[Blazej Czeladzki]

Hello,

I have question about output trafos for parallel push pull amps.

Are there any special differences between those trafos and standard push
pull trafos?




--
____________
Pozdrawiam:
BCZ

[Eeyore]

Blazej Czeladzki wrote:

Hello,

I have question about output trafos for parallel push pull amps

You mean 4 tubes in place of 2 ?


Are there any special differences between those trafos and standard push
pull trafos?

Aside from the turns ratio, no.

Graham

[Patrick Turner]

Blazej Czeladzki wrote:

Hello,

I have question about output trafos for parallel push pull amps.

Are there any special differences between those trafos and standard push
pull trafos?

There are no differences in operating principles.

However, where number of tubes in the output are increased,
the core size and wire sizes increase, and the number of turns
per volt decreases to suit the reduced primary load value,
while keeping the winding losses and core distortion low.

If you have transformer type X meant for 2 x EL34,
and you wish to use 4 x EL34, then get exactly twice the power
then transformer X cannot provide it using the same turn ratio.

OPT design can only successfully achieved by following all the necessary
design steps.
There are 47 steps listed out for you with examples at
http://www.turneraudio.com.au/output-trans-pp-calc.html

This page is sure to bamboozle most ppl, but
I don't give simple answers to uneducated minds.

However, should you wish to use 4 x EL84 instead of 2 x EL34, then
the same OPT might be able to be used, depending on
the operating voltages and winding resistances.
This is because two EL84 can each have say 30mA of idle current
and this can equal the 60mA in one EL34, and the load of
5k for the two EL34 will suit the quad of EL84.
But EL84 will not be able to be run at say +600V B+ in UL or triode
mode,
and about 350V is the safe limit.
So always there a lots of things to consider as soon as a the tube line
up is
changed.

Patrick Turner.


s

--
____________
Pozdrawiam:
BCZ

[Blazej Czeladzki]

Uzytkownik "Patrick Turner" napisal w wiadomosci
...


However, should you wish to use 4 x EL84 instead of 2 x EL34, then
the same OPT might be able to be used, depending on
the operating voltages and winding resistances.

I think thats my situation:
http://ecclab.com/schem/rtech1.gif
I have the trafo diagram too, but it seams to be too simple:
http://ecclab.com/schem/rtech2.gif

What do you think about it?

--
____________
Geets:
BCZ

[Blazej Czeladzki]

Uzytkownik "Eeyore" napisal w
wiadomosci ...


Blazej Czeladzki wrote:

Hello,

I have question about output trafos for parallel push pull amps

You mean 4 tubes in place of 2 ?


Are there any special differences between those trafos and standard push
pull trafos?

Aside from the turns ratio, no.

So, if I'll find a trafo with correct Raa, correct output power, required
output impedance and ultralinear taps it should work with my amp?

Second question is about ultralinear tap. The documentation I have
(http://ecclab.com/schem/rtech2.gif) suggests 33% ultralinear tap ratio, but
can I use 40%?


--
____________
Greets:
BCZ

[John Byrns]

In article ,
"Blazej Czeladzki"
wrote:

Uzytkownik "Patrick Turner" napisal w wiadomosci
...


However, should you wish to use 4 x EL84 instead of 2 x EL34, then
the same OPT might be able to be used, depending on
the operating voltages and winding resistances.

I think thats my situation:
http://ecclab.com/schem/rtech1.gif
I have the trafo diagram too, but it seams to be too simple:
http://ecclab.com/schem/rtech2.gif

What do you think about it?

I think there is something fishy about the transformer, the numbers just
don't add up, or divide out correctly.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[Phil Allison]

"John Byrns"

I think thats my situation:
http://ecclab.com/schem/rtech1.gif
I have the trafo diagram too, but it seams to be too simple:
http://ecclab.com/schem/rtech2.gif

What do you think about it?

I think there is something fishy about the transformer, the numbers just
don't add up, or divide out correctly.



** If the 4 x 125 turn secondaries are all in parallel, the impedance ratio
comes out about right.

With a circa 360 volt DC supply, 40 watts rms from a 4000 ohm primary is OK.

Be nice to know what the damn tubes are....



........ Phil

[Blazej Czeladzki \(ByCZy\)]

Phil Allison wklepal(a) i opublikowal(a) co
nastepuje:
"John Byrns"
I think thats my situation:
http://ecclab.com/schem/rtech1.gif
I have the trafo diagram too, but it seams to be too simple:
http://ecclab.com/schem/rtech2.gif
What do you think about it?
I think there is something fishy about the transformer, the numbers just
don't add up, or divide out correctly.
** If the 4 x 125 turn secondaries are all in parallel, the impedance
ratio comes out about right.
With a circa 360 volt DC supply, 40 watts rms from a 4000 ohm primary is


ECC82 and 4xEL84

--
_____________
greets:
Blazej Czeladzki

[John Byrns]

In article ,
"Phil Allison" wrote:

"John Byrns"

I think thats my situation:
http://ecclab.com/schem/rtech1.gif
I have the trafo diagram too, but it seams to be too simple:
http://ecclab.com/schem/rtech2.gif

What do you think about it?

I think there is something fishy about the transformer, the numbers just
don't add up, or divide out correctly.

** If the 4 x 125 turn secondaries are all in parallel, the impedance ratio
comes out about right.

True, but the drawing shows a series/parallel connection of the four
secondaries, with a note that implies that the secondary is 8 Ohms in
this configuration.

With a circa 360 volt DC supply, 40 watts rms from a 4000 ohm primary is OK.

If the 4 x 125 secondaries were all connected in series they would be
about right for a 70 Volt output from a 40 Watt amplifier.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[west[_3_]]

"Patrick Turner" wrote in message
...


Blazej Czeladzki wrote:

Hello,

I have question about output trafos for parallel push pull amps.

Are there any special differences between those trafos and standard push
pull trafos?

There are no differences in operating principles.

However, where number of tubes in the output are increased,
the core size and wire sizes increase, and the number of turns
per volt decreases to suit the reduced primary load value,
while keeping the winding losses and core distortion low.

