Test Equipment Anonymous (TEA) group therapy thread

[25 CPS]

I swept the idle output of a small modern Class D amplifier with a spectrum analyzer from 0 - 1MHz...   let's just say that "hi fi" was not the first thing that sprung to mind! 

I don't think "hifi" comes to anybody's mind as soon as you see the phrase "Class D" even before getting the test equipment on it.  But spectrum analyzer with tracking generator was the thought I had after I posted that about letting the 8903B loose on some of that old equipment.

It never occurred to me to sweep sound equipment up into radio frequencies well above the audio range like you did going all the way up to 1 MHz.  What did the amplifier do once the input started to get well into RF?  After saying that, you know the next time I have audio equipment on the bench, you know I'm going to hook it up to the spectrum analyzer and crank the tracking generator right up, now right?

[mnementh]

on other notes:

this is for our tea coffee dwagon:      Source: https://paradoxshirt.com/product/dragon-and-coffee-touch-my-coffee-and-i-will-drink-it-from-your-skull-shirt/

Poor font choice on that 'C', IMO - I stared at that in puzzlement for a few moments trying to figure it out as I was reading the first word as touGh, and couldn't figure out WTF toughing someone's coffee meant.

-Pat

It means they're drinking MY coffee... which is not only strong, but surly. It'll slap you awake. 

mnem
And that's exactly how I need it.   

[mnementh]

I swept the idle output of a small modern Class D amplifier with a spectrum analyzer from 0 - 1MHz...   let's just say that "hi fi" was not the first thing that sprung to mind! 

I don't think "hifi" comes to anybody's mind as soon as you see the phrase "Class D" even before getting the test equipment on it.  But spectrum analyzer with tracking generator was the thought I had after I posted that about letting the 8903B loose on some of that old equipment.

It never occurred to me to sweep sound equipment up into radio frequencies well above the audio range like you did going all the way up to 1 MHz.  What did the amplifier do once the input started to get well into RF?  After saying that, you know the next time I have audio equipment on the bench, you know I'm going to hook it up to the spectrum analyzer and crank the tracking generator right up, now right?

Sounds to me like a really good use case for tinySA. 

mnem
*knocks self unconscious with a MHz mallet*

[cyclin_al]

This video popped up in my Youtube feed yesterday and given the discussion here, I watched it:



It definitely agrees with BD's comments about Sony's house sound.  The descriptions in that video of the Sony and the Marantz agree with how I remember both of them.  My family had one of the smaller Marantz receivers from the same period for a long time and my best friend's family had a lot of Sony stereo equipment from the 80s and 90s.  It's too bad the guy who made the video isn't an electronics engineer/technologist/test equipment geek.  If it was me putting those two receivers up against each other and I heard that difference, they'd both have gotten carted downstairs and put them on the bench with the 8903B and sweep them to get some hard and fast numbers to see if Sony goosed the ends of the frequency response to tailor the sound compared to the Marantz.

Anyhow, I did shoot some unboxing video of the 34401A and the S-A-A-2N/TinySA packages.  The camcorder wasn't a Sony though!  If there's interest, I can try to stitch something together and toss it online later if anybody wants to see.

I'm not at all surprised by his conclusion here, the Marantz receiver has now for many years been considered to be one of the top hi-fi units you can get and that quality shone through just be looking at the 2 side by side and looking inside did not disappoint either and the sheer smoothness of the sound said it all. The Sony uses IC's to reduce the cost and IC's lend themselves to machine assembly and the Marantz, clearly much more complex to assemble, was hand built.

I won one of those Sony receivers on eBay recently for repair and the sound quality when repaired ready for flipping again was just described and after extended soak tests it was becoming clear the bass was very muddied, more like a one note samba, the mid-range was just about right and the high notes too bright. Just from that short experience of the modern Sony, it was enough to turn off them for ever as well.

