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John Warren

Crown D-45 schematic

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Anyone have a PDF of the schematic (or PDF of the service manual)?

 

If so, could you PM to me?

 

Thanks in advance! 

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I don't have the actual amp in my possession yet but I've been looking at the D-75 for insight.  Crown has a list of SMs on their website but the D-45 isn't there.  I did sent a request so we shall see.

 

Thanks for responding.

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1 hour ago, The Dude said:

Are you going to do some hot rodding? I have some 33uf black gates if interested.

 

I'm first trying the mods Mark Deneen proposed a while ago on the so-called "Duke".

I have a couple other ideas I'll investigate too.

 

 

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I'm first trying the mods Mark Deneen proposed a while ago on the so-called "Duke".







I have a couple other ideas I'll investigate too.







 







 



Thats why bought mine along with the black gates

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What were Marks mods? I remember the thread but I guess it's gone now? I have a D-45 myself. They are available for reasonable on Ebay all the time.

 

 

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What were Marks mods? I remember the thread but I guess it's gone now? I have a D-45 myself. They are available for reasonable on Ebay all the time.







 







 



If you haven't all ready, do a search of my threads. I started one a couple years back in regards to this amp and mods. Maybe it was lost or deleted.

I am on Tapatalk now and cant seem to find the search function

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I have the whole thread in a pdf on my phone if I could justfigure out how to attach it.

 

Just sold the Duke last week.  Miss it already

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Thanks Carl, Mark did make some interesting changes to the amp including faster op amps. One thing I didn't find is what op amps he installed?  

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1 hour ago, JL Sargent said:

Thanks Carl, Mark did make some interesting changes to the amp including faster op amps. One thing I didn't find is what op amps he installed?  

It might be mentioned here

 

From what I was told in the original thread,  there might better OP amps now.  So I started to do some research, but that was all the further I got.  I am glad to see this concept get some more attention.

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"I used the TLS084, mostly because of pinout restrictions and not wanting to out run the rest of the circuit."

It's all I can gather from the thread, other than a Texas Instruments device with 2X the speed.

 

Still pondering on the D75 locally...if it's still around in a week when I know my cash situation better I'll hit them up with a offer.

It's an older unit, with the aluminum knobs and gray faceplate...along with speaker binding posts, and balanced inputs, with 1/4" jack inputs as well.

It's a bad time of year for me to buy stuff...

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Except for the chassis, the power transformer, the PC boards and the front panel knobs, I can source everything needed to completely rebuild/mod this amplifier from Mouser and it's lower cost.  There are two 14 pin chips, one is the input stage (quad differential amplifier) and the other is a voltage comparator (to drive the overload LED indicators).  Everything else is a discrete. 

 

The power supply caps are screw terminal, high posts, 1/2" spacings.  The Mouser PN for a 12,000uF cap with the right configuration to shoe-horn into the D45 is http://www.mouser.com/search/ProductDetail.aspx?r=598-DCMC50V123

 

Does increasing the filter capacitor size improve things?  Well, I do measure a large drop in ripple when I straddle 9000uF to each side of the supply (scroll down):

http://www.northreadingeng.com/Forums/viewtopic.php?f=8&t=9

 

Will this translate into reduced distortion is still to be determined (my parts are on order).

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