Gibsonian's Cherry Pl 700 Ser I, soon to be a PLWO-1000

[laatsch55]

A very cherry example of an early Ser I. It's been around the block a time or two from the looks of the inside, but very savable platform for the White Oak upgrades. It is missing the plate where the caps bolt to mthe plate on the inside that also serves as a mount for the bridge rectifier. I have the OLD Ser I for parts so that's not a problem. Should be pretty straight forward. It's getting some fold away rack handles too, just does not look right without rack handles.

 

[stuwee]

Wow! that's purdy

Am I the only non-Pl owner at this forum??

 

[laatsch55]

No, we're still the minority I'm sure.

 

[orange]

Wow! that's purdy

Am I the only non-Pl owner at this forum??

I had an SAE XXX I decided not to fix but never a PL.

 

[laatsch55]

Beins this is a Ser I, new 2 point standoffs in the middl;e of the chassis to accomodate Joe's board. Bias transistors (2N3403's) go on the chassis also. The White Oak board was not made to replace the PL 0171 board as the '71 board had the bias transistors on the pcb. How they monitored heat sink temp from there is a mystery. Doesn't take much finegglin to adjust a Ser I to take the new board.
Scott, the 2N1304, 05 protect transistors were ECG 101, 102 parts . Wholly inadequate to replace the original TI 1304's, 05's.. ECG was the predecessor to NTE. That should tell ya something right there. Got plenty of the old TI's to make a no-sweater out of it.

 

[orange]

That's a sight! All that stitching almost made that Zenith stereo console chassis look empty below. It's really tidy though, like artwork.

 

[ksrigg]

YOU HAVE NO IDEA WHAT YOU HAVE DONE GIBSONIAN........I THOUGHT I KNEW, HAVING OWNED A PL BEFORE, BUT I WAS MISTAKEN...YOU ARE IN FOR THE SONIC TREAT OF A LIFETIME. THERE IS NO WAY TO DESCRIBE THE EXPERIENCE. YOU WILL JUST HAVE TO HAVE IT FOR YOURSELF. UNBELIEVABLE...

NOW I MUST GET THE BETTER A-7'S IN THE HOUSE. THE PLWO1000 REVEALS ALL..

 

[Gibsonian]

Good to see my first PL on the big screen Lee. Yeah, I think the overheat protection on the series 1 was really not functional, imo. The unit you have on the operating table I bought off of ebay about 8 yrs ago on a whim. I had never had that kind of power before and when I first really let it rip I was blown away with the bass and dynamics, just raw and clean. Had a Carver TFM25 with the D9's so I had heard loud but not LOUD. Phase sounded so much better too. Ended up repairing her a few times, then decided to recap it completely, bigger ps caps, 21996 output transistors. Was really happy with the sound after that but overheated it in a fit of stupid and ouch went some op transistors and it went on the shelf for awhile. I am now looking forward to a more reliable and even better sounding amplifier. I have much faster amps, much quieter amps, but none that sound better than a recapped PL. In my opinion, Bob's first was his best sounding amp he ever sold commercially, at least SS, never heard his tube efforts. Have had the series 2 but it's not as tasty as the series 1. I have another PL 700 that is doing sub duty most reliably and a 400 I bought for project at a later date. Pretty exited about having a piece of audio history in the house as reliable as any other and sounding better than nearly all of the contenders. Great idea from White Oak on the new boards and great work from this self named parts changer Lee - best parts changer I ever saw!

 

[Rex Everything]

Nice looking amo......Stuw, I don't have one....but maybe I should as the 240Ti's want POWER!

 

[laatsch55]

Scott, It was nice to get a review from someone who had heard a lot of amp/speaker combo's in their life like Sutton. Living in the great ,white wasteland my exposure to high end stuff is limited. Thanks to Larry and the other folks on this forum I am now getting exposure. But , the in person, sit down and lisaten to it is still hard to do. I knew when I fired up the first 700 Ser I with the White Oak board was special. I have 2 tricked Spec 2's and for 35 years they were the ALPHA DOG around here and still were till Sutton's OERW (one-eyed road warrior), that was when the improved low freq response mod from Joe was added. THAT was the one that did it. The Specs have bass in abundance, and it's tight and right, and until the latest 700 was preferred for anything under Mach 7, but after Mach 8 there really is no going back. there is forever something missing, like when a big kickdrum transient or multi instrument crescendo aurally as well as PHYSICALLY assaults you, well.,, has to be heard to really appreciate.

