scares me, but I know the difference between that and the usual "dual trace" feature that all other analog scopes have. I kinda sorta think I shudda got it, or at least asked the price. I've heard of a Tek yahoo group, but do I want to learn such a skill? I read where Jim Williams fixed/revived/rebuilt these things as a hobby - I wish he had written a book on it.

I can't imagine what a NEW analog oscilloscope would cost.
The 555 and 556 were a tube vendors dream. The 555 had a separate power supply that would put the high end audio variants to shame and weighed a whole lot. You can get more info than you would ever want at the Tek Scopes group at Yahoo.

You may be able to get decent modest analog scopes from China but never again a microchannel CRT with 1 GHz response.
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Old 24th December 2012, 06:21 AM   #1294
davada is offline davada  Canada
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Quote:
Originally Posted by 1audio View Post
There are 2 7L5's, the one in the cabinet has a tracking generator. The 3 bay box is a Wavetek/Rockland fft thing. It goes to 100 KHz but is only 8 bits. Fine for the output of the distortion analyzer however. It has been very useful. And there is both a TDR and a sampler/timebase (and a handful of plugins for those). This all started when I decided I could not trust what I hear or what the BS merchants of audio passed on. Then I could not trust the meters etc. (The calibration setup is in another part of the shop.) Its a slippery slope. Just get a QA400 and be happy. . .
LOL.

When they have all the bugs worked out.

I ordered an EMU0204 and the parts for a Twin T.
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Old 24th December 2012, 08:11 AM   #1295
mkc is offline mkc  Denmark
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This is a very interesting thread.

I have been in the process of getting some distortion measurement facility established. The QA400 certainly look good. especially if they can keep the $200 target. Then I have to get me one of these. Have you guys any idea of what release date they target?

Cheers,
Mogens
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Old 24th December 2012, 03:15 PM   #1296
davada is offline davada  Canada
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QuantAsylum was talking first release of software in the next few weeks but I don't know about the Hardware.

You can Email support at QuantaSylum and ask.

support@quantasylum.com

Cheers,
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Old 24th December 2012, 04:35 PM   #1297
guido is offline guido  Netherlands
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Quote:
Originally Posted by 1audio View Post
There are 2 7L5's, the one in the cabinet has a tracking generator. The 3 bay box is a Wavetek/Rockland fft thing. It goes to 100 KHz but is only 8 bits. Fine for the output of the distortion analyzer however. It has been very useful. And there is both a TDR and a sampler/timebase (and a handful of plugins for those). This all started when I decided I could not trust what I hear or what the BS merchants of audio passed on. Then I could not trust the meters etc. (The calibration setup is in another part of the shop.) Its a slippery slope. Just get a QA400 and be happy. . .
My 7L5 doesn't have the tracking generator unfortunately. There are not many around. An fft analyser is good to have. I've got an acient '84 advantest 100 kHz machine. 12bit, 2channels with differential inputs. It makes the 7000 mainframes look portable Also looking for a signal generator for that one..
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Old 24th December 2012, 05:13 PM   #1298
1audio is offline 1audio  United States
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The 7L5 w/ tracking generator is quite rare. I modified one of mine to have the interface to the 7854 to capture and save the output. It was a bear to add.

I used the QA400 for real work last week. I needed to characterize a headphone interface to sort out a problem. It worked very well. There are software bugs still but they are closing in on them. I suspect old hardware running old versions of Windows will be the biggest problem. The box is ideally suited to mobile electronics but needs external stuff for traditional audio. I am working on a solution for my needs.
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Old 24th December 2012, 10:52 PM   #1299
RNMarsh is offline RNMarsh  United States
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Quote:
Originally Posted by richiem View Post
@Richard -- The EMU drivers work for me in XP SP3; I think there is a driver package that runs in Win7, though Creative may call it a beta. ARTA then runs the EMU from its device setup menu. Like David, I'm beta testing the QA400. The EMU and QA both having rising noise floors (due to noise-shaping used) above 30kHz, so their dynamic range goes away fast. BTW, I have an HP 239 which is very similar, and it is equally good. But if you're going to be driving low-Z loads, then the LT1468 seems to be the real deal.
I have an EMu 0204/USb but yesterday my screen went dead on my old portable XP. Same PC I went to Taiwan with it in tow on so many trips. It finally died. I also needed it for Audio-Precision interface card (PCMCIA). Now its dead. Guess, I'll just wait for everyone to get the bugs out of the QA400. Its about time someone did a hard/soft combined and integrated test/measurement version at low cost.

I'm OK with the 339A oscillator for the time being as a low Harmonic source of mulitple freq... I can test some things with it as a signal source. Some might like it for the improved analyzer section as well.... Both source and analyzer are much improved now. And for super low thd, a spot frequency from Victors' gen is ready to be lashed up to a power supply. But still looking. Maybe the companion gen to the ShibaSoku 725 will pop-up at a bargin price.... Well, I live in hope. Thx-RNMarsh

Last edited by RNMarsh; 24th December 2012 at 11:07 PM.
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Old 24th December 2012, 11:10 PM   #1300
RNMarsh is offline RNMarsh  United States
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What would happen using another opamp in series with the oscillator opamp in such a way that it is one super high OLG opamp -- would the thd be even lower? Thx-RNMarsh
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