Need help with KR VV32B Tubes.
Mr Burn
history of these 2 tubes I have recently purchased. The tubes have a white base
and a VV32B writing on them. One of them has a KR
Sticker on it as well. The two serial number silver plate inside the tubes
say # 2616 and 2904. I have looked at the websites for Vaic and KR. I
received an email in answer to some of these questions from Vaic saying it's
hard to tell if the tubes are the newer or older versions. They also mentioned
that 2 weeks ago KR went bankrupt which I found interesting. Also can I
directly replace them in my power amp it is set up to drive a pair of Western
Electric 300B's. I do have adjustable bias on my amp.
Thanx
L.J. Timpert
The VV32B tubes are supposed to be electrically compatible with a "standard" 300B,
so they will work in a setup made for the WE.
What I am really interested in is the relationship between KR, AVVT and Vaic. Ok,
so I read that KR went bankrupt, and that some years ago Alesa Vaic and Ricardo
Kron couldn't get along anymore back when they were still working under the name
"Vaic Valve", so they split up in two companies, AVVT and KR.
But now there is a third company called Vaic, and they are marketed by the same
distributor as AVVT. But they are supposed to have no relationship. Interestingly,
AVVT stands for Alesa Vaic Vacuum Technology, so there are two possible situations:
1- they are related
2- they manufacture tubes like they were when when Kron and Vaic worked together,
and they simply used the old name because it had some reputation.
Anybody knows about the developments of the three companies?
Jurgen Timpert
RW
First, KR Enterprise did not go bankrupt people. They merely dissolved a
business relationship with their initial investors and in doing so put the
KR Enterprise SRO name to rest. The KR people are still in business
manufacturing tubes and amplifiers in Prague under the new name of KR Audio
Electronics. Mr. Vaic only wishes the KR people would go bankrupt. It's
too bad he feels the need to spread such false rumors....obviously a
reflection of his desparate personality.
The white base VV32Bs were manufactured at the time that Alesa Vaic and
Riccardo Kron went their separate ways. They were made in the factory, in
Prague, currently owned and operated by KR Audio Electronics. The KR
Enterprise sticker was added to the base of the "VV" tubes once the Vaic
Valve name of the company was changed to KR Enterprise SRO. The white base
VV32Bs were manufactured in the 1997 to 1998 time frame and were the
successor to the VV30B tube which had the faulty VAIC-designed filaments.
The VV32B will drop into all 300B amplifiers without
modification....except....the VV32Bs have a 2 ampere filament requirement as
opposed to the standard 1.2 ampere filament of a 300B. So if your filament
supply can provide the extra current, they will work fine. However, the
VV32B *is* a higher-power version of the 300B and can produce up to 18 watts
with the properly designed amplifier circuitry. If you have adjustable bias
on your amp, then you can increase this bias to obtain more power (please
consult the manufacturer of the amp before doing so).
Since your tubes have the serial number *tags* on the inside of the glass,
this is an indication of the later production tubes (after KR Enterprise had
taken control of the factory).
About one year after being booted from the KR factory, Alesa Vaic started
producing valves again with the help of Peter Quadrup (Audio Note UK) under
the name AVVT. These new tubes experienced severe reliability problems (bad
filaments again) and thus Mr. Quadrup bailed out of the partnership. Audio
Note UK was in and out of bankruptcy court at the time so this might have
had some bearing on the split too (i.e. no Audio Note money to fund the AVVT
startup tube production).
So, any tube with the "VV" designation (i.e. VV30B, VV32B, VV300B and VV52B)
were all made in the KR Enterprise facility regardless of the company name.
KR Enterprise later changed their tube names to "KR" (i.e. KR32B, KR300B,
KR2A3, etc.) while Alesa Vaic began using the "AVVT" designation. Alesa
Vaic may try to lead you into believing that he made tubes from his current
facility with the "VV" designation, but this is completely false.