One of the best budget (top end of the budget) range in the 70s to 80s was Nippon Sound, fully discrete alloy and wood cabinets but these amps and receivers kicked some arse I can tell you. Not sure what happened to them, but I have a hunch that they became Yamaha but not sure.

I remember the Marantz 22xx line well.  Actually, I have one downstairs that was a garage find that's waiting to go on the bench plus my family had one for many years when I was growing up.  That one died spectacularly though and my parents decided not to get it repaired but bought a Denon A/V receiver and a Denon DCD-15000 CD player to replace the Marantz when it blew up instead of getting it repaired.  I don't remember why they opted not to repair it.  Anyways, the CD player sounded quite good but that Denon receiver was awful.  The pre/power amplifier were mediocre.  So was the tuner.  The phono stage was awful.  Between getting the CD player at the same time and the truly awful sounding phono preamp in that Denon receiver, my family pretty much stopped playing our record collection overnight.

The Marantz was the much better receiver by far.  The Denon was unforgivably dull and sucked the life out of every piece of music that was passed through it for some reason.  If anything it was the opposite of every Sony stereo system that I encountered from the same time period which sounded so much better even though they had that goosed up overdone sound.  MSG, that was a good way of putting it.  Anyhow, the Denon receiver and CD player went in the garbage when my parents sold the house and moved into a condo.  I would've been curious to put the Denon on the bench and take some measurements on that too, just to see if I could identify why and how, what part of it's overall transfer function was responsible for sucking the life out and completely killing all the music played through this thing.  Unfortunately, my parents threw it out along with the DCD-1500 and didn't tell me until after they were gone so the idea of doing that and then using it in a sound system for the back yard here went out the window.

Actually, speaking of the Sony TV at my place, my parents threw out a beautiful, low hours Panasonic plasma TV a couple of weeks ago.  They decided to de-clutter one of the rooms in their condo and listed the TV on the condo building's internal buy and sell website but got no takers so they got the building maintenance people to carry it out of their condo and heave it into the bin and that was the end of that.  If I had known they were going to throw out that low hours Panasonic plasma, I would've happily taken it and kicked the Sony with the crappy backlight bleedthrough out of my living room and put it downstairs in the workshop.  What a waste of a beautiful plasma TV.  But, as usual with my parents, they made a point of telling me after it was already gone, just like they've done with a lot of things including my grandparents car when they gave up driving when I was in college and was taking public transportation two hours each way, tell me about the car becoming available after it had already been sold.

Yeesh !!!    Based on behaviour, you make it sound like we are from the same family ....

They My parents asked me about buying a car, then reveal that they already went out and bought the same car as I have.  Only they paid $3k more for it than I did.  However, they have the base model, and mine is one level down from premium.  If only they would have talked to me beforehand, I could have saved them at least $9k 

Geographically, I think you are not too far away from where my parents generation come from .... hmmmm

-- no escape from family; gotta luv em

[med6753]

So was it worth the 3 hours round trip and the gas to get these P6202 probes? Yes, they both work.  Not that I'll need to measure a 500MHz pulse any time soon but if I do I'm prepared. 

[doktor pyta]

@med6753

Question regarding 7000 series with 'analog' readout.
Does the readout slightly moves when You move vertical position knob fully CW and CCW?
I had three tek scopes which had this effect.

[Ice-Tea]

I bought today a home in the USA, for the same money:

- In Munich about 66 m² flat
- In USA, SC. home is about 490m² on about 4000 m² piece of Earth.

Fuuu yes, it is not a house, it's a piece of planet in my mind.

Only downside: Italy will be so far away, my heart is broken already.

Oh, wow! Congrats!

[capt bullshot]

@med6753

Question regarding 7000 series with 'analog' readout.
Does the readout slightly moves when You move vertical position knob fully CW and CCW?
I had three tek scopes which had this effect.

Though I'm not med, mine (7603 and 7623) have that effect too.

[Robert763]

@Cerebus

Posts posted

[Cerebus]

@Cerebus

Posts posted

 

Thanks again.

