Apt Holman Preamplifier Review (vintage Audio)

[EJ3]

No, identical:
View attachment 303023
Tape-out has buffers, you might be able to measure a tiny difference on those. Not likely to be audible. And it is a tape-out so not many devices inserted there will suffer the added noise of the buffers!

Don't forget that you also have an external processor loop! With both inputs & outputs.

 

[MAB]

Don't forget that you also have an external processor loop! With both inputs & outputs.

Thanks for pointing that out! And the processor loop isn't buffered like the tape-out loop. I had a MiniDSP inserted in the processor loop for a while, talk about gear that is still useful!

I also have an Apt Holman (third one, one was given to my brother...) Also restored by Peter at Quirk audio.

 

[EJ3]

I have a pair, both done by Peter @ Quirk Audio and, sometime in the first quarter of 24 I am going to (in conjunction with the SCHIIT SYN) do this:
Quadraphonic Synthesis

With two Holman Preamplifiers, you can synthesis and control four output channels from just two input channels.

Apply all your inputs to the first Holman Preamplifier. Use it for all your tone controls, filters and source and tape selections. Leave its Stereo Mode in Stereo.

Connect the first Holman Preamplifier's MAIN 1 output to one power amplifier and your two front speakers.

Connect the first Holman Preamplifier's MAIN 2 output to any line-level input of the second Holman Preamplifier.

Connect the second Holman Preamplifier's MAIN 1 output to the power amplifier for your two rear speakers.

Rotate the second Holman Preamplifier's stereo mode control to L-R, and start by setting it to about unity gain or a bit less, and keep its tone controls flat. The tone and filter settings of the first Holman Preamplifier are fed automatically to the second Holman Preamplifier.

Set balance on the first preamp. Set front-rear balance on the Volume control of the second preamp.

Leave the power switch of the second preamp ON, and plug its power cord into a switched outlet of the first Holman Preamplifier. Now the power is controlled by the first Holman Preamplifier, too.

 

[pseudoid]

Audiology eval 2 weeks ago are normal for age, 15-20 dBa up to about 8kHz then it’s 40-60 above that. My wife - whose voice is higher-pitched which is typical of females - says I don’t listen to her… or something.

I do not wish to make light of your calamity but your words should be remembered by all husbands; when being accused of "men-not-listen-to-women" accusation.
It may also help motivate all of us to get an audio eval... to objectively debunk that trope.

 

[drfous]

Thanks for pointing that out! And the processor loop isn't buffered like the tape-out loop. I had a MiniDSP inserted in the processor loop for a while, talk about gear that is still useful!

I also have an Apt Holman (third one, one was given to my brother...) Also restored by Peter at Quirk audio.

What does "restored" entail? Recap + ?

thx

 

[MAB]

What does "restored" entail? Recap + ?

thx

Relay replacement (it’s a weak link).
Controls needed cleaning.
And some additional mods.

Peter Williams at Quirk Audio can provide details.

 

[NormB]

What does "restored" entail? Recap + ?

thx

A little more detail as I contacted Peter a few weeks ago, he sent me the following:

Hi Norm
thanks for reaching out.

Currently turn around time is about 3 weeks or so.
I offer a full upgrade for the APT preamp for a fixed price of $475 including all parts and a 12 month warranty, but excludes shipping and paypal fee of 3%.

The upgrade involves the following:
Power supply- new bridge rectifier, new regulator IC's and new and uprated power supply capacitors- Some earlier models have a transformer that is known to fail, if this is the case I install a new uprated transformer for an additional $75.

Phono section- replace all electrolytics with new and uprated electrolytic capacitors, replace certain ceramic caps with film types, change mylar caps for polypropylene.

Main preamp section: replace all electrolytic caps with appropriate low impedance or bipolar caps,some of which are uprated, add additional decoupling caps in certain circuit locations,replace certain ceramics with film caps, replace some mylar caps with polypropylene film caps, replace all IC's with modern audio specific types. This includes the tone control section and headphone section.

Relay section: replace relay with new modern version, replace all electrolytic caps, some with film types.

All controls are deoxed and cleaned, the preamp is then tested.

Sonically there is a significant improvement from the reduction in the noise floor, giving better transparency and detail, with improved dynamics, with an excellent sound stage- overall making the unit sound excellent. I use my own APT preamp as my "lab" reference. Once upgraded these units measure very well.
I am based in Belmont, CA.