If you have transformer type X meant for 2 x EL34,
and you wish to use 4 x EL34, then get exactly twice the power
then transformer X cannot provide it using the same turn ratio.

OPT design can only successfully achieved by following all the necessary
design steps.
There are 47 steps listed out for you with examples at
http://www.turneraudio.com.au/output-trans-pp-calc.html

This page is sure to bamboozle most ppl, but
I don't give simple answers to uneducated minds.

It takes talent to do that. The type of talent a good teacher has.

huge snip

west

[Phil Allison]

"John Byrns"

** If the 4 x 125 turn secondaries are all in parallel, the impedance
ratio
comes out about right.

True, but the drawing shows a series/parallel connection of the four
secondaries, with a note that implies that the secondary is 8 Ohms in
this configuration.


** The schem is clearly WRONG.

Where does U3 come from ???




......... Phil

[Eeyore]

Blazej Czeladzki wrote:

Uzytkownik "Eeyore" napisal
Blazej Czeladzki wrote:

Hello,

I have question about output trafos for parallel push pull amps

You mean 4 tubes in place of 2 ?

Are there any special differences between those trafos and standard push
pull trafos?

Aside from the turns ratio, no.

So, if I'll find a trafo with correct Raa,

The required Raa for the *pair* of tubes not an individual one.


correct output power, required
output impedance and ultralinear taps it should work with my amp?

Absolutely yes.


Second question is about ultralinear tap. The documentation I have
(http://ecclab.com/schem/rtech2.gif) suggests 33% ultralinear tap ratio, but
can I use 40%?

You'll have to ask the experts who know more about ultralinear operation than
me.

Graham

[Eeyore]

Blazej Czeladzki wrote:

Uzytkownik "Patrick Turner" napisal

However, should you wish to use 4 x EL84 instead of 2 x EL34, then
the same OPT might be able to be used, depending on
the operating voltages and winding resistances.

I think thats my situation:
http://ecclab.com/schem/rtech1.gif
I have the trafo diagram too, but it seams to be too simple:
http://ecclab.com/schem/rtech2.gif

What do you think about it?

The skill is in determining the winding layers.

Graham

[Eeyore]

Phil Allison wrote:

"John Byrns"

I think thats my situation:
http://ecclab.com/schem/rtech1.gif
I have the trafo diagram too, but it seams to be too simple:
http://ecclab.com/schem/rtech2.gif

What do you think about it?

I think there is something fishy about the transformer, the numbers just
don't add up, or divide out correctly.

** If the 4 x 125 turn secondaries are all in parallel, the impedance ratio
comes out about right.

My thoughts too.

Graham

[Eeyore]

Phil Allison wrote:

"John Byrns"

** If the 4 x 125 turn secondaries are all in parallel, the impedance
ratio comes out about right.

True, but the drawing shows a series/parallel connection of the four
secondaries, with a note that implies that the secondary is 8 Ohms in
this configuration.

** The schem is clearly WRONG.

Where does U3 come from ???

Presumably also from U2.

Graham

[RapidRonnie]

If you are literate in German you will want to get Rainer zur Linde's
books, particularly his earlier ones which have very explicit
transformer design information in them.

The same transformer can be used with different numbers of tubes in
push-pull, one or two or two or more pairs in many cases. In fact
sometimes the larger designs had four tubes and they added two more in
many cases. The early Zenith Stratosphere console had 4 pairs of 45s
which could be simply replaced by two pairs of 2A3s. The cathode
resistor needed a little tweaking sometimes. There were also early
MC60 and MC75 prototypes with four 5881s instead of KT88 or 6550.

There is no optimal tap position for ultralinear taps although 43%
was quite common. In reality it is a tradeoff. The taps have to be at
a winding end so there are a limited number of choices for any winding
scheme chosen. For instance, on the Peerless transformers it was
common to have two half-primaries that could be seriesed or
parellelled. If they were seriesed the taps are of necessity at 50%.
Several companies are winding copies of Peerless transformers. You
could do worse.

[Patrick Turner]

Blazej Czeladzki wrote:

Uzytkownik "Patrick Turner" napisal w wiadomosci
...


However, should you wish to use 4 x EL84 instead of 2 x EL34, then
the same OPT might be able to be used, depending on
the operating voltages and winding resistances.

I think thats my situation:
http://ecclab.com/schem/rtech1.gif
I have the trafo diagram too, but it seams to be too simple:
http://ecclab.com/schem/rtech2.gif

What do you think about it?

The OPT is rated for 40 watts and has 33% UL taps
and which would be fine for 2 x EL34/6L6/KT66/5881/KT88/KT90.
The use of 4 x EL84/6V6 would also be quite OK, and about
the same power coud be expected.
a pair of EL84 make a compositr tube with Ra = 19kohms, gm = 20mA/V,
and µ = approx 400, and with max Pda = 24 watts, and EL34 have pda = 28
watts,
about the same.
This gives the pair of EL84 a greater figure of merit because
it has more gm, so more gain, so the drive voltage needed is lower.
Baird made amps with 6 x EL84 to achieve 60 watts.
Of course for real finesse you must stick with
lower amount of power with class A.
However, from the OPT diagram
the OPT has 2,700 P turns : 250 S turns, = TR 10.8:1, ZR = 116.64 : 1,
so the load of 4k for the tubes becomes 34 ohms.
If the S wnding uses all four 125 turn section all paralleled, S = 125
turns,
and TR = 21.6, ZR = 466 : 1 so 4k a-a is transformed to 8.57 ohms.

So each pair of EL84 see 8k a-a, but it isn't high enough
for all class A and AB is what you'll have to have.

The primary wire is only 0.224mm dia, very thin fragile wire only rated
for
120mA at 3amps/sq.mm, and a failing saturated pair of EL84
could possibly fuse the OPT as so often happened in old OPT
with such thin wire.
If you don't have active protection against bias failure,
a 100mA fuse soldered between each EL84 cathode and 0V is wise.
I like to use 0.3mm absolute minimum dia.

