My distortion analyser (Sound Technology 1701B) failed awhile back and
the job to repair it has proven to be quite involved. As a consequence,
I found a Japanese auction site, where I located a very impressive DA
for reasonable money. This is the device I purchased:

https://kenrockwell.com/audio/panasonic/vp-7721a.htm

Ken is correct. It is a brilliant DA. Fast and easy to use. Naturally, I
had to lift the lid. Construction is excellent and every one of it's 5
regulated power supplies measured within 1% of their stated figures.
Here is a graph of the oscillator distortion, plus some internal photos,
as measured with my Quantasylum QA403 (oh yeah, I bought one of those too):

https://imgur.com/a/d7PcSDV

I also purchased an HP339A for not much money. I must say that the
construction quality comfortably exceeded my expectations:

https://imgur.com/a/cX43Ydp

A bit rough on the outside, but it works. Note the heavy gold plated PCB
traces. Colour me stunned.

Nice enough to use, but not as good as the Panasonic, IMO.

Of course, the Quantasylum whips the hardware analysers with ease.

Trevor Wilson wrote:
=================

> My distortion analyser (Sound Technology 1701B) failed awhile back and
> the job to repair it has proven to be quite involved. As a consequence,
> I found a Japanese auction site, where I located a very impressive DA
> for reasonable money. This is the device I purchased:
>
> https://kenrockwell.com/audio/panasonic/vp-7721a.htm
>
> Ken is correct. It is a brilliant DA. Fast and easy to use. Naturally, I
> had to lift the lid. Construction is excellent and every one of it's 5
> regulated power supplies measured within 1% of their stated figures.
> Here is a graph of the oscillator distortion, plus some internal photos,
> as measured with my Quantasylum QA403 (oh yeah, I bought one of those too):
>
> https://imgur.com/a/d7PcSDV
>
> I also purchased an HP339A for not much money. I must say that the
> construction quality comfortably exceeded my expectations:
>
> https://imgur.com/a/cX43Ydp
>
> A bit rough on the outside, but it works. Note the heavy gold plated PCB
> traces. Colour me stunned.
>
> Nice enough to use, but not as good as the Panasonic, IMO.
>

** TW likes to buy old test stuff, when it gets cheap cos it is unwanted.

Since my early teens, the idea of making my own test gear was instilled - cos it was affordable and you could learn a lot from so doing.
So, aside from buying an analogue multimeter, I made a number of PSUs, two digital frequency counters, three audio frequency and one white /pink noise generator and one 5 valve scope.
I even built a DVM from an Intersil evaluation kit before cheap commercial ones arrived.

About 30 years back, I needed a way to measure THD quick and easily.
3 spot frequencies would do and it could be powered from my bench +/- 15V PSU.
Wound up with a die cast box( 120 x 90mm) with a Wein bridge notch inside filter settable to 66Hz, 996 Hz and 5280Hz.
Has a 3 pos rotary switch and 2 x WW, 10 turn pots for nulling.
Inside are a few polystyrene caps, a handful of MF resistors and 2 x op-amps.
It was crucial the filter have very low temperature drift.

The final version resolves to 0.001% and can be manually nulled in 30 seconds.
A bench scope acts as monitor for nulling and to view the THD residual wave up to 100kHz.
Cost me maybe A$60 to make.

> Of course, the Quantasylum whips the hardware analysers with ease.

** That is TW's opinion, but not mine.

No way do I want a PC on my workbench and to have to trust a sampled & highly processed digital display of simple analogue data.
DSOs just annoy me with false information.

Call me old fashioned if you like...