Please feel free to call if you would like to discuss
Best Regards
Peter
www.quirkaudio.com

————
I sent mine out about ten days ago, got a note from him that he received it, had it on the bench.

Two days later he sent pictures of a crude but effective bypass someone installed in lieu of s relay (which he planned on replacing anyway).

Having rebuilt a double handful of Acoustic Control Corp guitar and bass amps, Revox RtR decks, ADCOM preamps (400-something, 500, 555 I/II, 565 - two of them - and several amps (535-2, 545-2, 555-2) I have a good idea how much time and effort goes into recapping, matching transistors, troubleshooting and decided while I’m comfortable doing this kind of work, for once I’d pay a pro. Spend more time with my wife and dog.

Speaking of pros. I called Audioproz, waited about 9 days for a return call, deciding to go with Quirk Audio as Peter was easy to speak with, was responsive to my questions and just seemed like a nice guy.

Audioproz left a message on voicemail.

Customer service industry tip- when you leave messages for potential customers don’t inject politics in the first 25 words blaming supply chain issues on the other guy or whatever.

I don’t know Peter’s politics, I prefer it that way.

 

[TXinD76121]

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

It appears Adcom maybe copied the Braun/ADS stuff.

Your Adcom had the same industrial designer as the Apt Holman, Charles Rozier. He did the industrial design of a lot of '70s-'80s hifi gear. The charge of "copying" is pretty harsh, unless you have evidence for it. People tend to like the style of the moment, in many things, and most designers try to make their work look contemporary. Same with music, where everyone likes to sound with-it and "now" and lots of stuff ends up sounding pretty similar (and, later, dated).

 

[NormB]

Box, knobs, display, not a whole lot of ways of putting them together.

 

[pseudoid]

Box, knobs, display, not a whole lot of ways of putting them together.

OT: Perfect timing, @NormB ...a buddy just texted me he got a new car: I sent him your image, with this text:

Lemme guess it is one of these and I would guess probably an Audi

10Q

 

[EJ3]

Box, knobs, display, not a whole lot of ways of putting them together.

Crawford Performance Subaru CrossTreK (a slightly different path)

 

[Kimbrough Xu]

The tested unit here was one of my 2. I have used all of the inputs (except for the Tuner one & the phono ones) for all sorts of gear, they sound the same, so I presume that there are not any differences. Reel to Reels, Cassette decks, CD, VCR, DVD, Blu-ray, 4K equipment, all sound the same. If the input is being fed with the same signal power. If the power is higher or lower, you will have to adjust the volume. For more details, see either the owners manual (many sites have this) or this in depth revue of an unrepaired one: https://www.kenrockwell.com/audio/apt/holman-preamplifier.htm or you may text me at 1 843 789 9595.
I hope that this helps, if not, text me and I will try to answer your questions. EJ3

So they are just named with different names, but they are the same RCA inputs.

 

[Kimbrough Xu]

No, identical:
View attachment 303023
Tape-out has buffers, you might be able to measure a tiny difference on those. Not likely to be audible. And it is a tape-out so not many devices inserted there will suffer the added noise of the buffers!

Thank you, thats pretty clear.

 

[NormB]

Well… got my preamp back two days ago - one day faster than expected.

I took a peek inside as I took off the bottom panel to replace the electric power cord (a bit of fanaticism on my part, I use thicker gauge rubber small appliance - coffee pot, waffle iron - cords on most of my gear and cut them to 36 inches) and the number of MUSE capacitors inside took me by surprise. The total number of caps replaced was… a LOT. Nichicon, Nichicon, Nichicon… one of the reasons I decided to just pay a professional to do the upgrades.

Those MUSE caps are getting harder to find - I just replaced a pair of bipolar coupling caps in a Technics ST-9038 FM tuner (adding decoupling caps on the power pins and replacing the output opamp with… BB OPA2134) - as they’ve reached “end of life status” at Mouser dot com and elsewhere. As have, apparently, Nichicon UFG’s, UKA’s of many values.

Many other changes to the APT as well. Better OPAMPS (pretty sure there was an OPA2134 in there), opamp sockets, some engineering kludge hardwire replaced with the correct relay.

I’m waiting for some silicone rubber feet from amazon to arrive and hope to have it plugged in to my rack this evening and look forward to not hearing it at all.

Then I expect to have a recapped/opamp rolled ADCOM 565 up for sale on ePay by the end of the week.

Peter at QuirkAudio beat his estimate by about half (3-4 weeks was closer to 2) and has assured me I won’t hear the preamp.

