Remote Power Supply Connection

Re: Remote Power Supply Connection



Iain Churches wrote:
>
> "Patrick Turner" <info@turneraudio . com .au> wrote in message
> news:483BDA1F.DE1A2FD2@turneraudio . com .au...
> >
> >
> > Iain Churches wrote:
> >> What makes you think they quit? Tube audio is pretty addictive
> >> for most.
> >
> > No, it really isn't. For every 10 people who get a craze on audio,
> > the interest lasts for only 1 in 10, and of those the interest
> > dies usually when they have to buy an OPT.
>
> When at the entry level, one does not need Lundahl
> or Sowter. A much more modest OPT will give
> adequate results for a basicx project.
>
> > Most who are interested just want answers, not BS,
> > so they just surf the web, hence I get 500 hits a day,
> > but very few questions emailed.
>
> That's a huge number of hits. I saw no counter on your
> site. One would have thought that such a level of access
> would have generated considerable e-mail, resulting in
> a healthy order book.

Melbourne IT is my website hoster.

They have told me that's about the average number of hits
and its been like that for a couple of years.

I've had maybe 2 orders in 2 years, guys wanting bargains for
1/2 the price of equivalent amps in the shops.

Most results of having the website is that I get
people wanting their favourite 25 year old+ SS amp fixed.

>
> My own, much more modest webpage, gets some 50 hits
> per week, which generate about five interesting e-mails per
> day.

I'm in Oz, and in a 'regional area' and ppl tune out when they
just can't drive around to see me in 20 minutes.

I get maybe 3 emails a week with guys uncertain about how to make
something.
I wouldn't want 5 emails a day like that; it'd drive me mad.

They should find ALL the answers at my site if they look.
Some might want to dig deeper, and analyse further
than I have publicised, ok, I tell them to read old books
and solder their way to understanding just like I did over a long time.


> >
> >> > There is an extraordinarily SMALL number of people world wide actually
> >> > building their own audio gear, AND who also want to discuss it
> >> > to learn more.
>
> That's probably true, because the threshold is quite steep. But
> thanks to authors like Morgan Jones and Bruce Rozenblit, people
> are interested in finding out what tube audio is all about.
> >>
> > I do know 10 people interested in tubes.
> >
> > They are some of my customers. If I had no customers, maybe I'd know 4
> > interested in tube audio.
> > This is out of a population of 340,000 local people.
> > In Sydney, there are about 4 million+, and the club there only has about
> > 100 members.
> > Same for Melbourne.
>
> I probably know 100, and both HKI and Stockhom are much
> smaller cities.
> >
> > TV came into the home to replace music and books for most ppl.
> >
> > Even now, most people pay only lip service for audio; what is important
> > is the moving picture.
>
> Yes. It is true that listening to music which once the principle hobby
> for many, now has to compete with TV, computers, PlayStations,
> DVD rentals, HT etc etc. Although the percentage of disposable income
> has risen considerably, it is probably now spread more thinly.
> >
> > I feel I am the living dead watching TV.
> >
> > Why the fuck would I want to watch other ppl doing their lives instead
> > of doing my own??????
>
> One of my other hobbies is military history. Both the BBC and
> Discovery Channel have very good documentaries.

I do think a Spitfire is a nice aeroplane, but military history
isn't something I am much interested in.
I was never in a war against people, thank goodness.

I am in a perpetual war against unecessary noise and distortions,
but I don't care about its boring history!!



>Other than
> these, and the News, I watch very little TV which is a very poor
> substitute for the cinema, which I enjoy very much. Luckily my
> music room is on the lower ground floor. So I can go there to
> enjoy music whenever I choose, day or night, and annboy no-one.

My 10 hours a week on a bicycle is a fine substitute for TV, HT, games,
the pub, the brothel, and the betting rooms.

If I sin, its because I exercize too much.



