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Why does my Heathkit preamp have speaker terminals?

JoshHendi

JoshHendi

^ElectroNerd^
Subscriber
So I've had a Heathkit AP-1800 for a while now and have very much enjoyed it. However finding the manuals for the AP-1800, AA-1600 and AJ-1600 has been a daunting task, and am about ready to buy one for $35 from the only source I've found.

But to the question, why does this dedicated preamp have speaker terminals? If I didn't know any better (and really I don't) I'd think this AP-1800 looks like an integrated...

Any ideas? I haven't tried or tested them yet, like being cautious with the unknown. Note: this is not my picture, but is the same as mine.

702254-very_rare_heathkit_ap1800_needs_work.jpg
 
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I believe it's like some of the SAE preamps I've seen. You route the amplifier speaker output into the pre-amp (see the screws below the speaker binding posts) with the speakers wired to the binding posts. That way the preamp controls the switching between a/b sets.
 
It's supposed to get the signal back from the amp, that's why you have an input below the terminals under the speaker binding posts of the preamp. Apparently the amp used with this normally does not have speaker terminals?
 
One of my Marantz preamps has the speaker switching built in as well. I have a Sony power amp that has the speaker switching built in, nice feature.
 
The idea of running speaker connections through the preamp allows for having control without having to access any controls on the power amp. Then the power amp can be located somewhere other than prime shelf space.
 
Pretty cool feature.

I had the momentary mental image of a guy slumped in a beanbag chair with big Koss cans on reaching over to the Heathkit on a cinderblock & pine board set of shelves.
 
This is a good idea, particularly if you have a couple of huge mono-block tube amps that you can put in an unconditioned space instead of the living room.
 
fred soop said:
The idea of running speaker connections through the preamp allows for having control without having to access any controls on the power amp. Then the power amp can be located somewhere other than prime shelf space.
Click to expand...

Agreed, this was a feature hold-over from the 60sand 70s where many high end audio systems were permanently installed in custom cabinetry. With this arrangement, the preamps became the control center and the power amps were tucked away out of sight.

McIntosh, for instance, sold their power amps in 2 forms - one intended for internal cabinet mounting and a version for mounting in view. The internal versions had no speaker switching or headphone connections, which were provided on their preamps.

Harman-Kardon's Citation series preamps of the 70s also provided speaker/headphone switching features.

Cheers,

David
 
Also useful when buying on Ebay when seller states no output. Bought my Van Alstine modified Pat-5 cheaply because of no output, works perfectly.
 
Versatility was a major feature for preamps back in the day, routing speaker lines back thru the control center unit added more of it via front panel switching. Some like me saw it as an expression of exuberant signal path clutter that did sound quality no favors, and made trouble shooting a malfunctioning system more difficult.

Sent from my SM-N900V using Tapatalk
 
HK had the same setup in the 11 and 12 series. Allowed for speaker switching and use of the headphone jack. Nice feature but with the HK you needed a proprietary cable.
 
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