832 TWEEKS

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pre65
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#151

Post by pre65 »

Looking at the 10M45s data sheet I see the diagram for the current mode wiring BUT I don't understand it.

Look as I might, the way to connect it up is not obvious to me. :oops:

Now I assume the HT goes to A and that Rk will be the 560R resistor to give me 5.5ma but thats where it stops.

HELP !

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Nick
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#152

Post by Nick »

Add 470R or so grid (gate) stopper between the end of the 560R resistor and g, then connect the point where the 560R and the gate resistor join to the valves anode.
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pre65
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#153

Post by pre65 »

Like this ?

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#154

Post by Andrew »

Looks right to me. G= 1 A = 2 (and body) K= 3.

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andrew Ivimey
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#155

Post by andrew Ivimey »

heat sink?!!!
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pre65
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#156

Post by pre65 »

andrew Ivimey wrote:heat sink?!!!
Thanks Nick & both Andrews.

I had picked up the two mosfets from Mikes choke kit by mistake. :oops: (well they look similar !)

They will be mounted on the amp inside front panel so that should suffice as the heat sink.

Just been scraping ice off the car windows so I can get to the local town for supplies, so will have a go later Ron.
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#157

Post by Nick »

Remember to isolate them from the heat sink, the tab will be at b+ voltages.

They have the magic thing called writing on them so you can tell them apart :-)
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pre65
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#158

Post by pre65 »

Nick wrote:Remember to isolate them from the heat sink, the tab will be at b+ voltages.

They have the magic thing called writing on them so you can tell them apart :-)
Strangely enough, I checked the writing on the device with Google, and when I found it was a mos-fet my first thought was that you had sent them to me in error ! Then I suddenly realised what I had done. :oops: :lol:

I have got some insulating kits !
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pre65
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#159

Post by pre65 »

Does the gate stopper resistor body have to be hard against the gate pin, like on valve grid stoppers ?

And would a ferrite bead as well be overkill ?
Last edited by pre65 on Tue Dec 15, 2009 1:55 pm, edited 1 time in total.
The only thing necessary for the triumph of evil is for good men to do nothing.

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#160

Post by Nick »

Yes.
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pre65
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#161

Post by pre65 »

OK !

I added a bit about the ferrite bead while you were replying.
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pre65
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#162

Post by pre65 »

Well it works, had no doubts really !

Had to drill the reg mounting hole out to 4mm as the only plastic "top hat" washers I had were in a TO-3 kit. Forgot I'd used all the proper ones and I could not see any in the electronic choke kit

The area on the front panel where they mount is staying cool so there are no heat issues. Measured HT as approx 90V (87V & 93V).

Playing Dory Previn at the moment and there is a positive difference (can't explain at the moment) and there is less noise through the speakers when idling. Even with the 26 pre there is a bit less background noise.

Just had another listen and it just seems "clearer" to me !
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#163

Post by Nick »

Even with the 26 pre there is a bit less background noise.
Confused again, I thought this was for the 26 pre?
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pre65
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#164

Post by pre65 »

:lol: This is the 832 tweeks thread. :wink:

Ah ! I was going to ask if the CCS would also work on a 26 !

It is now on the 12A (112A) that drives the 832a PP amp, and jolly well it does too.

Where's the best place to get some more 10M45s ?
The only thing necessary for the triumph of evil is for good men to do nothing.

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#165

Post by Nick »

DigiKey
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