The difference between what you sent me and what you get back will hopefully make the lighter wallet seem insignificant. In my world great sound reproduction has saved a few lives and me in prison forever for murder, it's the " onerwhelming" factor like at a live concert that trips my trigger, I have never seen anyone exhibit confrontatonal behaviour after a good live show, just a feeling of companionship for surviving the same thing together.

 

[laatsch55]

Nice looking amo......Stuw, I don't have one....but maybe I should as the 240Ti's want POWER!

Nothing to it Paul. Order one of Joe's boards and get after it.

 

[Gibsonian]

Scott, It was nice to get a review from someone who had heard a lot of amp/speaker combo's in their life like Sutton. Living in the great ,white wasteland my exposure to high end stuff is limited. Thanks to Larry and the other folks on this forum I am now getting exposure. But , the in person, sit down and lisaten to it is still hard to do. I knew when I fired up the first 700 Ser I with the White Oak board was special. I have 2 tricked Spec 2's and for 35 years they were the ALPHA DOG around here and still were till Sutton's OERW (one-eyed road warrior), that was when the improved low freq response mod from Joe was added. THAT was the one that did it. The Specs have bass in abundance, and it's tight and right, and until the latest 700 was preferred for anything under Mach 7, but after Mach 8 there really is no going back. there is forever something missing, like when a big kickdrum transient or multi instrument crescendo aurally as well as PHYSICALLY assaults you, well.,, has to be heard to really appreciate.

The difference between what you sent me and what you get back will hopefully make the lighter wallet seem insignificant. In my world great sound reproduction has saved a few lives and me in prison forever for murder, it's the " onerwhelming" factor like at a live concert that trips my trigger, I have never seen anyone exhibit confrontatonal behaviour after a good live show, just a feeling of companionship for surviving the same thing together.

I think we are all especially glad you've chose the audio path over murder and jailtime Lee. Esp. the potential murderees!

Just curious now, is the Alpha amp in your house, in the mach 7 and under now PLWO 1000 or still the Spec 2?

 

[laatsch55]

The Pl has supremecy in every facet of musical repropduction. Soundstage, definition, bass response, clarity, you name it. The Spec does have the edge in complicated circuitry. The meter drives are world class, very responsive and actually pretty damn accurate representation of power out put and peaks. Amazing meter system. The 400 or 550 PLWO's are a pretty close match to the Spec's now. A few watts and a little current behind em, but sound just as good. Joe's low freq response mod is the coup-de-grace, let me see if I can post a response curve,.

 

[laatsch55]

Here they are.

 

[Gibsonian]

Lee,

Can't see the plot of the curves at all.

Scott

 

[laatsch55]

Aw jeez, gotta proof read this s%$%# before I post. I'll see if i can darken up the curves enough to see.

 

[laatsch55]

Or better yet , take a HiRes pic of em!!

 

[ksrigg]

Lee,

Are those from my OERW medical file? It would be cool to bee a before and after plot. Not being very familiar with these, is there any smooting to the graphs, or are they that slick? Down .50 db at 10 hz, and up .25 db at 20k hz? Am I reading them correctly? How do they compare to the curves from the Spec?

 

[laatsch55]

This is a plot from Joe's modeling of the predicted response from the mods. Joe hasd just now got the parts in to try some real world tests. I don't have the equipment to do actual testing and plotting of response curves .....yet. I believe the plots weigh in on the side of caution, to my ear, the response is considerably better. The one shortcoming of the PL amps was bass response to me anyway, it sounded mushy in comparison to the Spec's. Now these Spec's aren't stock either, they have been re-capped and upgrades in the drivers, and meter boards as per Echowars' recommendations on AK, so they are no slouch's in any regard, but the PLWO 1000's do everything the Spec's do.......just........A WHOLE LOT LOUDER!!!!!!!!!
And Joe being Joe has got some other stuff cookin too, he gave me some tantalizing tidbits and all I can say is, the guy is never content with "it'll do" . Just wait fellers, this guy is an amp guru bar none.
The 1.3 KW monster is not an attempt to get the K-Horns louder, but on certain comp[licated and extremely peaky transients and crescendo's I can detect a wee bit of compression before the onset of clipping. That is what I'm trying to head off at the pass. If I encounter a speaker which presents a considerably tougher load than the horns, I'm gonna need more power. NOT that I've gotten the PLWO 1000 to clip yet, but the pre-clip compression I have detected, very, very slight and then only at the extremes, BUT, ..............It can be fixed.

 

[Gibsonian]

As you likely know the drivers begin to compress the waveform well before their max output. With the power you are throwing at these drivers, the compression that is occurring is part driver compression for sure. Any idea of the wattage or voltage you are throwing at them when you are maxing them out?