.... how to build various amp topologies with one OPT.

http://www.mennovanderveen.nl/eng/index.html

Click on "the project" and see for yourself.

No affiliation, rgds,
Jan.

J.Koning wrote:
... how to build various amp topologies with one OPT.

http://www.mennovanderveen.nl/eng/index.html

Click on "the project" and see for yourself.


I've never been a fan at all of toroids for output transformers for
many reasons. I think they can work OK for power but it is vital to
avoid DC offset and that can happen on powerlines where you have a
"hot" and an "earthy" neutral. The prevalence of big switchers in the
home and in small businesses is a big reason to pay close attention to
this problem.

All push-pull OPTs should be specified to handle 10% imbalance in
quiescent current in the half-primaries while the amp fully met all
performance parms. Partridge's were about the only OPTs that really met
this fully but Peerless did come close.

"Bret Ludwig" wrote in message
oups.com...

J.Koning wrote:
... how to build various amp topologies with one OPT.

http://www.mennovanderveen.nl/eng/index.html

Click on "the project" and see for yourself.


I've never been a fan at all of toroids for output transformers ...

[...]

In that case you should have a look before you hit the keyboard.

Rgds,
Jan.

http://www.mennovanderveen.nl/eng/index.html

DV-GIT80: The universal output transformer for valve amplifiers
This web site contains the description of an unique project, totally
based on this special EI output transformer. Go to "Project" for
more details. The output transformer is intended for valve amplifiers
with output powers ranging from a mere 5 to a maximum 80-100 Watt. Its
windings are arranged in an universal manner, many primary and
secondary impedances are available. The core is annealed in a special
process, resulting in a very mild and friendly overload behavior;
guitarists will love this sound character. In high end audio
applications the extended and undistorted low frequency range is
remarkable. The smart construction of the transformer results in a low
price. Click here to download the technical details. Ir. bureau
Vanderveen is the sole distributor, for buying click at order.

Bret Ludwig wrote:
http://www.mennovanderveen.nl/eng/index.html

DV-GIT80: The universal output transformer for valve amplifiers
This web site contains the description of an unique project, totally
based on this special EI output transformer. Go to "Project" for
more details. The output transformer is intended for valve amplifiers
with output powers ranging from a mere 5 to a maximum 80-100 Watt. Its
windings are arranged in an universal manner, many primary and
secondary impedances are available. The core is annealed in a special
process, resulting in a very mild and friendly overload behavior;
guitarists will love this sound character. In high end audio
applications the extended and undistorted low frequency range is
remarkable. The smart construction of the transformer results in a low
price. Click here to download the technical details. Ir. bureau
Vanderveen is the sole distributor, for buying click at order.


Where does it say toroid?


Adam

Adam Stouffer wrote:

Bret Ludwig wrote:
http://www.mennovanderveen.nl/eng/index.html

DV-GIT80: The universal output transformer for valve amplifiers
This web site contains the description of an unique project, totally
based on this special EI output transformer. Go to "Project" for
more details. The output transformer is intended for valve amplifiers
with output powers ranging from a mere 5 to a maximum 80-100 Watt. Its
windings are arranged in an universal manner, many primary and
secondary impedances are available. The core is annealed in a special
process, resulting in a very mild and friendly overload behavior;
guitarists will love this sound character. In high end audio
applications the extended and undistorted low frequency range is
remarkable. The smart construction of the transformer results in a low
price. Click here to download the technical details. Ir. bureau
Vanderveen is the sole distributor, for buying click at order.


Where does it say toroid?

It would help if you clicked on the link !

Graham

J.Koning wrote:
... how to build various amp topologies with one OPT.

http://www.mennovanderveen.nl/eng/index.html

Click on "the project" and see for yourself.

No affiliation, rgds,
Jan.

I have Vanderveen designed and Amplimo- and Plitron-made custom and
catalogued transformers on amps of my own design and commercial amps
too. Menno contributed to some of my Glass Audio articles too. He's the
business. Mine are all toroids though.

This project has EI transformers and that can only be a good thing, as
it makes Menno's extraordinary talent available to a popular price
range. There can't be many places, if anywhere else, where you can buy
a transformer designed by someone of his talent for EUR70.

Andre Jute

"Andre Jute" wrote in message
ups.com...

[...]

There can't be many places, if anywhere else, where you can buy
a transformer designed by someone of his talent for EUR70.

Well, somebody wants VAT on top, evermind.
Guess I'll better swap to the somebody business.
No more blood sweat and tears, just 19% for nothing.

Rgds,
Jan.

Andre Jute wrote:
J.Koning wrote:
... how to build various amp topologies with one OPT.

http://www.mennovanderveen.nl/eng/index.html

Click on "the project" and see for yourself.

No affiliation, rgds,
Jan.

I have Vanderveen designed and Amplimo- and Plitron-made custom and
catalogued transformers on amps of my own design and commercial amps
too. Menno contributed to some of my Glass Audio articles too. He's the
business. Mine are all toroids though.

This project has EI transformers and that can only be a good thing, as
it makes Menno's extraordinary talent available to a popular price
range. There can't be many places, if anywhere else, where you can buy
a transformer designed by someone of his talent for EUR70.

Toroids are not intrinsically precious or high in build cost. Toroid
cores are often less expensive than C-cores and with the advent of the
higher speed winding machines the costs are coming down. Any moron with
a Gorman can crank out about any toroid! The classic EI and C-core
designs of yore had a lot of "black art"-nothing that cannot be derived
from patient and careful teardowns, but it's not going to be handed to
you.

No one has demonstrated a push-pull toroid OPT with the ability to
handle DC imbalance as well as a Partridge, or even a Peerless or UTC,
comparable symmetry in resistance, and similar ratios of primary to
leakage inductance. It just hasn't been done.