Reply
 
Thread Tools Display Modes
  #1   Report Post  
John L Stewart John L Stewart is offline
Senior Member
 
Location: Toronto
Posts: 301
Smile Wide Range Wein Bridge Oscillator

Go to this link- www.hparchive.com

to see the HP 207A Wide Range Oscillator listed under the equipment heading.

20 Hz to 20 KHz in one twist of the dial. Uses a modified Wein Bridge.

Cheers to All, John Stewart
Attached Images
 
  #2   Report Post  
Posted to rec.audio.tubes
Phil Allison[_3_] Phil Allison[_3_] is offline
external usenet poster
 
Posts: 500
Default Wide Range Wein Bridge Oscillator


"John L Stewart"

Go to this link- www.hparchive.com

to see the HP 207A Wide Range Oscillator listed under the equipment
heading.

20 Hz to 20 KHz in one twist of the dial. Uses a modified Wein Bridge.



** How funny, one of them sold on eBay yesterday:

http://www.ebay.com/itm/HP-207A-Audi...047675.l255 7


But does it use a tuning ganger or a multi-section pot?

( I cannot open that 12MB pdf at the moment. )


..... Phil


  #3   Report Post  
Posted to rec.audio.tubes
patrick-turner patrick-turner is offline
external usenet poster
 
Posts: 119
Default Wide Range Wein Bridge Oscillator


John Stewart recommended we go to a site for HP archived info including manuals and schematics........

Go to this link- www.hparchive.com
to see the HP 207A Wide Range Oscillator listed under the equipment
heading.
20 Hz to 20 KHz in one twist of the dial. Uses a modified Wein Bridge.
Cheers to All, John Stewart


The 207A is described as an audio sweep oscillator, which I assume means the F starts at 20Hz and over a time period the F is smoothly changed up to 20kHz, enabling the audio F response of filters and speakers etc to be seen on a CRO screen. The 207A is at http://www.hparchive.com/Manuals/HP-207A-Manual.pdf

I have not yet looked closely at the 207A schematic but there is a typical 4 gang tuning gang in a Wien bridge with each gang having C max = 500pf.

Its not a wide band instrument because it omits F below 20Hz and above 20kHz which prevents an audio engineer to examine the extremely important behaviour of audio gear below 20Hz and above 20kHz.

The HP 209A is a more interesting wien bridge oscillator with multi bands and 4Hz to 2MHz, but it uses all discrete bjts and j-fets. Hm, my latest little Oskar Layta goes 1Hz to 2MHz, but its oscillator amp is all tubed. Seems like HP couldn't seem to manage getting down to 1Hz, but lemme tellya, its dead easy now with discrete parts, and 0.1Hz is possible, and waves will have less THD than if you use the alterantive multi-pin signal gene chip which simply uses a pot to control DC on a pin chip to set the F, as in BWD161 function gene I restored&upgraded recently. The BWD161 calibration isn't very good. They seek to give too much too easily, and budget price and hence toylike quality that was affordable by hobbyists.

Getting down to 0.1Hz with a tubed amp and Wien bridge oscillator circuit may be difficult because the tube amp needs to be RC coupled, and hence is bandwidth limited, so perhaps a 0.1Hz-1Hz and 1Hz-10Hz may be best done with a phase shift oscilator, using R+C parts used in the biasing of the tubes, as in many guitar amps for tremelo.
Patrick Turner.





  #4   Report Post  
Posted to rec.audio.tubes
Phil Allison[_3_] Phil Allison[_3_] is offline
external usenet poster
 
Posts: 500
Default Wide Range Wein Bridge Oscillator


"patrick-turner"

The 207A is described as an audio sweep oscillator, which I assume means the
F starts at 20Hz and over a time period the F is smoothly changed up to
20kHz, enabling the audio F response of filters and speakers etc to be seen
on a CRO screen.

** Not at all, it is not a sweep generator.

Operation is purely manual and its uses rather limited to things like
testing audio lines ( in studio and broadcast) for flat response, checking
limiters and VU meters and also maybe speakers in production for unwanted
rattles and noises.

