Jump to content

Do amplifiers need a burn in time?


Recommended Posts

3 minutes ago, rawl99 said:

 

I am just wondering if you are having a go at me with the experience I shared about moving the 'cockroach' in a speaker cable in a post earlier.

Just in case, the cockroach was moved back to exactly the same marked positions on the floor so issues like cable geometry etc are moot.

 

https://www.transparentcable.com/products/opus-speaker-cable

 

To your other comments"

 

"I don't understand why people who do experience (to them) such noticeable changes don't explore all possibilities and causes, and question whether it should be an expected outcome."

Why do you assume this is the case??????

I have spent months trying to get to the root cause of some changes I have experienced and a decent number of things I have no answer for.  When I discuss them with fellow engineering types they often tell me that I am imagining 'it' as 'it' cannot be possible.

So then I plonk them down in front of the system and demonstrate and they just shake their heads in disbelief. 

 

The comment about 'expected outcome' gives me some insight into your thought process.

 

Since you have technical training and have been indoctrinated with the knowledge of electrical engineering you view the world through the looking-glass of YOUR programmed expectations.

Have you not considered that there may be **** that happens that is not FULLY understood and FULLY explainable by current Paradigms/Theories/Principles  (which people mistakenly call 'Laws')

I am glad you are not a research physicist at CERN

Yes I am being a bit insulting but it is deliberate to hopefully help you to see an alternative more open-minded point-of-view.

 

If we approached research from the viewpoint that we already understand it all then:

a: what would be the point in doing the research, and

b: what hope would we have of finding anything new...

 

 

You missed the bit where I said I was not rubbishing anyone..  And yes I have considered that there is more going on than what may be obvious. I just don't think it is going on in the piece of metal conductor, simply by moving it, or "burning it in"

 

I am also glad I'm not a physicist, I'd be tearing my hair out by now.. LOL

Link to post
Share on other sites
  • Replies 426
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

just to be the contrary voice here (who me??). Any difference you hear in a sold-state amp after at most, a couple of hours is (IMHO) due to your brain getting used to the sound rather than the sound

Exactly right.  I am Head of Engineering Quality at a multinational manufacturing company.  I find this idea people have, that high end audio companies would routinely release products from their manu

I’m not surprised that people disagree with me.  What does surprise me is that people are reacting as if no one has ever said it before. 

9 minutes ago, rawl99 said:

I will suggest that it does but virtually all control-system applications are closed-loop and therefore far less time dependent in terms of instantaneous signal than audio is.

(1) You also seem to dismiss (high quality) audio reproduction as being a simple thing to do.  Having designed/modified and hand-tuned a bit of gear over the years I would beg to disagree.

Remember that there is no feedback error correction in analog audio so small changes are amplified by the time they hit the listeners ears. (yes there is an exception with a servo-controlled subwoofer)

(2) Our ear/brain is amazingly acute at temporal discernment of an audio signal.

 

(3) If a missile veers by 1 minute of arc it will be corrected by a navigation system since that 1 second is quite a distance off target at the end of its trip.

Or is it just fire and hope and you are knackerd if there is some wind shear.

 

(4) Remember the days of fire and pray torpedoes/missiles vs wire guided??

(1) You assume a lot that isn't necessarily correct

(2) Yes, in combination they are. But they aren't as accurate nor as reliable, and repeatable as what modern test equipment is capable of.

(3) remember the TIC bit?

(4) I don't even know where you're going with that. It's not even relevant to my TIC comment.

Link to post
Share on other sites
On 24/09/2020 at 8:42 AM, bob_m_54 said:

That's my point though. In a very low current situation as you quoted, there is nothing to cause any change in the physical properties of the metal in the wire, unless you're using ridiculously small wire, down to single (hair sized) strands. Wiring that small simply isn't used in audio equipment. That's why I don't buy into such thing as wire "burn in" in amplifiers. ... burn out, yes that's real...

 

And no, I'm not going to sit and do the maths for you, as @Ittaku linked, there are plenty of wire charts and voltage drop calculators around for you to use. (admittedly, that one doesn't go to small enough units for your situation), but it isn't relevant to my point.

So given you stated that for the wire to change its performance it would have to be heat-damaged I can infer from your comment above that we would need something like a single strand of 0.1mm or somewhat smaller to be getting to a size where heating would become an issue?? 