> >
> > A lot of them are full of BS ideas that cannot stand up to scrutiny.
>
> I very much enjoy listening to people's opinions and ideas.
> I had lunch a few days ago with a very nice fellow, a
> lawyer, who is very interesting in music and tube audio. He was
> speaking sincerely when he told me that he has a great problem
> with amplifiers with feedback. He finds that they "smear" the
> audio signal.

If the NFB is done wrong and attempts at stabilization kill the HF
response.

One never knows what ppl really do with their amps.


> I tried to outline the benefits of NFB, flatter BW,
> lower THD, lower Zout, but he was of the opinion that all this
> was too high a price to pay for the negative aspects that he
> observed. None of us can connect our brains to his ears, so
> there is no way to know what he can or cannot hear. But, my
> point is, if he had made sauch a comment on Usenet he would
> have been ridiculed immediately, without any kind of discussion.

During listening tests of a re-engineered VAC 7070 amp a couple of weeks
back
with a client who is buying my 845 SET amps, I switched the FB off
on the VAC because it has switchable amounts of NFB.

My client said he liked the zero NFB option best in the VAC.

You've seen the latest test results I have posted on this VAC amp, and
its
a very good amp with or without global NFB.
I don't hear a great difference between 10dB FB or no FB.
None in fact.
It just proves triode amps don't need global NFB.

Better technical results from this VAC cold be had when the 8 ohm load
is connected to the
4 ohm outlet, and THD falls, damping factor doubles, and so on.

Its capable of 60 watts AB1 instantaneously, but only 52 watts
with a sine wave with cathode bias. The test results I posted
were for class AB1 with the cathode bias so at high output the amp
becomes
badly biased due to Ek rise but under dynamic music conditions the Ek
wouldn't move so then distortions would be a lot lower at high output.

People knock triode amps without NFB, especially SET amps.

They usually have bever listened to one that has a huge power reserve.


>
> > They will want silver wire and fancy connectors and caps and all manner
> > of
> > crap, but when you examine the amps they buy, such as the VAC 7070,
> > you immediately see that what they have bought fails miserably to be
> > reliable,
> > and its full of bean counter inspired design idiocy, and other design
> > features
> > to make the item very difficult to live with, such as the unit's weight,
> > because some fuctard has decided to make a pair of monoblocs on ONE
> > chassis.
> > The sound is severly compromised by hum that is too high,
> > and distortion is needlessly 4 times or more higher than it might
> > otherwise
> > be had the designer used about $20 more worth of parts, and 3 hours more
> > of design time.
>
> None of us, much as we would like to, can set ourselves up as judge
> and jury when people make their choices. If a client specifically
> request a shielded mains cable, then that's what he wants. If, after
> protracted listening tests he decides that four pairs of PPP EL84s
> produce musical Nirvana, you are wasting your time offering him
> a KT88 alternative.

I MUST give customers what they want, or I don't eat.

I had dozen pairs of mono block chassis made up professionally
3 years ago, and not one guy wanted what allowed me to use any of the
chassis
which allow 4 different types of amp.

It cost me $3,000 and I have not filled one chassis with parts yet.

* w w w .turneraudio . com .au/future-amps.html


> >
> > The vast majority of SET based forums have a lot of blind ppl leading
> > the blind.
> > They refuse to take technical issues and numbers seriously.
> > They'll argue about "the sound", but never measure anything.
> > I never go to other forums because I quickly find there's nothing I need
> > to say to them.
> > I've said it all here.
>
> Yes indeed. SET is in an interesting case, and can be relied upon to
> put the cat among the pigeons.
> >
> > If ya get ya triode amp to measure well, it'll sound well.
>
> But it's all relative. I strive for a noise floor of <100µV. People
> tell me that 1mV is OK :-)

Yes, with insensitive speakers, but your amps could be used with horns.

1mV is arbitary. If 1mV can exist, its possible some minor faults ups
that to 10mV,
then the amp needs fixing.

