FFT on WOA PL PCB

[laatsch55]

Unless of course you could write the sequel, like Joe....

 

[NavLinear]

THD&N,

I'm looking forward to your project. DIY can be lot's of fun and I hope you provide details as you go through this design and build effort. A very cool way to learn.

I never knew the books written by G Randy Slone were so popular amongst the audio community. I bought a couple of his books several years ago when I was thinking about getting my audio system back in gear. The two that I have are:

"High-Power Audio Amplifier Construction Manual"

and

"The Audiophile's Project Sourcebook: 80 High-Performance Audio Electronics Projects"

Very good reading.

 

[laatsch55]

Great minds think alike Dennis, thoise are the 2 i have. Great stuff. Still wanna build one of his hi power mosfets....

 

[THD+N]

THD&N,

I'm looking forward to your project. DIY can be lot's of fun and I hope you provide details as you go through this design and build effort. A very cool way to learn.

I never knew the books written by G Randy Slone were so popular amongst the audio community. I bought a couple of his books several years ago when I was thinking about getting my audio system back in gear. The two that I have are:

"High-Power Audio Amplifier Construction Manual"

and

"The Audiophile's Project Sourcebook: 80 High-Performance Audio Electronics Projects"

Very good reading.

I have been wanting to design a driver board for the 400 / 700 with a transistor based CCS (constant current source) for the VAS instead of the 'ole "bootstrap" method. However, the bootstrap method is inexpensive, almost foolproof and last but not least... it works.

The Series II seem to have a "love / hate" relationship attached to them. People love the cosmetics with the Battlestar Galactica LED's, but the op-amp based input section leaves some people snarling their upper lip. I like both designs and can appreciate both. From the history I've observed on ebay, almost any PL Series II will go for a higher price than an "original" or Series I, with the exception of some 700B's. It appears some people just want a 700B over the 700II. Then there is the 400II / 700II full comp models which usually fetch even more. I got a 400II full comp for a song due to the fact the guy selling it did not know what he had. His pix of the amp (on ebay) were not to good and I did not even know it was a full comp until I received it!

 

[laatsch55]

2 leters and 3 numbers-----LF-351....

 

[THD+N]

Is that a challenge to start a new thread and proclaim "op-amp" wars? )

 

[laatsch55]

No, not in the least. Just would be nice to find a replacement that didn't make the circuit somewhat unstable!!

 

[THD+N]

Ok, I have to ask... please give me the whole story on the last post.

 

[laatsch55]

I have tried several replacements of the LF-351 in a PL 300 Ser II. Has something to do with the phase lag(or lead) of the LF compared to the ones I was trying that they were getting over 180 degrees out from the original and quite unstable.

 

[fitz43]

Then there is the 400II / 700II full comp models which usually fetch even more.

OK. I'll bite. What's "full comp"?

 

[laatsch55]

Having the complemetary output section as in 15024/15025 pairs in a true AB push pull configuration.

 

[fitz43]

How would you identify these? By physically looking at the devices? By knowing they were used in a specific serial number run?

 

[laatsch55]

In the Pl's the only complementary pairs run were 15024/15025 Motorolas and 2SD555/ 2SB600 NEC pairs.

 

[laatsch55]

How would you identify these? By physically looking at the devices? By knowing they were used in a specific serial number run?

Ed has converted enough the serial number run is no longer valid.

 

[laatsch55]

And with every major change, so will the sound. Granted I have not heard a fully comp PL, other than the 300, but every other fully comp sounds dfferent than the quasi. The Spec 2 being a great example.