There is risk above 45 V. and it grows exponentially, as the voltage rises. One hand in a pocket or wrapped around the belt, at the small of the back or else.
When I fixed tube TVs just a touch of a cold TV chassis caused automatic reaction, adrenaline rush and fast drawing back of my hand.
kt88 and el34 tubes are similar. The amp with 6 output tubes are not harder to build than the amp with 4 output tubes. Actually, 4 of EL34 are enough for 100W of an output power.
Take that schematic, remove 2 output tubes, and use KT88 instead of EL34.
But please remember, high voltage kills.
patrick turner likes voltage doublers, harman kardon citation 2 used them and the marantz 9 monoblocks....
guys
i have looked at some much my head is spinning
i'm torn between 2 designs
1: w-6m can't seem to find clear drawing so items can be seen.
can't see all values for caps and resistors
2: the turneraudio 100watt this seems so complex that makes me scared to start. just looking at the power supply figure has me confussed
https://mail.google.com/mail/u/0/?u...1&disp=inline&realattid=f_ik8o6jzj0&safe=1&zw
it's clear i need some ground facts
is a tube amp the same as mosfet in that the rail voltage = watts output?
lower b+ means lower watts and higher b+ means more watts.
also looking at tubes data when it says max voltage at say 800v , does it mean it has to be that or it can run any voltage up to that?
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i have been diying since 1972
build ss amps , preamps, active crossovers, power cables, interconnect
and speakers at well over 320 pairs
my #1 build is 3 way with 4 dynaudio 7" woofers focal 4 1/2 cone mid and dynaudio d28 tweeter in each. these are second to none . and finish out at 11.2 ohm.
need power to drive this impedance
the st70 i had would not go louder then normal voice
switched to mono or 70 watts and it was ok
same for the cary rocket 88 40 watts x 2 but same thing
it was a jaw drop amp with 4 kt88 but when i needed at some times turn up the volume it just ran out of clear output.
these speakers with my 2 p101 amps built to 150 watts normally at good output are pulling 45 watts from the p101 with peak at 60 for not loud but good level where other speakers would need only 3 to 5 watts at the same level.
i never could see why 300b at only 8 watts where so in love with.
i also have never been a fan of large box horn speakers that are 94db and up
i prefer multi drivers and higher impedance
ok, then.....it's your amp, just wanted to clear something up, now i know where you are coming from.....
still, i will advise start with the speakers you will use in your build, that should give you a better idea of how much power you need...
short answer, yes, but tube have have such high internal resistance so that a matching transformer to couple the load is a must....
yes...
no, you do not run tubes at maximum voltage, usually half of that or lower,
depending on your load, the plate dissipation spec of the tube is the one to watch out for...
you do not want to go over the spec limits lest your tube live a shorter life...
tube plate voltage can go higher than 800 volts when in cut-off...
other more experienced members can correct me if i said something wrong...
still, i will advise start with the speakers you will use in your build, that should give you a better idea of how much power you need...
short answer, yes, but tube have have such high internal resistance so that a matching transformer to couple the load is a must....
yes...
no, you do not run tubes at maximum voltage, usually half of that or lower,
depending on your load, the plate dissipation spec of the tube is the one to watch out for...
you do not want to go over the spec limits lest your tube live a shorter life...
tube plate voltage can go higher than 800 volts when in cut-off...
other more experienced members can correct me if i said something wrong...
yes sir
this is my first build and fear stops me from to complex a first build.
but this one is not clear enough to see values.
power trans.is too vauge . no va rating and can't see the secondaries value.
can't see all caps there.
Ask SY if Williamson style is any good.
Low frequency instability is the "Achilles Heel" of the topology. You deal with that by spreading the high pass poles' "corner" frequencies out, using top notch low phase shift O/P "iron", and rolling infrasonic noise off at the circuit's I/P.
If you want an effects machine, Williamson style is not for you. OTOH, if highly accurate reproduction of the I/P signal, at substantially increased power, is the object of your desire, Williamson style circuitry is 1 of the better options. Sweat the details and the music will flow.
Low frequency instability is the "Achilles Heel" of the topology. You deal with that by spreading the high pass poles' "corner" frequencies out, using top notch low phase shift O/P "iron", and rolling infrasonic noise off at the circuit's I/P.
