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

[Veysel]

hi vzaichenko

I really like this design.
I want to try to set up the output stage so , do you have any suggestions?

 

[vzaichenko]

Ostripper actually removed the output decoupling caps from the last Slewmaster board. If I remember correctly, he found they could cause ringing in simulation.

OK... I never noticed risk or ringing in such cases... small electrolytics worked well there. So... up to the designer 🙂

 

[vzaichenko]

hi vzaichenko

I really like this design.
I want to try to set up the output stage so , do you have any suggestions?

Hi Veysel,

Let me run a few simulations. However, from the first glance - looks good 😎
Excellent performance/simplicity ratio 😛

Cheers,
Valery

 

[didiet78]

Guys, here is a great work by George (member filenet).

He has re-designed the PCB, combining the VERTICAL front-end and NS-OPS with 2SC5200/2SA1943 output devices, and making is easy to etch.
George allowed me to publish his photos, I also take the liberty to show a fragment of his message, so that you see the key amendments he did as well as his impressions:

I finished your Vertical NS-OPS. I made some `slight` modifications to it:
1. I am using +/-60v power supply with only 20000uF per rail from an old project.
2. I changed the output devices to 2SC5200/2SA1943. Also here i am using a zobel network and a big inductor with 10ohm resistor.
3. I changed R1 2k7 resistor with 4k7.
4. I changed 22uF capacitors to 47uF because this is what i had in stock.
5. The boards are THT single layer (see the pictures).
I must admit i was a little anxious when i first switch the power on, about everything turning into a 200w oscillator. That never happened 🙂.
The amplifier is stable. It has little hum when the inputs are not connected to a source, that`s ok , i do not intend to use the amp not connected to anything 🙂.
The sound is top class without the huge class A dissipation 😉
Now such an amp deserves a 21 century protection.

Congratulations George for your successful build and thanks for sharing your experience. The design becomes really mature 😛
You inspire me to come up with my version of the layout, combining both Vertical and NS-OPS on one board, having all the outputs on one side 😉

Cheers,
Valery

Will he share his layout ? 😀

 

[vzaichenko]

Will he share his layout ? 😀

PM me your email 😉

 

[didiet78]

Your inbox full. I reply to your gmail

 

[vzaichenko]

INDEX at post #1

OK, I have finally spent some time and added an index of the key things in this thread:

INDEX is here.

It looks like there are pretty many of them 😛
Many thanks to all the contributors! 😎

Have fun! 😉

 

[AndrewT]

Wonderful. Thanks.
Really helps when a popular thread becomes big and difficult to navigate.

 

[vzaichenko]

Wonderful. Thanks.
Really helps when a popular thread becomes big and difficult to navigate.

Andrew, it was actually you, who pushed me to do it. Thank you for that 😉

 

[AndrewT]

And I am being led to believe by some here that no one of any consequence reads any of my posts.

 

[vzaichenko]

You know, some people pretend they don't, while they actually do 😛

 

[jwilhelm]

And I am being led to believe by some here that no one of any consequence reads any of my posts.

I think everyone reads your posts. Most of them are really good information.

 

[AndrewT]

..............your posts. Most of them are really good information.

Am I allowed to conclude from this that the few that don't contain "really good information" must have absolutely wonderful insights into the workings of science ?

Rose tinted glasses syndrome!

 

[jwilhelm]

Am I allowed to conclude from this that the few that don't contain "really good information" must have absolutely wonderful insights into the workings of science ?

Rose tinted glasses syndrome!

The odd post isn't bang on, but someone will usually try to explain why.(Recent tapping advice comes to mind.)

 

[vzaichenko]

Vertical + NS-OPS combined PCB

Cooking my version of the combined one with the heatsink on one side 😉

 

[Cortez]

Wouldn't it be better to place the 470u caps closer to each other (shorter GND wire)
and closer to the output devices (smaller high current loops)?

 

[jwilhelm]

I usually try to keep both rail feeds close together so the wires can be twisted together. Here's where this type of layout becomes tougher to do.

 

[vzaichenko]

Good point - I will think a bit more about it. There's enough space for the front-end, so I can play with those caps placement quite a bit. On one hand, the main ground return from the speaker terminal goes directly to PSU, so here it does not have to be that tough. On the other hand, the rail traces must be tough, and I try to keep the terminals close to the output transistors. I can place the rail terminals close to the center, but then the rail traces become rather "dirty" when they reach the front-end...

 

[vzaichenko]

Separate rail terminals for the front-end will be a good solution. And then a builder can decide if he wants a separate PSU, probably regulated one, or just connect them to the same PSU, but with a separate set of twisted wires. Good point! 😎

 

[jwilhelm]

Here was my first attempt, but I didn't really like how it was coming out. I was thinking after doing a left and right version with an RCA connector on board each that would protrude through the back cover to remove signal/noise antenna wires.