Happy soldering,

Patrick Turner.



--
____________
Geets:
BCZ

[Patrick Turner]

Blazej Czeladzki wrote:

Uzytkownik "Eeyore" napisal w
wiadomosci ...


Blazej Czeladzki wrote:

Hello,

I have question about output trafos for parallel push pull amps

You mean 4 tubes in place of 2 ?


Are there any special differences between those trafos and standard push
pull trafos?

Aside from the turns ratio, no.

So, if I'll find a trafo with correct Raa, correct output power, required
output impedance and ultralinear taps it should work with my amp?

Second question is about ultralinear tap. The documentation I have
(http://ecclab.com/schem/rtech2.gif) suggests 33% ultralinear tap ratio, but
can I use 40%?

Anywhere between 25% and 50% is OK, and better than no UL tap at all.

Are you winding your own OPT?

Patrick Turner.

--
____________
Greets:
BCZ

[Patrick Turner]

Phil Allison wrote:

"John Byrns"

** If the 4 x 125 turn secondaries are all in parallel, the impedance
ratio
comes out about right.

True, but the drawing shows a series/parallel connection of the four
secondaries, with a note that implies that the secondary is 8 Ohms in
this configuration.

** The schem is clearly WRONG.

Where does U3 come from ???

I agree the OPT diagram is wrong.
As connected, the secs give 34 ohms for a 4k a-a loading


U3 is the CT voltage at the OPT, and isn't shown connected to anything.
But it could be connected to U2 and since there are 3 x 470uF B+ caps
and 350V rated,
we can assume B+ even at CT approx = 330V. Probably about 30watts AB1 is
possible with 4 x EL84.
The U3 to the PSU connection isn't shown, perhaps the original producer
of this technical information
had been on the booze that day when he failed to notice hish bloody
erruz.
Ripple voltage at 200mA will only be 0.32Vrms at 100 Hz.

Patrick Turner.




........ Phil

[Patrick Turner]

RapidRonnie wrote:

If you are literate in German you will want to get Rainer zur Linde's
books, particularly his earlier ones which have very explicit
transformer design information in them.

The same transformer can be used with different numbers of tubes in
push-pull, one or two or two or more pairs in many cases. In fact
sometimes the larger designs had four tubes and they added two more in
many cases. The early Zenith Stratosphere console had 4 pairs of 45s
which could be simply replaced by two pairs of 2A3s. The cathode
resistor needed a little tweaking sometimes. There were also early
MC60 and MC75 prototypes with four 5881s instead of KT88 or 6550.

There is no optimal tap position for ultralinear taps although 43%
was quite common. In reality it is a tradeoff. The taps have to be at
a winding end so there are a limited number of choices for any winding
scheme chosen. For instance, on the Peerless transformers it was
common to have two half-primaries that could be seriesed or
parellelled. If they were seriesed the taps are of necessity at 50%.
Several companies are winding copies of Peerless transformers. You
could do worse.

Yes the 43% UL taps for EL34 was regarded as most optimal,
because of the resulting THD and gain and Ra result, and further
increase in UL%
didn't give much benefit without curtailing power too much by the Ra
curve for where Eg=0V.
but 6550/KT88 often had 50% taps, and Leak made all their amps with 50%
UL.

43% = 3/7, and many OPT had 14 layers of primary wire at say 200 turns
per layer,
thus giving a typical 2,800 P turns.
So the UL tap was 3 layers out from the CT.

Lazy makers who didn't care too much about highish leakage L would place
two secondary
sections at the 43% distance from the CT to
give a bobbin winding layer arrangement staring at the bottom of a
single bobbin,
4P-S-3P-CT-3P-S-4P.

Far better winding arrangements and ideas for OPT can be found at
http://www.turneraudio.com.au/output-trans-theory.html
and related pages.

The UL tap is always most conveniently placed at the end of a layer of P
wire.
so where there are 16 layers, its easy to get 25%, 37.5%, 50% and 62.5%
taps for UL.
I recall ARC used 37.5% UL taps.

American makers in general didn't like UL % to be high because it
slightly
reduced the maximum power figures that are the main factor governing a
sale.

The better way to build an output stage is either to use triodes or
use CFB windings, IMHO.

Patrick Turner.

[Blazej Czeladzki \(ByCZy\)]

Patrick Turner wklepal(a) i opublikowal(a) co
nastepuje:
Anywhere between 25% and 50% is OK, and better than no UL tap at all.
Are you winding your own OPT?
I'm gona order it, but the construction is rather not typical. So I want to
have as much info about it as possible.

--
_____________
Pozdrawiam:
Blazej Czeladzki

[Ian Iveson]

west said

This page is sure to bamboozle most ppl, but
I don't give simple answers to uneducated minds.

It takes talent to do that. The type of talent a good teacher has.

huge snip

No, West, that's the type of talent a good dictionary has. The art of
enlightenment is quite different.

Stop being horrid to poor Patrick, you're making me jealous.

Ian

[Patrick Turner]

"Blazej Czeladzki (ByCZy)" wrote:

Patrick Turner wklepal(a) i opublikowal(a) co
nastepuje:
Anywhere between 25% and 50% is OK, and better than no UL tap at all.
Are you winding your own OPT?
I'm gona order it, but the construction is rather not typical. So I want to
have as much info about it as possible.

And you still won't know what you are getting, unless you get a Hammond,
who show something at their website about what you get.

Unless the person you are ordering the OPT from provides you with ALL
the winding interleaving details, insulation thicknesses, turn numbers,
wire type, core size,
core type, and guranteed performance with a known source resistance,
and varnishing technique, high voltage tests, don't buy the darn thing.

To get a special OPT, YOU have to know all about OPT and
specify what YOU want, and not let THEM sell you something
that does not comply with your expectations.