I liked how transparent it “sounded” from the start, I’m guessing it’ll be invisible now.

I’ll keep you (in suspense) posted.

 

[EJ3]

Well… got my preamp back two days ago - one day faster than expected.

I took a peek inside as I took off the bottom panel to replace the electric power cord (a bit of fanaticism on my part, I use thicker gauge rubber small appliance - coffee pot, waffle iron - cords on most of my gear and cut them to 36 inches) and the number of MUSE capacitors inside took me by surprise. The total number of caps replaced was… a LOT. Nichicon, Nichicon, Nichicon… one of the reasons I decided to just pay a professional to do the upgrades.

Those MUSE caps are getting harder to find - I just replaced a pair of bipolar coupling caps in a Technics ST-9038 FM tuner (adding decoupling caps on the power pins and replacing the output opamp with… BB OPA2134) - as they’ve reached “end of life status” at Mouser dot com and elsewhere. As have, apparently, Nichicon UFG’s, UKA’s of many values.

Many other changes to the APT as well. Better OPAMPS (pretty sure there was an OPA2134 in there), opamp sockets, some engineering kludge hardwire replaced with the correct relay.

I’m waiting for some silicone rubber feet from amazon to arrive and hope to have it plugged in to my rack this evening and look forward to not hearing it at all.

Then I expect to have a recapped/opamp rolled ADCOM 565 up for sale on ePay by the end of the week.

Peter at QuirkAudio beat his estimate by about half (3-4 weeks was closer to 2) and has assured me I won’t hear the preamp.

I liked how transparent it “sounded” from the start, I’m guessing it’ll be invisible now.

I’ll keep you (in suspense) posted.

I am very happy with both of my APT/Holman Preamplifiers (including the one tested here) that have been through Peter's hands (including the one that was tested here) as well as my 3 NAD's that have been through Peter's hands (including the one that was tested here [which, if you read the review, you will find that it did 95 SINAD through the LAB inputs {it was slightly less through the regular inputs]}), as well as my ADVENT 300 receiver (which was also tested here).

 

[DSJR]

Not sure we ever got any (many) of these preamps as by the late 70's, Naim's band limited and three input (only) was on the rise and every young audio 'expert' in the UK stores went with that approach. Our 'west end' store certainly knew of the Apt preamp but apart from the generally not-so-good Rappaport, the look to the US gradually petered out until the Threshold Stasis amps began to be imported (McIntosh was another 'known' brand but not popular amongst the UK audiophile 'tribe')

Got to say I worry about the high cost of surviving used ones followed by another huge cost in getting them serviced and restored to as near or better original spec. I suppose really now for several hundred quid in the UK, best to wait until the new Schiit preamp finds its way here and add a phono stage to it if necessary

 

[NormB]

I like it.

Been playing now since noon, maybe 8 hours already and it‘s just great.

I had my son - a multi instrument musician - over this afternoon and we went through some of my favorites, Gentle Giant, B52’s, Tears for Fears, then some of his stuff via bluetooth, back to my discs Lumineers, Kodaline, ELP, Old stuff, new stuff, he was as impressed as I was.

I think I’ll put in the Ortofon Cadenza black I’ve been saving for about six months as I “broke in” a Benz Micro Glider SL I’d forgotten I owned until last fall (long story), but if you’ve ever thought about having your APT updated, Peter Williams at QuirkAudio’s the guy.

Why not new?

I’ve seen/heard new. I’m not prepared to put out that kind of money for what a quarter the same money has done for me and I know how to repair this stuff - most of it, anyway - and I doubt there’s ever going to be a shortage of electronics/audio technicians willing to work on them.

Besides, I own all the original tech/service manuals. Can’t say the same for modern stuff - if it exists at all.


Current setup:

cartridge as mentioned, SME V tonearm (rebuilt by Albert at SME Canada, 1 meter 33g Cardas Litz wire), on a Thorens TD125 Mk II (Pat Pruitt electronics, Maple plinth by me), Quadratic MC-1 MC SUT, APT Holman preamp, Willsenton R8 tube amp (bought second-hand, then majorly modified by me, running 1943-dated 6C8G preamp tubes, Electro Harmonix 6CA7 mains in triode mode) into Klipsch Heresy IV’s. DAC is Chicom Topping D90LE.

Looking into a slightly used Tektron 300b tube amp but I’m going to hold off on that for a bit yet while I get used to NOT hearing the preamp (had been using an ADCOM 565 I updated per Blue Sky - Big sky? - audio recommendations found on DIYaudio), it’ll go into my garage setup.