........ Phil

On 6/05/2022 11:42 am, Phil Allison wrote:
> Trevor Wilson wrote:
> =================
>
>> My distortion analyser (Sound Technology 1701B) failed awhile back and
>> the job to repair it has proven to be quite involved. As a consequence,
>> I found a Japanese auction site, where I located a very impressive DA
>> for reasonable money. This is the device I purchased:
>>
>> https://kenrockwell.com/audio/panasonic/vp-7721a.htm
>>
>> Ken is correct. It is a brilliant DA. Fast and easy to use. Naturally, I
>> had to lift the lid. Construction is excellent and every one of it's 5
>> regulated power supplies measured within 1% of their stated figures.
>> Here is a graph of the oscillator distortion, plus some internal photos,
>> as measured with my Quantasylum QA403 (oh yeah, I bought one of those too):
>>
>> https://imgur.com/a/d7PcSDV
>>
>> I also purchased an HP339A for not much money. I must say that the
>> construction quality comfortably exceeded my expectations:
>>
>> https://imgur.com/a/cX43Ydp
>>
>> A bit rough on the outside, but it works. Note the heavy gold plated PCB
>> traces. Colour me stunned.
>>
>> Nice enough to use, but not as good as the Panasonic, IMO.
>>
>
> ** TW likes to buy old test stuff, when it gets cheap cos it is unwanted.
>
> Since my early teens, the idea of making my own test gear was instilled - cos it was affordable and you could learn a lot from so doing.
> So, aside from buying an analogue multimeter, I made a number of PSUs, two digital frequency counters, three audio frequency and one white /pink noise generator and one 5 valve scope.
> I even built a DVM from an Intersil evaluation kit before cheap commercial ones arrived.
>
> About 30 years back, I needed a way to measure THD quick and easily.
> 3 spot frequencies would do and it could be powered from my bench +/- 15V PSU.
> Wound up with a die cast box( 120 x 90mm) with a Wein bridge notch inside filter settable to 66Hz, 996 Hz and 5280Hz.
> Has a 3 pos rotary switch and 2 x WW, 10 turn pots for nulling.
> Inside are a few polystyrene caps, a handful of MF resistors and 2 x op-amps.
> It was crucial the filter have very low temperature drift.
>
> The final version resolves to 0.001% and can be manually nulled in 30 seconds.
> A bench scope acts as monitor for nulling and to view the THD residual wave up to 100kHz.
> Cost me maybe A$60 to make.
>
>> Of course, the Quantasylum whips the hardware analysers with ease.
>
> ** That is TW's opinion, but not mine.
>
> No way do I want a PC on my workbench and to have to trust a sampled & highly processed digital display of simple analogue data.
> DSOs just annoy me with false information.
>
> Call me old fashioned if you like...

**I prefer old school test equipment too, but I realise the obvious
advantages modern digital test equipment. I am presently tempted by one
of these:

https://w140.com/tekwiki/wiki/2245

The 'A' variant. Part of the last range of analogue CROs manufactured by
Tektronix. Although I love my Rigol 1054z (DSO), but I still enjoy using
a nice analogue CRO.

Trevor Wilson wrote:
=================
>
> >> My distortion analyser (Sound Technology 1701B) failed awhile back and
> >> the job to repair it has proven to be quite involved. As a consequence,
> >> I found a Japanese auction site, where I located a very impressive DA
> >> for reasonable money. This is the device I purchased:
> >>
> >> https://kenrockwell.com/audio/panasonic/vp-7721a.htm
> >>
> >> Ken is correct. It is a brilliant DA. Fast and easy to use. Naturally, I
> >> had to lift the lid. Construction is excellent and every one of it's 5
> >> regulated power supplies measured within 1% of their stated figures.
> >> Here is a graph of the oscillator distortion, plus some internal photos,
> >> as measured with my Quantasylum QA403 (oh yeah, I bought one of those too):
> >>
> >> https://imgur.com/a/d7PcSDV
> >>
> >> I also purchased an HP339A for not much money. I must say that the
> >> construction quality comfortably exceeded my expectations:
> >>
> >> https://imgur.com/a/cX43Ydp
> >>
> >> A bit rough on the outside, but it works. Note the heavy gold plated PCB
> >> traces. Colour me stunned.
> >>
> >> Nice enough to use, but not as good as the Panasonic, IMO.
> >>
> >
> > ** TW likes to buy old test stuff, when it gets cheap cos it is unwanted.
> >
> > Since my early teens, the idea of making my own test gear was instilled - cos it was affordable and you could learn a lot from so doing.
> > So, aside from buying an analogue multimeter, I made a number of PSUs, two digital frequency counters, three audio frequency and one white /pink noise generator and one 5 valve scope.
> > I even built a DVM from an Intersil evaluation kit before cheap commercial ones arrived.
> >
> > About 30 years back, I needed a way to measure THD quick and easily.
> > 3 spot frequencies would do and it could be powered from my bench +/- 15V PSU.
> > Wound up with a die cast box( 120 x 90mm) with a Wein bridge notch inside filter settable to 66Hz, 996 Hz and 5280Hz.
> > Has a 3 pos rotary switch and 2 x WW, 10 turn pots for nulling.
> > Inside are a few polystyrene caps, a handful of MF resistors and 2 x op-amps.
> > It was crucial the filter have very low temperature drift.
> >
> > The final version resolves to 0.001% and can be manually nulled in 30 seconds.
> > A bench scope acts as monitor for nulling and to view the THD residual wave up to 100kHz.
> > Cost me maybe A$60 to make.
> >
> >> Of course, the Quantasylum whips the hardware analysers with ease.
> >
> > ** That is TW's opinion, but not mine.
> >
> > No way do I want a PC on my workbench and to have to trust a sampled & highly processed digital display of simple analogue data.
> > DSOs just annoy me with false information.
> >
> > Call me old fashioned if you like...
> **I prefer old school test equipment too, but I realise the obvious
> advantages modern digital test equipment. I am presently tempted by one
> of these:
>
> https://w140.com/tekwiki/wiki/2245
>
> The 'A' variant. Part of the last range of analogue CROs manufactured by
> Tektronix. Although I love my Rigol 1054z (DSO), but I still enjoy using
> a nice analogue CRO.

