David's Phase Linear 700B Thread

[jbeckva]

I ran one last and final test for today. I decided to switch out input sources. I dropped my stereo racks preamp in favor of a cell phone with a 1/8" mini cord to L/R RCA's. Well......the result is the hum is now less audible. You have to turn the pots up pretty good with the phone on pause to hear it. The speakers still distort. It's almost as if they are playing out of phase? But they can't be since I wired + and - correctly. I triple checked this. I mean....It "looks" as if when a base note hits, the woofer caves IN instead of pumps out? But its too fast for me to see. And when one pot is all the way down, and the other up, you can hear like a farting noise with every base note in the woofer that has its pot all the way down. Its sorta like the left channel is leaking into the right and vise versa. And when both play, that's just amplified and they stab each other? Do I sound like an ass clown here? I change sources with the same results sooooooo are all of these shenanigans tied somehow to the same thing? It's the goofiest thing I have ever seen.............

OH ooooh ooooh (horseshack mode...)... I know!!!

It's the Zoebel that is missing right now i.e. part of the DCP. Sounds like you may be making some progress, so maybe try what you did 2 msg's ago, but put the DCP back "in circuit"..

I know... cuz did it myself and it sounded just like you described... horsepuckey...

 

[Phase Linear Phanatic]

OH ooooh ooooh (horseshack mode...)... I know!!!

It's the Zoebel that is missing right now i.e. part of the DCP. Sounds like you may be making some progress, so maybe try what you did 2 msg's ago, but put the DCP back "in circuit"..

I know... cuz did it myself and it sounded just like you described... horsepuckey...

Seriously? You think this whole thing is the Zoebel?! I have read about this from Joe and Lee several times elsewhere in the forum. The Zoebel Network. I think it's pretty critical? You didn't get it with the DCP? Where is it supposed to go? The board looks pretty occupied to me? Don't say between the binding posts?

Meanwhile...................reinstalling........................

 

[NavLinear]

Hey David,

I've been reading this thread and it has been very interesting and no you're not an ass clown. Always ask - you never know what sort of headaches can be avoided this way. I must ask though - does this mean you don't like hum(mers)? Trouble shooting long distance is kind of like phone sex or so I've been told.

Your speakers are awesome - you should do a thread on them if time ever permits. We really enjoy those sort of things.

 

[Gepetto]

Seriously? You think this whole thing is the Zoebel?! I have read about this from Joe and Lee several times elsewhere in the forum. The Zoebel Network. I think it's pretty critical? You didn't get it with the DCP? Where is it supposed to go? The board looks pretty occupied to me? Don't say between the binding posts?

Meanwhile...................reinstalling........................

View attachment 9879

The Zoebel network is the 2 paralleled 10 ohm resistors in series with the 0.1uF cap right next to it on the DCP board.

When the DCP board went in, the original Zoebel was removed. It is necessary to have one.

 

[jbeckva]

Seriously? You think this whole thing is the Zoebel?! I have read about this from Joe and Lee several times elsewhere in the forum. The Zoebel Network. I think it's pretty critical? You didn't get it with the DCP? Where is it supposed to go? The board looks pretty occupied to me? Don't say between the binding posts?

Meanwhile...................reinstalling........................

First of all let me make you didn't mean to be sarcastic.. if not, we cool and I'll continue... (never can tell sometimes with non verbal communication.. )

Now, go several posts back where you almost had a eureka moment with the hum monster. But in further attempts to turn it up a lil you encountered the hum and probably a few other nasty artifacts - when you started talking about bass that is when it hit me that your Zoebel is currently not in circuit.

Part of the DCP IS the Zoebel ... it's just been relocated and is part of the DCP itself. So, you might want to put the DCP back in (that puts the Zoebel back in with it), and repeat what you tried a few posts back when you didn't have a hum...

 

[jbeckva]

Hey David,

I've been reading this thread and it has been very interesting and no you're not an ass clown. Always ask - you never know what sort of headaches can be avoided this way. I must ask though - does this mean you don't like hum(mers)? Trouble shooting long distance is kind of like phone sex or so I've been told.

Your speakers are awesome - you should do a thread on them if time ever permits. We really enjoy those sort of things.

Believe me I aint knockin' em... I can only imagine the SPL's coming out of those at full tilt! David if ya can't get it figured out, ship me the speakers too... heheheheh

(I think we might be close to a breakthru.. maybe... )

 

[Phase Linear Phanatic]

Hey David,

I've been reading this thread and it has been very interesting and no you're not an ass clown. Always ask - you never know what sort of headaches can be avoided this way. I must ask though - does this mean you don't like hum(mers)? Trouble shooting long distance is kind of like phone sex or so I've been told.

