grapplesaw
Veteran and General Yakker
Nice shot. She is all dressed up. Great work
PL 700 Pro Build
- Thread starter George S.
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Glen, I spent about 30 minutes this afternoon searching and couldn't find it.
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- Halfbiass...Electron Herder and Backass Woof
It's pretty simple, wiper goes to the board...
grapplesaw
Veteran and General Yakker
Well I was wondering if there may be a new twist here but I now see there isn’t
thanks Lee
That's it!! Wiper goes to board. Wish I could find that old post where he explains why that matters. Pretty simple when you think about it when you have the phrase "wiper goes to board". Thanks Lee!
derek92994
Veteran and General Yakker
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- Those who enter the man cave will get WOPLed
She is super tidy, will behave nicely 
Waiting for the garage door guys to arrive and install the garage door I ordered back in August.
Thought I'd double check the WOAD Cylon wiring and fire her up and let her idle throughout the day until I can calibrate the meters.
Success, 1 red LED illuminated on each meter, yahoo!
Posting a photo from the top.
What are your all thoughts about spacing that control board out a little more from the back planes? Only issue I can think of is it may affect bias transistor temperature.
Thought I'd double check the WOAD Cylon wiring and fire her up and let her idle throughout the day until I can calibrate the meters.
Success, 1 red LED illuminated on each meter, yahoo!
Posting a photo from the top.
What are your all thoughts about spacing that control board out a little more from the back planes? Only issue I can think of is it may affect bias transistor temperature.
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It won't. Ambient is pretty isothermal inside the enclosure cavity once buttoned up. The back wall will obviously heat up as the heat source for that isothermal cavity. Moving the card one way or another won't impact much except for running into other things.
Cool, going to find some of those old style brass hexagonal stand offs and bring that control board out some. I built enough slack into the AC run that I can raise it away from the back planes quite a bit more. Thanks Joe.
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George, Glen and I ran some noise tests with different standoff heights years ago, some differences were noted. The further the better. Measure as you go and see what effect your movement has.
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Welcome Sir!!
The Cylons calibrated perfectly. Going to screw down the top plate and hook her up to the JBL Millenniums and listen to some music. Next weekend she'll be doing sub duty.
Looking at it I'm not struck or impressed by what I've done building this from a kit. What impresses me is one man had the drive and desire to engineer and produce such a complicated, sophisticated machine, and offer it to us.
Thank you Joe.
Looking at it I'm not struck or impressed by what I've done building this from a kit. What impresses me is one man had the drive and desire to engineer and produce such a complicated, sophisticated machine, and offer it to us.
Thank you Joe.
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grapplesaw
Veteran and General Yakker
Yes indeed. Raise it 1/2” if you can.
1/2" will be easy, lots of room. Thanks.
derek92994
Veteran and General Yakker
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The Pro series looks wonderful, something different.
Yup, different. Not as elegant as the other 700s. I think the Clair's are better looking.
So last night I played a Robin Trower digital file through her, then listened to some FM between the dog walk and locking up the house for the night. It works well, and somehow is slightly different from the 400 WOPLs, hence the following question related to the 50k attenuators in the 700 versus the 100k in the 400.
I think Joe has answered this, but I don't quite understand, so here's the question. If I measure resistance at a RCA jack between the center conductor and shield, I see close to 50k ohms on the 700 and 100k ohms on the 400s because of the pot value. Does the preamp "see" this resistance and what are it's effects?
So last night I played a Robin Trower digital file through her, then listened to some FM between the dog walk and locking up the house for the night. It works well, and somehow is slightly different from the 400 WOPLs, hence the following question related to the 50k attenuators in the 700 versus the 100k in the 400.
I think Joe has answered this, but I don't quite understand, so here's the question. If I measure resistance at a RCA jack between the center conductor and shield, I see close to 50k ohms on the 700 and 100k ohms on the 400s because of the pot value. Does the preamp "see" this resistance and what are it's effects?
Yes your preamp does see this input impedance, for sure. The consequence depends on your preamp output stage. Recall that the series 1 PL400 with no pots in the signal path present 49K ohms to the preamp. So your 700 measurement is very close to that.
If your Pro 700 pot is all the way up, you should see somewhere around 25K ohms (50K pot in parallel with 49K control board input resistance).
As I mentioned earlier, the Acurus pre that I use has an output impedance of 47 ohms so it doesn't really care if it is driving 25K ohms or 100K ohms and will have negligible effect. If your preamp has 50K output impedance then you will see some effects related to the preamp that is driving the amp, such as you will have to turn the preamp output up more to account for the attenuation of the combined preamp/amp resistor network.
Joe, thank you. Working now. Going to really drill down on this and understand this. This will be this weeks course of study!
I was seeing much higher gain out of the 700 versus the 400s for a given volume setting. Seemed like the difference in the higher # of outputs didn't totally account for this, and the pot values did.
For those of you reading and wondering about this, note this is with the pots at minimum value close to zero ohms. If I measure resistance of the center conductor from the RCA to the control board, the value is close to zero ohms.
This question has to do with the resistance measured at the RCA between the center conductor and the shield.
Joe's given us something to think about and ponder.
For those of you reading and wondering about this, note this is with the pots at minimum value close to zero ohms. If I measure resistance of the center conductor from the RCA to the control board, the value is close to zero ohms.
This question has to do with the resistance measured at the RCA between the center conductor and the shield.
Joe's given us something to think about and ponder.