Meanwhile, still working on finishing my “man cave” on my farm house in Tennessee where I’ll have some room to space these speakers out a few more feet, take advantage of the soundproofing I’m installing.

 

[EJ3]

I like it.

Been playing now since noon, maybe 8 hours already and it‘s just great.

I had my son - a multi instrument musician - over this afternoon and we went through some of my favorites, Gentle Giant, B52’s, Tears for Fears, then some of his stuff via bluetooth, back to my discs Lumineers, Kodaline, ELP, Old stuff, new stuff, he was as impressed as I was.

I think I’ll put in the Ortofon Cadenza black I’ve been saving for about six months as I “broke in” a Benz Micro Glider SL I’d forgotten I owned until last fall (long story), but if you’ve ever thought about having your APT updated, Peter Williams at QuirkAudio’s the guy.

Why not new?

I’ve seen/heard new. I’m not prepared to put out that kind of money for what a quarter the same money has done for me and I know how to repair this stuff - most of it, anyway - and I doubt there’s ever going to be a shortage of electronics/audio technicians willing to work on them.

Besides, I own all the original tech/service manuals. Can’t say the same for modern stuff - if it exists at all.


Current setup:

cartridge as mentioned, SME V tonearm (rebuilt by Albert at SME Canada, 1 meter 33g Cardas Litz wire), on a Thorens TD125 Mk II (Pat Pruitt electronics, Maple plinth by me), Quadratic MC-1 MC amplifier, APT Holman, Willsenton R8 tube amp (bought second-hand, then majorly modified by me, running 1943-dated 6C8G preamp tubes, Electro Harmonix 6CA7 mains in triode mode) into Klipsch Heresy IV’s. DAC is Chicom Topping D90LE.

Looking into a slightly used Tektron 300b tube amp but I’m going to hold off on that for a bit yet while I get used to NOT hearing the preamp (had been using an ADCOM 565 I updated per Blue Sky - Big sky? - audio recommendations found on DIYaudio), it’ll go into my garage setup.

Meanwhile, still working on finishing my “man cave” on my farm house in Tennessee where I’ll have some room to space these speakers out a few more feet, take advantage of the soundproofing I’m installing.

Very nice, like the picture. Very glad you are happy with the APT/Holman. I will be sending mine (one at a time) to Peter next year. As well as some of my NAD 2200's.
In both cases there have been certain improvements found in the last 5 years that I want installed. One thing some people don't understand is that as some things become better, some of them can be applied to the old tech, making it better than it ever was.
And Peter stays on top of those things & checks them out personally. He has the measuring instruments (perhaps not as great a standard as Amirm's) but can tell if the mod is better, the same or worse. With a piece of gear as good as these were back in the day, I like seeing how far the original circuit design can go. They were designed by people who were at the top of the game then, let's see where we can take it with folks like Peter, who are at the top of their game today. And as we have seen, can keep up up with and even exceed much high end gear being sold today.

 

[Ericco]

Question - I have been using an NAD 1300 Pre with a Bryston 3B for many years. Wondering if the Abt Holman, a vintage Bryston or other pre under $1k might be a worthwhile upgrade in search of better sound?

Just found this at Quirk Audio and it seems to partially answer my question. https://quirkaudio.com/?p=1144

 

[NormB]

Question - I have been using an NAD 1300 Pre with a Bryston 3B for many years. Wondering if the Abt Holman, a vintage Bryston or other pre under $1k might be a worthwhile upgrade in search of better sound?

Just found this at Quirk Audio and it seems to partially answer my question. https://quirkaudio.com/?p=1144

“Better”?

Certainly different.

For me, “better” is simply more transparent, less affected (unchanged or altered) or as little as possible.

What Peter Williams did to a 35 year old preamp was, simply, magic.

I’d tinkered with a handful of ADCOM preamps and the latest 565 experience did great things to the soundstage, bringing clarity, presence, better resolution and detail - what instrument was where, sticks on cymbals, sttack-sustain-decay, fingers on fret boards , etc but I found opamp swapping to be unsatisfactory, both limited and variable. Too many choices.

so I bought an APT, liked what I heard (and didn’t), sent it to Quirk for a tuneup and, wow.
I have it running into a TEKTRON Tk2 2a3/50I-S with EML 300b PT’s right now and am working through my Miles Davis vinyl collection- at the Dig-Cookin‘- Workin’ era (mid-late 50’s bebop) right now enjoying the investment enormously.

You might too.