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post #8701 of 13112
Quote:
Originally Posted by moodyrn View Post

Quote:
Originally Posted by analogsurviver View Post

I did write a comprehensive reply and hit the wrong button - POOF ! 

I will try again tomorrow, promise.

You don't have to go through the trouble. We can just respectfully disagree on the matter. I have my ears and you have yours. Personal enjoyment is all that matters to me. You continue to enjoy your amps and I will continue to enjoy mine.


I think that your statement "I have my ears and you have yours" is not correct, and that is the root of the disagreement.

 

The "output impedance" issue seems to originate from a web site where their concept is:

 

" You have your primitive unreliable ears, while I have superior advanced technology. "

 

They cannot seem to understand the end result of audio playback of music, is how it sounds to ears, and seem uncomfortable with the idea of making a judgement.

 

SO, to those people - if the output impedance is wrong, then it simply cannot sound better, and your ears must be wrong if you think it sounds better...

 

BTW, this new technology worship - to the point of self-loathing - is a fascinating psychology topic... which would unfortunately be off-topic in this forum...

post #8702 of 13112
Thread Starter 
No, I just refuse to go back and forth over a debate over "my amps can't be a good match for my headphones because of the output impedance being so high". That's not what this thread is all about. I've seen too many threads get lock because of similar discussions. Some of them were even larger than this massive thread. That's the last thing I want. I think this thread is special, it is for me anyway. That's why I left it at....we can respectfully disagree. And I refuse to comment any further regarding the topic. Those type of discussions belong in the science forum.
post #8703 of 13112
An observation has been raised about a headphone socket that is simply wired to the main speaker outputs via a large series resistor.

A.K.A.- vintage integrated amplifiers and receivers.

Does this resistor in the signal path change the frequencies on some headphones?

Can significantly better audio quality be obtained by connecting your line-level signals to a dedicated headphone amp?

My experience with high quality amplification using a resistive network to reduce output at the headphone jack, has been enjoyable.
Resistors are passive components, if there is a measurable interaction with audio frequencies and the resistive component, it certainly has not caused any troublesome reaction from my ears.

Audio includes math, which does not always play out in real world practice.
If I was mixing and monitoring using headphones, I might choose a different amplifier.
For home pleasure listening, I'll use my now vintage gear just as I always have since it was new.
post #8704 of 13112
I have used my vintage amplifiers for headphones and can't find a single reason for complaint. Ortho and stats are a treat and dynamics do well too based on purely my personal opinion.
post #8705 of 13112
Quote:
Originally Posted by moodyrn View Post

No, I just refuse to go back and forth over a debate over "my amps can't be a good match for my headphones because of the output impedance being so high". That's not what this thread is all about. I've seen too many threads get lock because of similar discussions. Some of them were even larger than this massive thread. That's the last thing I want. I think this thread is special, it is for me anyway. That's why I left it at....we can respectfully disagree. And I refuse to comment any further regarding the topic. Those type of discussions belong in the science forum.

+1

lets respectively leave the subject guys and just appreciate our vintage gear. This thread is our hide away in the corner of head-fi, No arguments here :) 

 

beerchug.gif

post #8706 of 13112
Quote:
Originally Posted by kstuart View Post

I would be interested in any recommendations of soldering gear to use on vintage amplifiers... I have a very generic "soldering iron" that is decades old, and I would want to get something a little more sophisticated if I was going to do something like "recap".

 

Either links to existing web pages, or your own personal experience would be fine, thanks!

Believe it or not, one of the most comprehensive independent reviews on soldering equipment ever published is right here on head-fi :

 

http://www.head-fi.org/t/416001/reviews-some-people-collect-amps-i-collect-soldering-stations

 

As usual, it all boils down to money. You can search as far and wide as you possibly might have wish to do so , you will always arrive at the universal agreement the best soldering equipment produced is JBC from Spain. It is so advanced and so high priced its use is economical only in an industrial setting operating round the clock, where it actually starts saving money. Beside high costs, I was put off by their relentless model changing, sometimes only aimed at cosmetics and "current latest/greatest" model and pricing policy both for new and used gear. It can go so far that even latest JBC equipment available at distributors is "obsolete" if you go and visit the JBC webpage. But it is what you will find where nothing but the best will do. A nice example JBC vs Others : http://www.eevblog.com/forum/reviews/jbc-t210-a-(and-pa120-a)-handpiece-compared-to-some-other-tools/?PHPSESSID=1105589fe4babb97aee029ebbe639390

If you ever decide to go that high, do yourself the favour and check whether latest/greatest model really incorporates meaningful advances or it is just a prettier face of the previous functionally equal version - it might save you a sizeable chunk of money.

