I have decided to build a new speaker. I'm going to try my hand at the Lowther TP-1 Isis using DX4 drivers. I'm curious what amplifier would NP recommend to power these? I'm looking for a range of ideas I guess. I'd love a gen-u-ine (with a Texas accent) INT-30A, and might be able to pull that off, but perhaps there is a better choice? a more realistic choice?
Hi,
I put here my own experience about matching mosfets.
The method :
On a thermostated table home made, regulated at 35°C +/-0.3°C :
I measure the Vgs when Gate and drain are connected, and Ids injected by a regulated source of current.
The Ids are 100ma and 200ma
Two full batches of Irfp240 and Irfp9240 (2x1000 mosfets).
Here the results for the two batches :
Vgs of the Irfp240 and 9240
Magenta : Batch 1, 200ma / Dark Blue : Batch 1 100 ma
Cyan : Batch 2, 200ma / Yellow : Batch 2, 100ma
You can see that the batches of 240 are better than the 9240 ones.
These batches permit to have a good sextet matching (1mv for 240 and 2mv for 9240).
I put here my own experience about matching mosfets.
The method :
On a thermostated table home made, regulated at 35°C +/-0.3°C :
I measure the Vgs when Gate and drain are connected, and Ids injected by a regulated source of current.
The Ids are 100ma and 200ma
Two full batches of Irfp240 and Irfp9240 (2x1000 mosfets).
Here the results for the two batches :
Vgs of the Irfp240 and 9240
Magenta : Batch 1, 200ma / Dark Blue : Batch 1 100 ma
Cyan : Batch 2, 200ma / Yellow : Batch 2, 100ma
You can see that the batches of 240 are better than the 9240 ones.
These batches permit to have a good sextet matching (1mv for 240 and 2mv for 9240).
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Check out the last newsletter with the article about Burning Amp. It discusses the amps Papa used and a filter to make it work..
Thanks for your feedback ...
philbyx said:
Hi Philippe,
Nice setup and interesting results
Thanks for sharing ...
Manu
Hm, I see the F2J mentioned and a network to integrate it with a Seas driver, but perhaps I missed something? Thanks for that though, it was a great read, even a second time
Hm, I see the F2J mentioned and a network to integrate it with a Seas driver, but perhaps I missed something? Thanks for that though, it was a great read, even a second time
Luvdunhill -
I use a F2J clone,
with a lowther PM5A, a 10R-10uf across the terminal sounds good to me. (running OB)
next choice was 10R across the terminals. I left out the 3x47R resistors in F2J.
I wonder what Papa or Jon ver Halen use in OB with PM5 or 6A.
I have not experimented around too much. it sounds really laid back, with a sweet mid and really nice top end.
Hm, I see the F2J mentioned and a network to integrate it with a Seas driver, but perhaps I missed something? Thanks for that though, it was a great read, even a second time
Sorry, you're right, the info was for the Seas driver. Still, clearly the F-2J is a contender!
Papa has a lot going on at the moment so can't post much, but maybe later..
I built one, and have gotten good review from one of my alpha testers.
It will be along soon enough.
I built one, and have gotten good review from one of my alpha testers.
It will be along soon enough.
ya mean this ?
Attached Files F6 leaked sch.pdf (38.6 KB, 44 views)
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