My "new" Apt 1 amplifier, Quality in unit and operator's manual

The Apt 1 power amp was delivered yesterday, and I had it installed in my main system and running within an hour. Very nice sounding amp, with an intelligent operator control scheme - no operator controls.

The amp, manufactured in Cambridge Massachusetts in the early '80s, came with a 32 page operator's manual (in English only - for a device with no operator controls, mind you) of considerable thoroughness, in language appropriate for comprehension by a reasonably intelligent reader, and laid out so that the reader is not apt to miss the important stuff, yet has the 'details' readily available. The lefthand 2/3rds of the typical page contains the 'important stuff'; the righthand 1/3rd has, in slightly smaller print, the informative details. I'll scan a page and see if I can get a file attachment to work.

As you may have noticed, I am as impressed with the manual as I am with the amp. I used to write manuals for a living, and this one is better than anything I ever did. That said, the amp is a fine one.

Bob

This post has been edited by Hilltroll on June 06, 2007 08:43 am

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cool feature, or lack thereof. got any pic's of the amp itself?

Very cool.

I lived about a 5 minute bike ride (maybe less) to the border of Cambridge 'till just a few years ago. I love that city.

cool feature, or lack thereof. got any pic's of the amp itself?

Here it is (maybe).

Of course there are operator controls - on the back face. I large 2-position toggle switch for selecting speaker impedance, and a small pushbutton for switching between stereo and bridged mono modes.

The amp is rated at >100 watts per channel RMS in 4 or 8 ohm loads, >150 watts in 2 ohm loads, and >75 watts in 16 ohm loads, with <0.03% THD in 8 to 16 ohm loads and <0.05% THD for 4 ohm loads. There's another full page of specs (like I say, the manual is thorough).

Bob

pic here?

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I like it. No-nonsense!

me too, i prefer minimal interaction with my gear.

Me likes.

I had never heard of the brand. probably for the US market only?

Jorge

You doesn't post the pic below , but could you please tell us what's that rear panel switch for..?

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That's the switch for "load impedance adjustment". The up position is labeled
Stereo 8 - 16
Mono 16 - 32

The down position is labeled
Stereo 2 - 4
Mono 4 - 8

The action of the LEDs on the front panel tells you when you need to change the setting. The manual says about this switch:

"This switch optimizes conditions in the power supply of the amplifier so that it may deliver an unusual amount of headroom in 8-ohm loads and high continuous power ratings into lower impedance loads." There is considerably more info on the subject, but that's the basics.

Bob

Gee, sounds good to me...
Tanx.

What do you do if you live in apartment #3?

cubdog

I don't know the company history. I suspect that they were a small outfit that didn't get out of the 'start-up' category far enough to go international.

Bob

The amp was an "apt/holman" amp, and a fairly decent, and not too expensive mid to hi-end product, sort of a precursor to Adcom and Hafler equipment. There was a matching preamp, with tiny, rather hard to use controls, about the same size as the amp.

I had this amp and used it in the bridged mode to drive a Dahlquist DQ-1W and it did a pretty good job, but when the amp self-destructed one day (I have no idea why), I replaced it with the Rotel RX-980B amp which all but blew away the apt/holman.

In stereo use, the apt/holman did a fair job of driving Dahlquist DQ-10's at modest levels, but struggled and clipped whenver driven hard. Fortunately, it had lights to indicate danger levels, and I backed off on the volume of my preamp so as not to cause any damage.

I also had a QED amplifier, made only a short while by former ESS engineers (Carver too was a former ESS engineer!) that was considered by many to be a rather good amp by all those acquainted with it. I can accurately state that switching from either the QED to the apt/holman, either to drive the DQ-10's, or the DQ-1W sub rarely resulted in any audible differences.

At least the apt/holman outlasted the QED, and, best of all, it was FREE.

The holman designation was applied to the preamp, but not to the power amp. The Holman guy designed and patented phono preamp circuitry which was then licensed to several outfits, including apt.

Thanks for the interesting data about your amp. I have so far had mine connected to a pair of fairly efficient and 'easy-to-drive' DIY speakers which, probably because I built them, are the best sounding speakers I own - I think. When I get a remodeling project done on my AR94Sx speakers (replacing that sock with painted sides and back, and making grilles for the front) I will hook them up. They are reputed to be a tough load to drive. Being a classical music listener with a fairly small living room, the apt amp may still not be stressed; not enough big bass to cause the reading lamp to dim.




Bob