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    Building, troubleshooting and testing of these amplifiers should only be
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Heathkit EA-2

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A co-worker has offered selling 2 Heathkit EA-2 amps he built years ago. He believes 1 output transformer is dead. Can anyone give me some feedback on what a fair price might be for these? They are mono 12W PP EL84 w/ preamp and phono stage. Also, if the transformer is dead, is there anywhere to find a NOS or used Heathkit transfo? Is rewinding possible?

If I obtain these, I will treat them like a learning project. Probably mod them per any feedback I can get and add a pre-in. Then build a pre-amp as my first real project. Maybe a Foreplay or something similar. I've been researching to build from scratch, probably a SE EL34 like the Angela Instruments design or PP like the Eico HF-87, so these would be in lieu of that plan. These plans stemmed because I really like the Edison 60, but can't part with that much $$ right now.

My speakers are 91.5dB, so any of these options should work ok.

I appreciate any feedback.
Thanks,
Dave
 
frugal-phile™
Joined 2001
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fdegrove said:
Maybe our frugal Dave carries a spare OPT?

No Heath's thru here yet... and PP EL84 OPTs that i'd be willing to spare are limited (and prossibly better suited for making a tweeter amp, ie smallish). I do have enuff sets of 4 SE OPTs that could be used, but i suspect you could find another amp for the tariff on those.

dave
 

PRR

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> 2 Heathkit EA-2 ... what a fair price might be for these?

A set "Heathkit Integrated Amp & Tuner, SA-2 & AJ10", in tired condition, just sold on eBay for $125. The SA-2 is similar to the EA-2, but stereo. While there are reasons to go mono-block in hi-end gear, in this popular-price stuff I think a stereo box "should" be worth more than two mono boxes.

In my opinion, this series of mini-amps was good but not great. And all HeathKits are a mix of some very good parts and some cheap parts that do not stand up.

If we break-up the SA-2 and AJ10 as $60 each, $50-$60 for two EA-2s seems reasonably fair to an interested buy who can do the repairs and cleanup old closet-Heaths always need. The Heaths are a very easy chassis to work in or to modify. Manuals are available, but you hardly need them.

> believes 1 output transformer is dead.

I would bet it is not a dead audio transformer. I don't know if you need to tell him that. If it is a dead audio transformer, that would significantly reduce value: $50 to $10 depending on if you need a mono amp or think you can find a suitable replacement without killing a healthy EA-2. If the power tranny is shorted, I would not give $10 for it.

If he will let you put a meter inside: with power OFF: from plate to plate should be several hundred ohms. From 0Ω to 16Ω should be about 1 ohm (not zero ohm). From plate to ground should be over 1K after the filter caps charge (showing no short to core). This will not rule out a few shorted turns, but will rule out bigger problems. You MUST use an analog meter for this: I have never seen a cheap DVM give usable readings on a high-inductance coil like an output transformer.

You should probably be prepared to replace most of the caps. The power supply caps and some of the coupling caps may be very leaky. Even if it works in a quick demo, it may fail soon. If it runs warm, measure all the resistors and replace any that have drifted.
 
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