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Apt Holman Preamplifier Review (vintage Audio)

amirm

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This is a review and detailed measurements of the Apt Holman vintage preamplifier. It is on kind loan from a member and has been refurbished by QuirkAudio.

The look is a cross between hifi and pro gear:

Apt Holman Preamplifier Review Phono  Vintage Stereo.jpg


Other than some scratches on top, the unit is a very good cosmetic shape. Rear connections are extensive:

Apt Holman Preamplifier Review back panel Phono  Vintage Stereo.jpg


Yes, there was a time we had outlets in the back of stereos. The more there was, the higher end the gear was said to be! Wonder what led to their demise.

In case you are wondering as I did when I was first contacted about this unit, Holman is Tomlinson Holman or the T in THX (now works for Apple). Owner sent me the service manual which is not only extensive but has excellent tutorials on the design, instruments to test it with, and pages and pages of detail. It is incredible what used to be available compared to now.

Apt Holman Measurements
Let's start with our dashboard input. I selected Tape 1 as input but oddly front panel selector doesn't have Tape 1. I set it to Aux 1 and then pushed Tape 1 switch:

Apt Holman Preamplifier Measurements Vintage Stereo.png


Wow, this is excellent! I expected SINAD in 60s or 70s and here we have 90 dB. It is dominated by second harmonic at that level. Even more impressive is the signal to noise ratio with same unity gain:
Apt Holman Preamplifier Measurements SNR Vintage Stereo.png


Frequency response was dead flat in audible band:
Apt Holman Preamplifier Measurements Frequency Response  Vintage Stereo.png


Crosstalk is better than many devices I test today:

Apt Holman Preamplifier Measurements Crosstalk  Vintage Stereo.png


There is essentially no frequency dependency in distortion+noise:

Apt Holman Preamplifier Measurements THD+N vs Frequency Vintage Stereo.png


Output level is optimized for about 0.4 volts or so:
Apt Holman Preamplifier Measurements IMD Vintage Stereo.png


So you may want to pair it with a power amplifier that puts out most of its power at the above level.

Apt Holman Preamplifier Phono Stage Measurements
I adjusted the volume control to give a nominal 40 dB level (higher than preamp tests):
Apt Holman Preamplifier Measurements Phono input Vintage Stereo.png


While I like to see no visible distortion spikes in this test, its level at -100 dB is still very good. SINAD is set by the slight amount of mains noise which I could not get rid of with various grounding methods (typical).

RIAA equalization is very good but there seems to be a high frequency resonance that causes error above 10 kHz:


Apt Holman Preamplifier Measurements Phono input frequency response Vintage Stereo.png


I did not look to see if there is an adjustment/compensation for this in the service manual.

Be sure to use the balance control to restore equal level in both channels.

Level of headroom is good:


Apt Holman Preamplifier Measurements Phono input THD+N vs Level Vintage Stereo.png


And doesn't change a lot due to frequency:
Apt Holman Preamplifier Measurements Phono input THD+N vs Level vs Frequency Vintage Stereo.png


Conclusions
The owner who sent me this has a knack for finding these past jewels with excellent engineering. Their performance post refurbishing is extreme good even by today's standard which sadly has sled backward. Hopefully no one sheds a tear next time I complain about an audio product producing SINAD of 70 dB and such which this level of performance was achieved years ago.

I am happy to recommend the Apt Holman preamplifier. I see one on ebay for $550 although it will likely need thorough service like the sample I tested.


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As always, questions, comments, recommendations, etc. are welcome.

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Mnyb

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Nice , this is good for geting a perspective over time .

But what year was this preamp manufactured ? And when was the design work done ?
 

Mnyb

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And it’s fully functional it has the expected features :) not like “audiophile” preamps that came later.

That said how is the performance with tone controls in circuit ?
 

charleski

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Yes, there was a time we had outlets in the back of stereos. The more there was, the higher end the gear was said to be! Wonder what led to their demise.
My first guess would be electrical safety regulations.
 

Mnyb

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APT Corporation Holman​

Stereo Pre Amplifier (1978-79)

1979 this thing exceeds the performance of any consumer media aviable at the time ?
And loudspeakers of that era how good where they.
At the time this would have been “transparent” to the end user . And probably still is today in most cases
 

Rja4000

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The volume knob on the left is unusual.
But the Tape selection is what you find on all those.
 