** Did TW read my post at all ?

If he did, he took no notice of it.

...... Phil

In article <jdjdevFj23nU1@mid.individual.net>, Trevor Wilson
<trevor@rageaudio.com.au> wrote:
> On 6/05/2022 11:42 am, Phil Allison wrote:

> >
> > No way do I want a PC on my workbench and to have to trust a sampled &
> > highly processed digital display of simple analogue data. DSOs just
> > annoy me with false information.
> >
> > Call me old fashioned if you like...

> **I prefer old school test equipment too, but I realise the obvious
> advantages modern digital test equipment. I am presently tempted by one
> of these:

> https://w140.com/tekwiki/wiki/2245

I was old fashioned for a long time. But the reality now is that - for
audio at least - you can get excellent USB ADCs and DACs these days. So can
pretty much make up a 'test bench' using software.

I don't use a 'PC' (by which I assume people mean Whinedoize). But use a
lower powered RISC based machine running RO and my own DIY software.

The linked images below example results using a cheap Scarlett 2i2 (3rd
gen)

http://jcgl.orpheusweb.co.uk/temp/Probe_SQ.png squarewave
http://jcgl.orpheusweb.co.uk/temp/Probe_SW.png sinewave

http://jcgl.orpheusweb.co.uk/temp/2i2-DMP.png sinewave check
http://jcgl.orpheusweb.co.uk/temp/WFHdemo.png Wave From Hell

The last one shows the output using the "Wave From Hell" that I devised to
test the ability of DACs to cope with intersample overs. The peak level
should be about +5dBFS - i.e. above the max possible individual sample
value. Good way to see if DACs can play without distorting recordings that
provoke overs.

Being software driven means I can switch test waveforms to any format I
want. So can use various types of noise, 2-tone for intermod tests, etc, in
sequence. The software does the basic analysis and dumps out the results as
a graphic and as text. If needed I can use Benchmark ADCs/DACs and they are
easier to set up. But the 2i2 works like a charm and gives result much
better than any of the old hardware I used in the past. Using 192k sample
rates means I can examine up to c 90kHz OK.

For RF I use a FUNCube for measurements/observations. Goes up to 2GHz.
Been tempted by an ADAPT-PLUTO (I think that's the name) but never got
round to it as I'm more interested in the audio.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html
Audio Misc http://www.audiomisc.co.uk/index.html

Jim Lesurf wrote:
=============
TW bullshitted
>
>>>Phil Allison wrote:
>
> > >
> > > No way do I want a PC on my workbench and to have to trust a sampled &
> > > highly processed digital display of simple analogue data. DSOs just
> > > annoy me with false information.
> > >
> > > Call me old fashioned if you like...
>
> > **I prefer old school test equipment too, but I realise the obvious
> > advantages modern digital test equipment. I am presently tempted by one
> > of these:
>
> > https://w140.com/tekwiki/wiki/2245

** Perfect, nut case collector's item.

> I was old fashioned for a long time.

** Then you became totally insane.

>But the reality now is ......

** What would YOU know about reality ?

( snip piles of diarrhoea coming out the back of JL's hobby horse )

BTW the nag is called " Obsession".

...... Phil

On 7/05/2022 6:55 am, Phil Allison wrote:
> Jim Lesurf wrote:
> =============
> TW bullshitted
>>
>>>> Phil Allison wrote:
>>
>>>>
>>>> No way do I want a PC on my workbench and to have to trust a sampled &
>>>> highly processed digital display of simple analogue data. DSOs just
>>>> annoy me with false information.
>>>>
>>>> Call me old fashioned if you like...
>>
>>> **I prefer old school test equipment too, but I realise the obvious
>>> advantages modern digital test equipment. I am presently tempted by one
>>> of these:
>>
>>> https://w140.com/tekwiki/wiki/2245
>
> ** Perfect, nut case collector's item.
>

**Why? I've used a series of Tek 'scopes for many years. I find them to
be reliable and easy to use. Not so easy to fix, mind you.

Trevor Wilson wrote:
=================
> > Phil Allison wrote:
> >>
> >>>>
> >>>> No way do I want a PC on my workbench and to have to trust a sampled &
> >>>> highly processed digital display of simple analogue data. DSOs just
> >>>> annoy me with false information.
> >>>>
> >>>> Call me old fashioned if you like...
> >>
> >>> **I prefer old school test equipment too, but I realise the obvious
> >>> advantages modern digital test equipment. I am presently tempted by one
> >>> of these:
> >>
> >>> https://w140.com/tekwiki/wiki/2245
> >
> > ** Perfect, nut case collector's item.
> >
>
> **Why?
> I've used a series of Tek 'scopes for many years.

** I was commenting on the scope.

Plus the fools who drool over them.