> >
> > If ya wanna gild tha lilly with fancy shmancy capacitors costing $100
> > each, don't lemme stop ya.
>
> That's exactly what some people want.
>
> I spent an interesting couple of hours on Thursday last,
> sitting in on a tube amp "fitting" session when a client
> came to discuss with a colleague of mine the remaining
> details of his new amp which is nearing completion.
>
> The listening tests had been carried out quite a while
> ago with a similar amp at the client's home, and at the
> voicing, he picked out the brands of tubes that pleased
> him, and some small adjustments were subsequently made.
> But this meeting was to decide on the final cosmetic details.
>
> I liked very much the way the builder handled the whole thing.
> He had six sets of solid teak side panels, ready oiled (three
> coats applied earlier in the week) and laid these out for the
> client to choose the pair with the grain he liked the best.
> He and I went away to make the coffee while the client
> deliberated, and looked at the panels in daylight and under
> artificial light. By the time the coffee was ready, he had
> made his choice, and put one pair of panels aside for his
> own amp.
>
> The stainless steel and copper chassis was now resplendent
> after many days of polishing, and transformers in their black
> powder coated pots, were fitted.
>
> He had not been impressed by any of the standard catalogue knobs,
> but very much liked those he had seen on an old Marconi receiver.
> A set of these, brand new, had been made up for him on CNC
> and anodised. He was delighted.

Fortunately, I don't get too many fanatics you get.

I couldn't help them much, and the cosmetics don't help the sound.

I am into sound engineering, not art.

Or trick engineering for its own sake.

>
> He approved the drawings for the front badge, and this
> will be ready, engraved on nickel plate on Monday.
>
> The client was a serious, middle-aged professional man, but I
> could see that beneath this calm exterior, and from the way his
> mouth turned up at the corners, and the glint in his eye, that he
> was excited as a kid at Christmas.

Some get real impatient.

They sure know how to want, but dunno how to wait.

What I make takes as much work a house extension or hand made violin or
cello.

They gotta wait. I sometimes even fib about the time it will take,
knowing
I'll get them used to Patrick's months are 6 of anyonje elese's

Lying about time helps the music more than rushing at a job.


>
> He had been given a level of product individuality and service
> that no dealer with a franchise in SS big names could even
> hope to match. I have no idea what he was paying for this
> tube amp amp. I would estimate that the CNC machined
> knobs cost about the same as a solid state power amp.
> But, so what? He has the money, and knows exactly what
> he wants
>
> Me? I just watched with interest and picked the largest slice
> of fruit cake, the one with the cherry on it:-)
>
> >
> > I ain't a feel good merchant. My website facilitates the efforts of the
> > diyer.
> > Once they have a working whatsit, they can then try all manner of snake
> > oils and witchcraft
> > audio techniques, and spend hours chatting about this stuff online but I
> > am not much interested
> > and don't have the time.
>
> But as a bespoke builder, you strive to give the client what he/she (thinks
> he/she) wants.

Of course. If they want DACT, they get it.
Usually I ask them to purchase the specials themselves, and they don't
have to pay me the % on top.
This % never covers my time, trouble and risk of ordering special stuff.


> >
> > I've tried AB comparisons between Wima and Auricap polyprops and heard
> > no differences at all.
> > Nor can my customers. I have conducted tests here to find out if anyone
> > came pick a difference better than
> > 50% of the time.
>
> I know people who insists on Jensen silver or copper paper in oil
> caps. They claim they can here the superiority of these, and are
> willing to put their money behind their opinions. That's fine by me.
>
> > But I would be like a pork chop in a synogogue if I try to tell the ppl
> > in little forums where
> > nobody ever really challenges anyone else that most percieved capacitor
> > differences are
> > ficticious.
>
> Yes indeed. It is better to let people believe what they want to believe.
> You cannot possibly "put yourself in their ears" so why make a big deal
> of it?

I don't. I just have default brands for caps and that's it.
The amps I make with all other parts being generic, with plain solder
and
plain copper wiring survive comparisons with all others.

Its not the brand that matters, its the way things are used in a total
package.
Get the design wrong and no amount of good brand names or even Jensen
caps will make any difference.


