Does the PL400 Capacitor Upgrade Kit work in all Phase Linear 400 Amplifiers?
Yes we have options for both the earliest 4 fin heat sink versions and the later
8 heat sink fin versions.
The Phase Linear 400 series of amps used a very obscure 1.75" diameter capacitor
which are no longer in volume production making reliable, high quality
replacements very hard to find, especially at a reasonable price. This void in
market availability is what drove White Oak Audio Design to develop its popular
replacement kit based on readily available 40mm diameter snap in capacitors.
The earliest PL400s produced had
the power supply capacitors mounted directly to the left side of the amplifier chassis
using 2 round capacitor band clamps. The rectifier bridge was also mounted to
the chassis side in this amplifier vintage. The White Oak Audio Capacitor
upgrade for this version comes with a plastic ring that expands around each
capacitor and allows the 40mm diameter capacitors to mount in the original band
clamps, preserving the spacing and eliminating the need to modify the amp
chassis.
The standard version of the kit WILL install in
any PL400 that has the transformer mounted with the aluminum die cast bracket that
incorporates both the capacitor cradle and bridge rectifier mounting. This
includes the Phase Linear 400 Series II. PL400 amps with this configuration
are by far the most prevalent. An aluminum hold down plate is provided for
mounting in 8 heatsink fin amplifiers with this mounting configuration.
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Does White Oak Audio have a Capacitor Upgrade Kit that works in Phase Linear 700,
700B and 700 Series 2
Amplifiers?
Yes. We offer a direct drop in 15,000uF, 160VDC, 105C rated capacitor to
replace the original 9,800uF, 100V, 85C rated capacitor. The Phase Linear 700
series of amplifiers uses a standard 2.5" diameter x 4.125" length computer
grade capacitor size. The White Oak Audio capacitor offering improves on
the original capacitors in capacity, voltage rating and temperature rating.
It is not recommended that you replace the original
100V caps with some other offerings that are only 100V rated. Modern
capacitors do not have the voltage leeway that the capacitors produced 40+ years
ago did.
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Does the PL400 LED Light Board work in all Phase Linear 400 Amplifiers?
It works in all but the earliest PL400s (but is not applicable for the PL400 Series
II). The earliest PL400s produced used 2 fuse type incandescent bulbs above
the upper edge of each of the VU meters. The good news is that not many PL
amps were produced using this illumination method.
The later production employed 4 small 4 grain of wheat style incandescents
that installed into holes in the lower edge of the later Dixson or the less
common Honeywell VU meters. Generally
speaking, if your amp has a Phase Linear PL18 light board in it, the White Oak Kit
will work in your amp. The White Oak Audio PL400 LED Light Board Upgrade Kit WILL
NOT install in amps using the fuse style lamps above the meters. The kit WILL
install in any PL400 that has the PL18 PC board. The PL400 LED Light Board
Upgrade kit is NOT APPLICABLE for the PL400 Series II. Check the
configuration in your amp before considering your purchase.
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How do I test my VU meters to know that they are working properly?
It is easy to test your VU meters. Using a 1.5V AA cell battery and a 3.9K
ohm resistor, attach the negative side of the battery to the minus terminal of the
meter. Attach the positive side of the 1.5V battery to one side of the 3.9K
ohm resistor. Attach the other side of the 3.9K ohm resistor to the plus terminal
of the meter. If the meter is good, the needle should move to approximately
the -4 dB meter position on the meter scale.
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Can I send my amp to White Oak Audio Design to have it upgraded if I cannot perform
the upgrade myself?
Generally speaking, White Oak Audio Design is NOT in the business of installing
upgrades in Phase Linear amplifiers. White Oak Audio Design's business is designing
and marketing high quality upgrade products for installation by DIYers or by a qualified
service professional.
We do work with and rely on qualified upgrade and repair professionals to install
our upgrade products. These professionals are well versed in White Oak Audio products
and are master upgrade technicians that perform quality repairs and restorations.
- Western US Region: Lee Laatsch of Laatsch Production Services in Wyoming (contact
us if interested in getting in touch with Lee Laatsch).
- Midwest US Region: Perry Boggs in Minnesota (contact
us if interested in getting in touch with Perry Boggs).
- Eastern US Region: Mark Lucitt is a former Navy electronics technician located in
Florida (contact us if interested in getting in touch with Mark Lucitt).
- France and surrounding European Region: Atlantic Audio Vintage (contact Alain Limas
at Atlantic Audio Vintage)
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