Audio sweep generators typically used the difference ( or beat) frequency
between two RF oscillators.

See pic of HP207A he

http://www.ebay.com/itm/HP-207A-Audi...047675.l255 7


.... Phil




  #5   Report Post  
John L Stewart John L Stewart is offline
Senior Member
 
Location: Toronto
Posts: 301
Smile

Quote:
Originally Posted by patrick-turner View Post
John Stewart recommended we go to a site for HP archived info including manuals and schematics........

Go to this link- www.hparchive.com
to see the HP 207A Wide Range Oscillator listed under the equipment
heading.
20 Hz to 20 KHz in one twist of the dial. Uses a modified Wein Bridge.
Cheers to All, John Stewart


The 207A is described as an audio sweep oscillator, which I assume means the F starts at 20Hz and over a time period the F is smoothly changed up to 20kHz, enabling the audio F response of filters and speakers etc to be seen on a CRO screen. The 207A is at http://www.hparchive.com/Manuals/HP-207A-Manual.pdf

I have not yet looked closely at the 207A schematic but there is a typical 4 gang tuning gang in a Wien bridge with each gang having C max = 500pf.

Its not a wide band instrument because it omits F below 20Hz and above 20kHz which prevents an audio engineer to examine the extremely important behaviour of audio gear below 20Hz and above 20kHz.

The HP 209A is a more interesting wien bridge oscillator with multi bands and 4Hz to 2MHz, but it uses all discrete bjts and j-fets. Hm, my latest little Oskar Layta goes 1Hz to 2MHz, but its oscillator amp is all tubed. Seems like HP couldn't seem to manage getting down to 1Hz, but lemme tellya, its dead easy now with discrete parts, and 0.1Hz is possible, and waves will have less THD than if you use the alterantive multi-pin signal gene chip which simply uses a pot to control DC on a pin chip to set the F, as in BWD161 function gene I restored&upgraded recently. The BWD161 calibration isn't very good. They seek to give too much too easily, and budget price and hence toylike quality that was affordable by hobbyists.

Getting down to 0.1Hz with a tubed amp and Wien bridge oscillator circuit may be difficult because the tube amp needs to be RC coupled, and hence is bandwidth limited, so perhaps a 0.1Hz-1Hz and 1Hz-10Hz may be best done with a phase shift oscilator, using R+C parts used in the biasing of the tubes, as in many guitar amps for tremelo.
Patrick Turner.
All should read the information carefully before submitting a learned reply. The HP 207A is in fact a sweepable oscillator. Not as one might think but by mechanical means. Go back to the manual & read carefully.

As for the superior ideas given in Pat's response, it is well known there is a very long road from a concept to a marketable product that makes a profit. Lets put your oscillator to that test!

Cheers, John
Attached Images
 


  #6   Report Post  
Posted to rec.audio.tubes
patrick-turner patrick-turner is offline
external usenet poster
 
Posts: 119
Default Wide Range Wein Bridge Oscillator

patrick-turner;973523 Wrote:
John Stewart recommended we go to a site for HP archived info including
manuals and schematics........

Go to this link- www.hparchive.com
to see the HP 207A Wide Range Oscillator listed under the equipment
heading.
20 Hz to 20 KHz in one twist of the dial. Uses a modified Wein Bridge.
Cheers to All, John Stewart



The 207A is described as an audio sweep oscillator, which I assume means
the F starts at 20Hz and over a time period the F is smoothly changed up
to 20kHz, enabling the audio F response of filters and speakers etc to


- show quoted text -
be seen on a CRO screen. The 207A is at
http://www.hparchive.com/Manuals/HP-207A-Manual.pdf

I have not yet looked closely at the 207A schematic but there is a
typical 4 gang tuning gang in a Wien bridge with each gang having C max
= 500pf.

Its not a wide band instrument because it omits F below 20Hz and above
20kHz which prevents an audio engineer to examine the extremely
important behaviour of audio gear below 20Hz and above 20kHz.