>
> > Just what value of capacitance you might have, and how the whole system
> > is composed
> > right down to the myriad little technical details is what
> > occupies my mind, and this is what is more important than brandname
> > bits.
>
> The engineering bit (correct values for optimum performance) is
> much more important that boutique caps and connectors.
>
> But if someone thinks otherwise, they are entitled to their opinion
> as far as I am concerned.

I always agree calmly with what ppl want if they seem utterly
fixated in their opinions and I have to sell them something.

If I ain't selling something to them I can be free about saying what
I think.

Patrick Turner.
>
> Iain

Re: Remote Power Supply Connection



"Patrick Turner" <info@turneraudio . com .au> wrote in message
news:483C1499.76416A4C@turneraudio . com .au...
>
>
> Iain Churches wrote:
>>

>> That's a huge number of hits. I saw no counter on your
>> site. One would have thought that such a level of access
>> would have generated considerable e-mail, resulting in
>> a healthy order book.
>
> Melbourne IT is my website hoster.
>
> They have told me that's about the average number of hits
> and its been like that for a couple of years.
>
> I wouldn't want 5 emails a day like that; it'd drive me mad.

Most are short and polite, on various subjects - not just audio.

>> One of my other hobbies is military history. Both the BBC and
>> Discovery Channel have very good documentaries.
>
> I do think a Spitfire is a nice aeroplane, but military history
> isn't something I am much interested in.
> I was never in a war against people, thank goodness.

The period that interests me is 1796 to 1918, and so covers
the Georgian and Victorian (British Empire) era up to WW1.

>
>> I very much enjoy listening to people's opinions and ideas.
>> I had lunch a few days ago with a very nice fellow, a
>> lawyer, who is very interesting in music and tube audio. He was
>> speaking sincerely when he told me that he has a great problem
>> with amplifiers with feedback. He finds that they "smear" the
>> audio signal.
>
> If the NFB is done wrong and attempts at stabilization kill the HF
> response.

The point he was making was that no SS amp pleased him,
and even the 12-15dB found it many tube amps was an excess.
I listened to his point of view with interest.
>
> During listening tests of a re-engineered VAC 7070 amp a couple of weeks
> back
> with a client who is buying my 845 SET amps, I switched the FB off
> on the VAC because it has switchable amounts of NFB.
>
> My client said he liked the zero NFB option best in the VAC.

Did he say why? Probably the 10dB was not enough to do anything
audible to the bandwidth or the noise floor when it was taken out.

I like the idea of having that option. Did you have level matching to
attenate the levels with no FB? Otherwise, in listening tests, louder
is usually better.
>
> You've seen the latest test results I have posted on this VAC amp, and
> its
> a very good amp with or without global NFB.
> I don't hear a great difference between 10dB FB or no FB.
> None in fact.
> It just proves triode amps don't need global NFB.
>
> Better technical results from this VAC cold be had when the 8 ohm load
> is connected to the
> 4 ohm outlet, and THD falls, damping factor doubles, and so on.
>
> Its capable of 60 watts AB1 instantaneously, but only 52 watts
> with a sine wave with cathode bias. The test results I posted
> were for class AB1 with the cathode bias so at high output the amp
> becomes
> badly biased due to Ek rise but under dynamic music conditions the Ek
> wouldn't move so then distortions would be a lot lower at high output.
>
> People knock triode amps without NFB, especially SET amps.
>
> They usually have bever listened to one that has a huge power reserve.

Yes. We have seen and heard plenty of evidence of that:-)
>
>
> I had dozen pairs of mono block chassis made up professionally
> 3 years ago, and not one guy wanted what allowed me to use any of the
> chassis
> which allow 4 different types of amp.
>
> It cost me $3,000 and I have not filled one chassis with parts yet.
>
> * w w w .turneraudio . com .au/future-amps.html

Shame. That's why I think the slab chassis is such a good idea.
You can have a standard front and back panel and just CNC the
top panel to suit.
>
>> > If ya get ya triode amp to measure well, it'll sound well.
>>
>> But it's all relative. I strive for a noise floor of <100µV. People
>> tell me that 1mV is OK :-)
>
> Yes, with insensitive speakers, but your amps could be used with horns.
>
> 1mV is arbitary. If 1mV can exist, its possible some minor faults ups
> that to 10mV,
> then the amp needs fixing.