Apparently Alesa Vaic has recently erected the Vaic Valve name again but for
the purpose of selling *amplifiers*, not tubes. So you have AVVT tubes and
Vaic Valve amplifiers. The amplifiers are made for Vaic by the Italian
company named Master Sound. Master Sound has been around for many years and
made the first few KR Enterprise amplifiers.
FYI, the KR Audio Electronics factory is part of an old Tesla research
facility. They actually developed and tested *new* tube designs in this
building (no production) and thus it was equipped with the necessary
plumbing, gas and vacuum lines required for making small quantities of
tubes. I've been to the KR factory and witnessed the production of their
tubes first hand. They are all indeed handmade (no assembly lines) and thus
the justified additional cost (IMO) as compared to mass produced Chinese and
Russian tubes.
I hope this answers your technical questions and helps to shed some light on
the KR/Vaic history.
Regards,
Ron Welborne
Welborne Labs
wl...@ix.netcom.com
Welborne Labs Web Site:
http://www.welbornelabs.com
Welborne Labs User Forum:
http://www.audioasylum.com/forums/welborne/bbs.html
"Mr Burn" <mrb...@aol.com> wrote in message
news:20010529191102...@ng-fi1.aol.com...
Vince Rhea
hard time following all the twists and turns. Any way to condense it to a
simple list of "buy these" and "don't buy these"? Us country boys like
things simple.
Vince
"RW" <wl...@ix.netcom.com> wrote in message
news:9faune$not$1...@slb6.atl.mindspring.net...
Patrick Turner
Hear, Hear, from land of Oz,
Ron's historical treatise is all well and good,
but where do we get guarenteed quality tubes
at the right price.
And are not the east european labour rates way below US,
or Australian rates?
Whoever makes tubes in that part of the world cannot
whinge about high labour costs of hand crafted tube working,
one after the other, in quick fashion, as they would be done.
Patrick Turner.
Patrick Turner
Thank you for making some of the history clear about the tubes in
question.
What seemed to be the focus of attention in posting today was the quality of
recent
samples, quite independant of the history.
Perhaps you could answer the posts on this.
I do find I know someone who got a pair of these "super"
300B tubes and they sounded well; I have no idea how they lasted,
as we have fallen out of touch for three years when I rewound his power
trannies.
Anyway I'd say that what we want in a triode output tube is:
plate dissipation :- 60 watts
plate resistance :- less than 1,000 ohms
transconductance :- more than 10 Ma per volt.
plate voltage limit :- 800 volts
tube socket type :- octal at least, or same as old 807
cathode type :- indirectly heated with good margin for heater voltage variation,
and maximum cathode current similar to KT90, or about an amp,
octal pin out :- pins 1 and 7 for heaters, pin 3 plate, pin 5 grid, pin 8
cathode,
pins 2, 4, 6 are not connected to anything .
This pinout will mean that anyone mistakenly plugging in the new triode
to an existing cuitcuit will find that it won't go due to the different heater
arrangement,
so nothing will blow up.
But the greater spacing between plate - heater - grid - etc, will mean less
likelyhood
of arcing in tube socket.
When I think of the EL36/6CM5 and KT90 and KT88/6550, and
and the 13E1, and the later developments of the late 50's and early 60's,
I see that there should be no problem making a decent triode
to the above specification.
I would suggest that since a triode has only three elements it should be
cheaper to produce than most other multi element tetrode or pentode,
and so the price to the end user, amp owner should be no more
than 30 dollars US.
So, when do you think that the folks in the factory who you
know, could have a prototype ready for a test?
Did I hear you say a month, at the latest?
Patrick Turner.
RW
Mr. Turner,
What is the right price?
I suppose you want a 300B that lasts for 10 years and only costs $10.
