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Re: Hi and a Few Questions [message #79576 is a reply to message #79575] Mon, 24 February 2014 21:39 Go to previous messageGo to next message
Michaelzh is currently offline  Michaelzh
Messages: 23
Registered: February 2013
Chancellor
You are right. I removed jumper at R5 and the amp works. The "sweet spot" seems expands a bit but not much.
Re: Hi and a Few Questions [message #79583 is a reply to message #79576] Tue, 25 February 2014 08:58 Go to previous messageGo to next message
Michaelzh is currently offline  Michaelzh
Messages: 23
Registered: February 2013
Chancellor
I pulled the plug on a pair of Delta 10A.

I will try to "shift the tweeter crossover down a smidge" with JBL 2123J in place. I need to go back to do some reading for this.

I checked the polarity according to the schematics and "reversed" polarity marks of the JBL drivers in use. Everything appears correct in that aspect.


On another note, I really enjoy my current set up with the TPA3116 digital amp. I used to use a 300B tube amp. I notice one interesting difference: with the tube amp. when the volume is low, the details and expression of the sound seem subdued, but with the digital amp, they are still there, making low volume listening much more enjoyalable.
Re: Hi and a Few Questions [message #79585 is a reply to message #79583] Tue, 25 February 2014 20:51 Go to previous messageGo to next message
Michaelzh is currently offline  Michaelzh
Messages: 23
Registered: February 2013
Chancellor
I checked polarities of connections again tonight and found that one channel had tweeter connected wrong. I have to say that making all connections right is as hard as math for me. After the correction, the sweet spot increased considerably. I am waiting for the Delta 10A woofers and will see how they compare to JBL2123J in directivity department. I probably would not have ordered them had I found the error early enough. I also realized that the 300B tubes are in use for over 11 years. They probably ran out juice and do not do drive low volume well.

I can't help feeling what a wonderful design Wayne made free for us. I am so very grateful for your help and generosity!

Re: Hi and a Few Questions [message #79654 is a reply to message #79585] Mon, 10 March 2014 19:49 Go to previous messageGo to next message
Michaelzh is currently offline  Michaelzh
Messages: 23
Registered: February 2013
Chancellor
I finally replaced JBL 2123Js with Eminence Delta 10As and added resistors and inductors to the crossover boards so that the crossovers are exactly the same as specified by Wayne's plan and connected the speakers according to Wayne's plan as well. I discovered that I have to move my seat 2 feet and maybe and half further away from the front wall to get a much larger sweet spot. The sound is more relaxed than before which I like a lot. Maybe this is what Wayne meant when describing the corner horn sound with Delta 10 as creamy?

Wayne, do Delta 10As require break in at all?
Re: Hi and a Few Questions [message #79663 is a reply to message #79654] Tue, 11 March 2014 10:47 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18669
Registered: January 2001
Illuminati (33rd Degree)

I hate using adjectives to describe sound, being more of a models and measurements kind of guy. Bill Epstein is breaking me of that hangup though, what with his descriptions over the years. Smile (Look 'em up, you'll see what I mean.) Anyway, adjective objections notwithstanding, it does sound kind of creamy, doesn't it? Sort of has a SET sound.

As for break-in, that Delta 10 has a stiff suspension that doesn't loosen up. I see no real change over time. And it isn't like some other drivers that change electro-mechanical properties dramatically at various power levels. Well, I mean, it does - all of 'em do - but this one is so stiff that it just goes from super-stiff to very stiff. Always stays in the same ballpark.

Re: Hi and a Few Questions [message #79674 is a reply to message #79663] Wed, 12 March 2014 07:56 Go to previous message
Michaelzh is currently offline  Michaelzh
Messages: 23
Registered: February 2013
Chancellor
I read some of Bill's posts and found his posts can be quite fun to read. I like the immediacy in his use of words and descriptions or storytelling. Let me know if he has written any books.

The biggest difference brought by the use of Delta 10A is everything becomes just right: very smooth, natural, expressive and quiet. The loud part and quiet part are all very expressive, making one feel here is the stop - no need for tweaking anymore.

I used to doubt when I read you saying loudspeaker is the most important part of audio chain. Now I agree with you.
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