THEY must be able to proove to you they are able and willing to wind
what you want.
Some things they say about your design may not matter, and if you want
teflon insulation,
they may not want to provide it.
A good design doesn't need teflon, and is in fact better without it
because
its unlikely the varnish will stick to it properly. Polyester insulation
is fine.
Some winders try to avoid vanishing, or even waxing, but these must be
done
properly.

This usually all far too much trouble for tranny winders who are
rarely ever very brainy people, and who spend most of the time winding
generic mains crap to make a living.

None of my advice is comfortable for anyone to accept.

However, because I found the tranny winding industry
is dominated by idiots and lazy ****wits i built
a lathe and learnt all about OPT and I wind them when i want them to
the kind of design details that makes most "professionals" have a
heart attack when they see what i expect.
None have ever heard of the design ideas at my website.

You may be able to buy something from Sowter, one of their stock lines
perhaps.

You will pay extra for the special work.

Patrick Turner.




--
_____________
Pozdrawiam:
Blazej Czeladzki

[Blazej Czeladzki \(ByCZy\)]

Patrick Turner wklepal(a) i opublikowal(a) co
nastepuje:
If you don't have active protection against bias failure,
a 100mA fuse soldered between each EL84 cathode and 0V is wise.
I like to use 0.3mm absolute minimum dia.

Could you draw it on schematics?

How should I adjust bias on finished monoblok?

Could you give me some hints for first powerup?


--
_____________
Pozdrawiam:
Blazej Czeladzki

[Patrick Turner]

"Blazej Czeladzki (ByCZy)" wrote:

Patrick Turner wklepal(a) i opublikowal(a) co
nastepuje:
If you don't have active protection against bias failure,
a 100mA fuse soldered between each EL84 cathode and 0V is wise.
I like to use 0.3mm absolute minimum dia.

Could you draw it on schematics?

How should I adjust bias on finished monoblok?

Could you give me some hints for first powerup?

--
_____________
Pozdrawiam:
Blazej Czeladzki

You want to have have 4 output tubes per channel
If I was doing this with EL84, I would have cathode bias RC network for
each EL84, about 270 ohms plus 1,000uF, 35V rated.
And I would have the 100mA fuses between the bottom of the R&C to
ground,
so that if a cathode cap shorts and / or a tube saturates with more than
100mA,
a fuse blows.

If you go to the page at
http://www.turneraudio.com.au/8585-a...ober-2006.html
and go about 2/3 the way down the page, you will find an elaborate
active protection schemaic for a stereo amp with the 8 tubes of the 8585
I have.
Read all about how it works and analyse what you'd need to do to apply
the idea to your amp.
To get this right, you need to know a heck of a lot!

But if all that is too hard, and it it would be for most ppl here,
then just use the cathode bias and 4 fuses.

If one tube out of 4 has a blown fuse, the amp will still work
without you suspecting anything is wrong at lowish levels.

Another schematic for active shut-down prorection and bias balance
indication
is shown at
http://www.turneraudio.com.au/leakampmods.html
Go to the bottom of the page.

Where one does have multiple output tubes with fixed bias,
another schematic for active shut-down protection is at
http://www.turneraudio.com.au/100w-monobloc-2004.html
Go 1/2 way down the page to see the schematic which
turns off the amp if one or more tubes conduct too much dc cathode
current.

With fixed bias, tubes suffer sudden death with bias failure.

I have just re-designed and re-wired a pair of Manley Labs Snappers
and have two leds mounted near each of 4 output tubes with fixed bias
which is adjusted with with 4 individual bias adjust pots.
Always ONLY have separate bias adjust pots, one for each tube, or a way
of balancing bias.
But with the Manleys, the red and yellow LED beside each output tube
is adjusted for equal brightness when the cathode is within 5% of the
wanted figure.
if the tube conducts too little Ik, the red goes out and yellow stays
bright,
indicating its a bit weak or sick, and if too much Ik flows, the
yellow goes out indicating too much Ok.
And if Ik goes to twice the wanted bias Ik for longer than 4 seconds,
the mains tranny
is turned right off, and separate red LED turns on, whaile all other
yellow LEDs are on, and no other red LED.

I don't like Ik meters with a switch,
I don't like reliance on owners having to use a screw driver and turn a
pot to adjust bias,
read a voltmeter, and make sure they adjust the right pot for the right
tube.
If technically illiterate owners can **** an amp up, they will very
easily find a way,
and in the case of the Manleys, the previous owner had mismanaged the
amp badly,
couldn't figure out why smoke happened so often, and sold these amps at
a low price.
The Manley Snappers have VERY GOOD OUTPUT TRANSFORMERS, and were able to
survive trouble when it happened.
Ive done lots more to fix these two amps, but that's a story for another
day.

So all sorts of faults and problems are indicated by the 8 LEDs poking
up
through the chassis so the owner can see if there's a problem in a
glance.
If one tube of 4 goes dead, then the other one in that side of the PP
circuit will show a rising red LED signal while the dead one just shows
the yellow one on.
So just which tube is stuffed becomes obvious without delay.

There is still a fuse of 0.5A between OPT CT and the PSU caps, so that
if a tube
arcs internally, the amp is well protected.

All these protection measures are best designed so a 10VA tranny with
240V : 12V winding
provides independant power to the protection circuit, and if a fault
happens,
the main power tranny is turned off by a relay generously rated for
mains AC and current,
so I use 240V @ 6A, and interupt both active and neutral lines.
The little auxilliary tranny is connected after the mains fuse, but
before the mains switch,
so the protection remains operative if the main PT is off.

Resetting an amp with such protection measures is easy
with a turn off, wait 3 seconds, then turn back on.
If the amp trips off again soon, and you see LEDs telling you something,
heed what they say to you.

With my way, one NEVER has any disasters.

I've had an EL34 develop a dry joint in one heater wire in its base,
and the owner soon saw he had a problem, and came to me asap,
and in ten minutes I found why and soldered the heater, and all was
fixed so easily.

Patrick Turner.

[Iain Churches]

"Patrick Turner" wrote in message
...
You may be able to buy something from Sowter, one of their stock lines
perhaps.

You will pay extra for the special work.