I'm sorry, but it would take me several pages of elaboration to explain the
difficulties associated with producing a product from China, the ex-Soviet
Union and former Eastern European countries and unfortunately I don't have
the time. But I'm sure that you are at least somewhat aware of their
political and economic histories. Well the politics may have changed in
some areas, but the economies have not. And many workers are from the
fabric of society that just 10 years ago were guaranteed a job regardless of
the quality of work they produced.
Remember the 70's when the labor unions here in the U.S. guaranteed auto
workers a job for life? Most U.S. cars sucked then!!! And the Japanese
proceeded to beat us at our own game....better quality, better reliability
and cheaper automobiles. It took us a good ten years to turn that trend
around. Well, due to the struggling economies in Russia and the former
eastern block countries, it may take them several generations to improve
productivity and the quality of their goods.
I'm not trying to make excuses for poor quality but only to enlighten you as
to the difficulties the owners of these factories face. I know first hand
that the KR people struggle with quality issues all of the time. But what
are they going to do, fire all of their employees and start over? No, they
can't do this. So they have to deal with these issues, train their
employess and hope that eventually life becomes easier for them and their
productivity improves.
At least KR offers a 2 year warranty on most of their tubes. I see posts on
these and other newsgroups, "I bought these KR tubes and they are
microphonic..KR sucks and they are making junky over priced tubes". Hell, I
guess it never occurs to these people to send them back for a warranty
replacement. We replace all the KR tubes covered under warranty and in most
cases...no questions asked!!! Our return is less than 5%, which means
either that people don't bother to return the tubes they aren't happy with,
or the KR quality is really pretty good.
But this is the situation in a nutshell. We belong to a hobby (tube audio)
that is only a spec of dust in the universe of economics. We have no real
monetary clout and thus we are really just along for the ride. We are
dealing with an antiquated technology with no monetary incentives for the
factories around the world to improve the technology or even upgrade their
tooling and equipment. And as the current machinery continues to wear out,
it becomes harder to maintain the quality of the product. So from an
audiophile's viewpoint, we must seek to encourage these companies to remain
in business and improve upon their product. Because the people that are
keeping these factories going aren't making a killing by doing so. How do
we do this? We buy their product. But what if the quality isn't so good?
Well, you don't whine on the newsgroups about it because most manufacturers
don't have the time to hang out here (or even speak the language). If the
quality isn't up to your standards, then send the tube back for a
replacement. This is best way for a company to receive feedback as to how
their product is being accepted. You may ask, why should I have to do this?
The answer is: because that's just the way it *is* and if you don't like it,
then buy a sand amp and the problem will go away (for you). Otherwise,
become part of the solution, get envolved, give these companies some REAL
feedback, not just a bunch of whining.
We aren't in a good position here people. NOS supplies of audio tubes are
quickly disappearing, and there's only a few factories left in the world
producing tubes. I personally don't see a bright future for the tube
industry. I'm sure we may see some new entrepreneurs in the future start up
tube production here in the states, but like Western Electric, these tubes
won't be cheap if they're made in small quantities in the good ol U.S. of A.
Moral of the story...buy a bad tube? Don't just sit on it and feel sorry for
yourself....send it back!! It's the only way the quality will get better.
Regards,
Ron Welborne
Welborne Labs
wl...@ix.netcom.com
Welborne Labs Web Site:
http://www.welbornelabs.com
Welborne Labs User Forum:
http://www.audioasylum.com/forums/welborne/bbs.html
"Patrick Turner" <in...@turneraudio.com.au> wrote in message
news:3B1A42FD...@turneraudio.com.au...
Les Lammers
complaints.
L.J. Timpert
Sorry to break so rudely into this discussion, but I guess you have read the
other thread about KR and AVVT, so you know where I stand.
I figure that you are right about the issues of producing in eastern Europe. But
what I do not understand is the quality control issue. Both KR and AVVT claim
that their tubes are the best tubes money can buy. They clearly have something
like a quality standard. And they have done well in the past, because both
brands have built a reputation. And you, as a reputable dealer, have put your
faith in one of the two.