...... Phil

In article <jdltvsF378jU1@mid.individual.net>,
Trevor Wilson <trevor@rageaudio.com.au> wrote:
> On 7/05/2022 6:55 am, Phil Allison wrote:
> > Jim Lesurf wrote:
> > =============
> > TW bullshitted
> >>
> >>>> Phil Allison wrote:
> >>
> >>>>
> >>>> No way do I want a PC on my workbench and to have to trust a sampled &
> >>>> highly processed digital display of simple analogue data. DSOs just
> >>>> annoy me with false information.
> >>>>
> >>>> Call me old fashioned if you like...
> >>
> >>> **I prefer old school test equipment too, but I realise the obvious
> >>> advantages modern digital test equipment. I am presently tempted by one
> >>> of these:
> >>
> >>> https://w140.com/tekwiki/wiki/2245
> >
> > ** Perfect, nut case collector's item.
> >

> **Why? I've used a series of Tek 'scopes for many years. I find them to
> be reliable and easy to use. Not so easy to fix, mind you.

My Tek scope was the TV industry standard about 50 years ago. Does
everything I need (in a fixed position) so why spend money just for the
sake of it?

--
*If you don't pay your exorcist you get repossessed.*

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

Dave Plowman ( Raving Nut Case ) wrote:

=========================
> >>
> > >>> https://w140.com/tekwiki/wiki/2245
> > >
> > > ** Perfect, nut case collector's item.
> > >
>
> > **Why? I've used a series of Tek 'scopes for many years. I find them to
> > be reliable and easy to use. Not so easy to fix, mind you.

> My Tek scope was the TV industry standard about 50 years ago.

** Yawnnnnnnnnnnnnnnnnnnnnnnnnnnnn....

He nicked it from the BBC one night.

> Does everything I need ......

** Which is next to fucking nothing, cos Plowhorse is not any kind of tech.

> so why spend money just for the sake of it?

** Tell the TW troll that - cos he is one heck of a status symbol drooler.

.... Phil

In article <15c40c65-67ee-4572-8ace-60c8bb7a6487n@googlegroups.com>,
Phil Allison <pallison49@gmail.com> wrote:
> Dave Plowman ( Raving Nut Case ) wrote:

> =========================
> > >>
> > > >>> https://w140.com/tekwiki/wiki/2245
> > > >
> > > > ** Perfect, nut case collector's item.
> > > >
> >
> > > **Why? I've used a series of Tek 'scopes for many years. I find them to
> > > be reliable and easy to use. Not so easy to fix, mind you.

> > My Tek scope was the TV industry standard about 50 years ago.

> ** Yawnnnnnnnnnnnnnnnnnnnnnnnnnnnn....

You really should stop playing with yourself and get a decent night's
sleep?

--
*I got a sweater for Christmas. I really wanted a screamer or a moaner*

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

On 7/05/2022 8:21 pm, Dave Plowman (News) wrote:
> In article <jdltvsF378jU1@mid.individual.net>,
> Trevor Wilson <trevor@rageaudio.com.au> wrote:
>> On 7/05/2022 6:55 am, Phil Allison wrote:
>>> Jim Lesurf wrote:
>>> =============
>>> TW bullshitted
>>>>
>>>>>> Phil Allison wrote:
>>>>
>>>>>>
>>>>>> No way do I want a PC on my workbench and to have to trust a sampled &
>>>>>> highly processed digital display of simple analogue data. DSOs just
>>>>>> annoy me with false information.
>>>>>>
>>>>>> Call me old fashioned if you like...
>>>>
>>>>> **I prefer old school test equipment too, but I realise the obvious
>>>>> advantages modern digital test equipment. I am presently tempted by one
>>>>> of these:
>>>>
>>>>> https://w140.com/tekwiki/wiki/2245
>>>
>>> ** Perfect, nut case collector's item.
>>>
>
>> **Why? I've used a series of Tek 'scopes for many years. I find them to
>> be reliable and easy to use. Not so easy to fix, mind you.
>
> My Tek scope was the TV industry standard about 50 years ago. Does
> everything I need (in a fixed position) so why spend money just for the
> sake of it?
>

**First off: My Rigol 1054z DSO does 90% of what I need (and a whole lot
more than that). So, there's that. My Tek 2232 recently lost one
vertical channel. It has had some annoying issues relating to bot-up for
quite some time. I will get around to fixing it one day. Maybe. I
decided for those rare times that I need an analogue 'scope that the
2245A will do all I require (and then some). I've done a bit of looking
around the the 2245A should be obtainable for the price of a 50 year old
Tek of similar performance. The 2245A is part of the final series of
analogue 'scopes made by Tek and is less than 30 years old.

Hence the desire to buy a new analogue 'scope.

Trevor Wilson wrote:
=================
>>>
> >>>>> **I prefer old school test equipment too, but I realise the obvious
> >>>>> advantages modern digital test equipment. I am presently tempted by one
> >>>>> of these:
> >>>>
> >>>>> https://w140.com/tekwiki/wiki/2245
> >>>
> >>> ** Perfect, nut case collector's item.
> >>>
> >
> >> **Why? I've used a series of Tek 'scopes for many years. I find them to
> >> be reliable and easy to use. Not so easy to fix, mind you.
> >

** The term " reliable " can only be used in the past tense.
Think about it.

>
> **First off: My Rigol 1054z DSO does 90% of what I need (and a whole lot
> more than that). So, there's that.