Patrick Turner.


There is no extra charge from Sowter for special designs.
This is clearly stated on their website. They have such a huge
range of standard models that most people find exactly what
they want.

[Iain Churches]

"Blazej Czeladzki (ByCZy)"
wrote in
message ...
Phil Allison wklepal(a) i opublikowal(a) co
nastepuje:
"John Byrns"
I think thats my situation:
http://ecclab.com/schem/rtech1.gif
I have the trafo diagram too, but it seams to be too simple:
http://ecclab.com/schem/rtech2.gif
What do you think about it?
I think there is something fishy about the transformer, the numbers just
don't add up, or divide out correctly.
** If the 4 x 125 turn secondaries are all in parallel, the impedance
ratio comes out about right.
With a circa 360 volt DC supply, 40 watts rms from a 4000 ohm primary is


ECC82 and 4xEL84
--
_____________
greets:
Blazej Czeladzki

Sowter UK have a transformer type UO65 for 2 pairs EL56 ppp.

http://www.sowter.co.uk/

Best regards
Iain

[Andre Jute]

Blazej Czeladzki wrote:
Hello,

I have question about output trafos for parallel push pull amps.

Are there any special differences between those trafos and standard push
pull trafos?


Yo, Blazej:

I haven't read the entire thread because the complexities of
transformers hurt my head and the ignorance of some of the clowns on
RAT drive my blood pressure up. However, I have specified and ordered
quite a few custom transformers without any problem, and I have many
off-the shelf transformers that do what I want them to do in my own-
design amps.

There are two things you need to do to avoid wasting your money on
transformers. You must for yourself acquire a certain miniimum of
knowledge about where the transformer fits in the scheme of things and
how it does its business. The best source for this is Menno van der
Veen's "Transformers and Tubes in Power Amplifiers", available from
Plitron in Canada; my Glass Audio review and contact information is
he
http://members.lycos.co.uk/fiultra/J...S%20T%26T.html

The other thing you need to do is to deal only with Plitron in Canada,
Amplimo in The Netherlands, Lundahl in Sweden, Sowter in England, and
the Hammond company whose products can be ordered through guitar shops
worldwide. The only exception is a known-good custom winder someone
will recommend to you (Patrick perhaps, if you can afford the postage,
or Lucas Cant also in Australia); however, this can be dangerous as
you can find, for instance, many recommendations of Magnequest, whose
products are poor-quality copies of transformers that were compromised
by accountants in the first instance and whose winder is a psychopath
who will set his gang on you if you complain about shoddy workmanship.

Of the commercial list above, I have transformers from all of them and
have found them all excellent. Lundahl transformers are currently the
best you can buy over the counter, and cheap at the price; they are
also very versatile in that all the winding segments are brought out
so you can reconfigure the transformer for any intended use; choose
one from the large Lundahl range for maximum versatility and you'll
never need to buy another output transformer. Next up are the superbly
made Plitron/Amplimo toroidals; pricey but superior. I have off-the
shelf Amplimo toroidal transformers on PPP on a 4x EL34 per channel
amplifier; It is has 18W in Class A and about a 100W in Class B. I
also have Vanderveen-designed custom winds by both Amplimo and Plitron
(as far as I know, they don't do custom work for DIYers though) which
are superb. Sowter is the only one of that commercial list who will do
custom work for DIYers but they essentially charge by the pound so
custom work from them is not overly expensive -- but first you need to
know precisely what you want. Hammonds are cheap because you benefit
from guitar-market production unit numbers; just don't hog out Hammond
transformers to the limit and you have an economical and perfectly
good alternative to the upmarket names. The Amplimo/Plitron lines
include a large number of very interesting transformers with feedback
winding schemes, the sort of thing we normally shorthand as CFB or
cathode feedback: see towards the bottom of
http://members.lycos.co.uk/fiultra/J...S%20T%26T.html
and check the illustration at the "Super Pentode" reference.

Menno van der Veen, the author of the book I'm recommending and the
head of the Bureau Vanderveen, designs transformers for Amplimo and
Plitron (the same designs but the catalogue numbers may be different),
so buying from Amplimo if you're in Europe can save postage. (Postage
for a pair of power supply trannies for an 80W SE amp cost USD90 from
Plitron in Canada to me in Ireland.) Menno's book also offers circuits
for amps of various output and Plitron sells a board to make
construction of the most popular of the designs easy..

HTH.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

[Blazej Czeladzki \(ByCZy\)]

Patrick Turner wklepal(a) i opublikowal(a) co
nastepuje:
You want to have have 4 output tubes per channel
If I was doing this with EL84, I would have cathode bias RC network for
each EL84, about 270 ohms plus 1,000uF, 35V rated.
And I would have the 100mA fuses between the bottom of the R&C to
ground,
so that if a cathode cap shorts and / or a tube saturates with more than
100mA,
a fuse blows.

I don,t get it. I'm not good enough in technical english. That's why I asked
you to draw it.
Can you download the gif and draw it in other colour?

The two first diagrams needs symetric power supply. I have power supply
trafo without symetric circuit.

Where one does have multiple output tubes with fixed bias,
another schematic for active shut-down protection is at
http://www.turneraudio.com.au/100w-monobloc-2004.html
Go 1/2 way down the page to see the schematic which
turns off the amp if one or more tubes conduct too much dc cathode
current.

Maybe AFTER runing the first verion of my amp I will build protection
circuit.

You haven't answer the question about adjusting bias in first start of the
amp.




--
_____________
Greets:
Blazej Czeladzki

[Patrick Turner]

"Blazej Czeladzki (ByCZy)" wrote:

Patrick Turner wklepal(a) i opublikowal(a) co
nastepuje:
You want to have have 4 output tubes per channel
If I was doing this with EL84, I would have cathode bias RC network for
each EL84, about 270 ohms plus 1,000uF, 35V rated.
And I would have the 100mA fuses between the bottom of the R&C to
ground,
so that if a cathode cap shorts and / or a tube saturates with more than
100mA,
a fuse blows.