As both manufacturers say that each tube is rigourously tested, then how is it
possible that tubes, that are so obviously bad, still make it into the box and
be sold? I take as example the 2A3 tubes in the first post of this thread. This
is no shipping or storage damage, they went into the box in the sorry state they
are in now. Clearly, those two 2A3 tubes belonged either in the trashcan of the
KR factory or at an employee's desk whose task it is to find out what is wrong
with the current production run. As the company has a reputation to hold, they
should make absolutely sure that tubes of this kind don't end up on a customer's
amplifiers.
The question is: how could tubes that are so obviously bad, still get sold? Is
their quality control lacking? Or are they unable to satisfy the present demand
and did they get sloppy as a result?
I can understand that, no matter how well you test a tube before it is sold,
there will always be some infant mortality. But things like terrible
microphonics, unstable bias current and large deviations from published specs
can be noticed right at the factory. But that didn't happen.
The majority of customers are willing to pay good money for good tubes. Quality
has its price. I understand that manufacturing in a country with an unhealthy
economy can be hard, but if you have a reputation to hold, I think it is better
to sell "sorry, not today" than it is to sell trash tubes when problems are
experienced. If a customer can not get the tubes, he might be a little
dissapointed, but I think that most can understand. If that same customer gets
tubes, but finds out that they do not meet his reasonable expectations, then he
gets very dissappointed, if not pissed. And reactions like these are to be
expected.
Obviously, mr. Kron and mr. Vaic can not get along very well. There are rumours
spread by both manufacturers about each other, but I really think that the truth
lies somewhere in the middle. I don't think it is very gentleman-like to spread
questionable rumours about a competitor, but since they both do this, they both
aren't gentle. They better stop spreading those rumours and put the amount of
energy saved this way into improving quality control.
Jurgen Timpert
JHPage
>
> At least KR offers a 2 year warranty on most of their tubes. I see posts on
> these and other newsgroups, "I bought these KR tubes and they are
> microphonic..KR sucks and they are making junky over priced tubes". Hell, I
> guess it never occurs to these people to send them back for a warranty
> replacement. We replace all the KR tubes covered under warranty and in most
> cases...no questions asked!!! Our return is less than 5%, which means
> either that people don't bother to return the tubes they aren't happy with,
> or the KR quality is really pretty good.
>
Mr. Welborne,
I, on the other hand, am not sorry to break in here.
I find your post a little heavy on attitude in this matter. As one who
owns a business that sells fairly expensive items to people who want them
rather than need them, I should think you would read the original posts
more carefully. The VV302Bs and the VV52Bs I bought on closeout from
Welborne Labs and both are out of warranty. I clearly stated this in my
post. The AVVT AV8Bs I did return in exchange for new ones, I also note
that Moth Audio no longer has AVVT tubes on their web site. And Hell, I
guess it DID occure to me to send the KR2A3s back if they don't sound any
better on Monday than they did on Friday, that's why I said it in my
original post.
And all this does not change the facts:
1) the VV52Bs are junk, I would not even GIVE them away as they are
little more than a fried OPT waiting to happen
2) the VV302B are the very microphonic tubes, but they sound good and if
I find an application where they are sure to never get bumped, I will
still use them
3) the KR2A3s both have highly distorted output, and as they were a
birtday gift to a good friend (nothing says Happy Birthday like a set of
expensive, bad sounding tubes) I will contact you personaly about the
matter
I would expect these problems from Hamfest or eBay tubes, but not from
new, expensive, premium tubes, even if they were 20 years out of
warranty. If you count the 4 people here who have raised questions about
KR and AVVT tubes here on RAT plus all the others you have seen in other
newsgroups, it sounds like customers ARE trying to tell you something:
They don't mind spending more money on premium tubes, but they do expect
them to be at least useable when they get them.
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RW
Jurgen,
Thanks for your post.