** Wonder what the other 10% is ?
That needs a 4 ch 100MHz scope ?

> My Tek 2232 recently lost one
> vertical channel. It has had some annoying issues relating to bot-up for
> quite some time. I will get around to fixing it one day.

** Used to be " reliable " once - eh ?

> I decided for those rare times that I need an analogue 'scope that the
> 2245A will do all I require (and then some).

** This vid might be interesting to you then:

https://www.youtube.com/watch?v=n1JgXudCmGg

My idea of " reliable " connects directly to ease of repair and having parts readily available.
Old teks and such don't come close.

...... Phil

On 8/05/2022 12:40 pm, Phil Allison wrote:
> Trevor Wilson wrote:
> =================
>>>>
>>>>>>> **I prefer old school test equipment too, but I realise the obvious
>>>>>>> advantages modern digital test equipment. I am presently tempted by one
>>>>>>> of these:
>>>>>>
>>>>>>> https://w140.com/tekwiki/wiki/2245
>>>>>
>>>>> ** Perfect, nut case collector's item.
>>>>>
>>>
>>>> **Why? I've used a series of Tek 'scopes for many years. I find them to
>>>> be reliable and easy to use. Not so easy to fix, mind you.
>>>
>
> ** The term " reliable " can only be used in the past tense.
> Think about it.

**Well, true enough. My experience with old Tek 'scopes is such that I
am aware that they use very high quality switches and pots. Not one Tek
'scope I've ever owned has developed a noisy switch or pot. I've owned 4
Tek 'scopes.

>
>>
>> **First off: My Rigol 1054z DSO does 90% of what I need (and a whole lot
>> more than that). So, there's that.
>
> ** Wonder what the other 10% is ?
> That needs a 4 ch 100MHz scope ?

**I rarely use the 4 channel capability of the Rigol. That said, there
has been odd time it has proven handy. If you're talking about the 4
channel capability of the 2245A, it is of little interest to me. Besides
which the 2 extra channels have limited capacity.

>
>
>> My Tek 2232 recently lost one
>> vertical channel. It has had some annoying issues relating to bot-up for
>> quite some time. I will get around to fixing it one day.
>
> ** Used to be " reliable " once - eh ?

**Even Teks break down.

>
>> I decided for those rare times that I need an analogue 'scope that the
>> 2245A will do all I require (and then some).
>
> ** This vid might be interesting to you then:
>
> https://www.youtube.com/watch?v=n1JgXudCmGg
>
> My idea of " reliable " connects directly to ease of repair and having parts readily available.
> Old teks and such don't come close.

**Fair point. I've owned a couple of BWD 'scopes (521 and 539) and they
are a delight to work on. Parts are readily available.

In article <jdivupFgn20U1@mid.individual.net>, Trevor Wilson
<trevor@rageaudio.com.au> scribeth thus
>My distortion analyser (Sound Technology 1701B) failed awhile back and
>the job to repair it has proven to be quite involved. As a consequence,
>I found a Japanese auction site, where I located a very impressive DA
>for reasonable money. This is the device I purchased:
>
>https://kenrockwell.com/audio/panasonic/vp-7721a.htm
>
>Ken is correct. It is a brilliant DA. Fast and easy to use. Naturally, I
>had to lift the lid. Construction is excellent and every one of it's 5
>regulated power supplies measured within 1% of their stated figures.
>Here is a graph of the oscillator distortion, plus some internal photos,
>as measured with my Quantasylum QA403 (oh yeah, I bought one of those too):
>
>https://imgur.com/a/d7PcSDV
>
>I also purchased an HP339A for not much money. I must say that the
>

>construction quality comfortably exceeded my expectations:
>
>https://imgur.com/a/cX43Ydp
>
>A bit rough on the outside, but it works. Note the heavy gold plated PCB
>traces. Colour me stunned.
>
>
>
>Of course, the Quantasylum whips the hardware analysers with ease.
>
>

Superb bit of gear got one here and tho we have a more recent
equipment's its still the go to machine!

Excellent meter on it, good for peaking tuner discriminator coils and
the like..

Very reliable one good idea is to swap out the power supply caps with
some decent ones and it will last till, well hereafter! And the
performance may well improve from .00*% to .000*%!

Only issue is the control knobs are liable to fall to bits and finding
new or replacements is neigh on impossible, i have heard that someone
made some on the 3D printer!...

Quite right re the PCB's and overall build quality and even those units
are now dating back since IIRC the 70's theres still a very good support
newsgroup!..

--
Tony Sayer

Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.

