16 Nov
2016
16 Nov
'16
6:59 p.m.
From: Mattis Lind <mattislind at gmail.com>
Subject: SPRAGUE capacitor for Tektronix 4051.
One of the DC filter capacitors has gone open circuit
in my Tektronix
4051.
It is a SPRAGUE 9600 uF - 30VDC with a little bit unusual foot print.
Check out www.cedist.com - they have a pretty good assortment of these
old-style capacitors available.
~~
Mark Moulding
16 Nov
16 Nov
8:10 p.m.
"Note the "tube audio" folks gravitate to that stuff and tend to cause
seriously sick prices, because tubes."
Ahem.. First off.. if it weren't for the large number of vintage (tube)
audio folks, these parts would most likely be even +more+ expensive than
they already are, if they were even available at all. Economy of scale
looms large over such products.
Secondly, I'd challenge you to take a fair look at the pricing of Mallory
FP-type parts from the classic era - when corrected for inflation, the
pricing of modern production is comparable with the pricing of that period.
These quality multi-section caps were never cheap items - and again,
consider the vast difference in production scale then and now, when
comparing economy.
FYI - I've installed dozens of the new-production CE / Mallory caps, all of
them in the 350-525V range. Zero complaints, zero comebacks, in as long as
I've installed them. For those of us in that field, they're like a gift
from the gods.
On Wed, Nov 16, 2016 at 8:59 PM, <mark at markesystems.com> wrote:
From: Mattis Lind <mattislind at gmail.com>
Subject: SPRAGUE capacitor for Tektronix 4051.
One of the DC filter capacitors has gone open circuit in my Tektronix 4051.
It is a SPRAGUE 9600 uF - 30VDC with a little bit
unusual foot print.
Check out www.cedist.com - they have a pretty good assortment of these
old-style capacitors available.
~~
Mark Moulding
8:44 p.m.
On 11/16/2016 10:10 PM, drlegendre . wrote:
"Note the "tube audio" folks gravitate
to that stuff and tend to cause
seriously sick prices, because tubes."
FYI - I've installed dozens of the new-production CE / Mallory caps, all of
them in the 350-525V range. Zero complaints, zero comebacks, in as long as
I've installed them. For those of us in that field, they're like a gift
from the gods.
Vintage tube audio doesn't need to get involved, except for
the old-style twist-lock Mallory cap design.
All the off-line switching supplies use either 250 V (120
supply only) or 400+ (120/240 supply) capacitors as the main
input filter. So, at least, capacitors in that voltage range
are STILL being made, and are in all computers, TVs and
other home appliances. (Yes, I know the OP needed a 30 V cap.)
So, some other tube gear replacement parts may be scarcer
than hen's teeth, but the HV caps are easily available.
Jon
9:37 p.m.
On 2016-Nov-16, at 8:44 PM, Jon Elson wrote:
On 11/16/2016 10:10 PM, drlegendre . wrote:
(tending off-topic . . )
As long as one is being careful about the size (capacitance) of the replacements.
IME, I've found limited benefit in trying to use/source/scavenge switching-supply caps
for tube gear.
The mains-side filter caps for switching supplies tend to be large in capacitance (100-200
and > uF), and typically are not suitable for replacing the ~ 8-40uF B+ filter caps in
vintage tube electronics that have tube rectifiers.
Maybe there are smaller ones in the smaller switching supplies around these days, I
haven't looked at those recently.
"Note the "tube audio" folks
gravitate to that stuff and tend to cause
seriously sick prices, because tubes."
FYI - I've installed dozens of the new-production CE / Mallory caps, all of
them in the 350-525V range. Zero complaints, zero comebacks, in as long as
I've installed them. For those of us in that field, they're like a gift
from the gods.
Vintage tube audio doesn't need to get involved, except for the old-style
twist-lock Mallory cap design.
All the off-line switching supplies use either 250 V (120 supply only) or 400+ (120/240
supply) capacitors as the main input filter. So, at least, capacitors in that voltage
range are STILL being made, and are in all computers, TVs and other home appliances.
(Yes, I know the OP needed a 30 V cap.)
So, some other tube gear replacement parts may be scarcer than hen's teeth, but the
HV caps are easily available.
11:42 p.m.
"The mains-side filter caps for switching supplies tend to be large in
capacitance (100-200 and > uF), and typically are not suitable for
replacing the ~ 8-40uF B+ filter caps in vintage tube electronics that have
tube rectifiers."
This is true.
All of the common vacuum diode rectifiers have fairly significant
limitations, for the 1st cap in a cap-input PSU.
Devices like the 5U4 and 5AR4 might tolerate as much as 40-80uF at the
first pole (which is still fairly light), while others such as 5V4 might
only tolerate as little 4uF.
Point of my post - it seems as if the tube audio folks were being blamed
and/or shamed for the cost of high-voltage electrolytics.. and if anything,
they keep both the volume and demand up, and the prices reasonable.
On Wed, Nov 16, 2016 at 11:37 PM, Brent Hilpert <hilpert at cs.ubc.ca> wrote:
On 2016-Nov-16, at 8:44 PM, Jon Elson wrote:
old-style twist-lock Mallory cap design.
On 11/16/2016 10:10 PM, drlegendre . wrote:
> "Note the "tube audio" folks gravitate to that stuff and tend to
cause
> seriously sick prices, because tubes."
>
>
> FYI - I've installed dozens of the new-production CE / Mallory caps,
all
of
> them in the 350-525V range. Zero complaints,
zero comebacks, in as long
as
I've
installed them. For those of us in that field, they're like a gift
from the gods.
Vintage tube audio doesn't need to get involved, except for the All the off-line switching supplies use either
250 V (120 supply only)
or 400+ (120/240 supply) capacitors as the main input
filter. So, at least,
capacitors in that voltage range are STILL being made, and are in all
computers, TVs and other home appliances. (Yes, I know the OP needed a 30
V cap.)
So, some other tube gear replacement parts may be scarcer than hen's
teeth,
but the HV caps are easily available.
(tending off-topic . . )
As long as one is being careful about the size (capacitance) of the
replacements.
IME, I've found limited benefit in trying to use/source/scavenge
switching-supply caps for tube gear.
The mains-side filter caps for switching supplies tend to be large in
capacitance (100-200 and > uF), and typically are not suitable for
replacing the ~ 8-40uF B+ filter caps in vintage tube electronics that have
tube rectifiers.
Maybe there are smaller ones in the smaller switching supplies around
these days, I haven't looked at those recently.
2734
days inactive
2734
days old
4 comments
4 participants
participants (4)
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drlegendre＠gmail.com -
elson＠pico-systems.com -
hilpert＠cs.ubc.ca -
mark＠markesystems.com