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

[jwilhelm]

Here's a drill template for the heatsinks.

 

[thimios]

Here's a drill template for the heatsinks.

Thanks.
My plan is to use a KSA1381 INSTEAD OF MJE350 for Vbe multipl. Easy mount without using mica insulator.

 

[mlloyd1]

be careful ...
don't the mj* parts behave a little differently than the ks* parts in this particular application?

mlloyd1

Thanks.
My plan is to use a KSA1381 INSTEAD OF MJE350 for Vbe multipl. Easy mount without using mica insulator.

 

[thimios]

be careful ...
don't the mj* parts behave a little differently than the ks* parts in this particular application?

mlloyd1

I had made the same in slewmaster power amplifier but better would be have the Valery opinion.

 

[jwilhelm]

Most used BD139 in the Slewmasters, but it didn't track temperature as closely as MJE340.

 

[thimios]

Most used BD139 in the Slewmasters, but it didn't track temperature as closely as MJE340.

So it's a bad idea...

 

[jwilhelm]

This is Valery's creation. He know best.

 

[thimios]

I have used ksa1220 ksc2690 instead of 340/350

Hi Evanc we speaking about Vbe multiplier
BTW let's wait for the Valery answer.

 

[mlloyd1]

yes, i kinda' sorta' remember OS similarly commenting about this, too.

Most used BD139 in the Slewmasters, but it didn't track temperature as closely as MJE340.

but, i agree - likely best to wait for Valery to comment ...

mlloyd1

 

[evanc]

Yes I thought you were speaking about the cap multipliers for the front end. My mistake... I deleted my post

 

[thimios]

Small progress on power supply board (modifications are just for test).
I'm afraid that is time to desolder some of the power amplifier transistors🙁
I believe that these must be mounted on main heatsink.
To be more clear,Jef i see two points where you type +24v/-24v on power supply board.Is it right? To my point of view this points are connected to main power supply board.

Sorry don't take in account the second picture where the IPS just placed on the OUT.
Wrong direction!

 

[vzaichenko]

Hi guys, sorry for delay - I use MJE340/350 in bias spreader as this setup is well-tested, providing predictable tempco.

I have never practically tested KSC3503/1381 in this role, except one case - in NS-OPS they are used in a clamping voltage spreader temperature tracking and seem to show rather similar tempco.

Thimios - worth trying it, just watch the bias setting curve during the first tests.
It normally goes a little bit above the desired value in the beginning, coming down to it in 10-15 minutes as the heatsink warms up.

 

[thimios]

Thanks Valery,i will stay to mje350 as i don't like lifted traces.
Here is the second channel VFA IPS.

 

[jwilhelm]

It looks like you're getting closer to running.😎

 

[thimios]

It looks like you're getting closer to running.😎

Evanc has sent to me the heatshinks but appears that they are traveling to France because of a wrong!😱

 

[evanc]

Sorry for the delay. We won't know the reason until Monday. The address is correct in the order and conformation from the supplier.

 

[thimios]

Sorry for the delay. We won't know the reason until Monday. The address is correct in the order and conformation from the supplier.

Don't worry my friend!
We will wait🙂
Waiting this i will go for the CFA IPS.

 

[jwilhelm]

How are the heatsinks shipping? Could they be changing carriers in France? This happens with EBay's global shipping program. Parts change carriers multiple times through their trip.

 

[evanc]

They went usps from heatsink usa to thimios. That is what I thought until I saw this.
https://tools.usps.com/go/TrackConf...llpage&tLc=1&text28777=&tLabels=CV042409431US

 

[thimios]

Don't worry my friend!
We will wait🙂
Waiting this i will go for the CFA IPS.

Finally i will go for VZ-X4😱
Those sod 323 4148