Actually, I somehow missed the other thread about KR and AVVT, but now that
you and Mr. Page have chimed-in I will try to address both of your posts and
then I will have to bail out of rec.audio for the time being. My phone has
been off the hook for the last week while we take time off to get some
chores done around the house, catch up on our order back log and squeeze in
a few hours of new product development work...so when I get back in the
office on Monday I'm sure I'll have a couple dozen calls from people wanting
to know where the hell their order is along with a 100 or so emails
demanding my attention :( So I'll take a few minutes to respond and then
you guys can have the last word. Sorry I can't stick around, but hanging
out on the newsgroups just requires too much of my time.
Mr. Timpert wrote:
There are several reasons as to how, what you call "an obviously bad tube",
makes it onto the market.
1) Lack of good quality control. As I stated in a previous post, KR like
any manufacturer, struggles with quality control on an ongoing basis. And
as I alluded to earlier, they struggle with it maybe more so than in other
parts of the world due the social and economic history of the Czech people.
2) Infant mortality failures. I can't speak for the other tube
manufacturers, but KR burns-in each tube for 24 hours, then tests and
matches them before boxing them up for shipping. Yes, one could make the
argument that they should burn them in longer, but you would have to factor
this extra cost into the price of the tube (I thought I heard people
complaining already about the high price).
KR has done life testing at the factory for all of their tubes and a design
is not released if this testing does not exceed 10,000 hours. Now when you
perform life testing of this type, you can also statiscally determine the
failure rate of the tube (mean time between failure) and also it's infant
mortality failure rate. Based on this testing, a company then makes the
determination of how much testing is necessary prior to shipping a product.
A company can also set its warranty period based upon this testing. KR was
the first 300B manufacturer to offer a 1 year warranty. Other companies
quickly followed suit. About six months later, after further development
and testing, KR increased this warranty to an unprecedented 2 years! Not
all of their competition has followed suit. This two year warranty isn't a
marketing gimmic...that would be really foolish! KR offers the 2 year
warranty for two reasons: 1) they understood that their tubes were expensive
and thus they wanted to give their customers some confidence that their
purchase would give them a lifetime of use. 2) they understood the fact that
tubes are gonna fail and occasionally a bad one (or maybe even a bad lot) is
going to escape from the factory and thus the warranty insures that the
customer can buy in confidence knowing that a defective tube will be
replaced.
3) These triode tubes are extremely fragile devices and thus can easily
become knocked out of alignment during shipping. In the case of the KR
tubes, previously they were first shipped to the worldwide distributor in
Switzerland, then shipped to me and then onto the customer. So that is 3
opportunities for the tubes to get rattled around and the shipping carton
may show absolutely no signs of mishandling. For example, Western Electric
used to place a shock indicator label on the side of their tube shipment
cartons. A red liquid would be visible inside of a small glass tube if the
package had been subjected to excessive shock. EVERY package I ever
received from them had the liquid visible but the boxes showed no signs of
abuse. So even if you pack them well, you will lose a small percentage to
mishandling.
4) And lastly: TUBES FAIL! Vacuum tubes are what is refered to in the
electronics industry as a "high failure rate - life limited electronic
device". What does this mean? It means that because of the way tubes are
manufactured (materials used, processes, etc) and the way they operate under
normal conditions (hot and cold temperature extremes, high voltage and high
current stresses, etc.), that they are more prone to failure under normal
operating conditions than say a transistor, capacitor, resistor, etc. So to
answer your question....yes, believe it or not, a tube can test PERFECTLY
GOOD at the factory and then after 10, 20, 100 or even 2000 hours, fail or
go out of spec. What are the failure modes you ask? Well, here are a few
examples: Loss of vacuum. Or constant heat expansion and contraction can
cause a weak metal component to eventually fracture, warp, or
move......causing the tube to short circuit, open circuit, electronically
drift or even become more microphonic. Many people think the invention of
the transistor killed the vacuum tube because it was smaller in size, but
the tube's demise was it's reliability. Transistors are much more reliable
and thus their real success over the vacuum tube.
