Re: my posts about an APT Holman pre-amp on the Larry Mellette Memorial thread

[62vauxhall]

I posted in the Larry Mellette Memorial thread about some pre-amps I have and implied that I would be content with either the Hafler, NAD or an APT Holman that I got last week. I stated that they as all sounded good yet different but I spoke a little too soon. In the time it took to unhook one pre-amp and hook up another, I kind of forgot how the first one sounded. I could tell they were different but without a faster switch over, I couldn't tell much. I just now used my phono switcher to do an immediate A/B comparison between a NAD and the Holman and Holt Crap - that Holman is in a different galaxy.

When I made the slow comparison, the Holman seemed more predominant with the higher frequencies but the NAD I was comparing it to was better with bass - or so I thought. Listening to either with the flick of a switch changed all that. The bass I thought the Holman was lacking seemed now way more precise than the NAD which now sounded bass heavy - way too over emphasized. Plus, the overall clarity and detail I was hearing through the Holman was totally gone when I switched in the NAD.

Still not completely done with "cleaning up" the Holman but jeez it sounds nice.

Some months ago, I used the same method to compare Hafler with NAD but those two were substantially more similar.

 

[nakdoc]

The Apt is going to be quieter too. While it is open, check to see if the output relay has been replaced. Typical replacement relays look like a kluge job, but that was what the factory told us to do. The original relay simply won't clean reliably.

 

[62vauxhall]

It's a bit of a beater and the covers have been off this thing more that a new bride's pyjamas. I'm fairly certain the relay is new as it's a different shape and color than those I've seen in online photos and there are also some of those copper/black colored Nicholson capacitors which I'm sure are newish. I was offered a manual and intend to do a capacitor tally when it arrives and possibly may do a wholesale replacement of all the electrolytics. Except those Nicholsons unless their values don't coincide with what's supposed to be in there.

I scoured online for info about it and read that the 6 micro/mini metal toggle switches were for aircraft - thought that was a neat bit of trivia.

 

[drummergrl]

still lovin' that Apt Holman pre-amp?

 

[62vauxhall]

still lovin' that Apt Holman pre-amp?

Funny you ask, I packed it up yesterday and it's going to Maryland for professional help.

How's your preamp hunt going?

After I replaced all the electrolytic capacitors, it was marvellous for 2 weeks but started producing noise randomly on one channel. I "trouble shot" as much as I dared short of pulling things off the board.

It is defiantly superior sounding to the other preamps I have at my disposal and the connectivity and specialized phono circuits probably make it impossible to duplicate. It will cost about $160 including return shipping for the refurb so my total dollar investment will be $300. Which I suppose is not bad for a decent preamp. Not as good as $75 plus 12 bucks of capacitors was but them's the breaks. I 'm shaving a few days of a road trip I'm taking to cover the cost plus will put a couple of redundant preamps up for sale when I get back.

Like I mentioned, it was great before this noise developed but what I'm told I'll get back is supposed to be better than it ever was. I guess I'll find out.

The person encouraging me to let him do his thing was I believe the production/service manager at APT Holman for at least the first years they made this preamp. I know that because a contributor on another forum knew him as a co-worker and (I think) took over his position.

What I was told, and it made sense, was that Holman preamps were never built to realize the potential the design could achieve. Apparently, and I've read this before about other products, there were limitations with components available at the time so they used what was necessary to meet a price point. This person stated these preamps when built correctly were/are laboratory standard. That may well be but I was quite happy with it before this noise thing started.

Coincidently, I was flipping through records at a thrift store today and spotted a Kenwood Basic C1 preamp for $5. Do not need it in the least but could not resist the gamble.

 

[stuwee]

I've never heard an APT Holman pre but, have always wanted one because it's phono section should sound waaaay better than most, those cool toggle switches for cap and imp! Gawd it's built nice but, by now needs an update...keep us posted buddy and don't underestimate the Kenwood C-1, it might surprise you

 

[laatsch55]

As it should....any Kenny gear...

 

[62vauxhall]

For the hell of it, I did an A/B between that Kenwood C1 and the Hafler DH101 which is now pulling duty while the APT Holman's gone for R&R. I did not expect to find fault with the Kenwood and didn't and they were close but I preferred the Hafler on the mid's and below. Maybe I'm just used to it.

I was a longtime Kenwood user up to 2006 having had one of their Ultimate Series Model 600's since new in 1978. Although an integrated, it smoked some well regarded power/pre's I was able to take home and compare. I had no reason to think that this Basic C1 would be inferior to it at least on the turntable side of things which is the only thing I've plugged into it. It's pretty good and solidly built - too bad it's black.

 

[drummergrl]

Can you explain to me please how you made the switching faster to compare the pre-amps? What's a phono switcher?

 

[62vauxhall]

Can you explain to me please how you made the switching faster to compare the pre-amps? What's a phono switcher?

Yes, I used a a phono switcher.

I split the turntable source signal into the inputs of both preamps.
The main preamp outputs went into the Turntable Inputs of the switcher.
The switcher's Output then went into the power amp.
At the onset I adjusted the volume controls of both preamps to the same level.

What I used was a cheapo "Made in China" switcher so I made sure that when I did flip from one preamp to the other, I did it quickly so as to keep any "switch noise" to a minimum.

In my case, the turntable I was using did not have a separate ground wire but if you are going to use a turntable that has one, attach it to both preamps with a jumper wire.

I was told that by splitting a phono cartridges's output into two preamps, the cartridge saw an odd load. While that may be technically true, I could not hear any obvious audio degradation so this method worked well enough for me.

Sometimes differences did not "stick out like a sore thumb" so I had to listen to same track a few times over and pay attention to certain instruments or voices before I could zero in on something.

It was an interesting experiment because without instantaneous switching, I easily forgot what one preamp sounded like in the time it took to hook up another.

 

[62vauxhall]

I've never heard an APT Holman pre but, have always wanted one because it's phono section should sound waaaay better than most, those cool toggle switches for cap and imp! Gawd it's built nice but, by now needs an update...keep us posted buddy and don't underestimate the Kenwood C-1, it might surprise you

The APT Holman came back about two weeks ago. One channel dropped out the following day but that was partially my fault as I misinterpreted an enclosed note advising me to exercise the pushbutton switches. I took that to mean periodically in the future, not right away. I called them and they set me straight. Turns out AudioProz uses a different polishing compound than what they had been and it is more tenacious than the old stuff. So after 50 or 60 ins & outs per switch, all is good.

This preamp had a hard life, and I did not make it any easier by re & re-ing all its electrolytics. What AudioProz did was replace two IC op amps, several transistors, some different capacitors and the relay which was once already replaced. There was damage to foil traces which they repaired but I'm fairly sure that was done before I got it. Since I put in all new electrolytics, I was told I'd get a cost break which was $160 including return shipping. That was quoted before they saw it so considering the amount of work they did, it was probably a good deal.

So I'm into it for less than $300 and I'm OK with that. It has all the inputs/outputs I'm likely to find, it's geared towards turntable playback (my main medium) and it sounds the best of what I have or had. I wound up selling three of my other preamps. My trusty NAD Monitor 1000 went to a local guy, the NAD 1020A went to Toronto and the Kenwood BASIC C1 to Ottawa. I am keeping the Hafler beause I like it, I put a lot of work into it and it too has a whack of inputs and outputs. Too bad it's nature is to be a little noisy.