The HP 209A is a more interesting wien bridge oscillator with multi
bands and 4Hz to 2MHz, but it uses all discrete bjts and j-fets. Hm, my
latest little Oskar Layta goes 1Hz to 2MHz, but its oscillator amp is
all tubed. Seems like HP couldn't seem to manage getting down to 1Hz,
but lemme tellya, its dead easy now with discrete parts, and 0.1Hz is
possible, and waves will have less THD than if you use the alterantive
multi-pin signal gene chip which simply uses a pot to control DC on a
pin chip to set the F, as in BWD161 function gene I restored&upgraded
recently. The BWD161 calibration isn't very good. They seek to give too
much too easily, and budget price and hence toylike quality that was
affordable by hobbyists.

Getting down to 0.1Hz with a tubed amp and Wien bridge oscillator
circuit may be difficult because the tube amp needs to be RC coupled,
and hence is bandwidth limited, so perhaps a 0.1Hz-1Hz and 1Hz-10Hz may
be best done with a phase shift oscilator, using R+C parts used in the
biasing of the tubes, as in many guitar amps for tremelo.
Patrick Turner.



All should read the information carefully before submitting a learned
reply. The HP 207A is in fact a sweepable oscillator. Not as one might
think but by mechanical means. Go back to the manual & read carefully.
As for the superior ideas given in Pat's response, it is well known
there is a very long road from a concept to a marketable product that
makes a profit. Lets put your oscillator to that test!
Cheers, John

I have no such intention to test my oscillator construction with a view to making a profit from sales after manufacturing say 1,000 units.

I'm not so sure my response was better ot worse than anyone else's but it seems the 207A was designed so you could manually alter F, and through such a wide range of F that you could gain a quick idea of where a -3dB point was on a filter response. The dial accuracy allowed pinpointing the -3dB point easy.

I made an audio sweep kit which was advertised in Electronics Australia, and it used a 555 chip and other chips to produce a variable sweep speed repeatedly. Unfortunately, it was rather useless because if you had the sweep going and on a CRO and showing the response of a filter, there was no blip marker for frequencie being displayed, so you could see the response, but not see at what F the -3dB pole happened. I rarely ever used that after making it. Its was useless with speakers as well.

But well before such toy type kits there were various types of sweeps, and what were called wobulators, which varied a range of F by perhaps using a tuning cap connected to an electric motor.

Today, its not to hard to make an audio gene with voltage controlled frequency, and apply a saw tooth wave whose rate can be altered with a range of switched F or a pot, and so the sweep rate can be slow or fast, hence response can then be displayed on the CR0, but you need to know the F range and where a certain F occurs when looking at the CRO, and that's the hard part the toy gear doesn't have.

I found pink noise testing and the switched tunable filter for 33 spot frequencies between 20Hz and 20kHz ( Q = 12 ) to be far superior to get meaningful results with speakers. But someting like the oscillator I've just made is far better for filters with R&L&C, and right up to 2MHz.

To get more accurate F readings than a dial can indicate, I use a chip based frequency meter which I also made using an EA kits from 1990's. It does 1Hz to 50MHz, enough for me. BUT, the F readings below 20Hz become unreliable because the digital readouts don't have decimal places for low F, so that 1Hz reading could be between 0.5Hz and 2Hz. so for calibration of 1Hz on my dial after trimming values of Wien netork I must count and time the waves and 10 waves over 10 seconds is 1Hz. The CRO can then be set for 1Wave = full screen width, then when 2 waves ocupy the same distance, you have 2Hz, and so on. By 20Hz, accuracy with decimals isn't important, and if I measure 20Hz without reading jitter down to 19 or up to 21, its near enough to 20Hz, and I am guided sufficiently well to proceed to engineer other stuff which works OK.
There is no need to be obsessive about having what can only be excessive accuracy.
I am building the new oscillator after re-furbishing 2 other BDW olduns purely as an exercize in retro hobby engineering, equivalent to making a decent wooden spoked wagon wheel but there are SFA carts requiring my kind of wheel.

