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Old 14th March 2013, 01:42 PM   #2081
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Funny. I would say I learned a lot with this project. Definitively not the best project for a beginner. Glad I at least did an ACA and F5 first. I thought I would have the Pearl 2 it up and running in a week when I bought the boards. F5 taught me it takes time and patience.

I am ready to bring it to the main room and spin some records. I have the Mobile Fidelity "Grateful Dead - Live Dead, Dark Star" to christen. Do you think I will hear the Fillmore West?
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Old 14th March 2013, 01:49 PM   #2082
6L6 is offline 6L6  United States
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LOL, yes, this hobby isn't for people without patience.

(Or for people who don't mind blowing up transistors once in a while)

That seems like it would be a great album - I bet you will hear the Fillmore!

Oh, if you ever are searching through the used record stacks somewhere and see "Virgil Fox, Heavy Organ Live at the Fillmore East" buy it. I will bet you a bottle of your favorite whisky that you will really enjoy it.
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Old 14th March 2013, 02:53 PM   #2083
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I have been having good luck with Discogs, great web site for the obsessive compulsive vinyl collector. I met an organ music freak at a local Audio Karma meet - good way to test the low end of the Pearl 2.

http://www.discogs.com/artist/Virgil+Fox

Need to make it Taiwanese Oolong - I do not drink.
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Old 14th March 2013, 04:38 PM   #2084
6L6 is offline 6L6  United States
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This one. http://www.discogs.com/Virgil-Fox-Ba...elease/2619709

Don't underestimate it because it's 2 bucks -- It sold a zillion because it's so good.
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Old 14th March 2013, 05:51 PM   #2085
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There is a near mint copy for $4.99. The trick is to find 4-5 others from the same seller to get shipping down. It can take an hour to surf through a sellers inventory to find a half dozen worthy. I may have to pick up later.

I had been using "Yes - Going for the One" as my Pearl 2 test record in my shop. Rick Wakeman plays a big church organ on a few tracks. Good recording with a lot of ambiance.
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Old 14th March 2013, 09:31 PM   #2086
6L6 is offline 6L6  United States
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What do you think of it in your main system so far?
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Old 14th March 2013, 10:47 PM   #2087
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Still in the shop. Hopefully I can move it up this weekend. Too much work lately, I have not been home much.
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Old 15th March 2013, 03:18 AM   #2088
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Got home at a decent hour and brought the Pearl 2 into the main room. WOW. Happy Camper! Coltrane is in the room. Bob Marley. Grateful Dead. Clarity is amazing. Definitely a lot of gain with the Rega 2 but no problems, just need to turn down volume a bit. I think my speakers (Polk TSI 300) are the bottlenecks now.:-) Also using preamp outs from Yamaha Receiver to an F5 probably move on to the B1 next.
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Old 17th March 2013, 05:11 PM   #2089
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I have now replaced R21-24 with 20R (and put back 10k for R10). Voltages around Q3 are now (L/R):

Vc 8.555 (8.717)
Vb 9.125 (9.260)
Ve 8.466 (8.603)

Is it a problem that Vb > Vc? Should I maybe drop R10 to 8k2 or 6k8?

Voltage drop at R21/24 is 109.9 - 112.7 mV (L) and 112.7-114.1 (R).

With a test record I noticed that the gain of the entire Pearl is less now. Where it used to have around 300mV output with a 1kHz tone cut at 3.54cm/s it now has around 200mV (and this is with R14 = 680R in stead of 1k).

Sound-wise I cannot really say I hear a difference (you can't really A/B them of course). I will do some more testing before I decide to keep it this way or to go back to 10R.
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Old 17th March 2013, 05:23 PM   #2090
rsavas is offline rsavas  Canada
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For some fun, I have simulated this ckt using Pspice, below are the DC bias values that I get.Since I have not fab'd this ckt, I'd be interested to hear, what the actual ckt bias values are? I see some #'s in post # #2043
Q6-9(s)=75mV, 7.54mA, for a total of around 30mA
Q6-9(d)=4.89V
Q3(b)=5.61V
Q3(c)=4.96V
Q1(e)=19.1V

Last edited by rsavas; 17th March 2013 at 05:30 PM.
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