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 The
Robin Hoods' are a newly designed series of four single ended output
transformers. The aim of the series is two- fold. First is to offer
a transformer for folks who are bi-amping and don't need the huge
inductances and AC power capabilities of say our legendary FS-030
single ended air-gapped output transformer. The second aim/goal
is to make these the best VALUE output transformers available
in the marketplace. The "Robin Hood" series is named
in honor of the man who took from the rich, as in riches of MQ vaults,
to give to the poor, as in DIY lovers who crave high value without
sacrificing top quality.
To get great sound, we have incorporated design techniques that
we have used successfully in our DS Series of output transformers,
as well as the successful interleaving techniques that we have used
in our EXO series of parafeeds.
The
new Robin Hood Series Output
Transformers are arguably the best value
transformers in the marketplace
The primary copper
circuit is well designed to keep resistive losses at a minimum (the
dcr is approx. 185 ohms). The copper losses from the full secondary
and the full primary are equal in magnitude. The primary inductance
is carefully designed to fully support the published low frequency
extension of each model at the maximum stated power level. The total
(AC and DC combined) magnetic flux density is kept BELOW 16kg in
each model offered in this series. Therefore, these will not saturate
or "run out of iron" when used within their published
specs.
Simply put, these are really nice coils. We didn't skimp much in
the goodies department. All of the RH series are made with Teflon
insulation on the inside. All soldered connections are made with
silver bearing solder. All units are housed in a nonmagnetic solid
brass channel frame with easy to solder to lugs.
Currently, four different
models will be available in the following configurations. All are
5K primary impedances with a UL tap at 43%. The first three models
are designed to carry unbal dc currents. The last type listed is
for Parafeed applications.
NOTE: Ms. R. Hood is not standin' on a Robin Hood Series,
which are Solid Brass Channel Frame. She's perched on an FS-030
(but she still loves the Robin
Hood like her own).
| Robin
Hood Series RH-40 |
$99
each |
|
5,000 ohm pri with 43% UL tap
8 and 16 ohm secondaries
40 madc unbal current capacity
40 henries of primary L
5 watts @ 30 hz (-3db low freq pwr. response)
small signal frequency response (varies a bit with source
impedance) should be good from
about 15 hertz to 30,000 hertz minimum.
Recommended applications:
designed to support the 45, 71A and other similar triodes. |
| Robin
Hood Series RH-60 |
$99
each |
5,000 ohm pri with 43% UL tap
8 and 16 ohm secondaries
60 madc unbal current capacity
30 henries of primary L
10 watts @ 45 hz (-3db low freq pwr. response)
small signal frequency response (varies a bit with source impedance)
should be good from about 25 hertz to 30,000 hertz minimum.
Recommended Applications:
first example from WE for 300B
plate volts 350
grid bias -76
dc plate current 50 madc
5000 ohm load impedance
6.2 watts output
second and third HD; -30db and -45db respectively
second example from WE for 300B
plate volts 400
grid bias -87
dc plate current 60 madc
5000 ohm load impedance
8.3 watts output
second and third HD; -30db and -46db respectively |
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