 

Being a pragmatical guy, after almost three months of self deliberation I opted for used Metcal soldering station, handle and enough tips to get me trough almost any imaginable job. The beauty of Metcal is the fact it is widespread enough to find good deals on ebay etc if you are patient. Few months later, I was able to add soldering tweezers. I can not think of anything else equaling it in bang for the buck department - only disadvantage is if you insist on Pb free soldering, where tip life is reduced. As this is vintage thread, I do not believe that will be of concern to you - all vintage equipment is soldered together with good ol' lead solder.

 

Metcal might be harder to source than XY??, specially if you are looking for older PS2E-01 (STSS-P2SE-01 (110 V model ))  that will do the basics as well as current much higher priced stations offering handy but not absolutely necessary frills ( and prettier face ). If I managed to obtain a  STSS-PS2V-02 230 V 50 Hz version in Europe, most of the US based readers should have incomparably easier job in its native land - but you will have to wait a bit to score a bargain.


Edited by analogsurviver - 8/7/13 at 1:02am
post #8707 of 13112

I'm sorry moody but I have to say my bit. Signals processing & Acoustics is my bread and butter and EE was my undergrad. I'm very familiar with the math involved here. I'm a big fan of having a large resistor in the output chain that the vintage amps do. From an engineering standpoint, it's fantastically simple. Also, if you like how the amp sounds with speakers, you'll already know how it'll sound, in general with your HP. Sure, they could do a better job of shielding those resistors. Most of your crosstalk and other issues will come from having them right next to each other with no shielding. Textbook interference. I agree with analogsurvivor that those tend to be a place the vintage guys could have spent a few extra cents.

 

Happily, if the circuit ended right there, it's still first order. If your HP were a pure resistive load, it would still be first order. But they're not. In general, most HPs are inductive loads (with a few tuned loads and a few capacitive loads in the mix depending on your HPs complexity and specific construction). Once you plug something in, it becomes a minimum 2nd order circuit. If you have beautifully engineered x-overs in your HP's it can be wayyyy higher orders than that. I think people are using the term "resistance" and "impedance" interchangeably, when they have discrete meanings. 

 

I hate to leave everyone hanging, but the real conclusion isn't so cut and dried. High output impedance amps are wasteful. That's why they moved away from them. The make a ton of heat and just eat up electricity. BUT, they are less likely to kow-tow to your complex hp's whims and it'll make them do what it says. On the other hand, that can potentially prevent a type of synergy that can get the sweetest sound out of your luxurious headphones. So it really depends if your HP's are more the type that need to be in charge or need being told, so to speak. Which, in summary, means it all comes down to a good pairing and personal preference.

 

 

*Last thing, the software to evaluate Nth order circuits is very good, but here's the problem - once one thing is out of spec or not as designed, your simulation will have less and less correlation with reality as the circuit gains in complexity. IMHO, new gear will fall on its face more often as they try to get hyper-complex due to build quality, basic design, and quality control. The math works in a perfect world, but "good enough" isn't "good enough" in a 9th order filter circuit.

post #8708 of 13112

Just made an offer on a Marantz 4400 on Craigslist. he wants $650 but I offered $400 I HOPE he accepts. it's missing the AM antenna and looks to not have been cleaned since the 70's. I'd have to get LED's put in it too and have it checked out. Oh jeeze I hope he accepts :D

post #8709 of 13112

I was told "the 1250, like many receivers of the day, drives the headphone output off the speaker outputs through a series resistor. No need for the mess of a speaker tap adapter."

If this is true, should I even have to bother with a speaker tap adaptor for my HE-6's?

post #8710 of 13112
Quote:
Originally Posted by analogsurviver View Post

It is not what is "liked" - it is what most closely resembles the real thing. It may well be the frequency response deviations that do occur with high impedance drive suit your ear. That could be recreated through use of an equalizer. What is more critical is the loss of control of the amp has over the headphone driver if its output impedance is high ( or its damping factor is consequently low ). We react first to frequency response anomalies, everything else must be very much higher in magnitude to be directly audible. Say 1 dB at lower extreme can be the threshold between Personal Gotterdammerung and - inaudible. Distortion has to reach much more than 1 % to be directly objectionable - but you have first to be able to hear the basic signal. That means frequency response takes precedence.

 

Based on what little I (think I) know, FR changes are more due to the impedance of the headphone than anything in this situation. For headphones with a flat impedance curve across the frequency spectrum, you shouldn't see any changes to the FR despite the output impedance of the amp. You can measure direct changes to the FR, however, if the headphone does not have a flat impedance curve and the output impedance on the amp isn't low enough.