In article <513c2de4-9cb2-422f-a3bf-ebdbee61fd87n@googlegroups.com>,
Phil Allison <pallison49@gmail.com> scribeth thus
>Trevor Wilson wrote:
>=================
>>>>
>> >>>>> **I prefer old school test equipment too, but I realise the obvious
>> >>>>> advantages modern digital test equipment. I am presently tempted by one
>> >>>>> of these:
>> >>>>
>> >>>>> https://w140.com/tekwiki/wiki/2245
>> >>>
>> >>> ** Perfect, nut case collector's item.
>> >>>
>> >
>> >> **Why? I've used a series of Tek 'scopes for many years. I find them to
>> >> be reliable and easy to use. Not so easy to fix, mind you.
>> >
>
>** The term " reliable " can only be used in the past tense.
> Think about it.
>
>>
>> **First off: My Rigol 1054z DSO does 90% of what I need (and a whole lot
>> more than that). So, there's that.
>
>** Wonder what the other 10% is ?
> That needs a 4 ch 100MHz scope ?
>
>
>> My Tek 2232 recently lost one
>> vertical channel. It has had some annoying issues relating to bot-up for
>> quite some time. I will get around to fixing it one day.
>
>** Used to be " reliable " once - eh ?
>
>> I decided for those rare times that I need an analogue 'scope that the
>> 2245A will do all I require (and then some).
>
>** This vid might be interesting to you then:
>
>https://www.youtube.com/watch?v=n1JgXudCmGg
>
>My idea of " reliable " connects directly to ease of repair and having parts
>readily available.
>Old teks and such don't come close.
>
>
>
>..... Phil
>
I think that for most of us if a scope plays up and its something more
complex than power supply issues then best bet is to buy another surplus
second hand one.

Got a decent Phillips 4 channel one for around 150 UKP a few years ago
works fine!

--
Tony Sayer

Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.

On 12/05/2022 6:56 am, tony sayer wrote:
> In article <jdivupFgn20U1@mid.individual.net>, Trevor Wilson
> <trevor@rageaudio.com.au> scribeth thus
>> My distortion analyser (Sound Technology 1701B) failed awhile back and
>> the job to repair it has proven to be quite involved. As a consequence,
>> I found a Japanese auction site, where I located a very impressive DA
>> for reasonable money. This is the device I purchased:
>>
>> https://kenrockwell.com/audio/panasonic/vp-7721a.htm
>>
>> Ken is correct. It is a brilliant DA. Fast and easy to use. Naturally, I
>> had to lift the lid. Construction is excellent and every one of it's 5
>> regulated power supplies measured within 1% of their stated figures.
>> Here is a graph of the oscillator distortion, plus some internal photos,
>> as measured with my Quantasylum QA403 (oh yeah, I bought one of those too):
>>
>> https://imgur.com/a/d7PcSDV
>>
>> I also purchased an HP339A for not much money. I must say that the
>>
>
>
>> construction quality comfortably exceeded my expectations:
>>
>> https://imgur.com/a/cX43Ydp
>>
>> A bit rough on the outside, but it works. Note the heavy gold plated PCB
>> traces. Colour me stunned.
>>
>>
>>
>> Of course, the Quantasylum whips the hardware analysers with ease.
>>
>>
>
> Superb bit of gear got one here and tho we have a more recent
> equipment's its still the go to machine!
>
> Excellent meter on it, good for peaking tuner discriminator coils and
> the like..
>
> Very reliable one good idea is to swap out the power supply caps with
> some decent ones and it will last till, well hereafter! And the
> performance may well improve from .00*% to .000*%!

**Already done. Squeezed in some caps that are three times the value of
the originals. That said, the originals measure fine WRT stated
capacitance and ESR.

>
> Only issue is the control knobs are liable to fall to bits and finding
> new or replacements is neigh on impossible, i have heard that someone
> made some on the 3D printer!...

**The knobs are an example of (rare) really crappy HP design.

>
> Quite right re the PCB's and overall build quality and even those units
> are now dating back since IIRC the 70's theres still a very good support
> newsgroup!..
>

**The biggest improvement one can make (apparently) is to replace the
output level control with a cermet type. Measured distortion is reduced
significantly. When my pot arrives, I'll perform some comparison tests.

That said, I prefer my Panasonic VP-7721A. Much faster and easier to
use. Plus, it resolves distortion levels 10dB lower than the HP.

On Thu, 12 May 2022 07:21:45 +1000, Trevor Wilson
<trevor@rageaudio.com.au> wrote:

>> Only issue is the control knobs are liable to fall to bits and finding
>> new or replacements is neigh on impossible, i have heard that someone
>> made some on the 3D printer!...
>
>**The knobs are an example of (rare) really crappy HP design.