Doodski

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And loudspeakers of that era how good where they.
Hit and miss. There where North American made speakers and Euro too and such that where pretty good. Some even sound decent today. But the Japanese speakers generally cranked pretty loud and thumped well but the top end was usually lacking.

EDIT: Here is a very popular Kenwood speaker of the time. Expensive and often peeps bought 4 of them.
Kenwood_KL-777_Stereo_Speakers_web.jpg

Another perhaps a bit higher model.
8ec344c9c670c61b663e5d8dce1db18f.jpg

Cerwin Vega was popular then too.
9SrCIEY.jpeg

Vintage-1978-Pair-Cerwin-Vega-S1-Loud-Speakers.jpg

REFERENCE SERIES MODEL 105 (1977-79) These KEF 105 and 5.2 are nice speakers even today.
First-References22.jpg

gkuA_-tDtgbgXVK0_bJFM1e4Gk1xNt8ko11YeJiCRM2U8swWWHdvMJuyX5BoMLibEaz7CLV6pPbJa6yf4T0Fe2aGfi0SWecMwqOHXSXhNyO9qqQU7jJyS3shPbsiTjbMR830
 
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EJ3

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This is one of two of my APT/Holman Preamps. Normally it only has a DUAL 1229 in it's Phono input and puts out into the AUX 2 of my other APT/Holman Preamp. That one has my Technics SL-M3 in it's phono 1, my oppo 205 UDP in it's AUX 1 and various rotating things in other inputs. The Pre Out goes through a HARRISON LABS passive crossover 80 Hz & down goes to a NAD 2200 (see AMIRM's review of this one here) running stereo 2 ohms into a pair of Large Radio Shack ported sub woofer cabs using a custom setup of dual 4 ohm voice coil 12 inch automotive Pioneers with a FR of 20Hz-80Hz (set up as 2 ohm) and above 80 Hz goes into a pair of NAD 2200's running bridged mono into a pair of Dahlquist M-905's (these have measured +-2 Db from 26 Hz-20 KHz with their original spec [but new modern caps] passive crossovers on their original stands). It's mostly vintage but sounds quite good. I use a NAD 4300 tuner (I get quite good FM for about 75 miles from my 3rd story high attic antenna). Yes, there are a few stations that actually are still producing very close to CD quality sound. This is all gear that I have collected over the years, a hodgepodge of good stuff. To my ears, anyway.
 
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Dennis_FL

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The more there was, the higher end the gear was said to be! Wonder what led to their demise.
Just wondering the same myself last week. I had thought it might be audio interference reduction but probably simple cost reduction in the era of Jack Welch.
 

Grotti

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Hit and miss. There where North American made speakers and Euro too and such that where pretty good. Some even sound decent today. But the Japanese speakers generally cranked pretty loud and thumped well but the top end was usually lacking.

EDIT: Here is a very popular Kenwood speaker of the time. Expensive and often peeps bought 4 of them.
Kenwood_KL-777_Stereo_Speakers_web.jpg

Another perhaps a bit higher model.
8ec344c9c670c61b663e5d8dce1db18f.jpg

Cerwin Vega was popular then too.
9SrCIEY.jpeg

Vintage-1978-Pair-Cerwin-Vega-S1-Loud-Speakers.jpg

REFERENCE SERIES MODEL 105 (1977-79) These KEF 105 and 5.2 are nice speakers even today.
First-References22.jpg

gkuA_-tDtgbgXVK0_bJFM1e4Gk1xNt8ko11YeJiCRM2U8swWWHdvMJuyX5BoMLibEaz7CLV6pPbJa6yf4T0Fe2aGfi0SWecMwqOHXSXhNyO9qqQU7jJyS3shPbsiTjbMR830
That brings back memories.... *sigh*.
 

EJ3

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This is a review and detailed measurements of the Apt Holman vintage preamplifier. It is on kind loan from a member and has been refurbished by QuirkAudio.
Rear connections are extensive:

View attachment 167045
As the owner of this I want to mention the Load Capacitive/Resistance Cartridge Termination selection that is on the right of the rear. At the time (and it is still available through some channels, if you need one for one of these, PM me [I do not have them but can put you in touch with someone who had some & can do this the last time I talked to him]) there were available MC cartridge circuits for phono 2 that are customized per order for your particular MC cartridges output. These also had Rack Mount face plates available (which can still be obtained). In fact, this unit had one but I changed it to the household style faceplate.
 
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