Larry's Phase Linear 700B

[laatsch55]

Re: Larry's 700B

Didn't get around to a comparison yet. Thats on the agenda for tonight if the oilfield gods cooperate.

 

[speakerman1]

Re: Larry's 700B

Sell it to you. LOL

Larry

 

[laatsch55]

Re: Larry's 700B

That was a joke right??

 

[speakerman1]

Re: Larry's 700B

Yes

Larry

 

[laatsch55]

Re: Larry's 700B

Opened up the 700B from Cal. Bought it as a non-worker, wouldn't power up they said. 10 amp main ac fuse obliterated, not a good sign. Upon further investigation the power switch was bad. Bypassed the switch things lit up. Put it on the scope , not a thing wrong with it. My 100.00 700B

 

[speakerman1]

Re: Larry's 700B

Well how did they compare sound wise? You better tell me mine blew it away. I have gotten a lot of stuff that was listed as broken and was nothing really wrong. That makes life good. All most like Christmas. Tom is looking for the meters for me. Are you going to be able to put the IEC connector in? When I looked at it. It didn't look like much room.

Larry

 

[laatsch55]

Re: Larry's 700B

The IEC connector is going in the unswitched auxiliary outlet hole. Looks like a little hand filing will be all that takes. Just finished up the power supply for the DC protect PCB's. I was experimenting with a zener regulated supply coming off the B+ and B- rails but dropping that much voltage through a 750 ohm 5 watt resistor was creating a lot of heat so we canned that idea. Wound up going with a small transformer to supply the 24 volts to the PCB's. Had to find an 18 volt secondary that was small enough to fit between the PS caps. Just had to get to the right box of stuff. I knew I had one. So the rest of today and tonight will be guttting that area of the amp and finishing the binding posts, IEC socket, and the DC protects. The DC protects will be mounted over the top of the posts and will be supported on one end by the posts. On the other side by an L bracket to the side of the chassis. Should look pretty slick when I'm done. Then all we'll have is the LED board, and that might cure the sluggish meters. I'll post some more pics later tonight. I was about to unhook your 700 from my Spec 1 and the Kornerhorns when Jazz corrnered me for Kitty cuddles that's now overwith so the 700 goes back on the bench. Haven't listened to my "B"yet, maybe later tonight.

A little ohms law at work.............................
The transformer secondary is rated at 18 volts. It measured 16.6 ohms resistance. How much current will it provide?
I= E/R I= 18/ 16.6= 1.08 amps

The PCB relays measured 1097 ohms with 24 volt supply.
How much current is needed?
I=E/R I=24/1097=.0218 amps times 2 relays=.04376 amps.
Amps measured .044. Ohms law works.

 

[speakerman1]

Re: Larry's 700B

My gosh I haven't used those formulas in years. I always did the pyramid thing to remember them. You haven't used that meter much have you? Well if Tom finds the meter that matches. You will have an extra set of meters. If mine get fixed.

So explain what will happen now that you dropped the voltage on the rails. Or did you? I'm sitting here with a sinus headache from hell. Trying to figure this out. LOL

OK about the Black Gates were they a waste of my time and money?

Thanks
Larry

 

[laatsch55]

Re: Larry's 700B

I didn't go with the zener regulated supply for the DC protect PCB's, like I said generated way too much heat. A small x-former, tiny bridge rectifier and a 35volt 1000mfd cap and voila" power supply.
The Blackgates were not a waste of your time or money. There is a hundred hour burn-in on them and they do keep sounding better. More pics in a bit.

 

[speakerman1]

Re: Larry's 700B

I can hardly wait; but take your time. I may send a gift to you later. Will see. Yeah I'll get some lacquer polish and polish the face up when it gets back home. I still have to do my speakers yet.

This sinus headache is getting better; but I'm still in pain.

Larry

 

[laatsch55]

Re: Larry's 700B

There isn't a piece of gear that leaves here that doesn't get the "Jani" treatment. My wife does something to them that lasts, very good stuff. It's a VERY LARGE MYSTERY though.

 

[Elite-ist]

Re: Larry's 700B

I'm very impressed with your workmanship, Lee. I'm beginning to learn a little more about amplifier design and your abilty to improve and affect sound performance from your step-by-step process on Larry's 700B. It takes a good amount of effort to provide forum submissions to keep members apprised of what you've been able to modify and improve on Larry's amp. Had you shared what you did to improve the innards of your Pioneer Spec 2 amplifier, in another thread?

Nando.

 

[laatsch55]

Re: Larry's 700B

No, Nando i haven't. The only Spec 2 thread is on AK where I had implored the help of Echowars. Thats when I started fixing gear. Nobody up here fixed 40 year old, obsolete, musty, dusty, rusty old school stuff. I've studied a lot since then and bought a lot of stuff to fix, to see if I could. I now have a lot of stuff.
I have my second Spec 2 that is virgin. When I go through it I will start a thread. My third Spec 1 is also in the queue for audio grade caps and upgraded power supply. I will thread that one too.

 

[speakerman1]

Re: Larry's 700B

Hi Lee

Is there any thing else you need besides money? LOL Are you going to buy that tonearm? You have a TT coming don't you.

Larry

 

[laatsch55]

Re: Larry's 700B

No, too many projects going on the way it is, sure made me miss mine though. I had a fine TT setup.
Got a little done on the amp last night. Its 10:00 PM here and I just got in, it was a long one. don't know if I'll get anything done tonight. Seems like after days like this, as soon as the belly is full the eyes close.
Funny thing about the old PS caps, they aren't even the 9800mfd, these were 7500 mfd. Hadn't seen those in a 700 before.

 

[speakerman1]

Re: Larry's 700B

Hi Lee
Take your time. No rush. Don't kill your self doing this . Like I said I'm im no hurry.

Larry

 

[laatsch55]

Re: Larry's 700B

I'm back on it today though, should get quite a bit done.

Did get the 2nd Cal 700 B in Friday, looks better than the first one.

 

[speakerman1]

Re: Larry's 700B

Hi Buddy

Did the meters start working? LOL Just take your time. I have to print this order tomorrow than I can start on the speakers. Gotta get my garage organized. I think I have enough tape on the floor to load another 100 tapes. LOL

Larry

 

[speakerman1]

Re: Larry's 700B

Do you want some spare 10" reels? For that R2R? I can send you a care package for all you have done for me.

Larry

 

[laatsch55]

Re: Larry's 700B

Nope Larry, got plenty, That's Orange's RTR now anyway.