 

I wish I had your absolute knowledge of physics as mine seems to be a bit lacking.

 

So to extend this a little bit:

If I use wire from the output of a dac (approx 600 ohms) to the input of an amplifier (approx 50k) should I expect a sonic difference between using wire of:

0.5 mm diameter

0.6 mm diameter

0.7 mm diameter

0.8 mm diameter

 

 

current approx 0.08mA

skin depth calculates at 0.46mm 

 

If yes, why?

If no, why?

 

Interested in your thoughts please.

 

Cheers

Rawl

 

 

 

  • Like 1
Link to post
Share on other sites
44 minutes ago, bob_m_54 said:

You missed the bit where I said I was not rubbishing anyone..  And yes I have considered that there is more going on than what may be obvious. I just don't think it is going on in the piece of metal conductor, simply by moving it, or "burning it in"

 

I am also glad I'm not a physicist, I'd be tearing my hair out by now.. LOL

One of the good parts of getting old is that one can tend to go bald so hair-tearing becomes a moot point    :-)

 No I did not miss what your words said but there seemed to be an underlying intention that I was questioning.

 

So if I build 2 dacs with hand-selected/matched parts and build one with brand-new wire and one with burnt-in wire (500 hrs) you would expect them to sound the same?

But my experience is that they did not Not at all.. (All the other components were run-in prior to assembly so i could tune a final sound rather than tuning an initial sound which would change over time.

The one with the burnt-in wire had a more relaxed,less etched,  more cohesive sound than the one with the new wire.

After putting a few hundred hours on the one built with the new wire i could not pick the difference between them..

 

I have done similar comparison with burn-in of speaker cables, interconnects etc and the results are consistently similar

 

So please give some probable reasons why such a dramatic degradation was heard when moving the cockroach of the speaker cable and then returning it to its original position.

No geometry change

No proximity change

No connections undone/redone

So the only thing that occurred was the movement of the wire

And over the period of the next week of playing the system  the sound progressively improved back to its original glory....

Link to post
Share on other sites


35 minutes ago, rawl99 said:

So given you stated that for the wire to change its performance it would have to be heat-damaged I can infer from your comment above that we would need something like a single strand of 0.1mm or somewhat smaller to be getting to a size where heating would become an issue?? 

 

I wish I had your absolute knowledge of physics as mine seems to be a bit lacking.

 

So to extend this a little bit:

If I use wire from the output of a dac (approx 600 ohms) to the input of an amplifier (approx 50k) should I expect a sonic difference between using wire of:

0.5 mm diameter

0.6 mm diameter

0.7 mm diameter

0.8 mm diameter

 

 

current approx 0.08mA

skin depth calculates at 0.46mm 

 

If yes, why?

If no, why?

 

Interested in your thoughts please.

 

Cheers

Rawl

 

 

 

My thoughts? you probably wouldn't be interested in them LOL.

 

 

Link to post
Share on other sites
28 minutes ago, rawl99 said:

One of the good parts of getting old is that one can tend to go bald so hair-tearing becomes a moot point    🙂

 No I did not miss what your words said but there seemed to be an underlying intention that I was questioning.

 

So if I build 2 dacs with hand-selected/matched parts and build one with brand-new wire and one with burnt-in wire (500 hrs) you would expect them to sound the same?

But my experience is that they did not Not at all.. (All the other components were run-in prior to assembly so i could tune a final sound rather than tuning an initial sound which would change over time.

The one with the burnt-in wire had a more relaxed,less etched,  more cohesive sound than the one with the new wire.

After putting a few hundred hours on the one built with the new wire i could not pick the difference between them..

 

I have done similar comparison with burn-in of speaker cables, interconnects etc and the results are consistently similar

 

So please give some probable reasons why such a dramatic degradation was heard when moving the cockroach of the speaker cable and then returning it to its original position.

No geometry change

No proximity change

No connections undone/redone

So the only thing that occurred was the movement of the wire

And over the period of the next week of playing the system  the sound progressively improved back to its original glory....

Your two identical amps/DACs wtf ever won't sound the same because your hand picked parts will have much greater variation than Identical wire types, with different number of hours carrying current.

 

As for your "cockroach" I have no idea what it is, or is made of, so haven't a clue. But cables moved from point A to point B, may sound different, but very unlikely if they are moved back to A again.