I don,t get it. I'm not good enough in technical english. That's why I asked
you to draw it.
Can you download the gif and draw it in other colour?

The two first diagrams needs symetric power supply. I have power supply
trafo without symetric circuit.

I am not sure whether you cannot download the gifs on the pages at my
site
or you don't understand them or have difficulty seeing which part of the
schematic is for the protection
circuit because some are drawn as part of the whole amplifier schematic.

The power supply for the protection circuits often use a symetrical
power supply
which is easily made with a small ADITIONAL 5VA power transformer about
the size
of a radio speaker output transformer and which will fit inside most
existing amplifier chassis.
There are two diodes, and a two caps for +15V and - 15V.
Some of my circuits use a voltage quadrupler circuit to work off the
existing 6.3Vrms
heater circuit, so that the 3.3Vrms is rectified up to make +12V,
and the relay just interupts HT winding on the PT.

My problem is that everyone builds different amplifiers and wants many
different things, and
while I am happy to share all my information free of charge to everyone,
people still say they can't understand and they do not see the reasons
why I have built the circuits, and cannot tailor the designs of mine to
do what they want.

There is just as much knowledge required to design and build a
protection circuit as one needs to build an amplifier.

The idea of having a 100mA fuse in each cathode circuit is therefore the
simplest that
can be understood, and it will work OK with either fixed bias or cathode
bias.




Where one does have multiple output tubes with fixed bias,
another schematic for active shut-down protection is at
http://www.turneraudio.com.au/100w-monobloc-2004.html
Go 1/2 way down the page to see the schematic which
turns off the amp if one or more tubes conduct too much dc cathode
current.

Maybe AFTER runing the first verion of my amp I will build protection
circuit.

You haven't answer the question about adjusting bias in first start of the
amp.




When you have plugged in 4 new tubes for the first time make sure the
bias adjustment
potentiometers are adjusted for maximum negative grid voltage.

After about 30 seconds, begin to slowly turn up each pot until the
wanted bias cirrent flows.

If you have fixed bias, you should have a 10 ohm 5 watt resistor between
cathode and 0V,
and if you want 35mA of bias current for EL84 which would be about right
in your case,
then you adjust the bias pot so 0.35Vdc appears across te 10 ohm cathode
resistor.


BTW there probably would be a transformer which will suit you well
which is part of a standard product line made by
Sowter in England,
Plitron in Canada,
Amplimo in The Netherlands,
Lundahl in Sweden,
Hammond of Canada, whose products can be ordered through guitar shops
worldwide.

Unless you know all about OPT you will never get a special tranny wound,
and you should try one of the above which will be a lot easier than
learning
so much.

I would go to Sowter, see
http://www.sowter.co.uk/

There are 2 choices you could make for a quad of EL84.


They have a UA65, meant for a quad of EL84, 30 watts class AB, 4k
primary, 3.6Kg, 127 british pounds.

There is also UA21 meant for 2 x EL34, 40 watts, 6k6 primary, 4.9Kg, 145
british pounds.
This one would allow Ea = 350V and Ia = 34mA per tube,
and could give you more pure class A power, about 25 watts.
Its a big heavy tranny for 4 little tubes, but this means good
performance,
and it is least likely to become damaged if a tube becomes saturated.

Sowter can be emailed at

Patrick Turner.







--
_____________
Greets:
Blazej Czeladzki

[west[_3_]]

"Ian Iveson" wrote in message
. ..
west said

This page is sure to bamboozle most ppl, but
I don't give simple answers to uneducated minds.

It takes talent to do that. The type of talent a good teacher has.

huge snip

No, West, that's the type of talent a good dictionary has. The art of
enlightenment is quite different.

Stop being horrid to poor Patrick, you're making me jealous.

Ian

I don't get it? Patrick and I have a dark, mercurial sort of mutual
attraction. I can't quite put my finger on it. Nothing sexual. At least I
don't think so. If I was horrid to him how does that make you jealous? I
don't understand the jealous part and you piqued my curiosity. Please
explain.

Cordially,
west

[Patrick Turner]

west wrote:

"Ian Iveson" wrote in message
. ..
west said

This page is sure to bamboozle most ppl, but
I don't give simple answers to uneducated minds.

It takes talent to do that. The type of talent a good teacher has.

huge snip

No, West, that's the type of talent a good dictionary has. The art of
enlightenment is quite different.

Stop being horrid to poor Patrick, you're making me jealous.

Ian

I don't get it? Patrick and I have a dark, mercurial sort of mutual
attraction. I can't quite put my finger on it. Nothing sexual. At least I
don't think so. If I was horrid to him how does that make you jealous? I
don't understand the jealous part and you piqued my curiosity. Please
explain.

Cordially,
west


Ian quite likes to be "intellectually" sadistic in a bwitish twisted up
sort of way
which would be amusing if it was not so sad to witness.

He likes to BS almost continuously and resents my more down to earth
approach to
everything.

We must all get on because like the early white inhabitants of Pitcairn
Island,
there isn't anywhere else we can go. So I am not one to start a war when
I am so busy,
and when nothing is gained from war except regrets.
I tend to finish what is started though.
I don't like everyone I meet, and they surely don't like me,
and i could not care less; I'd rather point out their many errors in
technical reasonings
and suffer the backlash than agree with their BS.

Ian has built 1 amplifier in 7 years as far as I know.

Patrick Turner.

[Iain Churches]

"Iain Churches" wrote in message
i.fi...

"Blazej Czeladzki (ByCZy)"
wrote in
message ...
Phil Allison wklepal(a) i opublikowal(a) co
nastepuje:
"John Byrns"
I think thats my situation:
http://ecclab.com/schem/rtech1.gif
I have the trafo diagram too, but it seams to be too simple:
http://ecclab.com/schem/rtech2.gif
What do you think about it?
I think there is something fishy about the transformer, the numbers
just
don't add up, or divide out correctly.
** If the 4 x 125 turn secondaries are all in parallel, the impedance
ratio comes out about right.
With a circa 360 volt DC supply, 40 watts rms from a 4000 ohm primary is


ECC82 and 4xEL84
--
_____________
greets:
Blazej Czeladzki

Sowter UK have a transformer type UO65
http://www.sowter.co.uk/

Best regards
Iain
Sorry - typo. I meant of course two pairs EL84 ppp !!!

