My new baby amp

[suzyj]

Hi guys,

Here's a gratuitous pic of my new amp - a little 50W lateral MOSFET design destined for my study. It's essentially the same topology as my 100W one (in turn based on David Tilbrook's AEM6000), but I've taken advantage of the lower supply rails (+/-40V rather than +/-56V) and used MMBT06/56s in place of many of the MJE340s and 350s. It also only uses one pair of 2SK1058/2SJ162 lateral MOSFETs.



It simulates very well - 0.0005% THD at 1KHz (50W into 8 Ohms), and 0.004% THD at 10KHz (50W into 8 Ohms).

Cheers,

Suzy

[fluckscapacitor]

can you post the schematic?

[suzyj]

Originally posted by fluckscapacitor
can you post the schematic?

Ask and ye shall receive: http://www.littlefishbicycles.com/poweramp/50W_amp.pdf

Cheers,

Suzy

[bushroot]

Very nice work. If I wasn't scared of SMD, I might give it a try.

[The Saint]

Awesome Suzy

Perfect layout as usual
I love those low profile caps...

Here is my latest little amp what do you think?

[suzyj]

Originally posted by The Saint
I love those low profile caps...

Here is my latest little amp what do you think?

I'm squeezing a pair of these, a 120W toroidal transformer, a preamp board, and a control board into a box 170 x 185 x 100mm. The 25mm high caps (highest that will fit) were really hard to get.

Your board looks really well laid out. You really need some SMD parts though You could start with the odd melf resistor. It's a slippery slope from there.

Cheers,

Suzy

[FastEddy]

" ... 0.0005% THD at 1KHz (50W into 8 Ohms), and 0.004% THD at 10KHz (50W into 8 Ohms) ..." ==== Aaaw 'some ...
...

Yes, what exactly is the total vertical height including any required stand offs or insulators?? (Will it fit inside a 1U rack mount chassis?)

A heat sink not required ?? (or is there some more parts we can't see yet?)

Kit soon? Modular amp soon?

" ... a preamp board, ..." ... ?? got a pic of that too?

[djQUAN]

a kit would be interesting!

fasteddy,
from what I can see the mosfets are under the holes between the power caps......then the board mounts on the heatsink much like the P68 or P101 amps from ESP.

[felixx]

@suzyj
It seems you have a plate with an operational.
That don't "apear" on your schematics.
Could you tell us more about that?

[suzyj]

Originally posted by FastEddy
Yes, what exactly is the total vertical height including any required stand offs or insulators?? (Will it fit inside a 1U rack mount chassis?)

A heat sink not required ?? (or is there some more parts we can't see yet?)

Kit soon? Modular amp soon?

" ... a preamp board, ..." ... ?? got a pic of that too?

It's 33mm tall. 5mm for the MOSFETS (under the PCB), 3mm for the PCB, and 25mm for the filter caps. It'll fit easily into a 1U box.

The heatsink goes on the back. a pair of bolts go through the PCB, through the MOSFETs, and into the heatsink. It's a similar arrangement to what I did with my 100W amp.

Dunno about kits. It's too much of a derivative of Tilbrook's work for me to make money from.

The boards are designed but yet to be made for the preamp. It's a fairly simple affair with switching done using SSM2404 quad switches, an OPA2134 as a buffer, and a PGA2310 volume control.

Originally posted by felixx
@suzyj
It seems you have a plate with an operational.
That don't "apear" on your schematics.
Could you tell us more about that?

I assume you're referring to the 8 pin SOIC? That's the SST404 matched dual JFET.

Cheers,

Suzy