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

[laatsch55]

Rule number 2 : semiconductors fail; prematurely, with help.

 

[laatsch55]

Re: DC protect board update

Just wanted to update the group on the latest happenings with Cathy. In another thread I crapped on it kinda by going into the problem with Cathy cutting out (no output) at high volume play. Lee sent me a new dc protect board and I installed her and the issue appears to be gone. I need to test a little more but am 99% sure it's fixed. Had the needles pegged last night and no drop outs. Issue seems to be contained within the original dc protect board. To be 100% sure I will need to test again recreating original conditons - drink a few extra cold ones and have a loud music enthusiast freind drop over for a listen.

That I am glad to hear. Scott thanks for handling that. The 2 resistors that Don said were shipped with the wrong value now appears to be the primary area of investigation. Looking forward to getting my hands on it and seeing if changing those 2 to the correct values does it.

 

[mlucitt]

And the proper values for the R-X resistors would be ???????????????

 

[Gepetto]

BTW guys, I ran the SPICE model for the PL14_20 amp board all the way to clip and even in clip, the symmetry was amazingly good comparing the positive half to the negative half of the signal.

 

[mlucitt]

And Lee wants to hear it at Mach 8...

 

[laatsch55]

I may even be measuring that phase shift tonight.
He mixed up 10K for 100K's .....or the other way around.

 

[mlucitt]

Thx

 

[Gibsonian]

BTW guys, I ran the SPICE model for the PL14_20 amp board all the way to clip and even in clip, the symmetry was amazingly good comparing the positive half to the negative half of the signal.

This helps me trust the accuracy of the SPICE modeling as my ears think they are hearing good symmetry near or at clipping.

 

[mlucitt]

Joe, which frequency or frequencies are you using when you compare the signal amplitudes in the SPICE model?

 

[Gepetto]

I do a sweep from 5 Hz to 50Khz, same sweep when I do the Bode analysis for it.

Then I do a static scan at 20, 100, 1K, 10K Hz to look at a constant sine wave virtual oscilloscope signal.

 

[laatsch55]

Cathy made it back to Poppa. Just when ya think there are some components that rarely if ever need replaced, well, you're proven wrong.

 

[laatsch55]

So, can't let it out the door without a complete wire of the backwall. Couple output sockets have experienced a thermal event or two. Emitter resistors need to go, new silver hookup wire (thanks Dennis!!), what else??

 

[Gibsonian]

What else

Lee, think you have my wish list, right??

 

[laatsch55]

Yep , time to change wishes to orders....

 

[Gibsonian]

Alrightee then. I will be ready to fire it up after the mini upgrade. I miss her already.

 

[laatsch55]

The post-partum stuff never gets easier....

 

[Gibsonian]

No doubt about it, it is not easy, esp. since WO. I've had a thing for Cathy since I first had her though.

 

[laatsch55]

Senor Joe,a minute of your time please Sir......Cathy has an "A"-A board. Gepetto mod on the back, standard value electro'... to get to the non-thump territory can I change the values to the latest "C" caps or to get the complete effect I need the latest "C" with the latest BOM??

 

[laatsch55]

No doubt about it, it is not easy, esp. since WO. I've had a thing for Cathy since I first had her though.

Never forget the first Eh??

Scott I got a 700 Ser I in from Montana today tyhat out-chertries your cherry AND THE ONE Jer got. This thing IS museum quality!!

 

[laatsch55]

Didn't gewt much done last night..Got some ER out , right side cleaned up, on to the left...