I do remember one aspect of crappy HP design from my days with Marconi
Instruments. They designed their power supplies for 60Hz operation and
neglected what happened at 50Hz if you left the things switched on for
extended periods. They got hot - I mean failure type hot. They were
just marginally short of primary inductance.

d

On 12/05/2022 5:19 pm, Don Pearce wrote:
> On Thu, 12 May 2022 07:21:45 +1000, Trevor Wilson
> <trevor@rageaudio.com.au> wrote:
>
>>> Only issue is the control knobs are liable to fall to bits and finding
>>> new or replacements is neigh on impossible, i have heard that someone
>>> made some on the 3D printer!...
>>
>> **The knobs are an example of (rare) really crappy HP design.
>
> I do remember one aspect of crappy HP design from my days with Marconi
> Instruments. They designed their power supplies for 60Hz operation and
> neglected what happened at 50Hz if you left the things switched on for
> extended periods. They got hot - I mean failure type hot. They were
> just marginally short of primary inductance.
>
> d

**YIKES! That's worse than poor quality knobs. Betcha Tektronix never
made such mistakes.

On Fri, 13 May 2022 04:50:56 +1000, Trevor Wilson
<trevor@rageaudio.com.au> wrote:

>On 12/05/2022 5:19 pm, Don Pearce wrote:
>> On Thu, 12 May 2022 07:21:45 +1000, Trevor Wilson
>> <trevor@rageaudio.com.au> wrote:
>>
>>>> Only issue is the control knobs are liable to fall to bits and finding
>>>> new or replacements is neigh on impossible, i have heard that someone
>>>> made some on the 3D printer!...
>>>
>>> **The knobs are an example of (rare) really crappy HP design.
>>
>> I do remember one aspect of crappy HP design from my days with Marconi
>> Instruments. They designed their power supplies for 60Hz operation and
>> neglected what happened at 50Hz if you left the things switched on for
>> extended periods. They got hot - I mean failure type hot. They were
>> just marginally short of primary inductance.
>>
>> d
>
>**YIKES! That's worse than poor quality knobs. Betcha Tektronix never
>made such mistakes.

The best were Rohde and Schwartz. But they always had non-intuitive
interfaces, particularly on their spectrum analysers. You get used to
control groupings that everybody pretty much shared, but R&S would
always do something different.

d

Trevor Wilson wrote:
=================
>
> >> **The knobs are an example of (rare) really crappy HP design.
> >
> > I do remember one aspect of crappy HP design from my days with Marconi
> > Instruments. They designed their power supplies for 60Hz operation and
> > neglected what happened at 50Hz if you left the things switched on for
> > extended periods. They got hot - I mean failure type hot. They were
> > just marginally short of primary inductance.
> >
>
> **YIKES! That's worse than poor quality knobs. Betcha Tektronix never
> made such mistakes.
>

** It's a mistake I have seem many times in other gear.

Some Yank transformer winders see no issue with having twin primaries on a core sized for 60Hz - ie Pacific Transformers.
A 20VA example dissipated 9 watts, * off load * at 240V 50Hz.

But the prize goes to a Taiwanese power amp amp that used a large toroidal, about 1.2 kVA.
The primary rms current rose to 8 amps at 260VAC, a common occurrence in Western Australia.

...... Phil

On 13/05/2022 5:36 am, Phil Allison wrote:
> Trevor Wilson wrote:
> =================
>>
>>>> **The knobs are an example of (rare) really crappy HP design.
>>>
>>> I do remember one aspect of crappy HP design from my days with Marconi
>>> Instruments. They designed their power supplies for 60Hz operation and
>>> neglected what happened at 50Hz if you left the things switched on for
>>> extended periods. They got hot - I mean failure type hot. They were
>>> just marginally short of primary inductance.
>>>
>>
>> **YIKES! That's worse than poor quality knobs. Betcha Tektronix never
>> made such mistakes.
>>
>
> ** It's a mistake I have seem many times in other gear.
>
> Some Yank transformer winders see no issue with having twin primaries on a core sized for 60Hz - ie Pacific Transformers.
> A 20VA example dissipated 9 watts, * off load * at 240V 50Hz.

**The worst I've seen goes to Chinese crap. One product that landed on
my bench had a power transformer that saturated at around 200VAC.

>
> But the prize goes to a Taiwanese power amp amp that used a large toroidal, about 1.2 kVA.
> The primary rms current rose to 8 amps at 260VAC, a common occurrence in Western Australia.

**YIKES! Don't get me started about WA. When I was at Marantz, our Perth
service agent would order spare parts that no one else in the country
ever ordered. When I questioned him, he explained about the wild mains
swings.