 

That's about the extent of my knowledge. When people start talking about headphone being a resistive load, not being affected much by impedance/electrical damping much, or just how vintage receivers are designed, I get lost. Pretty clueless in those areas...

 

Either way, I have directly compared my Mad Dog on my Sansui 5000A vs. the Leckerton UHA-6S Mk.II with the 209 opamp. I was specifically listening for the differences people attribute to amps with too high of an output impedance, and I just could not hear it. Again, I'm not sure if this is due to how the headphone is designed (how it handles loads and/or its flat impedance curve), how the vintage receiver is designed, how the two interact together, and so on.

 

I dunno...wish I understood electronic topics like these more.

 

Unrelated question for anyone: I have some internal shots of my Sherwood RX-4503 stereo receiver (not vintage by any means), and I'm trying to figure out if the headphone out is powered by the speaker amps or not. Would someone be willing to take a look at the shots and check for me? Also curious on any additional thoughts about the receiver and design itself...

post #8711 of 13112
Quote:
Originally Posted by PhoenixG View Post

I'm sorry moody but I have to say my bit. Signals processing & Acoustics is my bread and butter and EE was my undergrad. I'm very familiar with the math involved here. I'm a big fan of having a large resistor in the output chain that the vintage amps do. From an engineering standpoint, it's fantastically simple. Also, if you like how the amp sounds with speakers, you'll already know how it'll sound, in general with your HP. Sure, they could do a better job of shielding those resistors. Most of your crosstalk and other issues will come from having them right next to each other with no shielding. Textbook interference. I agree with analogsurvivor that those tend to be a place the vintage guys could have spent a few extra cents.

 

Happily, if the circuit ended right there, it's still first order. If your HP were a pure resistive load, it would still be first order. But they're not. In general, most HPs are inductive loads (with a few tuned loads and a few capacitive loads in the mix depending on your HPs complexity and specific construction). Once you plug something in, it becomes a minimum 2nd order circuit. If you have beautifully engineered x-overs in your HP's it can be wayyyy higher orders than that. I think people are using the term "resistance" and "impedance" interchangeably, when they have discrete meanings. 

 

I hate to leave everyone hanging, but the real conclusion isn't so cut and dried. High output impedance amps are wasteful. That's why they moved away from them. The make a ton of heat and just eat up electricity. BUT, they are less likely to kow-tow to your complex hp's whims and it'll make them do what it says. On the other hand, that can potentially prevent a type of synergy that can get the sweetest sound out of your luxurious headphones. So it really depends if your HP's are more the type that need to be in charge or need being told, so to speak. Which, in summary, means it all comes down to a good pairing and personal preference.

 

 

*Last thing, the software to evaluate Nth order circuits is very good, but here's the problem - once one thing is out of spec or not as designed, your simulation will have less and less correlation with reality as the circuit gains in complexity. IMHO, new gear will fall on its face more often as they try to get hyper-complex due to build quality, basic design, and quality control. The math works in a perfect world, but "good enough" isn't "good enough" in a 9th order filter circuit.

Great post - as well as your measurements "a couple posts back". I will have to put up some similar pc based measuring setup, but it means desktop

pc, good enough soundcard etc - just for that purpose. Any suggestions for "something" that measures at least up to 50 , preferably (close to ) 100 kHz - both hardware and software ? Money IS tight ...

 

It is amusing but not funny to observe how many errors is there in audio equipment, like the closely spaced unshielded resistors for hp out on vintage gear mentioned. Or not so vintage gear - how one can comment on "sonic superiority" of a piece of electronic audio equipment when measurements show channel separation deteriorating to 20 dB at 20 kHz is beyond me. Such piece of electronics should have been redesigned, not raved about in the subjective audio press.

 

I may sound like measurement maniac - nothing could be more off. I always try to find a correlation for something that is audible, be it good or bad, in order to be able to improve performance. 

 

Vintage gear is great - it can still hold its own against modern day x times more expensive competition. But please - do not defend its weakest point, that poor series resistor connected headphone output. It introduces another variable that will vary from amp to amp, meaning headphone X can sound waaayy different with an amp Y or Z - FAR more so than with different dedicated headphone amps. I try to have the least variables possible; no one has a perfect solution in the real world, but reducing their number to an absolute minimum  usually means better performance.

post #8712 of 13112
Quote:
Originally Posted by PhoenixG View Post

I'm a big fan of having a large resistor in the output chain that the vintage amps do.
So it really depends if your HP's are more the type that need to be in charge or need being told, so to speak. Which, in summary, means it all comes down to a good pairing and personal preference.
Quote:
Originally Posted by analogsurviver View Post

do not defend its weakest point that poor series resistor connected headphone output.
It introduces another variable that will vary from amp to amp...reducing their number to an absolute minimum  usually means better performance.



