Phase linear & High-Tech Audio.

skipshot12

Sa-Weetness

skipshot12

Giving the 4000 II some listening...
https://youtu.be/YeC5FZ85oHA

skipshot12

Been able to do some critical listening and wanted to share some findings on the preamp.

The first thing is the difference in driving the phase linear amp directly via the Oppo vs the preamp. This has nothing to do with the work that’s been done just an observation.
There’s a huge difference in impact, slam, and actually being able to feel the lower frequencies of my SDA’s.
Bass, drums and all lower frequencies are so much more impactful that I’m feeling the sound in my body.
I thought the SDA’s really had a grip on the lower frequency extremes but, this is a huge difference.
I’m sure the Oppo being used as the preamp works just fine directly into the amp electrically but there’s a difference.
I find that the Polk’s now deliver the same bass impact as my Infinity Kappa 9’s. No small feat to do as the Kappa’s bested my Legacy-Audio Focus speakers. The Legacy’s can dip down into the teens in hertz but, how it’s perceived when listening to music is the key.
The Kappa 9’s are only spec’s into the high 20 hertz region. But when you feel the those notes physically it’s a different experience.
I’ll go out a limb here and will say the Polk’s have surpassed the Kapaa’s.
Very happy to hear this next level out of the SDA’s.

The work that’s been done on my PL preamp…
Absolutely top notch as far as quality of the troubleshooting, findings and upgrades.
While I can’t say that I now have a dead quiet Phase Linear 4000 II preamp it is far and above what it provided before the re-do.
These preamps are known to be noisy from their original design. Part of that has to do with the features that were included with the preamp… the expander, correlator and tone control features.
Side note on the expander, it’s not really a dynamic range expander as what a DBX provides. It provides some benefits when using formats such as an FM tuner and playing vinyl.
Not needed with the new formats we have available. Actually would recommend not using it all with digital disc and the rest.

Rolland’s work on my preamp is incredible.
All switches and dials are dead silent when operating. Try to find another Audio place that takes that fine a detail in their work on a 44 year old piece of gear.

I had Rolland do the whole nine yards on 4000 II.
Which included upgraded op-amps along with a really sweet remote volume control. Can’t say enough about that remote capability, my wife absolutely loves it!
Me being a fiddler I had never minded playing with the volume control from years back. But I’m loving this remote.
I’m not sure how much the upgrades made in the difference of the impact of having the Oppo played thru the preamp vs driving the amp directly but I’m sure it’s substantial.
This will come come into play, to have the power supply of the preamp, when I finally get to biamping my SDA’s with the Clair Bros amps.
The muscle of the 4000 will show its glory.

Rolland has earned my trust with the rest of my Phase Linear gear.
I’m so looking forward to him weaving his magic on some of the rarer pieces I have from over the years.
Can’t decide whether to send the 1100 II Parametric next or the 1200 Analyzer….

It’s so nice nice to have these decisions to worry about 🤣

Thank you Rolland.

skipshot12

Not sure yet what Rolland @ Hi-Tech Audio is gonna see next but, I do know its one of these...

newbie308

Nice! I have always liked the appearance of the Phase Linear equipment. That 70's style brushed aluminum is sexy.

skipshot12

Same here, fell in lust at first glance.

engie490

skipshot12 wrote: »

No luck trying to find someone willing to try a repair on the B.A.S.H amps in my Infinity Prelude MTS’s.

Skipshot12,

These guys claim to specialize in Infinity BASH amps:

http://montebellospeakerrepair.com/infinity-speaker-repair-rebuild.html

Good luck!
Jeff

audioluvr

engie490 wrote: »

These guys claim to specialize in Infinity BASH amps:

http://montebellospeakerrepair.com/infinity-speaker-repair-rebuild.html

Looks legit (ish).

skipshot12

Oh wow audioluvr.
I'll be giving them a contact.

Thank you...

engie490

There was a guy on AVS Forum that was in contact with them back in 2020 about getting his IL60s repaired. He didn’t ever get around to mentioning if he actually sent them his amp.

On the IL60s, there was a single resistor that was the most likely culprit on those amp failures. Not sure if the Prelude MTS used the same amp or a version of it.

engie490

Someone on AK sent his IL60 amps to Midwest Speaker Repair for servicing. You might want to check with them instead.

skipshot12

I’ve had an absolute dead end since my first plate amp went out ten years ago.

It’s nice to have some leads, I couldn't even find a place willing to look at them.

The crap part about the Prelude MTS’ plate amps is they’re configured specifically to that subwoofer enclosure. Because of its construction the B.A.S.H amps on those subs are pretty much one offs.
Might be the reason nobody was willing to work on them.

Will report back on what that outfit says….

engie490

The service manual is pretty widely available, so I'm surprised no one wants to touch it.