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Sourcing parts [message #30126] Tue, 18 January 2005 19:45 Go to next message
colinhester is currently offline  colinhester
Messages: 1349
Registered: May 2009
Location: NE Arkansas
Illuminati (3rd Degree)
Seems we're going "balls out" getting a custom wound trany. I was wanting to keep the project around $100, but WTF. What's the best part for each component? If we're goin' do it, let's do it right.....Colin

Re: Sourcing parts [message #30127 is a reply to message #30126] Wed, 19 January 2005 06:45 Go to previous messageGo to next message
Manualblock is currently offline  Manualblock
Messages: 4973
Registered: May 2009
Illuminati (13th Degree)
Touche' now your talkin'! That was the drawback all along, go cheap and you have a Foreplay. Sign me up. Big transformers and caps here we come.
I always felt the difference between cheap and done right is not that signifigant with a pre-amp; money wise.

Sourcing parts [message #30128 is a reply to message #30127] Wed, 19 January 2005 07:20 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
Hey-Hey!!!,
For output coupling caps, Allied Electronics 7.5 uF ASC motor run caps. less than 10 each, any voltage rating is OK, but I slightly prefer the 440vac. Seem to be a slight improvement, and higher voltage will improve their recycleability.

Cascode the active loads. This is the single most important thing. One more mosfet and gate stopper each. Can't over-emphasize this one. Might be best to design to put it in later, just for effect. Battery bias on the CCS is an improvement as well, but is a bit more complex and perhaps can be done o a rev. 2 ( and more comfort has been achieved with the design ).

I don't quite agree with the cheap leads to ForePlay. The original as drawn will do quite well( better I think by a mile, but that's opinion for the time being ).

regards,
Douglas



Re: Sourcing parts [message #30131 is a reply to message #30128] Wed, 19 January 2005 09:05 Go to previous messageGo to next message
Manualblock is currently offline  Manualblock
Messages: 4973
Registered: May 2009
Illuminati (13th Degree)
O'Kay thats fair, I didn't mean to suggest the pre is weak just that the Foreplay is obviously a compromise since they must make some profit and at that price there isn't much room for frills.
Douglas; do we need a new schematic for the changes?
And about the filter choke; why not add it to Heybeors list?

Re: Sourcing parts [message #30133 is a reply to message #30131] Wed, 19 January 2005 09:44 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
The big choke is PN HTS 8039. I don't see any reason not to do it this way. There were a few things which were specified at minimum price and complexity. Make sure you specify the type of endbells you want for the choke, I had a nice pair of vertical ones from my salvage bin and told them to put it together any way they wanted...

The 'Swiss Army Knife' sort of Power Iron and the big choke will move things nicely up the performance ladder. In my book, $350-500 is a reasonable parts bill for a simple linestage.

With labour and profit margins, a $350 parts bill would work out to something like a $4k linestage once it was properly dressed...
regards,
Douglas

Re: Sourcing parts [message #30134 is a reply to message #30133] Wed, 19 January 2005 10:38 Go to previous messageGo to next message
colinhester is currently offline  colinhester
Messages: 1349
Registered: May 2009
Location: NE Arkansas
Illuminati (3rd Degree)
Is the original schematic posted in the below link still valid? I want to start ordering parts within the next couple of days.....Colin

most of it is... [message #30135 is a reply to message #30134] Wed, 19 January 2005 11:59 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
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Registered: May 2009
Illuminati (2nd Degree)
There are a few changes. One being the rectifier. The new revision is a standard full wave. HV to the plates, ground the CT and continue as drawn. No SS required to assemble a full bridge. The choke is now changed to the big Heyboer 8039, but the 100 uF/370VAC from eBay's midorimeadows is not changed. probably best to run the 6CA4, though a pair of 6AX4 or 6W4 are also 'do-able' since we have 3A to cover the 2.4A required for using two damper diodes.

Look at Bas Hornman's site on the active loads.

I can't think of anything else of any importance.
regards,
Douglas


Wayne, Can you OrCAD this? [message #30136 is a reply to message #30135] Wed, 19 January 2005 12:33 Go to previous messageGo to next message
colinhester is currently offline  colinhester
Messages: 1349
Registered: May 2009
Location: NE Arkansas
Illuminati (3rd Degree)
I'm still pretty new, and I don't want to make any mistakes. In your "spare" time, could you pretty please CAD this to include recent changes. Pleeeeeesa......Colin

Dual rectifiers [message #30137 is a reply to message #30135] Wed, 19 January 2005 12:48 Go to previous messageGo to next message
colinhester is currently offline  colinhester
Messages: 1349
Registered: May 2009
Location: NE Arkansas
Illuminati (3rd Degree)
It is worth upgrading to dual rectifiers? Seems like the cost would be minimal.....Colin

Re: Wayne, Can you OrCAD this? [message #30138 is a reply to message #30136] Wed, 19 January 2005 12:52 Go to previous messageGo to previous message
Wayne Parham is currently online  Wayne Parham
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Registered: January 2001
Illuminati (33rd Degree)
You betcha. I'd be glad to. I'm a little busy at the moment, but I'll try to draw it up sometime in the very near future.

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