Iain

[Ian Iveson]

west wrote

This page is sure to bamboozle most ppl, but
I don't give simple answers to uneducated minds.

It takes talent to do that. The type of talent a good teacher
has.

huge snip

No, West, that's the type of talent a good dictionary has. The art
of
enlightenment is quite different.

Stop being horrid to poor Patrick, you're making me jealous.

Ian

I don't get it? Patrick and I have a dark, mercurial sort of mutual
attraction. I can't quite put my finger on it. Nothing sexual. At
least I
don't think so. If I was horrid to him how does that make you
jealous? I
don't understand the jealous part and you piqued my curiosity.
Please
explain.

Perhaps, like Patrick, you are confusing jealousy with envy?

I sensed infidelity. I demand your undivided abuse.

Ian

[Ian Iveson]

Patrick only picks on me because I can spell:

Ian has built 1 amplifier in 7 years as far as I know.

Two, to be pedantic. We have stereo here. Why would I want more?
Perfection is singular.

Anyway, they're not finished yet. I'm still struggling with the
microcontroller programming, and then I might rework the feedback.

Sounds good though, still.

Luckily, I ignored all your advice. Particularly concerning the output
transformer, which you said is all wrong. Especially with respect to
the load distribution and the bifilar winding, which you said are
unnecessary contrivances. A few other things too, which you are so
proud of now, but poured mountains of drivel over at the time. No
make-do-and-mend, no muddle-through. I calculated, I simulated, I
built, I listen.

In retrospect, a lesson in

How to Make Things so they are Easy to Take Apart

wouldn't have gone amiss. I guess that is naturally a two-pass
revelation.

glumly, Ian

[Patrick Turner]

Ian Iveson wrote:

Patrick only picks on me because I can spell:

Ian has built 1 amplifier in 7 years as far as I know.

Two, to be pedantic. We have stereo here. Why would I want more?
Perfection is singular.

Anyway, they're not finished yet. I'm still struggling with the
microcontroller programming, and then I might rework the feedback.

Sounds good though, still.

Luckily, I ignored all your advice. Particularly concerning the output
transformer, which you said is all wrong. Especially with respect to
the load distribution and the bifilar winding, which you said are
unnecessary contrivances. A few other things too, which you are so
proud of now, but poured mountains of drivel over at the time. No
make-do-and-mend, no muddle-through. I calculated, I simulated, I
built, I listen.

In retrospect, a lesson in

How to Make Things so they are Easy to Take Apart

wouldn't have gone amiss. I guess that is naturally a two-pass
revelation.

glumly, Ian

Ian, if your arse was on fire, you would smell smoke, but take years to
understand where it was coming from.

Then as the years went by you can say how overjoyed you are about
ignoring me,
and finding your own way with a Sowter output transformer after
misquoting
the general ideas I conveyed to your very dumb self 6 years ago.

Sowter use the very same principles and techniques that I use to arrive
at a working
OPT design.

When you insult me so stupidly, you insult the makers of the
transformers you bought,
and you have us all laughing at you, like you are the village idiot.

Meanwhile, you have not designed or wound a single OPT.

You are a clueless twisted idiot posing as a know all, while really
knowing **** all.

And you say
"I'm still struggling with the
microcontroller programming, and then I might rework the feedback."

You admit you are ****ing around in circles and cannot conclude to make
a decent thing.

Then you contradict yourself by saying
" No make-do-and-mend, no muddle-through. I calculated, I simulated, I
built, I listen. "

You ARE making and mending, muddling along, and making no more
calculations than I would,
and as we all know simulations and listening are not reliable ways to
build simple audio gear.

I dunno why you bother to defend yourself by raising your arse so high
above the parapet
i can take a nice clear shot at it.

Wouldn't it be easier to hide?

Patrick Turner.

[west[_3_]]

"Patrick Turner" wrote in message
...


"Blazej Czeladzki (ByCZy)" wrote:

Patrick Turner wklepal(a) i opublikowal(a) co
nastepuje:
Anywhere between 25% and 50% is OK, and better than no UL tap at all.
Are you winding your own OPT?
I'm gona order it, but the construction is rather not typical. So I want
to
have as much info about it as possible.

And you still won't know what you are getting, unless you get a Hammond,
who show something at their website about what you get.

Unless the person you are ordering the OPT from provides you with ALL
the winding interleaving details, insulation thicknesses, turn numbers,
wire type, core size,
core type, and guranteed performance with a known source resistance,
and varnishing technique, high voltage tests, don't buy the darn thing.

To get a special OPT, YOU have to know all about OPT and
specify what YOU want, and not let THEM sell you something
that does not comply with your expectations.

THEY must be able to proove to you they are able and willing to wind
what you want.
Some things they say about your design may not matter, and if you want
teflon insulation,
they may not want to provide it.
A good design doesn't need teflon, and is in fact better without it
because
its unlikely the varnish will stick to it properly. Polyester insulation
is fine.
Some winders try to avoid vanishing, or even waxing, but these must be
done
properly.

This usually all far too much trouble for tranny winders who are
rarely ever very brainy people, and who spend most of the time winding
generic mains crap to make a living.

None of my advice is comfortable for anyone to accept.

However, because I found the tranny winding industry
is dominated by idiots and lazy ****wits i built
a lathe and learnt all about OPT and I wind them when i want them to
the kind of design details that makes most "professionals" have a
heart attack when they see what i expect.
None have ever heard of the design ideas at my website.

You may be able to buy something from Sowter, one of their stock lines
perhaps.

You will pay extra for the special work.

Patrick Turner.