I found that ground layout is critical if you want to wring the very
last dB out of the SNR.

>> I spent an interesting couple of hours on Thursday last,
>> sitting in on a tube amp "fitting" session when a client
>> came to discuss with a colleague of mine the remaining
>> details of his new amp which is nearing completion.
>>
>> The listening tests had been carried out quite a while
>> ago with a similar amp at the client's home, and at the
>> voicing, he picked out the brands of tubes that pleased
>> him, and some small adjustments were subsequently made.
>> But this meeting was to decide on the final cosmetic details.
>>
>> I liked very much the way the builder handled the whole thing.
>> He had six sets of solid teak side panels, ready oiled (three
>> coats applied earlier in the week) and laid these out for the
>> client to choose the pair with the grain he liked the best.
>> He and I went away to make the coffee while the client
>> deliberated, and looked at the panels in daylight and under
>> artificial light. By the time the coffee was ready, he had
>> made his choice, and put one pair of panels aside for his
>> own amp.
>>
>> The stainless steel and copper chassis was now resplendent
>> after many days of polishing, and transformers in their black
>> powder coated pots, were fitted.
>>
>> He had not been impressed by any of the standard catalogue knobs,
>> but very much liked those he had seen on an old Marconi receiver.
>> A set of these, brand new, had been made up for him on CNC
>> and anodised. He was delighted.
>
> Fortunately, I don't get too many fanatics you get.

I was just an observer. I don't know how much was paying for the
amplifier, but I would think one does not need to sell to many like
that in a year to make a very good living indeed.
>
> I couldn't help them much, and the cosmetics don't help the sound.

How true. But, as we have discussed before PQ (percieved
quality) is all part of the requirement. My early "agricultural"
efforts certainly don't cut the mustard any more, even though
they sound well, and have a good measured performance.

* w w w .kolumbus.fi/iain.churches/Pics/252Amplifier/252.02.jpg


>
> I am into sound engineering, not art.

The engineering and design style are closely linked.

> Some get real impatient.
>
> They sure know how to want, but dunno how to wait.

Money burning a hole in the pocket! This is made worse
by the fact that he could buy a SS Krell amp over the
counter at 25% discount and have it delivered ti his home
within the hour.
>
> What I make takes as much work a house extension or hand made violin or
> cello.

I admired the patience of a colleague who had been polishing
a stainless steel chassis for four days. He replied: "This is quick
and easy compared with preparing an acoustic guitar body"
>
> They gotta wait. I sometimes even fib about the time it will take,
> knowing
> I'll get them used to Patrick's months are 6 of anyonje elese's
>
> Lying about time helps the music more than rushing at a job.

I have worked a lot in audio post. One of the first thing one learns
is that there is no such thing as a "dead simple job" as described
by the client's secretary when she tries to get you to stay on, "just
fifteen minutes" after normal hours. If you get away by midnight
you are lucky. I also learned never, ever, to promise anything
which I was not 100% sure I could deliver.
>
>> But as a bespoke builder, you strive to give the client what he/she
>> (thinks
>> he/she) wants.
>
> Of course. If they want DACT, they get it.
> Usually I ask them to purchase the specials themselves, and they don't
> have to pay me the % on top.
> This % never covers my time, trouble and risk of ordering special stuff.

Yes. I know builders who do this with tubes also, particularly Tesla,
KR. The client has no comeback then if there is a premature cathode
to heater short.


> I just have default brands for caps and that's it.
> The amps I make with all other parts being generic, with plain solder
> and
> plain copper wiring survive comparisons with all others.
>
> Its not the brand that matters, its the way things are used in a total
> package.
> Get the design wrong and no amount of good brand names or even Jensen
> caps will make any difference.