[bd139]

I swept the idle output of a small modern Class D amplifier with a spectrum analyzer from 0 - 1MHz...   let's just say that "hi fi" was not the first thing that sprung to mind! 

I don't think "hifi" comes to anybody's mind as soon as you see the phrase "Class D" even before getting the test equipment on it.  But spectrum analyzer with tracking generator was the thought I had after I posted that about letting the 8903B loose on some of that old equipment.

It never occurred to me to sweep sound equipment up into radio frequencies well above the audio range like you did going all the way up to 1 MHz.  What did the amplifier do once the input started to get well into RF?  After saying that, you know the next time I have audio equipment on the bench, you know I'm going to hook it up to the spectrum analyzer and crank the tracking generator right up, now right?

With a class D, it's probably integrated with whatever speaker system is glued to it and tuned accordingly (unless it's a low ball bidder where the engineering stopped at "it mostly works"). Best to evaluate this as a combination rather than just the amplifier into an ideal load.  The class D has an (RF-ish) LPF on the output so it should be fairly clean, at least -30dBc within 2x the LPF frequency.

Really one of those HP dynamic signal analysers is probably a better tool for the job than an RF SA as the 0-20KHz span is the most important. Also if you were to do measurements you'd have to set a reference system up and that's pretty difficult because there's no such thing as perfect audio reproduction or measurement

I mostly use some fruit branded class D earbuds and they don't sound any different to my HD25's in practice other than a bit more low end and better volume which I find pleasing. Thus subjectivity it is again.

[med6753]

@med6753

Question regarding 7000 series with 'analog' readout.
Does the readout slightly moves when You move vertical position knob fully CW and CCW?
I had three tek scopes which had this effect.

On this 7904 the readout does not move regardless of the position of the trace either vertically or horizontally.

[med6753]

I mostly use some fruit branded class D earbuds and they don't sound any different to my HD25's in practice other than a bit more low end and better volume which I find pleasing. Thus subjectivity it is again.

Audio reproduction to the individual listener is always subjective.

You never read "my ears can hear the 0.1% distortion on the horns but not the .001% on the strings".

[Specmaster]

@Cerebus

Posts posted

That's what I like to see, members helping each other when possible, well done. 

[bd139]

I mostly use some fruit branded class D earbuds and they don't sound any different to my HD25's in practice other than a bit more low end and better volume which I find pleasing. Thus subjectivity it is again.

Audio reproduction to the individual listener is always subjective.

You never read "my ears can hear the 0.1% distortion on the horns but not the .001% on the strings".

That'll be why the audiophiles invent new words and concepts for things; they can be discussed free of actual measurable parameters. Then they can be experts on subjective things which is possibly a paradox.

[25 CPS]

Yeesh !!!    Based on behaviour, you make it sound like we are from the same family ....

They My parents asked me about buying a car, then reveal that they already went out and bought the same car as I have.  Only they paid $3k more for it than I did.  However, they have the base model, and mine is one level down from premium.  If only they would have talked to me beforehand, I could have saved them at least $9k 

Geographically, I think you are not too far away from where my parents generation come from .... hmmmm

-- no escape from family; gotta luv em

No kidding.  It's exasperating.  When the phone rings and I see the call display, I groan and wonder what wonderful news is about to be dumped on my head.

With a class D, it's probably integrated with whatever speaker system is glued to it and tuned accordingly (unless it's a low ball bidder where the engineering stopped at "it mostly works"). Best to evaluate this as a combination rather than just the amplifier into an ideal load.  The class D has an (RF-ish) LPF on the output so it should be fairly clean, at least -30dBc within 2x the LPF frequency.

Really one of those HP dynamic signal analysers is probably a better tool for the job than an RF SA as the 0-20KHz span is the most important. Also if you were to do measurements you'd have to set a reference system up and that's pretty difficult because there's no such thing as perfect audio reproduction or measurement

I mostly use some fruit branded class D earbuds and they don't sound any different to my HD25's in practice other than a bit more low end and better volume which I find pleasing. Thus subjectivity it is again.