Nobody can make a profit making test gear which uses vacuum tubes. There would be many ways of achieving a Wien bridge oscillator using only solid state, and there is probably an active electronic equivalent version of a wien bridge. I can imagine much brighter young minds than mine could brew up an oscillator making 7Vrms at 50 ohms Rout from 0.1Hz to 10MHz in 8 decade ranges and the electronics on a little board would cost 50c in China to have made. I cannot figure out how to even begin to use a Spice Simulation program, I am dumb as an ox with simulation software, and I could not even figure out how to diplay the functions of a simple RC filter, let alone a single bjt or triode. I tried, but my mind went blank, and the nerds who wrote the "how to use this stuff" section have ZERO communications abilities. But I don't need to CAD because my brain does it all for me in its guess and try method - until it works well and be proved to always work well with wanted stability and no spurious outcomes.

The point is, I happen to like Tubes, even wagon wheels, and i like steam engines, propeller driven aircraft, I like nice women who are faithful and who like to ****, and all manner of old fashioned things that today's youth is trying to leave behind as it too puts on the Agony and Style, just as that old song says. It was written during the Californian Gold Rush of about 1850. Humans get sick&tired of the same old thing, and replace stuff because the new stuff has more features and bells and whistles while costing nothing, weighing nothing, and being transportable and able to hook up to the wireless Internet.

So what chance for a tubed 6 band oscillator? Some day, when the house cleaner-outers clean out my house for an auction sale after I die, someone will see the oscillator and it may fetch $1. Then, if it is sold, it is likely to spend 20 years in some old-bar-studs's garage gathering dust because the bloke said he wanted to study electronics, but he never seemed able to get away from TV, wife, PC, grand kiddies, and 101 other meaningless ways to waste ones end time.

But then, life has no meaning. We like to think is has, when in fact it only may have once, or even twice ot more often when young, but when old, it ceases to seem to have meaning. Life's meaning is that Life Just Is, OK, so enjoy it while ya can, until interuptions force you to stop doing what you like while you still can. Once over 65, and retired, one joins the Army Of Irrellevants. The young have zero need of us at all, so it seems to me. We represent what they don't want to become. They are too occupied repeating our mistakes when we were younger. That's my larger view in stuff, but then there are exceptions to all summations, and we all can point to young ppl who value their elders, and for more than what they are worth in money and inheritances. But my pointing finger looks young because it points to so few exceptions.

I find that Farnarkling around in a shed has inherent sublime peacefullness..
I forgive anyone who uses a tube amp I made to listen to outpourings of one Lou Reed.

Patrick Turner.
  #7   Report Post  
Posted to rec.audio.tubes
GRe GRe is offline
external usenet poster
 
Posts: 67
Default Wide Range Wein Bridge Oscillator


"Phil Allison" wrote in message
...

"patrick-turner"

The 207A is described as an audio sweep oscillator, which I assume means
the F starts at 20Hz and over a time period the F is smoothly changed up
to 20kHz, enabling the audio F response of filters and speakers etc to be
seen on a CRO screen.

** Not at all, it is not a sweep generator.

Operation is purely manual [...]


....unless one employes the 1950's way of sweeping by using a motor fitted to
the protruding rear end of the tuning dial shaft.

HP-297A Sweep Drive, not sure if this device does fit to the 207A, but
anyway:
http://www.hparchive.com/Manuals/HP-297A-Manual.pdf

Gio Re


  #8   Report Post  
Posted to rec.audio.tubes
Phil Allison[_3_] Phil Allison[_3_] is offline
external usenet poster
 
Posts: 500
Default Wide Range Wein Bridge Oscillator


"GRe"
"Phil Allison"
"patrick-turner"

The 207A is described as an audio sweep oscillator, which I assume means
the F starts at 20Hz and over a time period the F is smoothly changed up
to 20kHz, enabling the audio F response of filters and speakers etc to be
seen on a CRO screen.

** Not at all, it is not a sweep generator.

Operation is purely manual [...]


...unless one employes the 1950's way of sweeping by using a motor fitted
to the protruding rear end of the tuning dial shaft.



** Which is not part of the 207As capabilities NOR has anything to do with
PT's silly assumption above.

Did you even read it ?

FYI:

The max manual sweep rate HP recommend is one in 20 seconds.

OTOH a sweep generator has to produce a viewable trace on a scope - so 10
to 20 sweeps per second, at least.



