Doug G.
Lunatic Member
OK, my quad system has all Heathkit -29 amplifiers, one in the form of the AR-29 receiver to use the tuner.
These all originally used #44 lamps for illumination and pilot lamps. The AA-29s use just one for the pilot but the AR-29 uses 5 for dial and meter illumination. I also have an AJ-29 tuner with the same complement.
Back when these were new, #44 lamps were different than they are now. The metal base was shorter and the glass bulb longer. The filament was positioned farther away from the base. These differences don't make any difference in the pilot lamp illumination because it's just a single jewel with a lamp behind it.
The Dial is a different story, however. The original style #44s lit it very evenly and you couldn't see any darker spots along the dial, the area being completely and evenly lit. The newer style #44s are OK but with the filament closer to the rear, the dispersion of the light was not as wide and there were slightly darker spots where the light from one lamp didn't quite fully overlap the next.
That's not the worst, however. The older #44s lasted a very long time, several years. The newer ones I have been using last a year AT MOST with most of them burning out in a matter of months. The worst lasted only a couple of weeks.
Replacing the dial lamps isn't too big a deal Just remove the four screws holding the wood case to the chassis and remove a bulb from its holder and replace. The pilot lamps in the amplifier are a bearcat. The front panel must be removed and the bottom plate needs to be slid back - it's a real pain.
It still sucks having to replace any of the lamps so often, however.
So, I got some bright white LEDs from Radio Shack and made replacements for the single pilot lamps. They look just like the orginals.
For the dial lamps, since they need to have a fairly wide dispersion of light, I took a chance and got some ready-made concave style lamps from Titan although I was leery of them not completely filling the dial area without dark spots. They were only about 5 bucks for a pack of 10 so I thought what the heck, take a chance. They came today and, when I put the first one in the holder, it sure seemed like a different color than the incandescent versions but when it was installed, I couldn't tell where I had put it in comparison wih the #44s still there. After replacing them all, it looks terrific. Just like original and the dial area is all evenly lit. Maybe not quite as well as with the original #44 lamps but real close and a lot better than the later #44 lamps. It used to be very obvious when looking at the dial from a side angle but now it looks fine. Much less heat too. Actually, almost none.
I wanted to keep these units all original but the poor quality of modern incandescent lamps threw me to the LED route.
Oh yeah, a veil has been lifted. PRaT in spades.
Doug
These all originally used #44 lamps for illumination and pilot lamps. The AA-29s use just one for the pilot but the AR-29 uses 5 for dial and meter illumination. I also have an AJ-29 tuner with the same complement.
Back when these were new, #44 lamps were different than they are now. The metal base was shorter and the glass bulb longer. The filament was positioned farther away from the base. These differences don't make any difference in the pilot lamp illumination because it's just a single jewel with a lamp behind it.
The Dial is a different story, however. The original style #44s lit it very evenly and you couldn't see any darker spots along the dial, the area being completely and evenly lit. The newer style #44s are OK but with the filament closer to the rear, the dispersion of the light was not as wide and there were slightly darker spots where the light from one lamp didn't quite fully overlap the next.
That's not the worst, however. The older #44s lasted a very long time, several years. The newer ones I have been using last a year AT MOST with most of them burning out in a matter of months. The worst lasted only a couple of weeks.
Replacing the dial lamps isn't too big a deal Just remove the four screws holding the wood case to the chassis and remove a bulb from its holder and replace. The pilot lamps in the amplifier are a bearcat. The front panel must be removed and the bottom plate needs to be slid back - it's a real pain.
It still sucks having to replace any of the lamps so often, however.
So, I got some bright white LEDs from Radio Shack and made replacements for the single pilot lamps. They look just like the orginals.
For the dial lamps, since they need to have a fairly wide dispersion of light, I took a chance and got some ready-made concave style lamps from Titan although I was leery of them not completely filling the dial area without dark spots. They were only about 5 bucks for a pack of 10 so I thought what the heck, take a chance. They came today and, when I put the first one in the holder, it sure seemed like a different color than the incandescent versions but when it was installed, I couldn't tell where I had put it in comparison wih the #44s still there. After replacing them all, it looks terrific. Just like original and the dial area is all evenly lit. Maybe not quite as well as with the original #44 lamps but real close and a lot better than the later #44 lamps. It used to be very obvious when looking at the dial from a side angle but now it looks fine. Much less heat too. Actually, almost none.
I wanted to keep these units all original but the poor quality of modern incandescent lamps threw me to the LED route.
Oh yeah, a veil has been lifted. PRaT in spades.
Doug
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