Link to post
Share on other sites
1 hour ago, rawl99 said:

So to extend this a little bit:

If I use wire from the output of a dac (approx 600 ohms) to the input of an amplifier (approx 50k) should I expect a sonic difference between using wire of:

0.5 mm diameter

0.6 mm diameter

0.7 mm diameter

0.8 mm diameter

 

 

current approx 0.08mA

skin depth calculates at 0.46mm 

 

If yes, why?

If no, why?

Only if your wires were about 1km long, or longer. The differences in conduction will be far less than the random electrical fluctuation within the DAC itself from playback to playback (and that is exceptionally small already.)

  • Like 1
Link to post
Share on other sites
3 hours ago, rawl99 said:

Either you don't want to listen and accept what I am telling you or you are just being deliberately antagonistic. I am not certain which.

And then you say

3 hours ago, rawl99 said:

Anyhows, I am happy to continue to responding to your little digs.

 

Sounds like you are actually quite certain.

 

3 hours ago, rawl99 said:

 So keep it up.

 

no point really

Link to post
Share on other sites


44 minutes ago, Ittaku said:

Only if your wires were about 1km long, or longer. The differences in conduction will be far less than the random electrical fluctuation within the DAC itself from playback to playback (and that is exceptionally small already.)

What? you are introducing common sense into the discussion? Unheard of...

  • Like 1
  • Haha 1
Link to post
Share on other sites
1 hour ago, rawl99 said:

So please give some probable reasons why such a dramatic degradation was heard when moving the cockroach of the speaker cable and then returning it to its original position.

I'm quite sure you don't want to hear or believe in what our explanation would be of this.

  • Like 1
Link to post
Share on other sites

I have never heard the science of engineering described as "indoctrination".

 

Would indoctrination apply to cable designers as well?

 

Possibly not as I have read recent patents to do with cable design that refer to their methodology as "the art of cable making".

Link to post
Share on other sites
4 hours ago, rawl99 said:

@bhobba  I think we were discussing this so please pop in with your comments and correct me as appropriate

Rob Watts has apparently done extensive experimentation with filter design in which the only difference was in the digital noise floor being down in the weeds at approx -140 and approx -150dB.  His engineers claimed that it was below the thermal noise floor so could not be audible but he did the filter design and then blind tested the engineers between the 2 implementations and they heard a clearly audible difference.  Apparently they were quite stunned.

Yes - Rob Watts, impeccably credentialed in both electronic engineering and applied math, has done tests on this, and demonstrated it to other engineers much to their astonishment.   Rob thought, along with just about any other engineer out there, that distortion below 120db was inaudible.   But during development of his DAVE DAC found distortion well below that was clearly audible, and to the astonishment of other engineers clearly demonstrated it to them:

 

 

 

Regarding amps there are a number of issues not easy to measure, but amp designers know only too well not to do.   One is using massive amounts of global feedback to reduce distortion to levels that are virtually not even measurable.   Electronics Australia many years ago published such a design - distortion so low even the binding posts used had to be chosen carefully otherwise they produced distortion more than the amp.   But what did it sound like - evidently it sounded like all the life had been sucked out of the music.   The designers described it as sounding significantly cleaner than any other amp they have heard - but others thought that 'cleanliness' was the life sucked out.   These days most amp designers would not do that - they use small amounts of local feedback, that while not having spectacular measured distortion figures, sounded better, to the designer anyway.   The question is why?   I do not think anyone knows for sure, but the general conjecture is there is a time lag for global feedback to take effect - music is always changing, it is not a steady state sine wave used in distortion measurements.   When it changes the feedback does not work instantly - and a small amount of distortion gets through for a moment - but long enough for the ears to be sensitive to it.

