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Apt Holman Preamplifier Review (vintage Audio)

GWolfman

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What's the 18VDC out near the mains cable? Old version of (today's 12V) trigger?
 

Doodski

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What's the 18VDC out near the mains cable? Old version of (today's 12V) trigger?

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dasdoing

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So what was the price back then?
many times when we have the impression that old products where better it is because they were not as afordable
 

al2002

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These are very much underrated. I’ve owned one of these for donkey’s years, so it’s good to see a test The Apt power amp is excellent too and deserves to be tested.

The phono section has a very useful feature not seen on any other preamp I know of: the ability to adjust the relative levels of the two channels. The pre is set to L-R then a record is played and the gain of one channel of the phono stage is adjusted to get minimum output. This is an adjustment that every phono stage ought to have.
 

al2002

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The phono stage RIAA is non-inverting, hence the rising response at HF. Needs a tweak to the RIAA network to correct.
 

al2002

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al2002

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I was comparing the front panel Adcom to the Braun/ADS gear in post #17 not the Apt. Otherwise yes, I agree the Apt has more features. :D

Sorry, misunderstood.

Agree. I also have the ADS CC4 , CD and cassette.I‘ve always liked the styling of Braun components.
 

dasdoing

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This was (and is) a truly excellent preamp that, teamed with a Hafler amp and various input devices, constituted my stereo system for many years. Until my ex- took it to spite me in the divorce. Sigh.... :)
I too owned this preamp, with the Hafler amp, which I purchased and built in kit form. That saved me some money! I ultimately sold the Hafler when I upgraded my ADS L710 speakers to the L1590s with the PA-1 biamp module option, which neatly fit into a recess in the back of those towers.
 

Doodski

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Sorry, misunderstood.

Agree. I also have the ADS CC4 , CD and cassette.I‘ve always liked the styling of Braun components.
CC4 looks like a tidy pre. Nice and clean front panel. There are very few details and pics on the web for it and it has no blue LEDs. I like that.:D
re_braun_cc4.jpg
 

eddantes

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@amirm Why did you put the signal through the tape loop, instead of just IN>Aux 1 | OUT>Main Out 1.

Also - it would've been nice to see the effect of Tone Defeat - is it really cleaner or just nominally?
 
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Gorgonzola

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Oh my!! :D What a delight to see this vintage component review by Amir -- I'm grateful for it.

I bought an APT Holman preamp in 1978 or '79. I paid Cdn$900 for it which for me at the time was a pretty steep price: I never regretted it though. I owned for many years, selling about 10-12 years ago: the APT Holman is one of the few components that I greatly regret selling.

On the down side, it did have to have the APT repair on two occasions in the early and late '90s. The other big downside, obviously, is that it doesn't have remote control which I consider essential today.

Clearly the APT doesn't measure as well as the best avail able today. Subjectively I can't comment on the APT's sound given all my other components have changed since I last used my copy. But it is very positive to see that it's highest distortion component by far is 2nd order HD; if you're got to have distortion, this is the best kind to have.

Speaking of reviewing vintage or semi-vintage components, I love to send Amir my Sonic Frontiers Line 1 with 'SE+' upgrade but my trust of the public carriers is pretty low.

My APT Holman, (with Radio Shack knobs which I preferred) ...
 

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The design is very reminiscent of classic 1960's-and-on Dieter Rams Braun styling like the Braun/ADS Atelier series gear, although the Atelier series came out a couple years after this did.

View attachment 167088
The industrial design of the Apt/Holman preamp and power amp was done by Charles Rozier.

Charles Rozier has an undergraduate degree in engineering and an M.A. in electrical engineering from Brown University, and a master's in fine arts in industrial design from Cranbrook Academy. He later did design work for Snell, Adcom, Boston Acoustics, NAD, Hafler, and Knoll.
 
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Dmitri

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Great Review Amirm! ....And brought back lots of memories...

This was my dream preamp. I spent many an hour plotting ways to access the buy in price, but ultimately, like many dream audio purchases at the time, my fantasies were quashed by the meager funds within my wallet. I finally broke down and purchased an NAD 1020. Poor thing never stood a chance...

To my eyes, the industrial aesthetic of the Apt Holman Pre is timeless. So nice to have proof that there was substance behind that pretty face.
 

Frank Da Si

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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:

View attachment 167044

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

View attachment 167045

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:

View attachment 167047

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:
View attachment 167048

Frequency response was dead flat in audible band:
View attachment 167049

Crosstalk is better than many devices I test today:

View attachment 167050

There is essentially no frequency dependency in distortion+noise:

View attachment 167051

Output level is optimized for about 0.4 volts or so:
View attachment 167052

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):
View attachment 167053

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:


View attachment 167054

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:


View attachment 167055

And doesn't change a lot due to frequency:
View attachment 167056

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 sampl
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As always, questions, comments, recommendations, etc. are welcome. have owned this since new a have done ba refurbishment last winte. It still sinsings driving my Bryston and DCM Time Windows,

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 ?
It is actually quite good on tone controls, I like the shelving control it comes in handy on some albums.
 
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