Your speakers are awesome - you should do a thread on them if time ever permits. We really enjoy those sort of things.

I wondered where you went Dennis? Haven't seen you here in a while. Yeah.............I always have stayed silent about my speakers. I mean; custom built isn't really something people care for? They only go for name brands like klipsh and Fisher and Altec and so on and so on. But I could not find anybody out there selling speakers the size of the one's in the 60's and 70's? So I decided to take what was already designed and engineered in the 60's, and double it's power and capacity. (which was already over the top back then!) Today's BIG BOOM, with yesteryears high fidelity. And thus began my speaker building years. That was two decades ago. If digital camera's had been around then, I would have had a crap ton more pictures. But I don't and had to scan those old photo's in my computer here. My dad always said to never mention it cause people would scoff at "home made". So yeah, I talk mostly about what I know PEOPLE know of. And that's the amps that drive my mammoth monsters.

Not many people know the name Bozak. It was an expensive hi-fi speaker even then. But everybody has heard of Phase Linear? Whether it be good or bad. (Only bad cause of the name flame linear. Thanks to the bands abusing them.) Maybe I will get into the speakers more at a later time. It wasn't until Jerry really asked me how I had them wired, that I had to ask my father. he helped me do the wiring. And I only see him maybe once a month? I think I have more pics around here somewhere? I will dig them up and post them when I find them.

-Dave

 

[Phase Linear Phanatic]

First of all let me make you didn't mean to be sarcastic.. if not, we cool and I'll continue... (never can tell sometimes with non verbal communication.. )

Now, go several posts back where you almost had a eureka moment with the hum monster. But in further attempts to turn it up a lil you encountered the hum and probably a few other nasty artifacts - when you started talking about bass that is when it hit me that your Zoebel is currently not in circuit.

Part of the DCP IS the Zoebel ... it's just been relocated and is part of the DCP itself. So, you might want to put the DCP back in (that puts the Zoebel back in with it), and repeat what you tried a few posts back when you didn't have a hum...

Yeah. No. Not at all. I was NOT being sarcastic. I was having a (gasp) moment when I heard you say it could be really something simple? Working on putting the DCP back. BUT.............remember Lee's thing. I should be relocating your ground wire to Joes board from 5R and running it to star ground instead. But before I whip out the soldering station and make a bigger mess, we will put the DCP back first, cause I am running out of day. I might have to come back to this project next Saturday.

 

[jbeckva]

Yeah. No. Not at all. I was NOT being sarcastic. I was having a (gasp) moment when I heard you say it could be really something simple? Working on putting the DCP back. BUT.............remember Lee's thing. I should be relocating your ground wire to Joes board from 5R and running it to star ground instead. But before I whip out the soldering station and make a bigger mess, we will put the DCP back first, cause I am running out of day. I might have to come back to this project next Saturday.

That's a good idea to relocate the DCP ground/white and run it to star ground, so yeah definitely do that before you put the DCP back in. Also if you can, I would take the two AC lines plus the new one you're running back to the cap/star ground and twist all three together, twisted pair style. That could further decrease the interference.

Dang.. hmmmm..... I am supposed to fly into St Louis late on Sunday, next weekend... wonder if I can catch something earlier (feel like a trip to the airport??).

 

[Phase Linear Phanatic]

That's a good idea to relocate the DCP ground/white and run it to star ground, so yeah definitely do that before you put the DCP back in. Also if you can, I would take the two AC lines plus the new one you're running back to the cap/star ground and twist all three together, twisted pair style. That could further decrease the interference.

Dang.. hmmmm..... I am supposed to fly into St Louis late on Sunday, next weekend... wonder if I can catch something earlier (feel like a trip to the airport??).

Twist all THREE? The two AC lines with the white ground? Don't we want to keep that separate? And I have not run the new wire. I am out of day. I did reconnect the DCP Board. And yes. The Zoebel stops the speaker issue. But it brings us BACK to the continuous HUM regardless of preamp or source or pot volume. Also I get huge meter swing to red then back at power on now. My hair is going grey.............. It stays the same loud/audible hum in ANY situation. So yeah, if this is all related to running the DCP board THROUGH Joes driver board, then it may be as simple as running from the DCP straight over to star point. And gee.....I am soooooooooo glad we have spent eight hours agreeing that this is our possible cause. ONLY............I have to wait to next week.

Yeah ummmmm Jerr. If you want an extra day of vacation, a house call would be neat. Then I'd have proof you've seen the system and the guys on the forum can drool with you! He he!..........................