Adding the speaker system is where things get interesting since those are not an ideal resistive load by any means and things like Quad ESL 57s are extremely capacitive and can really torture some amplifier designs.  A lot of home theatre receivers now have huge wattage capability on each channel only because they're class D.  What I've got set up here is a Pioneer HT receiver because I needed the HDMI capability driving a pair of Kef Concertos.  To make it even more interesting, these aren't Kef Concertos as you guys would know them, they're the Barney Smyth / Smyth Sound built in Longueil, Quebec version.  The crossover circuit is different and internal construction is different from the ones made in England.

Anyhow, if I was to torture an audio amplifier with a spectrum analyzer and tracking generator, the machine I had in mind for that was the HP 3588A.  It's range is 10 Hz to 150 MHz so it's ideal for starting a sweep out just below audio frequency and carrying it up into the RF region.  Off the top of my head, the 3562A sitting next to it tops out at 100 KHz so it's good for covering the audio portion but wouldn't work for taking a circuit from audio up into RF.

[Specmaster]

Wow, CPC have excelled themselves, ordered some batteries, AAA and PP3 and a button cell for the 1906 yesterday and at 9:10 this morning they were here. Only downside of that was that they were packed with 4 air pockets in the box. The box was a bit damaged and the contents were rattling about inside. Opened the box to find the air pockets were all flat, the PP3's were all over the box, and the terminals were exposed (as they are).

Measured the volts, and they ranged from 9.7V to 8.8V, so they had been shorting on the metal cases of the other PP3's in the box. Photos taken and email sent along with the photo, now waiting to see what they are going to do. 

On the plus side, button cell fitted to the 1906, after I tagged in another 3v supply to retain the calibration tables, and meter reassembled and tested, all works fine and dandy, and it is in calibration as well, just require a replacement foot now, and it's a Gooden.

TTi gear for the win. 

Winner Winner Chicken dinner!

[med6753]

Yeesh !!!    Based on behaviour, you make it sound like we are from the same family ....

They My parents asked me about buying a car, then reveal that they already went out and bought the same car as I have.  Only they paid $3k more for it than I did.  However, they have the base model, and mine is one level down from premium.  If only they would have talked to me beforehand, I could have saved them at least $9k 

Geographically, I think you are not too far away from where my parents generation come from .... hmmmm

-- no escape from family; gotta luv em

No kidding.  It's exasperating.  When the phone rings and I see the call display, I groan and wonder what wonderful news is about to be dumped on my head.

Are your parents "baby boomers" like me? (Post WW2 until late 1950's or so). Most of us are still pretty aware and on top of things but there is a certain sub group of us that are dumber than a box of rocks.   

[25 CPS]

Are your parents "baby boomers" like me? (Post WW2 until late 1950's or so). Most of us are still pretty aware and on top of things but there is a certain sub group of us that are dumber than a box of rocks. 

Absolutely.  The rampant sense of entitlement and the willingness combined with the economic means to throw away perfectly good cars, expensive electronics that have barely been used, the works is a pretty good clue that we're dealing with total heads in the clouds baby boomers here.  To their minds, it's still 1968, good jobs are plentiful, housing's cheap, energy's cheap, cars are cheap, everything's cheap and there's unlimited prosperity out there.  So clearly there's something wrong with everyone who's still in the workforce earning stagnant since 1980 wages and complaining that they can't afford a $1-million-plus teardown in suburban Toronto.

To be fair there are people who are dumber than a box of rocks in every generation but the out of touch and entitlement I've seen with a good cross section of baby boomers starting within immediate family is jaw dropping.  I've given it a lot of thought and the only conclusion that I've been able to come to is there's a lot of them out there that don't understand that the decades of post war prosperity are over and a lot of people have been born into a world where the music's stopped and all the chairs have already been taken.