I agree with that entirely.
>
> I always agree calmly with what ppl want if they seem utterly
> fixated in their opinions and I have to sell them something.
>
I helped a pal out my making up some screened mains cables.
He sold them to his client because he (the client) had asked
for them. Not because he (the builder) claimed they had any
magic capabilities or would enhance in any way the performance
of an amplifier.

Iain

Re: Remote Power Supply Connection



Iain Churches wrote:
>
> "Patrick Turner" <info@turneraudio . com .au> wrote in message
> news:483C1499.76416A4C@turneraudio . com .au...
> >
> >
> > Iain Churches wrote:
> >>

snip,

> The period that interests me is 1796 to 1918, and so covers
> the Georgian and Victorian (British Empire) era up to WW1.

I don't have time to enjoy culture and read books and
study history.

And studying history teaches you how stupid the present lot of
military minds are; masters of war.

I'm too busy.


>
> >
> >> I very much enjoy listening to people's opinions and ideas.
> >> I had lunch a few days ago with a very nice fellow, a
> >> lawyer, who is very interesting in music and tube audio. He was
> >> speaking sincerely when he told me that he has a great problem
> >> with amplifiers with feedback. He finds that they "smear" the
> >> audio signal.
> >
> > If the NFB is done wrong and attempts at stabilization kill the HF
> > response.
>
> The point he was making was that no SS amp pleased him,
> and even the 12-15dB found it many tube amps was an excess.
> I listened to his point of view with interest.

I get very mixed opinions about NFB.

In the past I have demonstrated some of my finer amplifiers and speaker
systems to the
Sydney based audiophile society.

The classic comment I overheard in a toilet during a break in
proceedings at a demo meeting
with my 25 watt 13Ei SEUL amps was ".. well Joe, I guess this prooves
that ya can use NFB
with an SE amp..."

My bloody oath you can.

I filled a big room with splendid music with 35 ppl present, all smiles.

Not one bloke said he disliked the NFB, or that he could hear the
terrible signature
of electro capacitors that were not Black Gate, or coupling caps that
were not
AuriCaps, or resistors that were not metal film, or gain pots that were
not
DACT attenuators etc.

I used plain old Radio Shack grade generics, and got a rave reception.
((Now I use better parts just in case someone does look "under the
bonnet".))

But the speaker cabs and drivers and effort put into getting a flat
response
was second to none.

So I have heard just about every complaint, every whinge, every sour
comment,
every smartarse wannabe critique, and I don't them worry me.
If they really get passionate about their concerns, then I ask them to
set up
an AB test to demonstrate what they believe is true.
Usually they dissapear in disgust, but I can't please all the people all
the time!


> >
> > During listening tests of a re-engineered VAC 7070 amp a couple of weeks
> > back
> > with a client who is buying my 845 SET amps, I switched the FB off
> > on the VAC because it has switchable amounts of NFB.
> >
> > My client said he liked the zero NFB option best in the VAC.
>
> Did he say why? Probably the 10dB was not enough to do anything
> audible to the bandwidth or the noise floor when it was taken out.

Well, I knew there wouldn'r be much audible difference with/without
GNFB.
The guy didn't specify exactly why he found zero GNFB so nice.
But he turns to me and asks "So why use NFB?"
I paused, and and all I could say, knowing this guy is 100% technically
illiterate, was
"Well, in this case there is not any huge reason."

But that test was done BEFORE I cleaned up and de-shiterized the VAC
power supply,
revised the cathode circuits and made some subtle but effective
improvements to the driver stage loading,
and replaced the shielded input cabling.

If I had done the latter improvements prior to the listening tests I
think
the VAC would have then matched the other amps being tested on the
night, ie
my pair of 60W 845 SET amps.
At the evenings end, it was the 845 that were better overall.

I first heard the VAC amp soon after my customer bought it and before
it started filling his room with smoke.
I thought it was a very decent amp, and despite
its faults it must have had while I listened.
Everyone thought so too.


> I like the idea of having that option. Did you have level matching to
> attenate the levels with no FB? Otherwise, in listening tests, louder
> is usually better.

