Home |
Search |
Today's Posts |
#1
|
|||
|
|||
Old amp reconditioning and mods questions
I got a Hoffman Stereo Hi-Fi console at the Goodwill because it had a tube
amp in it and I wanted to pirate the amp for a fun project. Well I pulled it out of the console and fired it up and it hummed badly. It has two multi part can style caps on the chassis. I found caps at the local supply house and wired them in below the chassis to the terminals on the original caps. The amp sounds fine now but I figured I'd ask if there are any issues with not having removed the original caps from the circuit? I hooked the caps up with what I think is about 18ga speaker wire, with the copper conductor on one side and silver conductor on the other. This shouldn't cause any issues should it? How hot might one expect the power transformer to get? I can touch it but it's hot enough you don't want to hold you finger on it long. My guess is around 110 - 120 degrees. I have seen reference to adding a modern power socket like a computer would use and using the 3 prong grounded cord, grounding the chassis to help reduce hum or noise. Is this usually OK or might I somehow get myself into trouble doing this? I want to make a wooden enclosure for this with a metal screen top or something like that. It seems that 17" is about the width of most components? Reading the comments along with new tubes it looks like JJ/tesla might be the winner of not being the cheapest or the most expensive, just inexpensive yet good sound. I would need 2 x 12AX7 and 2 x 6BQ5. Should these work well or might I consider others? The amp has a switch for off, stereo 1, stereo 2, mono 1, and mono 2. There are only one set of speaker outputs. Is this maybe a setting for 4 ohm and 8 ohm? I think the volume goes up a bit in the 1 positions. Are there voltages I should be checking or stuff like that? There is a little pot on the back marked HUM what should I do with this adjustment? Well it's late and I am sure there may be more questions but that's all I can think of for now. More than enough for one post anyways. TIA, Bryan |