Had a chuckle over this chart from the latest AudiogoN newsletter.

Enjoyed reading both your posts, very happy I'm not defending my thesis this morning with the pair of you on the board!

Underscores the importance of auditioning your ear speakers with a prospective amplifier or vice versa.
Most listeners have to go with a leap of faith and a mix of science if auditioning isn't possible.
Some of what makes these threads so amusing, is the inordinate amount of anguish after a headphone/amp mismatch, compared to people that have found a piece of audio bliss.

Few topics bring as wide a smile to me, for example, than reading how the Fostex TH-900 is impossible to own without a Bakoon HDA-5210mk3 amplifier.
Until someone pops in a says: "but you haven't heard the Fostex with the Zana Deux SE, people who already have the ZD Balancing Act consider purchasing the ZD SE exclusively for the TH-900"

I chuckle over this stuff too.wink.gif
post #8713 of 13112
Quote:
Originally Posted by analogsurviver View Post

Great post - as well as your measurements "a couple posts back". I will have to put up some similar pc based measuring setup, but it means desktop

pc, good enough soundcard etc - just for that purpose. Any suggestions for "something" that measures at least up to 50 , preferably (close to ) 100 kHz - both hardware and software ? Money IS tight ...

 

 

It is amusing but not funny to observe how many errors is there in audio equipment, like the closely spaced unshielded resistors for hp out on vintage gear mentioned. Or not so vintage gear

 

 

Hmm, it is possible to get really high sampling frequencies, but it gets pricey. You can get a used oscilloscope with a serial output and load whatever it does into your computer. You might be able to import that into your evaluation program. I'd want a tone generator that I can sweep through frequencies, or let the computer do that. The problem with letting the comp do it is that it'll have quantization noise at the sampling frequencies. (1024 hz and 2^n harmonics often)

If you do it by hand, a decent o-scope will run $200-300. The software will be anywhere from free to $800 (MATLAB). Using MATLAB is what I'd do, but it's like using a pile driver to put in a finishing nail.

 

Regarding errors in vintage AND modern gear - I really understand where they come up. It's not that they didn't know what would happen. Often, they just decide that the spec they have to live or die by is the height of their stack of dollars they have to spend on making the amp compared to the one they get for selling the amp.

If you compare truly TOTL modern equipment to TOTL vintage gear, they are more similar than different. TOTL technology hasn't changed much, besides putting a computer between your hands and the amp, and some extra buttons to fiddle with to decode new formats. From there down the chain, it's just a matter of quality parts - power supplies, filters, caps, transistors, resistors, inductors, and SHIELDING. I like overbuilt amps with discrete components because they're more likely to be easy to fix and upgrade. I like amps that are heavy, with massive, overbuilt power supplies and components, and I demand shielding on components carrying the sound signal, especially low powered lines. While those things all exist in some modern equipment, they exist in spades in the vintage market at a price range I can hit and afford to experiment with. Can I get an amen?

post #8714 of 13112
Quote:
Originally Posted by 5aces View Post





Had a chuckle over this chart from the latest AudiogoN newsletter.

Enjoyed reading both your posts, very happy I'm not defending my thesis this morning with the pair of you on the board!

Underscores the importance of auditioning your ear speakers with a prospective amplifier or vice versa.
Most listeners have to go with a leap of faith and a mix of science if auditioning isn't possible.
Some of what makes these threads so amusing, is the inordinate amount of anguish after a headphone/amp mismatch, compared to people that have found a piece of audio bliss.

Few topics bring as wide a smile to me, for example, than reading how the Fostex TH-900 is impossible to own without a Bakoon HDA-5210mk3 amplifier.
Until someone pops in a says: "but you haven't heard the Fostex with the Zana Deux SE, people who already have the ZD Balancing Act consider purchasing the ZD SE exclusively for the TH-900"

I chuckle over this stuff too.wink.gif

I chuckle over it too. Ultimately, we all want our music out of our equipment to sound to our liking - and if possible, within what we can still beg/borrow/steal/mortgage/worse. 

 

There may indeed be exclusive combinations of gear that work well together and can sound awful if paired to another "neutral" design. Certain Scottish manufacturer did adhere to this philosophy, at least in the past. I try to avoid that approach, or if it is unavoidable, because it really delivers results unattainable by other means, it should be clearly stated " These PQ macaroni taste as advertised only when cooked in XY bottled water".