There is no attempt in the VAC to maintain sensitivity of input to
output
when switching the NFB from 0dB to 12dB in 5 different amount to a max
of 12dB with no load.
So as you add NFB, it goes quieter, so you must increase the preamp
gain,
and during the process, audio memory suffers.

And during many AB tests i have done where levels were carefully matched
with a signal and meter, people sitting with the switch to go from one
amp to another
with same source and same speakers often have not heard any difference
and cannot
pick whether FB is used or not, let alone which amp has better
capacitors and cabling et all.

But as soon as I make one amp only 1dB louder, hey presto, its "better".

So its very easy to rig a test to get a wanted outcome.



Snip,

> Fortunately, I don't get too many fanatics you get.
>
> I was just an observer. I don't know how much was paying for the
> amplifier, but I would think one does not need to sell to many like
> that in a year to make a very good living indeed.
> >
> > I couldn't help them much, and the cosmetics don't help the sound.
>
> How true. But, as we have discussed before PQ (percieved
> quality) is all part of the requirement. My early "agricultural"
> efforts certainly don't cut the mustard any more, even though
> they sound well, and have a good measured performance.

Average wages in Oz are now around USD $45,000 pa.

If someone makes a "perfect" integrated tube stereo amp, say 50W/ch,
and its price is $6,000, then the labour content is $4,000.
This includes profits, insurance, and taxation etc.

To make average wages in a year, one would have to make 11 amps per
annum.
Or ONE per MONTH.

This is utterly impossible for one man to achieve including
winding all the OPT, PT and chokes.

Nobody in Oz or anywhere else has ever wanted to pay
me the same price they would pay if they bought the same watts from ARC,
CJ, etc.

South of the equator, demand for tube gear is disgustingly low.

>
> * w w w .kolumbus.fi/iain.churches/Pics/252Amplifier/252.02.jpg
>
> >
> > I am into sound engineering, not art.
>
> The engineering and design style are closely linked.
>
> > Some get real impatient.
> >
> > They sure know how to want, but dunno how to wait.
>
> Money burning a hole in the pocket! This is made worse
> by the fact that he could buy a SS Krell amp over the
> counter at 25% discount and have it delivered ti his home
> within the hour.
> >
> > What I make takes as much work a house extension or hand made violin or
> > cello.
>
> I admired the patience of a colleague who had been polishing
> a stainless steel chassis for four days. He replied: "This is quick
> and easy compared with preparing an acoustic guitar body"
> >
> > They gotta wait. I sometimes even fib about the time it will take,
> > knowing
> > I'll get them used to Patrick's months are 6 of anyone elese's
> >
> > Lying about time helps the music more than rushing at a job.
>
> I have worked a lot in audio post. One of the first thing one learns
> is that there is no such thing as a "dead simple job" as described
> by the client's secretary when she tries to get you to stay on, "just
> fifteen minutes" after normal hours. If you get away by midnight
> you are lucky. I also learned never, ever, to promise anything
> which I was not 100% sure I could deliver.

The bloke wanting the 845 has learnt patience.

First I re-engineered his 5050 amp which was one of the very worst
amplifiers money could buy
made by CR Developments in the UK.
The poor bloke paid $5,500 and got what was an absolute lemon
with bad sound, and a very bad smoking habit.

He travels a lot, maybe 40% of his life is spent outside Oz and
that revised amp I did convinced him he was onto a good thing because
nothing he heard in his travels sounded any better.

Its quite usual for me to have to proove myself first before anyone
is prepared to take a plunge on something a little more serious such as
the 845 amps.

Sometimes it doesn't work out. Sometimes a customer runs out of money
and you're stuck with an amp that takes 5 years to ever sell.
I know what its like to work six months for nothing.

I know why there are so few amp builders in Oz; it just don't pay.