 

[Phase Linear Phanatic]

And you KNOW Joe's just sitting back and watch us wiggle, struggling for air? He wants to see if we will figure it out on our own? Lee says he will do that sometimes. (That smart son of a gun).

 

[Phase Linear Phanatic]

Believe me I aint knockin' em... I can only imagine the SPL's coming out of those at full tilt! David if ya can't get it figured out, ship me the speakers too... heheheheh

(I think we might be close to a breakthru.. maybe... )

Jerry, they take a forklift to move, and a mayflower truck to deliver. Want to pay crate and shipping NOW? LOL!

 

[laatsch55]

Those speakers of yours are pretty F&^%$# neat. A thread on them would be cool.Bozak is not as low radar as you think. Maybe with the lo-fi crowd.

 

[laatsch55]

And you KNOW Joe's just sitting back and watch us wiggle, struggling for air? He wants to see if we will figure it out on our own? Lee says he will do that sometimes. (That smart son of a gun).

Joe's a helluva teacher........ Plus he's way busy right now....

 

[laatsch55]

The lack of a Zoebel will cause all kinds of unpleasant things. I was going from right to left eliminating possible sources. One does not necessairly need a Zoebel checking for hum. But as we eliminated it, it was going back in.

 

[jbeckva]

The lack of a Zoebel will cause all kinds of unpleasant things. I was going from right to left eliminating possible sources. One does not necessairly need a Zoebel checking for hum. But as we eliminated it, it was going back in.

Might just be the DCP, Lee?? Those transistors, perhaps??

 

[laatsch55]

I've had shorted outputs mess with those 2N6517's in the past...

 

[laatsch55]

Ed's 2 cents worth......


I noticed in Phase Linear Phanatics photos with the front panel removed and set aside that he does not have the front panel grounded to the chassis with an alligator clip which is a must when testing the 700 series amplifiers. The 400 series 1 front panels do not have to be grounded in the same manner. This is probably due to volume pots being grounded in some manner to the front panel. This will make a difference in the hum you will hear when you are testing the amp. Give it a try and you'll see what I mean. It shows up more when the AC plug is plugged in the outlet the "wrong" way. The hum will go down when the AC plug is reversed. I have also seen hum problems when there is a broken lead to the volume pots.

Ed

 

[Phase Linear Phanatic]

Ed's 2 cents worth......


I noticed in Phase Linear Phanatics photos with the front panel removed and set aside that he does not have the front panel grounded to the chassis with an alligator clip which is a must when testing the 700 series amplifiers. The 400 series 1 front panels do not have to be grounded in the same manner. This is probably due to volume pots being grounded in some manner to the front panel. This will make a difference in the hum you will hear when you are testing the amp. Give it a try and you'll see what I mean. It shows up more when the AC plug is plugged in the outlet the "wrong" way. The hum will go down when the AC plug is reversed. I have also seen hum problems when there is a broken lead to the volume pots.

Ed

Huh? I thought the volume pots were grounded by way of the braided shield to the floating RCA bar? Is that Signal ground? So then the pots were earth ground by way of front panel. I see why Joe said phase had this scheme wrong from the factory. Because the pots signal ground went to the RCA bar, then a solid wire connected the RCA bar to the coupled switch and negative speaker binding posts, which then lead to star ground. Or chassis. Sooo you were looping earth ground and signal ground in with each other? No wonder we started this whole thing with me cutting the leads to the copper RCA buss bar.

Once the face plate is off, the pots no longer have an earth ground. And when i put dons DCP board back together, i just laid the faceplate up against the chassis slanted. To test the amp. Never having a solid ground? I guess its best to do each test, then put two bolts back on to make a solid connection. Its a hassle, but ensures the best connection. Ed is also right on the international versions having the three prong plug. I guess no body here has one except me? From what I have heard feedback wise, nobody has seen one from factory or wasn't sure. If turning the two pronged cord around fixes a hum designed from the factory that way.........hmmmmmmm. Phase.....what were you guys thinking? Lol!

Soooooo I need a consensus on the best path to take the two AC wires on their way from Don's board over to the other side. And the same goes for the white ground from dons DCP over to star point.I don't want to run them together for obvious reasons. But running one on top and one on bottom would be okay except for the fact we have the left and right channel rail wires at the top. I don't think I want to route AC there? But then again, i have all the trim pot wires to Joe's board at the bottom, so i don't want to cross paths at the bottom either? Suggestions?

 

[laatsch55]

Twist the 2 ac wires together, run those straight through the middle where the Thermoswitch wires run. Run the ground around on the bottom.