.... Phil





  #9   Report Post  
Posted to rec.audio.tubes
GRe GRe is offline
external usenet poster
 
Posts: 67
Default Wide Range Wein Bridge Oscillator


"Phil Allison" wrote in message
...

"GRe"
"Phil Allison"
"patrick-turner"

The 207A is described as an audio sweep oscillator, which I assume means
the F starts at 20Hz and over a time period the F is smoothly changed up
to 20kHz, enabling the audio F response of filters and speakers etc to
be seen on a CRO screen.

** Not at all, it is not a sweep generator.

Operation is purely manual [...]


...unless one employes the 1950's way of sweeping by using a motor fitted
to the protruding rear end of the tuning dial shaft.



** Which is not part of the 207As capabilities ...


See manual: http://www.hparchive.com/Manuals/HP-207A-Manual.pdf , .pdf page
6, 2nd paragraph.


... NOR has anything to do with PT's silly assumption above.


With different wording the manual says what PT says.


Did you even read it ?


Did you?



FYI:

The max manual sweep rate HP recommend is one in 20 seconds.

OTOH a sweep generator has to produce a viewable trace on a scope - so 10
to 20 sweeps per second, at least.


Read (& interpret) the manual.
Use a paper chart X-Y recorder instead and a 20 sec. sweep (or slower) is
fine.

Gio Re




  #10   Report Post  
Posted to rec.audio.tubes
Phil Allison[_3_] Phil Allison[_3_] is offline
external usenet poster
 
Posts: 500
Default Wide Range Wein Bridge Oscillator


"GRe"
"Phil Allison"
"GRe"
"Phil Allison"
"patrick-turner"

The 207A is described as an audio sweep oscillator, which I assume
means the F starts at 20Hz and over a time period the F is smoothly
changed up to 20kHz, enabling the audio F response of filters and
speakers etc to be seen on a CRO screen.

** Not at all, it is not a sweep generator.

Operation is purely manual [...]

...unless one employes the 1950's way of sweeping by using a motor
fitted to the protruding rear end of the tuning dial shaft.



** Which is not part of the 207As capabilities ...


See manual: http://www.hparchive.com/Manuals/HP-207A-Manual.pdf , .pdf
page 6, 2nd paragraph.



** It is not one of the 207A's capabilities.


... NOR has anything to do with PT's silly assumption above.


With different wording the manual says what PT says.



** ROTFLMAO !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!

With DIFFERENT wording, anything says what any ****ing thing else says.

FFS - you are one STUPID ****ing ****head !!!!!!!!!!!

---------------------------------------------------------------
PT never mentioned any ****ing **chart recorder** !!!!!
---------------------------------------------------------------



Did you even read it ?


Did you?



** Go **** your mother - you lying, nut case POS.



FYI:

The max manual sweep rate HP recommend is one in 20 seconds.

OTOH a sweep generator has to produce a viewable trace on a scope - so
10 to 20 sweeps per second, at least.



Read (& interpret) the manual.
Use a paper chart X-Y recorder instead and a 20 sec. sweep (or slower) is
fine.



** See the words " ... on a CRO screen " ??????????

Or have you wanked yourself ****ING BLIND ????????

FYI:

Smartarse, ****wit, autistic ****s like you need a large calibre bullet in
the head.

Or maybe two or three.





..... Phil







  #11   Report Post  
Posted to rec.audio.tubes
GRe GRe is offline
external usenet poster
 
Posts: 67
Default Wide Range Wein Bridge Oscillator


"Phil Allison" wrote in message
...

FYI:

Smartarse, ****wit, autistic ****s like you need a large calibre bullet in
the head.

Or maybe two or three.


Thanks for the flowers, one is enough for me.
Others reserved for Down Under pest control.

Gio Re







  #12   Report Post  
Posted to rec.audio.tubes
Phil Allison[_3_] Phil Allison[_3_] is offline
external usenet poster
 
Posts: 500
Default Wide Range Wein Bridge Oscillator


"John L Stewart"

Go to this link- www.hparchive.com

to see the HP 207A Wide Range Oscillator listed under the equipment
heading.