> >
> >> But as a bespoke builder, you strive to give the client what he/she
> >> (thinks
> >> he/she) wants.
> >
> > Of course. If they want DACT, they get it.
> > Usually I ask them to purchase the specials themselves, and they don't
> > have to pay me the % on top.
> > This % never covers my time, trouble and risk of ordering special stuff.
>
> Yes. I know builders who do this with tubes also, particularly Tesla,
> KR. The client has no comeback then if there is a premature cathode
> to heater short.

I have KR Audio 845 in the 845 amps. About $400+ each.
In my design, it doesn't matter if they ain't matched, and a Chinese 845
can be used in parallel with a KR845 without a huge sonic penalty;
maybe it even sounds better; I may not ever know, but its OK to do it
technically.

So If the KR845 proove to be unable to last well, and this is really
something
I have no idea about whatsoever, then the amp isn't a throaway; Chinese
tubes can be fitted,
and they are only $150+.

The KR845 have oxide coated cathodes needing only 1A and they run dull
red.
Don't ask me how reliable a cathode is that is only a fine bitta wire
that glows with only 1A of current.
I have Ea = 1,050V, about what KR recommend.
It is said that in tubes where Ea is over 500V, the speed of positive
ions
hurtling into the cathode is extremely high and its this that damages
cathodes.
One never ever sees indirectly heated cathodes used in tubes where Ea is
above 1,000V.
Anyway, the Chinese 845 have the old bright emitter thoriated tungsten
cathode
which is much more rugged with regard to positive ion bombardment.
Ik heating current = 3.3 amps, and the cathode material is probably
fairly rugged.
The 211 and some other tubes have similar cathodes so much higher Ea can
safely be used.
Its never the case on SE amps though, becayse in SE you want a lowish
Ea, and high Ia
so that RL is a low enough value for which making an OPT is feasible.
The higher the RL, the more inductance you need, so the wire is thin,
and turns are high
and capacitance becomes high when you interleave a lot to get some
bandwidth
and the darn OPT becomes fragile.
Lemme tellya, winding an OPT for 30k and 25 watts and to operate at
1,000Vdc is a real PITA.
In PP, the Ea can be a bit higher than SE, and the AB action will
handle the lower load per tube than in SE.

I have designed the 845 amps so that in the event that the 845 tubes
proove to be unreliable, then a pair of 13E1 can be used or a quad of
KT90
with a total revision of the PSU.
There are plenty of taps and options on the PT which has a total of 48
connections.

The OPT primary can be re-arranged to have two halves paralleled to make
a load for SEUL
or triode of 1k5 instead of 6k0.
4 x parallel KT90 in triode can be quite exquisite.

Frankly, after hearing what I did after revising a pair of SEUL amps
with 13E1 to
33% CFB, and getting a sublime 30 watts instead of only 25,
I am not frightened to ever have to fall back to something easier or
simpler.

A colleague is making a pair of monos with 3 parallel 13E1 in SE with
20% CFB and
this will give 85 watts for use with Quad ESL2805.
I will be intersted to see how my design for the OPT works out.
The colleague is now having difficulties getting his winder to wind what
he wants.
Usual trouble, the winder hates doing trannies with more than 4
connections,
ie, two for Pri and two for Sec. The colleague doesn't like paying much
because his client doesn't pay much.

> > I just have default brands for caps and that's it.
> > The amps I make with all other parts being generic, with plain solder
> > and
> > plain copper wiring survive comparisons with all others.
> >
> > Its not the brand that matters, its the way things are used in a total
> > package.
> > Get the design wrong and no amount of good brand names or even Jensen
> > caps will make any difference.
>
> I agree with that entirely.
> >
> > I always agree calmly with what ppl want if they seem utterly
> > fixated in their opinions and I have to sell them something.
> >
> I helped a pal out my making up some screened mains cables.
> He sold them to his client because he (the client) had asked
> for them. Not because he (the builder) claimed they had any
> magic capabilities or would enhance in any way the performance
> of an amplifier.

Some audiophiles have a terrible condition known as mainzitis.

The very idea of plugging anything into a wall socket
brings on this fearfull neurosis.

Patrick Turner.
>
> Iain