Further upgrading my first built WOPL, a 400 S1 8 fin, with a few goodies.

Gepetto said:
Hi George
Remember the meters are calibrated at 0dB to 50W. 20Vrms into 8 ohms is that 50W. PL did that or the meters would never get off the stops and users would think the meters were broken.
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Got it Joe, my error 50 watts. THANK YOU! Hmm, I'm going to think about going in and doubling that resistor value. Thanks!
 
George S. said:
Checking meter calibration.
Here's how on the 400 S1.
Connect your signal generator to the RCA inputs.
Connect your VAC meter to the speaker jacks.
Input a 500 Hz sine wave starting at 1 VAC amplitude. Slowly raise the amplitude, stop when the VAC meter shows 20 VRMS.
The VU meters needles should be close to the "100" on the VU meter. This "100" means 100 watts output.
These meters are not very accurate or highly responsive to output levels.
One reason some of us prefer the WOAD Cylon meters, in the Series 2 style amps.
These meters never move or swing in the small room system I use it in.
Tomorrow, I'll put this in the big system driving the JBLs and stress test it. Will get her as warm as she has ever gotten and take her temperature at the transformer, vents, and heatsinks.
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darn....i just put my signal generator in the shop....seems it wasnt generating...
 
George S. said:
Checking meter calibration.
Here's how on the 400 S1.
Connect your signal generator to the RCA inputs.
Connect your VAC meter to the speaker jacks.
Input a 500 Hz sine wave starting at 1 VAC amplitude. Slowly raise the amplitude, stop when the VAC meter shows 20 VRMS.
The VU meters needles should be close to the "100" on the VU meter. This "100" means 100 watts output.
These meters are not very accurate or highly responsive to output levels.
One reason some of us prefer the WOAD Cylon meters, in the Series 2 style amps.
These meters never move or swing in the small room system I use it in.
Tomorrow, I'll put this in the big system driving the JBLs and stress test it. Will get her as warm as she has ever gotten and take her temperature at the transformer, vents, and heatsinks.
Click to expand...
way cool!!!!
 
Gepetto said:
I thought you did that before and did not like the meter sitting there doing nothing :)
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Joe, you are correct, but I thought 20 Vrns was 100 watts on the VU meter, and 40 Vrns was 200.
I looked back at that thread, and, best to just leave the resistors as they are.
 
gene french said:
darn....i just put my signal generator in the shop....seems it wasnt generating...
Click to expand...
Gene, don't sweat checking the meters. Joe did all the hard work for us by selecting the proper calibration resistors on the LED board.
 
gene french said:
what are you using for a dac???
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On the small system, upstairs in my oldest son's former bedroom which is now my computer/electronics hobby room, I have only one source of media. I use a Lenovo S30 with a Asus Xonar Essence sound card.
The big system uses a Lenovo S30 and Schiit Modi 3, and the garage system is a antiquated Dell XPS 720 with a Creative Soundblaster Card. The Dell will soon be replaced by another Lenovo S30.
I do have a 4th S30 at my mother's house. She reads her emails and photos on a hexa core Xeon with hyper threading turned on. 12 threads, SSD boot drive and 500 Gb storage drive, and a decent older EVGA video card. It's incredibly fast
 
Good Morning Joe,
Could you clarify what you mean by "3 switch, or jumper selectable meter sensitivity".
Is that applicable to the 700b light boards as well, or just for the 400's?
I have installed 3 on the 700b's and do not remember seeing a mention of it.
Thank You
 
Vintage 700b said:
Good Morning Joe,
Could you clarify what you mean by "3 switch, or jumper selectable meter sensitivity".
Is that applicable to the 700b light boards as well, or just for the 400's?
I have installed 3 on the 700b's and do not remember seeing a mention of it.
Thank You
Click to expand...
Only the latest PL400 RevC light board has this feature. The PL700B has 2 sensitivity settings.
 

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Got it set up, Pink Floyd discography on Foobar. Preamp is turned up to 3/4 position. Needles are in the red on some of the milder base, should peg on deep bass.
Sounds really good from upstairs, so going to crank it a little more.
Then do a little reading on how to take accurate temps with one of those laser guns.
Going to keep the dog upstairs and away. Nothing I can do for the tropical fish tank
 

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Well, I've never cranked the system so loud, I'm well over 3/4 on the preamp. Sounds fantastic and very loud upstairs.
Have to admit that these amps may need a fan at these outrageous volumes and a 8 fin is very desirable. The fins had more heat than I've ever felt before.
Hope my recently retired neighbor lady doesn't get pissed!
I'll keep it cranking for at at least a hour.
Going back down and turn it up a little more. More concerned about possibly driving the pre into distortion than anything else.
 
This is the next upgrade project, it's full WOPL including the Cylons. It'll get what the S1 got. I really like the S2 stuff.
 

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Here are the temps. Transformer 103 deg F., Chassis top plate by vents 104 deg F, transistor cover 109 deg F, heatsink by chassis 130 deg F, that second heatsink that's screwed and glued on 131 deg F, heatsink fin tip furthest from chassis 106 deg F.
Am I ever glad I have now turned it down. Just totally brutal sound pressures.
Conclusion: If your going to build a WOPL, get a 8 fin. If your using the amp at a club or band or have the amp in a enclosed space or rack, use a fan.
And, if the amps going to sit on a shelf and see normal volumes, nothing else is needed. At normal volumes my amps have a warm transformer and chassis vents, fins just slightly warm.
Stress testing the S1 was interesting, don't think the JBls could have taken much more. A WOPL is a amazing thing!
 
good morning crew....hope all is good in your world...
george of the jungle, i hope your neighbor is still speaking to you....lol
some of my stuff is due to arrive today....or tomorrow at the latest...
one must learn patience to live here!!!!
:cool:
 
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