So like any manufacturer, there is balance between profitability and the
amount of cost figured into a product for quality control. This balance can
be a moving target, i.e. if in-house testing or the "field failure rate"
dictates more stringent quality control measures, then you implement them.
If nothing is failing, then maybe you slack off a bit.
Mr. Page wrote:
If you count the 4 people here who have raised questions about
KR and AVVT tubes here on RAT plus all the others you have seen in other
newsgroups, it sounds like customers ARE trying to tell you something:
They don't mind spending more money on premium tubes, but they do expect
them to be at least useable when they get them.
Now many of you seem to think that KR has a quality control issue just
because several people post on the newsgroups that they've had problems, but
I'm afraid to say, that the world doesn't revolve around these newsgroups
and in fact most audiophiles don't even hangout on these newsgroups. AND IN
FACT, I'll be the first to tell you that KR has had A LOT MORE FAILURES than
have been reported on these newsgroups.
Now I'm not trying to belittle you about your statement, but I just can't go
to Riccardo Kron and say "Riccardo, people are complaining about tube
problems on RAT". Because Riccardo will say, "Ron, send me the faulty tubes
and I will replace them." "Well, uh, Riccardo, many of these people didn't
bother to return the defective tubes so I can't send them back to you for
testing...says Ron." How do you expect Riccardo to respond? I think you
can figure it out. But I'll just reiterate what I said in the previous
post. If you have a faulty tube, return it to the manufacturer. This is
the absolute BEST form of feedback a manufacturer can receive when there are
problems. For one; it immediately alerts them to the fact that a failure(s)
has occurred and two; if there is a quality problem they can identify the
possible cause in a more timely fashion. The fact is, when we receive a
defective tube back from a customer, we replace it. So you don't see too
many of *these* people complaining on the newsgroups because they were
eventually satisfied with the product and the service. From what I've seen,
most people that have complained are the ones that didn't bother to seek a
remedy for their dissatisfaction. People, ya gotta help me.... to help you.
Now Mr. Page, I agree with you 100% when you state "They don't mind spending
more money on premium tubes, but they do expect
them to be at least useable when they get them." So I hope I've been able
to shed a little light on the subject of tube failures. Now once again I
must state that I haven't spent the last 30 minutes typing this explanation
just to make excuses for KR. But I hope you see that there are real reasons
(other than poor quality control) why you can receive a new set of tubes
that don't function properly the minute you drop them into your amps.
However, you aren't the first person that has experienced multiple problems
with the KR tubes and you probably won't be the last but I can honestly say
that based on my experience as the U.S. importer for these tubes, that this
type of situation is a rarity. Sorry, I can't help you with your out of
warranty tubes but I do apologize for the inconvenience you've experienced
with your most recent purchase and will glady replace them with a good pair.
KR manufactures about 800 tubes per month. So as you can see, any type of
additional testing or quality control enhancements, advertising, returns,
promotions and other such expenses get amoritzed over a very small number of
tubes. We're not talking hundreds of thousands of tubes but rather only a
few thousand each year and thus it is very easy for them to go into the red
with even the smallest of problems. My experience with the KR tubes is
such: Yes, they've had a few quality hickups in the past and most likely
will experience some in the future but we generally catch these problems
rather quickly and not too many tubes of this type reach the customers these
days before the problem is caught. Some of the problems in the past, like
excessive microphonics, were part of the company's growing pains (or sort of
a learn as you go) but most manufacturers of new technology experience this
to some degree. And as I stated previously, generally the return rate is
less than 5% which is really pretty good for a vacuum tube and it is an
acceptable rate for a manufacturer to not be overly concerned about because,
of this 4-5% failure rate, the failure modes will be somewhat evenly split
amongst the 4 cases mentioned above.
I hope this helps. Thanks for the bandwidth.
Ron
Patrick Turner
However your later postings suggest you are too busy
to lend us your ear.
