Revisiting some "old" ideas from 1970's - IPS, OPS

[jwilhelm]

The On Semi parts can directly replace the Sanken parts. No changes needed other than larger driver heat sinks.

 

[carlmart]

Don't the drivers share the same heatsink as the output transistors?

Are there any LTSpice simulations with this output and bias arrangement?

 

[vzaichenko]

Don't the drivers share the same heatsink as the output transistors?

Are there any LTSpice simulations with this output and bias arrangement?

In the 3-pair version they don't. In the 6-pair version they do

I use Multisim, so I have many simulations in Multisim.

 

[vzaichenko]

As well as the live measurements. Very good ones

 

[jwilhelm]

The boards arrived today. The boards are so large hey won't fit in my toaster oven so I had to solder them with a hot air rework gun. I don't have enough output devices to power it up though.

 

[still4given]

Very nice!

 

[jwilhelm]

Thanks Terry! Nice to hear from you again. Been a while!

 

[jwilhelm]

It's alive! I've just powered it up and did some basic no load quick tests to see if everything is stable. Bias is a bit high so I need to sort that out. My scrap aluminum heat sink won't take long to overheat!

 

[vzaichenko]

Cool

 

[stocktrader200]

I am assuming bias is set by the slight current differences between the drivers?

 

[vzaichenko]

I am assuming bias is set by the slight current differences between the drivers?

It's actually Vbe difference between the Sanken and ON Semi devices due to some manufacturing specifics. Not really important - a matter of a single R value amendment (R30 in the schematic from the post #2874).

 

[jwilhelm]

If I recall correctly earlier versions of this amp required some adjustment to driver current due to higher LED forward voltage than expected. I'll fine tune everything before any further testing.

 

[vzaichenko]

If I recall correctly earlier versions of this amp required some adjustment to driver current due to higher LED forward voltage than expected. I'll fine tune everything before any further testing.

That's right Plus we have switched to the red LEDs here, so some reference voltage deviations may occur.

 

[thimios]

It's alive! I've just powered it up and did some basic no load quick tests to see if everything is stable. Bias is a bit high so I need to sort that out. My scrap aluminum heat sink won't take long to overheat!

Monster is alive!
Don't worry, tuning is always necessary!

 

[jwilhelm]

I actually find it kind of boring when a new design fires up with no glitches. I enjoy troubleshooting problems.

 

[jwilhelm]

It's running nicely now. I did some quick scope tests with +/- 56V rails with teh X4-JFET input and an 8 ohm dummy load. I gave it a short audition too, sounds great, very punchy bass! Dead silent with no signal as always.

Pictures are 1k sine at clipping, 1k square waves, 50k square waves at 100k sine.

Next I need to put together a chassis with proper cooling so I can done some proper high power testing and stereo audition.

 

[kawihornet]

It's running nicely now. I did some quick scope tests with +/- 56V rails with teh X4-JFET input and an 8 ohm dummy load. I gave it a short audition too, sounds great, very punchy bass! Dead silent with no signal as always.

Pictures are 1k sine at clipping, 1k square waves, 50k square waves at 100k sine.

Next I need to put together a chassis with proper cooling so I can done some proper high power testing and stereo audition.

what are you running for the output stage? Bi-Polar?

 

[jwilhelm]

Yes this is BJT outputs.

 

[kawihornet]

Yes this is BJT outputs.

This is in regards to the new 600watt beast coming up soon? Would this be mono blockable? and could we use a tube input stage?

 

[jwilhelm]

Yes this is the big power amp. It can be built as a monoblock. TubSuMo will plug right in.