Hackernap parallel output transistors

[timH]

GWM - yes my bolt down NAP160 had the transistors bolted on the outside of the case with leads to the amp board

Andrew - yes indeed and that’s what the NCC300 board has

 

[andrewsutton]

So how much would I need to do to change my NCC220 boards to parallel output transistor configuration?
Cheers Andy.

 

[Pete MB&D]

Mjl4203 transistors ordered from On semi!

$14.99 for 5 as samples.

Pete

 

[timH]

Andy
2 extra transistors per board ( but I went for four new ones per board just in case) 4 off 0r33 emitter resistors per board some 1¼ x 1¼ 3mm Ali u channel ( I’ll dig up a link) some heat sinks and bolts

 

[timH]

Just realised your boards have those TO3 devices so you may have to do it a bit differently to how Pete and I have.

 

[juz400]

I got a meter long bit of U channel from these guys, came shipped in a cardboard tube.
http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=262725531977
Easy to cut with hacksaw and tidy up afterwards

EDIT: Didnt see Tim`s second post! They do all sorts of shape bits of Ally

 

[timH]

Don’t think u channel would work after all. The NCC300 puts the devices side by side so if you have enough width that would be feasible. If not you could put them behind each other on a deeper piece of Ali. Either way you would need a little connector board and join them underneath

 

[timH]

Mjl4203 transistors ordered from On semi!

$14.99 for 5 as samples.

Pete

Beat me to it All I’ve done is etch a board so far

 

[Pete MB&D]

Beat me to it All I’ve done is etch a board so far

Ooo show us your board, I still haven't decided on the best way forwards.

Pete

 

[TOR]

Very exciting, I’ll have to have a dig through the bits boxes and join the party!

 

[Pete MB&D]

'ant no party like a paralleled output transistor party...

Pete

 

[timH]

 

[Boxmaster]

 

[Boxmaster]

My question about using 0,33 ohm emitter resistors ; why are they 0,33 ohm, and not 0,22 ohm ? I believe in the NCC300 they are also 0,22 ohm. Why not follow this ? My compliments about your efforts in trying to give the NCC200 a second life.

 

[Boxmaster]

My question about using 0,33 ohm emitter resistors ; why are they 0,33 ohm, and not 0,22 ohm ? I believe in the NCC300 they are also 0,22 ohm. Why not follow this ? My compliments about your efforts in trying to give the NCC200 a second life.

And of course the Hackernap

 

[bugbear]

My question about using 0,33 ohm emitter resistors ; why are they 0,33 ohm, and not 0,22 ohm ? I believe in the NCC300 they are also 0,22 ohm. Why not follow this ?

I can't help with the why, but in my parallel/complementary (Sanken 2SA1216/2SC2922) Sugden Au51p the emitter resistors are also 0.33Ω (55V rails if it matters).

BugBear

 

[timH]

Well in the DIYAudio Honey Badger amp they’re also 0r22 but in the RCA circuit diagram I have they’re actually 0r39 !

 

[Pete MB&D]

Looks wrong to me, the bottom holes seem to short out two connections.
Which end is the board connections?

Pete

 

[timH]

Board connection is at the bottom.
It’s a double sided pcb.
The top image shows the board from the device side and shows the emitter track cut and a hole for the extra emitter resistor.
Bottom image shows the board from the amp side and shows where the C and E cross over. I’m pretty sure it works but I’ll have another look

 

[Pete MB&D]

If you solder both sides of the board on the left hand bottom hole you will short out two connections.

Pete