I understand you are busy and that the world is far from perfect.
I have some old Sylvania 6CA7 tubes in an ancient but rewired
amp in my shed which I use for all sorts of testing.
They must be 30 years old and although they are 20% down on emission,
they continue to be excellent in my application.
So I do expect tubes to last at least 10 years.
No, I don't expect tubes to cost 10$ as you suggest.
I only suggested retail 30$ US, as the eastern labour rates are low,
and triodes are simple things.
I think the working folks over in east europe are more
than willing to produce good tubes given the conditions and guidance to do so
by the management, who are really the ones responsible for what goes on.
Progressive labour relations always quickly solve production problems,
or else all industry would be in dire straights, but it isn't; the coming
information age
will make sure that the keen young minds of Eastern Europe will
take advantage of the possibilities of good tube making. The East will not
be held back by the west any more, and I see a bright future for them.
Hopefully they will proceed to exclude the western middlemen as much as
possible to get the largest part of the market price, and thus be able to afford
reliablity to their customers.
My suspicion about chinese, russian, or other east-west business dealings
is that they are probably subject to all sorts of greed related problems by
multiple
handling, and the corruption of officials and management. Everyone trying to
milk
the industry for all they can. Just compare the retail price to the ex-factory
price.
So the demise of eastern tube making will more likely be due to greed
over the prices eventually having to be paid for the luxury that tubes are.
Demand won't cease though.
There will be a bright and rosy future for any company who
produces good gear in competition with those that cannot.
I expect tubes just won't go away, not in a hurry.
It does seem some factories seem free of the bothers you state.
None of us here would expect you to have the Superman touch and solve all
problems all at once; but we do have something to say.
OK, it seems we are not about to see a decent 60 watt indirectly heated
new triode coming out from the factories in Eastern Europe.
It's a funny thing, but here is Australia I have quitely researched and
developed a few new and different complete amplifiers and speaker systems,
whilst surviving on a third of average weekly earnings.
I enjoy this and I don't complain. R and D is not so bloomin costly as we are
led to
believe!
But what we get from you is that it is all too hard to change anything,
we get a long story on historical difficulties et all.We are made to feel
sorry for being concerned.
And all I asked for was for you to consider a new triode idea.
You would sell heaps if the quality and price are right.
Now perhaps you don't have much control over tube manufacture
but we'd like you to consider us and pass our sensible concerns on to
the folks who do make the tubes.
You are correct about sending crook gear of all descriptions back to
the maker. I sent a soldering iron back last month and the maker was delighted;
so few people ever did, so he got a look at one of his products after
a bit of real world use to see how it went. Their R and D man had something to
go on.
The local council had contaminted the water supply with salt during the week
of manufacture and this had contaminated the ceramic sealing in the heating
element.
The company replaced the item even though I'd had 9 mths use.
The fellow I dealt with was happy for my suggestions about strain relief for the
mains cabling, and other minor improvements.
If anthing goes wrong with anything I build I expect to be contacted.
Luckily, my telephone is quiet.
Patrick Turner.
L.J. Timpert
Thank you very much for your post. The fact that you as a dealer responded to
this thread tells a lot about how you care for the business.
Apperently, you are in a position to give the manufacturer feedback about their
product. There is no way for a customer to get in touch with them directly. But
I do have some thoughts, I hope to hear from you if you think they are sensible
or not.
Both KR and AVVT have a group of very satisfied users. So the tubes they build
are potentially great tubes. And, as they are less than 10 years in business,
and have gone through the process of basically re-inventing the wheel, they do
not have the experience and routine the established manufacturers had (and in
some cases still have) so no, it would not be realistic to expect that
production is entirely trouble free.
So, the tubes are potentially great. I think that, when they want to establish a
rock-solid reputation, that they should not for the time being put any effort in
improving their sound or issue more types, as this seems quite OK as it is now.