 

I must also add that while such audible differences do exist, what you prefer is your choice.   The EA guys thought the ultra low distortion amp sounded clean, others the life had been sucked out of it.   Music reproduction is an illusion - it tries to 'trick' your brain into thinking - this is real.   Both myself and Rawl (sometimes together) have been to many listening sessions, often with extremely experienced audiophiles (and Rawl is too modest to say this - but he is in that category - I would not describe myself in that category yet, though I have heard quite a lot of audio gear over the years).   One must always listen to audio gear before purchasing.   At the moment Rawl has my Chord TT2 and M-Scaler.  I heave heard it, and directly driving speakers it is overall the best DAC I have yet heard - even beating a Gradinote I also own.   As an aside good thing because the interface to drive the Gradinote IMHO is atrocious - but that is another story.   Rawl prefers it without the M-Scaler and driving a little SET amp he has.   He describes direct connecting and the M-Scaler as making things sound a bit 'cold'.   Because of Covid I have not been on over to Rawls place to hear it on his system so cant say what I think - except as I said with the M-Scaler and direct connected it is the best I have heard, but on another system and not compared to a small SET.   I may still prefer it to the small SET Amp - I do not know untill I hear it - but Rawl and I, while often agreeing on what sounds best, sometimes do not.  And I have to say as my experience has grown, some things I once disagreed with Rawl about I now agree - not all - but some.   Nor is their any issue with this - it is just what personally 'tricks' you better.

 

Bottom line is have a glance at measurements, but do not get too caught up in them - judge for yourself by listening.

 

Thanks

Bill

Edited by bhobba
  • Like 1
Link to post
Share on other sites


1 hour ago, bhobba said:

Regarding amps there are a number of issues not easy to measure, but amp designers know only too well not to do.   One is using massive amounts of global feedback to reduce distortion to levels that are virtually not even measurable.   Electronics Australia many years ago published such a design - distortion so low even the binding posts used had to be chosen carefully otherwise they produced distortion more than the amp.   But what did it sound like - evidently it sounded like all the life had been sucked out of the music.   The designers described it as sounding significantly cleaner than any other amp they have heard - but others thought that 'cleanliness' was the life sucked out.   These days most amp designers would not do that - they use small amounts of local feedback, that while not having spectacular measured distortion figures, sounded better, to the designer anyway.   The question is why?   I do not think anyone knows for sure, but the general conjecture is there is a time lag for global feedback to take effect - music is always changing, it is not a steady state sine wave used in distortion measurements.   When it changes the feedback does not work instantly - and a small amount of distortion gets through for a moment - but long enough for the ears to be sensitive to it.

This question has long since been answered. The low distortion levels only applied to a single frequency at a single power rating. It wasn't the feedback at fault, but the implementation of trying to just fix a number. At normal listening levels everything broke down and distorted up the wazoo in the audible range. Listen to the ex-Hypex engineer - Bruno Putzey's interviews where he expands on this.

Edited by Ittaku
  • Like 2
Link to post
Share on other sites
15 minutes ago, bhobba said:

Rob Watts, impeccably credentialed in both electronic engineering and applied math

So I've looked and I can't find anything online referring to Rob Watts' credentials in these fields. Do you have a link that shows them?

Link to post
Share on other sites
17 minutes ago, bhobba said:

Yes - Rob Watts, impeccably credentialed in both electronic engineering and applied math,

 

In Oz we call it 'maths ', Bill - 'math' is Septic Tank-speak.  xD

 

Andy

 

 

  • Like 2
  • Haha 1
Link to post
Share on other sites


38 minutes ago, bhobba said:

Yes - Rob Watts, impeccably credentialed in both electronic engineering and applied math, has done tests on this, and demonstrated it to other engineers much to their astonishment.   Rob thought, along with just about any other engineer out there, that distortion below 120db was inaudible.   But during development of his DAVE DAC found distortion well below that was clearly audible, and to the astonishment of other engineers clearly demonstrated it to them:

 

 

Regarding amps there are a number of issues not easy to measure, but amp designers know only too well not to do.   One is using massive amounts of global feedback to reduce distortion to levels that are virtually not even measurable.   Electronics Australia many years ago published such a design - distortion so low even the binding posts used had to be chosen carefully otherwise they produced distortion more than the amp.   But what did it sound like - evidently it sounded like all the life had been sucked out of the music.   The designers described it as sounding significantly cleaner than any other amp they have heard - but others thought that 'cleanliness' was the life sucked out.   These days most amp designers would not do that - they use small amounts of local feedback, that while not having spectacular measured distortion figures, sounded better, to the designer anyway.   The question is why?   I do not think anyone knows for sure, but the general conjecture is there is a time lag for global feedback to take effect - music is always changing, it is not a steady state sine wave used in distortion measurements.   When it changes the feedback does not work instantly - and a small amount of distortion gets through for a moment - but long enough for the ears to be sensitive to it.