20 Hz to 20 KHz in one twist of the dial. Uses a modified Wein Bridge.



** OK - I have had a look at the manual now and that is one cleverly
designed piece of kit.

Getting a 1000:1 frequency range from a tuning gang oscillator is quite a
feat and HP make it look so easy.

The four tube sustaining amplifier and output buffer is a winner too.

Shame the unit appears to be quite rare.


..... Phil


  #13   Report Post  
Posted to rec.audio.tubes
GRe GRe is offline
external usenet poster
 
Posts: 67
Default Wide Range Wein Bridge Oscillator


"Phill Allison" wrote in message
...

[...]

Shame the unit appears to be quite rare.


Fortunatly, you too.

Gio Re


  #14   Report Post  
Posted to rec.audio.tubes
Phil Allison[_3_] Phil Allison[_3_] is offline
external usenet poster
 
Posts: 500
Default Wide Range Wein Bridge Oscillator


"John L Stewart"

Go to this link- www.hparchive.com


**This article from the HP Journal ( January 1957 ) gives more detail on the
theory of operation.


http://www.hpl.hp.com/hpjournal/pdfs...Fs/1957-01.pdf



.... Phil


  #15   Report Post  
Posted to rec.audio.tubes
GRe GRe is offline
external usenet poster
 
Posts: 67
Default Wide Range Wein Bridge Oscillator


"Phil Allison" wrote in message
...

[...]

**This article from the HP Journal ( January 1957 )
gives more detail on the theory of operation.


http://www.hpl.hp.com/hpjournal/pdfs...Fs/1957-01.pdf



I'd say thanks for the link if it was'nt from you.
Decent RAT's stop reading, just feeding a.m. 130dB Chihuahua.

.... external motor drive ...
.... plotted on ... oscilloscope or ... X-Y recorder.
.... extension of ... shaft is available at the rear ...

See the words?

LBNL, dear ill Phalluson, 130dB Chihuahua ...
.... tuck tail between legs.
.... get a shot-myself-in-the-foot cure.

Gio Re
anglo-alien








  #16   Report Post  
John L Stewart John L Stewart is offline
Senior Member
 
Location: Toronto
Posts: 301
Smile

Quote:
Originally Posted by Phil Allison[_3_] View Post
"John L Stewart"

Go to this link- www.hparchive.com


**This article from the HP Journal ( January 1957 ) gives more detail on the
theory of operation.


http://www.hpl.hp.com/hpjournal/pdfs...Fs/1957-01.pdf



.... Phil
Thanks for posting that link Phil. A very good description of the HP 207A.

Cheeers to all, John
  #17   Report Post  
Posted to rec.audio.tubes
Holm Tiffe Holm Tiffe is offline
external usenet poster
 
Posts: 3
Default Wide Range Wein Bridge Oscillator

On 28.10.2013 14:49, John L Stewart wrote:

Go to this link- www.hparchive.com

to see the HP 207A Wide Range Oscillator listed under the equipment
heading.

20 Hz to 20 KHz in one twist of the dial. Uses a modified Wein Bridge.

Cheers to All, John Stewart


No. I think it must be a Wien-bridge sincs it's german inventor was
called Max Wien (Max Karl Werner Wien)

Regards,

Holm
Reply
Thread Tools
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Compton reverse log pot, tubed Wien Bridge oscillator patrick-turner Vacuum Tubes 10 October 15th 13 10:14 AM
Tuning gang C value for Wien bridge oscillator patrick-turner Vacuum Tubes 0 September 26th 13 12:23 PM
Best op amp for wien bridge oscillator for highest BW. Patrick Turner Vacuum Tubes 8 February 10th 09 10:51 AM
Neutrik TRS too wide! boydp Pro Audio 48 June 2nd 04 11:35 PM
hp 200cd wide range oscillator coitmusic Tech 3 September 24th 03 03:26 AM


All times are GMT +1. The time now is 07:06 PM.

Powered by: vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AudioBanter.com.
The comments are property of their posters.
 

About Us

"It's about Audio and hi-fi"