Hallicrafter's HT-41 Amp

[W9GB]

R -

Appears you asked this same quesiton over at WorldWideDX, unless that is another Rob is California asking the same question.

Appears that many of these hallicraters HT-41 and the Loudenboomer (in fair to poor condition) are very popular amplifier sales items this month.

w9gb

[WB2WIK]

I've got an old Heathkit SB-220. Now, I'll have to find an old boat anchor
transmitter and receiver to go with it. I'm afraid the Icom 706 MKii-G won't
match with it too well.

Why not? Sure it will, you just need a soft key interface which can be built for $5.

[KI6USW]

Sounds to me like this thing is screaming, "Leave me alone! Don't buy me!". I'd put my money away and save for a better amp.

I've got an old Heathkit SB-220. Now, I'll have to find an old boat anchor
transmitter and receiver to go with it. I'm afraid the Icom 706 MKii-G won't
match with it too well.

Respectfully submitted,
73,

Don/KA5LQJ

When I was a kid, I always seem to get involved in some project that I got over my head with. The net result was learning. It wasn't always pleasant and sometimes found myself in a place that I did not imagine nor expected to go. But I did remember how I got there.

I have no problems with the learning process. But it has also been tempered with the expectations and caveats from others. Since this amp is not compatible with modern rigs without a minor modification, would cost a bit to get into some ordered working condition, it may not be the best practical 'learning/solution' project. I suppose I should set my sights a bit higher; but find it hard to turn down a respectable challenge. Since the cost of that amp isn't going to allow for a cheap solution - as money doesn't grow on trees and is a prime factor - then I will have to wait for a better subject/price. If I don't find such, then in the mean time I will have saved enough to get what I need. If I find a Henry 2KD or a fair buy on a AL-80B/82 this next year; then I will go with that.

Thanks for the input and help.

[W9GB]

Since this amp is not compatible with modern rigs without a minor modification, would cost a bit to get into some ordered working condition,
it may not be the best practical 'learning/solution' project.
I suppose I should set my sights a bit higher; but find it hard to turn down a respectable challenge.

The Hallicrafters HT-41 and Loudenboomer amplifiers that I have seen advertised over the past 12 months have been in terrible shape.
They are TRUE Full Restoration Projects for someone with $$ and experience (not a first time project).
These 1950s and early 1960s tube amplifers are hitting the market --
due to the deaths or declining healths of original owners (equipment is 50 years old !!).

Sadly, many were my Elmers, mentors are friends over the past 40 years in radio.

Since the cost of that amp isn't going to allow for a cheap solution - as money doesn't grow on trees and is a prime factor

Flying solo is expensive and time-consuming learning -- in the vaccum tube and HV days -- some would pay with their life or badly shocked/burned.

[K1ZJH]

My HT-41 is going to be a starting point for a homebrew pair of 813 tubes in GG. Unit was gutted years ago, and I have
enough tubes and parts to salvage most of what is there into something useful.

I also have the RF deck and power transformer from a HT-33, that will be another project way down the road.

Pete

[KM1H]

Replacement 100 mfd @ 450 volt electrolytic capacitors are less than $3 each from Mouser. I would go to 220 mfd @ 450 volt capacitors and those are still well under $4 each.

Those are not the caps you want to use in that PS, they are OK in an old radio or transmitter but not for the ripple current of a serious HV supply. They will run hot and eventually rupture. There are several quality Snap-In caps that will do well and Id recommend the 105*C versions.

The 7094 was a big RCA mistake as they had hoped to have a 813 replacement that would have been as respected. Instead they had a short service life and were quickly discontinued.
The 813, 4-125A or 572B would all make good GG replacements. Universal or bare input boards are available as are the software programs to select values. With the 813 and 4-125A I'd lose the filter choke, switch to SS rectifiers, run about 20-25uF of total filter C and take advantage of the higher B+ for tube efficiency and meanwhile not exceeding about 800W out. The 4-125A is more efficient than the 813 above 20M or so.

Carl