 

In say last 30 years, there has been enough advances in electronics components and price reductions for what was once was over the top luxury to be regarded order of the day. ICs that were available 30 years ago are now to large extent still with us, but are much more affordable than they were back then. One can replace them today with SOTA designs that have vastly improved everything - but basic opamp of three decades ago at very reasonable price will still give more predictable results with more headphones than using resistor at the output of a power amp.

 

There are cases where REALLY dedicated headphone amps are unavoidable - electrostatics. Of course one can use normal power amp and connect it to ESLs with a transformer. But it will never be the same as with a dedicated high voltage transformerless amp. Trouble, as usual, it looks expensive,,,

 

One aspect must never be forgotten - what is the input signal. In usual studio recording, the sound has gone through so many bottlenecks a la series output resistor in headphone output that yet one more bottleneck does not really matter much. But if these bottlenecks, one by one, are finally eliminated, that is then another story.

 

It is easy to say "ah, that does not matter much". Say it n times - they add up and it is easy to end up with "telephone" sound in the end.

 

The amount of objective measurements done today is very low compared to technical possibilities. Back in vintage times, when audio was a serious player in even large corporations, there were far more and more comprehensive measurements than today, despite lesser possibilities.. Far from saying that if it measures right, it must sound right - but if it even measures poorly, I can like it as much as possible, that still does not make such a device accurate. The effects of damping ( or lack thereof ) could be measured with pulses - back in the day, packets of pulses at discrete frequencies were sent to the speaker and its output was measured by microphone in an anechoic chamber. Guess what - best "midrange" pulses I ever saw belonged to Quad ESL ( now often referred to as 57 ) - and this is widely recognized as one of the midrange, if not THE midrange speaker of all time. The same could be used for headphones and their amplification; it is more difficult due to head/ear interface that is not linear as with loudspeakers, but this is single frequency test and should not be affected in any way save for amplitude ( if we ignore harmonic distortion etc ). If a speaker/headphone produces very similar acoustic output to its electrical input, it must be regarded as accurate. If it is sloppy/floppy ...

 

How does that compare to listener impressions and ultimately sales figures of the manufacturer is unfortunately entirely different matter, If customers vote with their wallets for fat, overblown bass - guess what will end up being in production. 

 

Enough of this rant - I do not own any receiver, vintage or otherwise, but have vintage integrated amps, tuners, preamps, equalizers, power amps and some much more esoteric vintage audio equipment. And will post a pic ocasionally - but do not expect to see headphones plugged into headphone output jack.

post #8715 of 13112
Quote:
Originally Posted by PhoenixG View Post

 

Hmm, it is possible to get really high sampling frequencies, but it gets pricey. You can get a used oscilloscope with a serial output and load whatever it does into your computer. You might be able to import that into your evaluation program. I'd want a tone generator that I can sweep through frequencies, or let the computer do that. The problem with letting the comp do it is that it'll have quantization noise at the sampling frequencies. (1024 hz and 2^n harmonics often)

If you do it by hand, a decent o-scope will run $200-300. The software will be anywhere from free to $800 (MATLAB). Using MATLAB is what I'd do, but it's like using a pile driver to put in a finishing nail.

 

Regarding errors in vintage AND modern gear - I really understand where they come up. It's not that they didn't know what would happen. Often, they just decide that the spec they have to live or die by is the height of their stack of dollars they have to spend on making the amp compared to the one they get for selling the amp.

If you compare truly TOTL modern equipment to TOTL vintage gear, they are more similar than different. TOTL technology hasn't changed much, besides putting a computer between your hands and the amp, and some extra buttons to fiddle with to decode new formats. From there down the chain, it's just a matter of quality parts - power supplies, filters, caps, transistors, resistors, inductors, and SHIELDING. I like overbuilt amps with discrete components because they're more likely to be easy to fix and upgrade. I like amps that are heavy, with massive, overbuilt power supplies and components, and I demand shielding on components carrying the sound signal, especially low powered lines. While those things all exist in some modern equipment, they exist in spades in the vintage market at a price range I can hit and afford to experiment with. Can I get an amen?

Thank you for the suggestions regarding measuring equipment. Ideally, we all would like sports bulldozers with low mileage, yet in real life...

 

I could not agree with you more regarding both vintage and modern gear. I prefer vintage for the very same reason you do - one can fiddle with something that is basically well made and its present cost is reasonable and within reach, allowing for upgrades - although similar improvements to modern gear are possible, it is far too costly for such things. 

 

A.M.E.N.

 

May I ask one non gear related question - which kind of music is most dear to your heart ?

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