If you want an effects machine, Williamson style is not for you. OTOH, if highly accurate reproduction of the I/P signal, at substantially increased power, is the object of your desire, Williamson style circuitry is 1 of the better options. Sweat the details and the music will flow.
guys
i found a very clear drawing of the heath w-6m and can now see values.
tranny looks like 6.3v and center tap to ground
then 170v looks like 1 leg
on the bottom looks like maybe 130v or maybe 1.30v not sure
so last night i sent a copy of this amp to one of the worlds best producers.
they replied today with 6.3v, 170v & 130v but one catch , nothing in the world with these values.
custom made pair $1400
i'm still in shock
closest in hammond i can see is # 369ex but 190v rails and 1 x 6.3v @ 2.5a.
will this one or another work?
then what do i do for the remaining 130v leg?
i found a very clear drawing of the heath w-6m and can now see values.
tranny looks like 6.3v and center tap to ground
then 170v looks like 1 leg
on the bottom looks like maybe 130v or maybe 1.30v not sure
so last night i sent a copy of this amp to one of the worlds best producers.
they replied today with 6.3v, 170v & 130v but one catch , nothing in the world with these values.
custom made pair $1400
i'm still in shock
closest in hammond i can see is # 369ex but 190v rails and 1 x 6.3v @ 2.5a.
will this one or another work?
then what do i do for the remaining 130v leg?
ok , i'm listening
as title states design advise please
i'm a old newb never built a tube amp
what else out there i can make with sensible design and power
It's universal but still incorrect to think about amplifier power in linear numbers. We pay for watts on a linear scale but hear on a log scale. On a log scale 1 Watt is 0dBW and 100 Watts is +20dbW. 50 Watts is (as earlier pointed out) only 3dB less than 100, hardly enough to matter.
An amplifier being driven hard enough to worry about its output capability is almost certainly sometime (or often) being driven into clipping, being asked to deliver more than its capability. The details of that amplifier's reaction to being overdriven are actually more important than a dB or three of unclipped output into a bench load.
A well designed amplifier will have enough headroom in all stages earlier than the final so that the earlier stages don't limit output.
Output will be limited by the output stage being driven beyond its linear range - this part is all pretty obvious.
In conventional RC coupled amplifiers without followers to the output tube grids (unlike the W6M) clipping occurs when the output grids are driven positive, and conduct, like diodes do. The driving stage tries its best to maintain the voltage at the output tubes' grid that it considers proper, but is clamped down somewhat by the grid conduction.
When the output tubes' grids conduct some DC voltage offset appears, changing the tubes' bias until the offset can bleed back down. Bleeddown time depends on the RC values, coupling cap plus circuit resistances, and must be balanced against low frequency response. Williamson's revisions to his original paper give a wonderful description of that choice and of the placement of the RC time constants of a Williamson (or other) three stage amplifier.
An amplifier designed for use near, and inevitably above, rated output *must* clip cleanly and have fast overload recovery. 1/4 second is a common design goal.
All good fortune,
Chris
An amplifier being driven hard enough to worry about its output capability is almost certainly sometime (or often) being driven into clipping, being asked to deliver more than its capability. The details of that amplifier's reaction to being overdriven are actually more important than a dB or three of unclipped output into a bench load.
A well designed amplifier will have enough headroom in all stages earlier than the final so that the earlier stages don't limit output.
Output will be limited by the output stage being driven beyond its linear range - this part is all pretty obvious.
In conventional RC coupled amplifiers without followers to the output tube grids (unlike the W6M) clipping occurs when the output grids are driven positive, and conduct, like diodes do. The driving stage tries its best to maintain the voltage at the output tubes' grid that it considers proper, but is clamped down somewhat by the grid conduction.
When the output tubes' grids conduct some DC voltage offset appears, changing the tubes' bias until the offset can bleed back down. Bleeddown time depends on the RC values, coupling cap plus circuit resistances, and must be balanced against low frequency response. Williamson's revisions to his original paper give a wonderful description of that choice and of the placement of the RC time constants of a Williamson (or other) three stage amplifier.
An amplifier designed for use near, and inevitably above, rated output *must* clip cleanly and have fast overload recovery. 1/4 second is a common design goal.
All good fortune,
Chris
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