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Old 21st September 2009, 08:41 PM   #51
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If these are going to be matched, I would like 8 (ie 4 per channel).
It would be nice if you labelled them with the values. A bit of masking tape will do.

I just need the matching for equal heat dissipation, so they just need to be matched in pairs.

Last edited by Melon Head; 21st September 2009 at 08:43 PM.
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Old 21st September 2009, 08:52 PM   #52
mos57 is offline mos57  Italy
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Quote:
Originally Posted by thanh1973 View Post
If these are going to be matched, I would like 8 (ie 4 per channel).
It would be nice if you labelled them with the values. A bit of masking tape will do.

I just need the matching for equal heat dissipation, so they just need to be matched in pairs.
At this moment, please you must follow the thread opened by Magura in Group Buy.

Best regards, Francesco

Last edited by mos57; 21st September 2009 at 08:56 PM.
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Old 21st September 2009, 08:55 PM   #53
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Thanks for the info
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Old 22nd September 2009, 06:25 AM   #54
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Quote:
Originally Posted by Blues View Post
my first thread in years and just over a weekend and it's already 5 pages...

Morten, I'm interested in your GB the jfets being TO-247s...

Mr. Pass, are the Lovoltechs even an option for the "other" output jfet (CCS)? Might be useful to some who have a stash of those...and cheaper.
The upper FET would appear to have to dissipate as much power as the lower FET, so no dice with the tiny Lovoltech. Using a MOSFET as a cost saving option up there is more realistic.
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Old 22nd September 2009, 08:11 AM   #55
MRupp is offline MRupp  Germany
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Mr. Pass, are the Lovoltechs even an option for the "other" output jfet (CCS)? Might be useful to some who have a stash of those...and cheaper
I was thinking along the same lines. The Lovoltechs are depletion mode devices and the Semisouth are enhancement devices, so just with a bipolar supply there is no headroom for biasing the Lovoltechs. However, an extra voltage source for the input stage of a few Volts and cascaded under the negative supply voltage should work?

Quote:
The upper FET would appear to have to dissipate as much power as the lower FET, so no dice with the tiny Lovoltech. Using a MOSFET as a cost saving option up there is more realistic.
The Lovoltech need to be cascoded, same as in the F3 so that takes care of dissipation. Since the Mu follower should be there to cancel distortion, I presume upper and lower device should be the same. The one caveat is that the (Lovoltech + Mosfet) cascode already removes a lot of distortion so it is not clear what effect the mu follower would still have.

My two cents ...
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Old 23rd September 2009, 01:46 PM   #56
sekess is offline sekess  United States
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Default Power Supply

Quote from the owner's manual:

"On the front panel there are two blue LED lights, one for each channel, indicating regulated power to the channel."

Does this mean that the J2 will be getting a regulated power supply instead of the unregulated First Watt power supplies in the previous offerings?

Steve
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Old 23rd September 2009, 08:07 PM   #57
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No, it means that that this section of the manual was cut
and pasted from an F3 manual.

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Old 23rd September 2009, 08:12 PM   #58
DougL is offline DougL  United States
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Originally Posted by Nelson Pass View Post
No, it means that that this section of the manual was cut
and pasted from an F3 manual.


Funny how that works.
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Old 23rd September 2009, 08:33 PM   #59
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I speculate it uses a 24v dual rail supply
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Old 23rd September 2009, 08:34 PM   #60
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Default p channels

Nelson, have you asked them if they could do p-channels as well http://www.semisouth.com/products/custom.html ?

Kind regds

Rolv-Karsten
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