Glen Zook wrote:
> One thing is with the circuitry of the HT-33A. Some of the later units
> actually had HT-33B circuitry. The HT-33A that I obtained a few months ago
> is definitely marked as an HT-33A. However, it came from the factory with
> the additional VR tubes and circuitry of the H-33B.
>
Surprising is all of the HT-33As I've seen had the holes punched for the
additional VR tubes, but no tubes.
The entire amp is easy to recondition unless it has corrosion on the
chassis. There really is no such thing as a proper paint color as they
came from the factory in a number of shades. I purchased some custom
mixed paint, but Gray gloss and black satin in shades that match the
cabinet or other Hallicrafters equipment you may have such as an HT-32,
and SX-101
The cabinets are very easy to recondition to look like new unless
physically damaged. They are easy to clean and strip "if necessary". A
couple of light coats are all that are necessary, but it does take a
little painting skill and surface preparation.
The PS is built on an Aluminum sub chassis which is 1/8" SOFT aluminum
that has been Alodined which is a Chromate conversion process that can
just be wiped on after prep. (wear good rubber gloves and do the process
in a plastic container.) Even though it's a standard layout and there
aren't all that many, take photos and remove all parts (that choke and
transformer are HEAVY) The inner framework is thinner and of a harder
alloy but it too is Alodined and easy to refinish. The key to
discovering if one has been dropped: Look at the transformer and choke
mounting ears to make sure they are straight and not bent. The power
supply chassis should be flat, not bowed as it will be if dropped. Check
the back corners of the inner Aluminum frame. there will be a notch cut
into it from the corner brace in the back of the cabinet that lines up
with the cabinet hinge. Even those are *relatively* easy to repair with
a few basic metal working tools and can be alodined again so the fix
doesn't even show.
As I've mentioned before, the common most problem is the thing being
dropped by well meaning helpers. At 113 to 120# it is a bit heavy for a
table top unit. Some have handles in the case, but most I've seen do not.
Pulls and used tubes are not normally very expensive, but as I've said
before, the PL-172/8295As with the glass to metal seal tend to get gassy
if not used while the straight 8295A which is ceramic and metal don't
normally. OTOH Checked and tested PL172/8295As are a tad pricey. OTOH
they aren't bad compared to new 4CX1500s or 8877s. However "Tested"
8295 are expensive at roughly twice the price of the PL-172/8295A.
I've seen tested with a guarantee running over $1200 to $2400
respectively. Just hypotted and resistance checked are a fraction of
that being in the $50 to $100 range. OTOH you do see the occasional one
the seller must think is made of solid gold even without the testing.
If you want to keep it original and use it a good tube is worth the
price when compared to other amps running the legal limit with external
anode tubes. Surprisingly I have no problem running an honest 1.5 KW PEP
out and staying within the ratings of the tubes. I'd not want to do that
with RTTY or other data modes. That and running the thing a bit easier
is likely to give you an amp that is still original that lasts a
lifetime. Just remember to tune it up like a tetrode and not a triode.
Those tubes are big compared to an 8877. I'd guess about 50% larger. The
cooling fins are coarse with lots of space meaning the tube requires
little back pressure so even with the fan on high it's quiet. If you
want to convert to a more modern/available tube I'd pick a Tetrode like
the 4CX1500B although the socket is a bit expensive. However conversions
may not be all that simple. Going to an 8877 would require a different
cooling configuration as the physically smaller tube requires a lot more
air.
The main drawbacks are good tubes may take a while to find and the
transformer which is 110 VAC input only. So you need a short run of
heavy wire for the AC main.
> Glen, K9STH
>
> Website: http://k9sth.com
>
>
> --- On Fri, 7/24/09, Colin Lamb <k7fm@teleport.com> wrote:
>
> I think the comment was directed at condition. A higher price for those that
> look pretty. Same thing with cars. A driver is much less than a looker.
>
> Also, as I recall, the HT-33 uses a nice oil filled cap that should be good
> for a few hundred more years.
>
>
>
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