The majority of tubes sold will remain 300B and 2A3-ish types anyway. Here are
my thoughts.
There are two ways to look at a production process. One of it is: the things
that happen in a factory. The other one is: everything it takes to make a
customer get a product. This includes shipping and marketing the product as
well, which also implies that the manufacturer stays responsible for the quality
of the product throughout the entire process chain all the way to the customer's
door.
90% or more of the tubes reach the customers by mail. You said that rough
handling was a good cause of infant mortality. I can believe that, as I know
first hand that the mail service is not very gentle with packages, no matter how
many times the word "fragile" appears on the packkage. I thinkt that it would be
a very wise thing to do, both for AVVT and KR, to put a great deal of their
research effort into increasing the mechanical ruggedness of the existing tube
types. This will reduce infant mortalities as well, and also microphonics, as a
rugged tube is also less prone to get microphonic.
While this is done, put a small team of people to run critically through the
test process. My idea for a killer test procedure after burn-in and function
check is something like:
a: electrical test. Do the tubes meet the published specification of Gm, mu and
Ia at a fixed Va and Vg whithin previously defined margins?
b: microphonics test: gently subject the tube to vibrations of different
frequencies, and measure the amount of anode AC current that results from the
vibrations. A resonance spectrum like this can tell a great deal about which
part of the tube is sensitive to vibration.
c: drop test in non-operating conditions. To see if the tube meets ruggedity
standards and thus will survive shipping.
d: electrical test again: no parameters should have shifted after the drop test.
e: microphonics test again: if the resonance spectrum shows peaks that weren't
present in test b, an experienced tester can quickly see what the problem is.
Of course, the resonance and drop tests do not have to be run on each tube, but
rather as a test on randomly picked samples of a batch. Testing each tube for
microphonics by gently tapping it with a little rubber hammer (like it was done
at the Philips factory) should do the trick.
The tube can then get accompanied by an acceptance sheet on which the results
are indicated. I know that these tests are far more extensive than usual in the
glory days of tube audio, but today's market is entirely different and very
demanding. Also, due to automation, testing procedures are possible that weren't
possible when computers weren't available. That is my idea about the ultimate
tube factory: to let modern day technology help in getting the old craft of
vacuum tube production up to a level where it's never been before.
Of course this is only an idea. And beating the problems associated with
manufacturing is not done in one day, I fully understand. But I think that,
given the situation you pictured, this is the most sensible course to follow.
So to make a long story short: no more new types, but improve on ruggedness of
existing types and quality control procedures.
Jurgen Timpert
RW wrote:
> Jurgen,
>
> Thanks for your post.
>
> Actually, I somehow missed the other thread about KR and AVVT, but now that
> you and Mr. Page have chimed-in I will try to address both of your posts and
> then I will have to bail out of rec.audio for the time being. My phone has
> been off the hook for the last week while we take time off to get some
> chores done around the house, catch up on our order back log and squeeze in
> a few hours of new product development work...so when I get back in the
> office on Monday I'm sure I'll have a couple dozen calls from people wanting
> to know where the hell their order is along with a 100 or so emails
> demanding my attention :( So I'll take a few minutes to respond and then
> you guys can have the last word. Sorry I can't stick around, but hanging
> out on the newsgroups just requires too much of my time.
>
>
CHOKY
maybe with diff. envelope and with octal base;higher I and U ratings.....
But,then came the war,production (of everything) go down,and YU 300B gone with the wind;
only for now,I hope.
Choky
Patrick Turner
So maybe you saw my posting to Ron Welbourne
about a new possible 60 Watt Triode which does not have a
lousy direct heated cathode. Sort of like a taller KT90,
but without screen and suppressor grids.
The quality must be good and the price just right.
Triodes are simpler than pentodes to make,
and should be cheaper.
Have a talk to EI and tell them they can trade their way
out of any trouble if quality and price is good.
The wind will blow the other way, I am sure.
Patrick Turner.