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

Hi Valery,

I loaded those gerbers/drills, for the VHEX designs, they look fine to me upon a first glance.
In the schematic I see a R symbols, some "<" and some ">" 🙂 I assume that they are rotated 180, you did not have them in your legend that you supplied the other day, what are those wattages?
Mouser has these
0.22/3W 660-MOSX3CT631RR22J for $0.288CDN and
0.22/5W 660-MOSX5CR22J 5W for $1.34CDN

For those diodes, 1N4004, is it not best for them to be a fast recovery type? something like UF4004 and is a 1A diode sufficient in size for the o/p stage back emf clamp diode?

Thanks
Rick

Hi Rick,

Those resistors are 5W. As you can see from the board outline, two different types of resistors can be used - cement ones (longer body) and plastic ones (shorter but taller body).

I used 1N400X countless number of times at these positions - never had issues like damaging them or something. Fast recovery is an advantage in general, but in case back emf clamping really happens - that's a rather "bad" extraordinary operating condition, so I consider possible slightly slower recovery as ok.

Cheers,
Valery
 
VHex+ OPS - PDFs for etching (2P and 3P)

PDF files for etching - all variants.

Have fun!
Val
 

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Valery:

Have you ever considered error-correction added to these output stages?

mlloyd1

Hi Mlloyd, a good question - of course I did 😀

However, I'd like to perform proper testing before I show the feed-forward EC solution for these output stages. My plan is to see highly accurate spectrums and do some listening with EC on and off in order to assess if it's really worth some extra parts.

I will let you know how it goes. If you would be interested to perform this kind of test as well - please PM me 😉

Cheers,
Valery
 
Hi Andrew and All,

Please see the good-matching OPS section documents attaches - 2-pairs and 3-pairs OPS options.

Optimal rails for 2-pairs OPS = +/-50...60V DC
Optimal rails for 3-pairs OPS = +/-65...75V DC

NOTE! Different rails require some resistors'value adjustment in Lichtstark front-end module!!! Let me know the rails you are going to use - I will let you know the values.
No changes in the OPS though.

Also note! Connectors on Lichtstark IPS and VHex OPS modules are mirrored with regards to each other! If they are placed one next to the other, IPS module has to be mounted either upside-down, or 90 degrees.

Cheers,
Valery

Can you tell me where is the whole schematic for this amp?
 
Nice!

Are there other options suggested for the IPS stage, perhaps something "Goldmund like" in LTP and VAS?

Hi Carlos,

Then I would recommend VHex+ design - see these posts >HERE< and >HERE<

Current-driven VAS is excellent performer. Here is the schematic and information on PCBs ordering (shipping is $15): VHex+ amplifier

Let me know if you will have questions 😉

Cheers,
Valery