Does the PL400 Capacitor Upgrade Kit work in all Phase Linear 400 Amplifiers?
It works in all but the earliest PL400s. The earliest PL400s produced had
the power supply capacitors mounted directly to the left side of the amplifier chassis
using 2 round capacitor brackets. The rectifier bridge was also mounted to
the chassis side in this amplifier vintage. The White Oak Audio Capacitor
upgrade WILL NOT install in amps of this vintage. 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 although due care must be taken in the series
II amplifiers because the front panel LED logic boards in this series of amplifiers
leaves very little room.
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Does White Oak Audio have a Capacitor Upgrade Kit that works in Phase Linear 700B
Amplifiers?
Not at this time. 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 35 and 40mm diameter snap
in capacitors. The Phase Linear 700B uses a much more standard capacitor size
which allows users to find quality, high reliability replacements with comparable
ease in the market in the original computer grade format. If market conditions
change, White Oak Audio Design will respond by introducing a kit to satisfy this
application.
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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 instead of the 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.
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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 Gillette WY (contact
us if interested in getting in touch with Lee Laatsch).
- Eastern US Region: Mark Lucitt is a former Navy electronics technician located in
Northern Virginia (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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