[Specmaster]

Here is something that I don't recall ever seeing before on any board and shows the attention to detail that TTi out put into their products. There seems to be a ground ring around the sensitive terminals on the board, and it seems to work OK because the readings are rock solid. Now I have to rearrange my stacks again,

[McBryce]

I mostly use some fruit branded class D earbuds and they don't sound any different to my HD25's in practice other than a bit more low end and better volume which I find pleasing. Thus subjectivity it is again.

Audio reproduction to the individual listener is always subjective.

You never read "my ears can hear the 0.1% distortion on the horns but not the .001% on the strings".

You've obviously never read any of the Audiophool forums!

McBryce.

[mnementh]

Are your parents "baby boomers" like me? (Post WW2 until late 1950's or so). Most of us are still pretty aware and on top of things but there is a certain sub group of us that are dumber than a box of rocks.   

*raises hand* My dad.

He's been putting off "setting up" the iPad I sent him for Christmas until his friend Margaret can help him.

It's a iPad. And I configured the WiFi on it based on a pic of the label from his MODEM before I sent it out.

mnem
Hey, at least I got him using rechargeables on his AM/FM WalkMan...

[mnementh]

Are your parents "baby boomers" like me? (Post WW2 until late 1950's or so). Most of us are still pretty aware and on top of things but there is a certain sub group of us that are dumber than a box of rocks. 

Absolutely.  The rampant sense of entitlement and the willingness combined with the economic means to throw away perfectly good cars, expensive electronics that have barely been used, the works is a pretty good clue that we're dealing with total heads in the clouds baby boomers here.  To their minds, it's still 1968, good jobs are plentiful, housing's cheap, energy's cheap, cars are cheap, everything's cheap and there's unlimited prosperity out there.  So clearly there's something wrong with everyone who's still in the workforce earning stagnant since 1980 wages and complaining that they can't afford a $1-million-plus teardown in suburban Toronto.

To be fair there are people who are dumber than a box of rocks in every generation but the out of touch and entitlement I've seen with a good cross section of baby boomers starting within immediate family is jaw dropping.  I've given it a lot of thought and the only conclusion that I've been able to come to is there's a lot of them out there that don't understand that the decades of post war prosperity are over and a lot of people have been born into a world where the music's stopped and all the chairs have already been taken.

Hmmm... Okay, then how do you see the same propensity in yuppies, Gen Xers and millenials...?

Baby boomers were by far the least "head in the clouds" of the recent generations, IMO. My dad may be daft in terms of tech (even tho he was a programmer for the Air Force back in the day); but in terms of knowing where his place in the world is and what goes into all the stuff we need to survive, he's got a pretty good head on his shoulders.

I think maybe you have the generations mixed up; it was my generation (post-Summer of Love) of clueless self-important fuckwidgets that blew up the US economy and turned it into a multinational Ponzi scheme; his was the ones that were trying to stop them.

mnem
*not living in the alternate reality bubble*

[BU508A]

Are your parents "baby boomers" like me? (Post WW2 until late 1950's or so). Most of us are still pretty aware and on top of things but there is a certain sub group of us that are dumber than a box of rocks.   

*raises hand* My dad.

He's been putting off "setting up" the iPad I sent him for Christmas until his friend Margaret can help him.

It's a iPad. And I configured the WiFi on it based on a pic of the label from his MODEM before I sent it out.

mnem
Hey, at least I got him using rechargeables on his AM/FM WalkMan...

English subtitles are available. 

[med6753]

Are your parents "baby boomers" like me? (Post WW2 until late 1950's or so). Most of us are still pretty aware and on top of things but there is a certain sub group of us that are dumber than a box of rocks.   

*raises hand* My dad.

He's been putting off "setting up" the iPad I sent him for Christmas until his friend Margaret can help him.

It's a iPad. And I configured the WiFi on it based on a pic of the label from his MODEM before I sent it out.

mnem
Hey, at least I got him using rechargeables on his AM/FM WalkMan...

English subtitles are available. 

Video unavailable here. Got a different link?