I don't think many people on this NG can argue with you about the merits of
a quality transformer. However, respectfully, are you not being a bit
impractical? How many xfr.companies can you order the aforementioned
specific construction techniques from? Can we (hobbyists) not rely on
companies like Sowter and Lundahl to met those lofty qualities with their
stock transformers?

west



--
_____________
Pozdrawiam:
Blazej Czeladzki

[west[_3_]]

"Patrick Turner" wrote in message
...


Blazej Czeladzki wrote:

Hello,

I have question about output trafos for parallel push pull amps.

Are there any special differences between those trafos and standard push
pull trafos?

There are no differences in operating principles.

However, where number of tubes in the output are increased,
the core size and wire sizes increase, and the number of turns
per volt decreases to suit the reduced primary load value,
while keeping the winding losses and core distortion low.

If you have transformer type X meant for 2 x EL34,
and you wish to use 4 x EL34, then get exactly twice the power
then transformer X cannot provide it using the same turn ratio.

OPT design can only successfully achieved by following all the necessary
design steps.
There are 47 steps listed out for you with examples at
http://www.turneraudio.com.au/output-trans-pp-calc.html

This page is sure to bamboozle most ppl, but
I don't give simple answers to uneducated minds.

However, should you wish to use 4 x EL84 instead of 2 x EL34, then
the same OPT might be able to be used, depending on
the operating voltages and winding resistances.
This is because two EL84 can each have say 30mA of idle current
and this can equal the 60mA in one EL34, and the load of
5k for the two EL34 will suit the quad of EL84.
But EL84 will not be able to be run at say +600V B+ in UL or triode
mode,
and about 350V is the safe limit.
So always there a lots of things to consider as soon as a the tube line
up is
changed.

Patrick Turner.

When going from 2 to 4 EL-34s, is it possible to parallel 2 "X" OPTs (X||X)?
If yes, how does the X||X sound compare to a 4 tube Y OPT?

west


s

--
____________
Pozdrawiam:
BCZ

[west[_3_]]

"Iain Churches" wrote in message
news

"Iain Churches" wrote in message
i.fi...

"Blazej Czeladzki (ByCZy)"
wrote in
message ...
Phil Allison wklepal(a) i opublikowal(a) co
nastepuje:
"John Byrns"
I think thats my situation:
http://ecclab.com/schem/rtech1.gif
I have the trafo diagram too, but it seams to be too simple:
http://ecclab.com/schem/rtech2.gif
What do you think about it?
I think there is something fishy about the transformer, the numbers
just
don't add up, or divide out correctly.
** If the 4 x 125 turn secondaries are all in parallel, the impedance
ratio comes out about right.
With a circa 360 volt DC supply, 40 watts rms from a 4000 ohm primary
is


ECC82 and 4xEL84
--
_____________
greets:
Blazej Czeladzki

Sowter UK have a transformer type UO65
http://www.sowter.co.uk/

Best regards
Iain
Sorry - typo. I meant of course two pairs EL84 ppp !!!

Iain
Iain ... I know this is a novice type question, but I just do not have the
experience here. In your opinion, who makes the better interstage and output
transformers, Sowter or Lundahl? Remember, just opinion. :-)

west

[Patrick Turner]

west wrote:

"Patrick Turner" wrote in message
...


"Blazej Czeladzki (ByCZy)" wrote:

Patrick Turner wklepal(a) i opublikowal(a) co
nastepuje:
Anywhere between 25% and 50% is OK, and better than no UL tap at all.
Are you winding your own OPT?
I'm gona order it, but the construction is rather not typical. So I want
to
have as much info about it as possible.

And you still won't know what you are getting, unless you get a Hammond,
who show something at their website about what you get.

Unless the person you are ordering the OPT from provides you with ALL
the winding interleaving details, insulation thicknesses, turn numbers,
wire type, core size,
core type, and guranteed performance with a known source resistance,
and varnishing technique, high voltage tests, don't buy the darn thing.

To get a special OPT, YOU have to know all about OPT and
specify what YOU want, and not let THEM sell you something
that does not comply with your expectations.

THEY must be able to proove to you they are able and willing to wind
what you want.
Some things they say about your design may not matter, and if you want
teflon insulation,
they may not want to provide it.
A good design doesn't need teflon, and is in fact better without it
because
its unlikely the varnish will stick to it properly. Polyester insulation
is fine.
Some winders try to avoid vanishing, or even waxing, but these must be
done
properly.

This usually all far too much trouble for tranny winders who are
rarely ever very brainy people, and who spend most of the time winding
generic mains crap to make a living.

None of my advice is comfortable for anyone to accept.

However, because I found the tranny winding industry
is dominated by idiots and lazy ****wits i built
a lathe and learnt all about OPT and I wind them when i want them to
the kind of design details that makes most "professionals" have a
heart attack when they see what i expect.
None have ever heard of the design ideas at my website.

You may be able to buy something from Sowter, one of their stock lines
perhaps.

You will pay extra for the special work.

Patrick Turner.

I don't think many people on this NG can argue with you about the merits of
a quality transformer. However, respectfully, are you not being a bit
impractical? How many xfr.companies can you order the aforementioned
specific construction techniques from? Can we (hobbyists) not rely on
companies like Sowter and Lundahl to met those lofty qualities with their
stock transformers?

There are a couple of lesser companies here who I could try, but never
ever would because they can't/won't perform the wonders I expect.

There are not a huge number of winders who can do really detailed work
when you want it and for a competitive price.
So for specials, the person ordering must specify the special properly
and be an expert in design, and the person winding must be capable.

Obviously just going to Sowter or Lundahl etc is a whole lot easier for
a hobbyist.

Both these companies are more expensive than Hammond who probably
doesn't have such
splendid quality in terms of wasteless winding arrangements and low
leakage inductance.

People could do a lot worse than try my OPT No1 design at my web pages.
The full details of a splendid OPT are at
http://www.turneraudio.com.au/output-trans-pp-calc.html
Its a design that suits many tube types but which would cause
heart problems for many winders.

Patrick Turner.



west



--
_____________
Pozdrawiam:
Blazej Czeladzki