 

I must also add that while such audible differences do exist, what you prefer is your choice.   The EA guys thought the ultra low distortion amp sounded clean, others the life had been sucked out of it.   Music reproduction is an illusion - it tries to 'trick' your brain into thinking - this is real.   Both myself and Rawl (sometimes together) have been to many listening sessions, often with extremely experienced audiophiles (and Rawl is too modest to say this - but he is in that category - I would not describe myself in that category yet, though I have heard quite a lot of audio gear over the years).   One must always listen to audio gear before purchasing.   At the moment Rawl has my Chord TT2 and M-Scaler.  I heave heard it, and directly driving speakers it is overall the best DAC I have yet heard - even beating a Gradinote I also own.   As an aside good thing because the interface to drive the Gradinote IMHO is atrocious - but that is another story.   Rawl prefers it without the M-Scaler and driving a little SET amp he has.   He describes direct connecting and the M-Scaler as making things sound a bit 'cold'.   Because of Covid I have not been on over to Rawls place to hear it on his system so cant say what I think - except as I said with the M-Scaler and direct connected it is the best I have heard, but on another system and not compared to a small SET.   I may still prefer it to the small SET Amp - I do not know untill I hear it - but Rawl and I, while often agreeing on what sounds best, sometimes do not.  And I have to say as my experience has grown, some things I once disagreed with Rawl about I now agree - not all - but some.   Nor is their any issue with this - it is just what personally 'tricks' you better.

 

Bottom line is have a glance at measurements, but do not get too caught up in them - judge for yourself by listening.

 

Thanks

Bill

And not to confuse Noise with Distortion.. two completely different things.

But the Amplifier you're talking about may have been the 20W Class-A amplifier in the May 2007 edition of Silicone Chip Magazine.

 

https://ia800503.us.archive.org/33/items/Silicon_Chip_Magazine_2007-05_May/Silicon_Chip_Magazine_2007-05_May.pdf

Edited by bob_m_54
Link to post
Share on other sites
53 minutes ago, Ittaku said:

This question has long since been answered. The low distortion levels only applied to a single frequency at a single power rating. It wasn't the feedback at fault, but the implementation of trying to just fix a number. At normal listening levels everything broke down and distorted up the wazoo in the audible range. Listen to the ex-Hypex engineer's interviews where he expands on this.

 

You could be right - as I said - this was just a conjecture.   Regarding Hypex amps they were really hyped a number of years ago now and someone from WA was kind enough to send one he built over to me to check out against other amps - much more expensive ones.   I will first say - value for money it was unassailable - the Hypex beat everything hands down.   But first up was a test against a top of the line Macintosh.   The Mac - killed it.   Then against a very high quality 300B 8W SET, whose name I forget, I used at the time - again it killed it.   I tried it against others I forget with the same results.   But, as I said, the quality of sound you got out for the money was amazing.    I believe they have undergone a lot of changes since then so I do not know about them now.   I posted what I found on this long thread on the Hypex modules and the designer replied.   He said what I was comparing it against was a very tough test, because they were all well known to be very good sounding amps, but still maintained his amps were more accurate.

 

Thanks

Bill

Link to post
Share on other sites
47 minutes ago, bob_m_54 said:

And not to confuse Noise with Distortion.. two completely different things.

But the Amplifier you're talking about may have been the 20W Class-A amplifier in the May 2007 edition of Silicone Chip Magazine.

 

https://ia800503.us.archive.org/33/items/Silicon_Chip_Magazine_2007-05_May/Silicon_Chip_Magazine_2007-05_May.pdf

 Could be - my memory is not what it once was.

 

Thanks

Bill

Link to post
Share on other sites
1 minute ago, bhobba said:

 

You could be right - as I said - this was just a conjecture.   Regarding Hypex amps they were really hyped a number of years ago now and someone from WA was kind enough to send one he built over to me to check out against other amps - much more expensive ones.   I will first say - value for money it was unassailable - the Hypex beat everything hands down.   But first up was a test against a top of the line Macintosh.   The Mac - killed it.   Then against a very high quality 300B 8W SET, whose name I forget, I used at the time - again it killed it.   I tried it against others I forget with the same results.   But, as I said, the quality of sound you got out for the money was amazing.    I believe they have undergone a lot of changes since then so I do not know about them now.   I posted what I found on this long thread on the Hypex modules and the designer replied.   He said what I was comparing it against was a very tough test, because they were all well known to be very good sounding amps, but still maintained his amps were more accurate.