In article <je2nnbFgolfU1@mid.individual.net>, Trevor Wilson
<trevor@rageaudio.com.au> scribeth thus
>On 12/05/2022 6:56 am, tony sayer wrote:
>> In article <jdivupFgn20U1@mid.individual.net>, Trevor Wilson
>> <trevor@rageaudio.com.au> scribeth thus
>>> My distortion analyser (Sound Technology 1701B) failed awhile back and
>>> the job to repair it has proven to be quite involved. As a consequence,
>>> I found a Japanese auction site, where I located a very impressive DA
>>> for reasonable money. This is the device I purchased:
>>>
>>> https://kenrockwell.com/audio/panasonic/vp-7721a.htm
>>>
>>> Ken is correct. It is a brilliant DA. Fast and easy to use. Naturally, I
>>> had to lift the lid. Construction is excellent and every one of it's 5
>>> regulated power supplies measured within 1% of their stated figures.
>>> Here is a graph of the oscillator distortion, plus some internal photos,
>>> as measured with my Quantasylum QA403 (oh yeah, I bought one of those too):
>>>
>>> https://imgur.com/a/d7PcSDV
>>>
>>> I also purchased an HP339A for not much money. I must say that the
>>>
>>
>>
>>> construction quality comfortably exceeded my expectations:
>>>
>>> https://imgur.com/a/cX43Ydp
>>>
>>> A bit rough on the outside, but it works. Note the heavy gold plated PCB
>>> traces. Colour me stunned.
>>>
>>>
>>>
>>> Of course, the Quantasylum whips the hardware analysers with ease.
>>>
>>>
>>
>> Superb bit of gear got one here and tho we have a more recent
>> equipment's its still the go to machine!
>>
>> Excellent meter on it, good for peaking tuner discriminator coils and
>> the like..
>>
>> Very reliable one good idea is to swap out the power supply caps with
>> some decent ones and it will last till, well hereafter! And the
>> performance may well improve from .00*% to .000*%!
>
>**Already done. Squeezed in some caps that are three times the value of
>the originals. That said, the originals measure fine WRT stated
>capacitance and ESR.
>

** Bet they have already been replaced!
>>
>> Only issue is the control knobs are liable to fall to bits and finding
>> new or replacements is neigh on impossible, i have heard that someone
>> made some on the 3D printer!...
>
>**The knobs are an example of (rare) really crappy HP design.

** Yes not their finest hour!..
>
>>
>> Quite right re the PCB's and overall build quality and even those units
>> are now dating back since IIRC the 70's theres still a very good support
>> newsgroup!..
>>
>
>**The biggest improvement one can make (apparently) is to replace the
>output level control with a cermet type. Measured distortion is reduced
>significantly. When my pot arrives, I'll perform some comparison tests.
>

** Not heard that, how would it make any real difference?, seems like
snake Oil!..

>That said, I prefer my Panasonic VP-7721A. Much faster and easier to
>use. Plus, it resolves distortion levels 10dB lower than the HP.
>

** Really 10 dB lower in percentage terms how low is it or are you
claiming?..

--
Tony Sayer

Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.

In article <je56ktFgdgU1@mid.individual.net>, Trevor Wilson
<trevor@rageaudio.com.au> scribeth thus
>On 13/05/2022 5:36 am, Phil Allison wrote:
>> Trevor Wilson wrote:
>> =================
>>>
>>>>> **The knobs are an example of (rare) really crappy HP design.
>>>>
>>>> I do remember one aspect of crappy HP design from my days with Marconi
>>>> Instruments. They designed their power supplies for 60Hz operation and
>>>> neglected what happened at 50Hz if you left the things switched on for
>>>> extended periods. They got hot - I mean failure type hot. They were
>>>> just marginally short of primary inductance.
>>>>
>>>
>>> **YIKES! That's worse than poor quality knobs. Betcha Tektronix never
>>> made such mistakes.
>>>
>>
>> ** It's a mistake I have seem many times in other gear.
>>
>> Some Yank transformer winders see no issue with having twin primaries on a
>core sized for 60Hz - ie Pacific Transformers.
>> A 20VA example dissipated 9 watts, * off load * at 240V 50Hz.
>
>**The worst I've seen goes to Chinese crap. One product that landed on
>my bench had a power transformer that saturated at around 200VAC.
>
>>
>> But the prize goes to a Taiwanese power amp amp that used a large toroidal,
>about 1.2 kVA.
>> The primary rms current rose to 8 amps at 260VAC, a common occurrence in
>Western Australia.
>

>**YIKES! Don't get me started about WA. When I was at Marantz, our Perth
>service agent would order spare parts that no one else in the country
>ever ordered. When I questioned him, he explained about the wild mains
>swings.
>

** Just how bad are they then?..

In the UK, the declared voltage and tolerance for an electricity supply
is 230 volts -6%, +10%. This gives an allowed voltage range of 216.2
volts to 253.0 volts.

--
Tony Sayer

Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.

tony sayer = know nothing fool wrote:
=============================
>
> >
> >**The biggest improvement one can make (apparently) is to replace the
> >output level control with a cermet type. Measured distortion is reduced
> >significantly. When my pot arrives, I'll perform some comparison tests.
> >
> ** Not heard that,

** Boo hoo...

> how would it make any real difference?,

** FFS carbon track pots often become horribly noisy and distorted.

> seems like snake Oil!..

** Only to tolling dopes like you.

.... Phil