 

I don't disagree. I've been saying for a while that what Putzey's done with class D amplification has killed the affordable range class A/AB by a million miles, and there really is no reason for solid state class A/AB to exist in that range any more. It's only a matter of time before this is so obvious that the marketplace is unrecognisable. Once you get to serious high end gear, or compare them with valve amplification, it's a very different equation.

Link to post
Share on other sites
4 minutes ago, Ittaku said:

Once you get to serious high end gear, or compare them with valve amplification, it's a very different equation.

Not just hi end.

 

Class D amplifiers are ok to replace gear up to about $2K, depending on brand and implementation of both D and A/B, after which the desirability factor falls off a very sheer cliff.

 

I don't use or like subs, but I am reliably informed that class D amps work well in that situation

Link to post
Share on other sites
1 hour ago, sir sanders zingmore said:

My kids call it math, Andy. I fear we are the last generation to say it correctly  :)

I do not know about now but when I did my degree in math at the QUT 40 years ago now, we called it applied math as opposed to puerile math they did at the UQ (or was that pure math - like I said my memory is not as good as it once was) 😝😝😝😝.  Don't worry - the pure math guys got their own back - it was all good natured - the truth is each requires the other.

 

Thanks

Bill

Link to post
Share on other sites
2 hours ago, sir sanders zingmore said:

So I've looked and I can't find anything online referring to Rob Watts' credentials in these fields. Do you have a link that shows them?

 

I did read somewhere he studied both electronics and math at a top UK university - but I too tried to find it and couldn't.   I found a lot of references like the following where his ideas started at university eg 

https://www.head-fi.org/threads/chord-electronics-dave.766517/page-478

 

Thanks

Bill

Edited by bhobba
Link to post
Share on other sites
37 minutes ago, rantan said:

Class D amplifiers are ok to replace gear up to about $2K, depending on brand and implementation of both D and A/B, after which the desirability factor falls off a very sheer cliff.

 

Actually the best amp I have heard is no amp - its the DAC output stage of the Chord TT2 - it produces 18W.   But while digital it runs at 5bit 104 Mhz.   But since some like verification of these sort of claims I found the following:

https://www.audiosciencereview.com/forum/index.php?threads/chord-upsampling.9109/

 

I honestly believe it is the future - but they do need to get the power up a bit - I would prefer 50W - although on the speaker I used it on 18w worked fine.   But when reproducing HT I have found they wind the dialogue volume down so the booms and bangs have better impact.   Interestingly on my system with 89db speakers into 500w Arions and using the volume control on my Direct Stream which is in .5 db increments I listen to music at between 40-50, normal HT at about 60, but some movies etc I have to wind up to 80.   That corresponds to about 1W normally, 5 watts for normal HT, but 50w when I wind it up to 80.   I just hope everything works out ok when I get the TT2 into my system.

 

Thanks

Bill

Link to post
Share on other sites
50 minutes ago, rantan said:

 

I don't use or like subs, but I am reliably informed that class D amps work well in that situation

 

 

My 800w Hypex amps work superbly, driving my subs.  :thumb: (All subs need is grunt - not 'finesse'!  :) )

 

And if you don't use them, r ... you don't know what you're missing!  xD

 

51 minutes ago, bhobba said:

I do not know about now but when I did my degree in math at the QUT 40 years ago now, we called it applied math as opposed to puerile math they did at the UQ (or was that pure math - like I said my memory is not as good as it once was) 😝😝😝😝.  Don't worry - the pure math guys got their own back - it was all good natured - the truth is each requires the other.

 

Thanks

Bill

 

When I did my 1st degree, from '66 to '69 ... it was maths.  Both pure and applied.  :)  IMO, the Yanquis are the cause of the degradation of the English we use.  :(

 

Andy

 

  • Love 1
Link to post
Share on other sites
7 minutes ago, sir sanders zingmore said:

Which hypex amps do you have Andy ?

 

Hypex Subwoofer Module DS8.0, Trevor.  Interestingly enough, they have a linear PS.  :thumb:

 

Andy

 

  • Like 1
Link to post
Share on other sites
  • Recently Browsing   0 members

    No registered users viewing this page.




×
×
  • Create New...