Fet Limiter from a well known designer??

http://sound.westhost.com/project67.htm

Figure 1 is adapted from a published circuit from a well respected designer :-O

Click to expand...

what's that for a schem...??


:wink:


mat

I gather this is from a design that's been in this forum?

It's interesting. It is also true that the objection to the 1/2 drain voltage feedback is easily met with slightly different circuit configurations and does not entail control voltage feedthrough or long attack times. But I guess that is what the circuit shown is doing in its way.

BTW a good ref for FET use as voltage-controlled R's is in Designing with Field-Effect Transistors, second edition, revised by Ex Oxner, McGraw-Hill, 1990.

The idea behind that topology is of course identical/close to several designs. Would be interesting to know who exactly was meant.

FWIW, it won't be Boss/Roland I guess because of the clear hint at some famous individual, but of the few I looked up I must say the topology of the Boss NF-1 noise gate (and another pedal which shall remain nameless for now) was/were most close.
So who knows their comp-pedal from back then uses an alike approach, dunno.

Anyone knows which design the ESP-page is exactly referring to ?

Sorry, I don't get it. :roll: And am admitting it :wink:

I think he's suggesting that Phil Allison gets into arguments with knowlegeable folk...

I feel driven to say that even though it appers all parties to the arguments are smart people, the level to which the name-calling descends is more than a little alarming!!!

Keith :shock:

I think he's suggesting that Phil Allison gets into arguments with knowlegeable folk...

I feel driven to say that even though it appers all parties to the arguments are smart people, the level to which the name-calling descends is more than a little alarming!!!

Click to expand...

Thanks & right, people were having a good time at that link... :?

Hmm, the ESP-hint didn't seem to be towards Phil A, so I'm still wondering.

It isn't the 1176, it isn't the Trident. Iiiiiiiitssss........ (Monty Pythons Flying Limiter ?!)

Bye !

Peter

> Would be interesting to know who exactly was meant.

"Everybody". That first figure has to be the most common FET limiter on the planet. (Tho IIRC, the LevelLock doesn't bother with the distortion cancellation....)

> ESP-hint didn't seem to be towards Phil A,

The second, improved, version mentions a "Phil", and Phil A is a possibility. I had not seen that exact scheme, but similar themes are pretty common.

> a good ref for FET use as voltage-controlled R's is in Designing with Field-Effect Transistors, second edition, revised by Ex Oxner, McGraw-Hill, 1990.

From http://abe.com I find two books of that name:

Designing With Field-Effect Transistors (ISBN:0070574499)
Siliconix Incorporated; Evans, Arthur D.
McGraw-Hill. 1981.
Price: US $14.00-$40.00

Designing With Field-Effect Transistors (ISBN:0070575371)
Incorporated Siliconix
1/10/1989 McGraw-Hill Companies.
Price: US$ 29.95

Designing With Field-Effect Transistors. Second Edition (ISBN:0070575371)
Oxner, Ed
Book Description: McGraw-Hill 1990.
US$ 120.00

Sadly for everybody but me, I just ordered the $30 copy dated 1989. I assume this is the same as your 1990 citation. The ISBN is the same as the 1990 $120 copy, so it should be......

The 1990 version says Ed Oxner, which sounds a lot like "Ex Oxner" to me... so looks like that's a safe bet!

-Sadly for everyone else because....?

... ... ...-They only had one?

Keef

Heh. Yeah. It is a great book all around, and certainly the two with the same ISBN's are the ones. Seems to me I picked mine up on eBay not too long ago. The FFEP says 22.50 in pencil but I think it was one of those books nobody was interested in at the time so probably cheaper.

Fortunately I held it out from the bulk of my books and have it at hand rather than in one of several hundred boxes in a 10 x 30 storage space. I haven't been as lucky with many others.

Thanks, all is OK.
It's about that FET-circuit - I should stop wondering who's actually meant by Rods riddle.

So my last words on that:
I focussed too much on the specific component values & topology-details. PRR's of course right, the essence of the circuit is used everywhere.

So very much stating the obvious: a famous designer or FET-compressor ? --> let's simply assume Mr. Putnam was meant.

With that off my chest my weekend can start :wink:

Have a good weekend all,

Peter

> looks like that's a safe bet!

I bet nickels, maybe a twenty or two if bcarso says to; not $120 bills.

> -Sadly for everyone else because....? ... ... ...-They only had one?

ABE is a lot of small used-book seller listings. It is a good place to find second-hand textbooks etc without running all over the Web. They listed several of the 1981 edition; indeed if a book sold well, ABE will usually find a bunch and you can pick condition/price.

But there were only two listings that looked like bcarso's cite. One at $120!!! One at $30. The cheap one lists the author as "Incorporated Siliconix", which isn't Ex/Ed but I note several of the 1981 editions list both Arthur and Siliconex as co-authors so I figured this was the right book. The date is different; maybe there is a copyright date and a printing date. They are too close to be totally different editions. ALso the publisher and ISBN are the same, so it "should" be the same book right down to the binding (not that I'd care if I got a pre-press proof).

So I'm gambling the $33 to get the one copy of the 1989 listing. SO you can't have it. You either get the $120 copy, or go digging elsewhere. Try putting the ISBN into Google. You get a few odd hits, but most are book-links.

Ah: BookFinder4U lists 15 copies at $20-$120, half in the USA and the rest all over the world. Powells wants $25 and they are top-notch. Even if you are not in the USA, Powells will get it to Germany cheaper than the German seller will.

Powells is really cool. Every time I walk into the store I end up getting two or three used technical books at about $10 each. My favorites are transistor circuit design books from sixties and seventies. It is interesting how much they were able to accomplish with a few transistors that we think need several opamps to do now.

Tamas I would get into so much trouble if I lived in Portland.

Actually Powell's has got their database working so well that if I know what I want it is easy to see if they have it, and I have bought plenty from them over the years. But the danger of a serious browsing session when I have some credit lines with room left---dangerous indeed.

> BTW a good ref for FET use as voltage-controlled R's is in Designing with Field-Effect Transistors, second edition, revised by Ed Oxner, McGraw-Hill, 1990.

Got it last week.

First two chapters are MUST-KNOW for anybody yacking about FETs.

The section on FET VCRs is possibly the best single treatment I know. Still skimpy.

The rest of it is good but hardly brilliant. More a collection of Application Engineer essays/articles than a holistic exploration of FETs. Some passages beat small details to death, others gloss over broad concepts hastily. Some typos seem to be multi-generation.

I like the page that says DMOSFETs have negative tempco, and the chart on the next page clearly shows positive tempco. As we all know (no?), it is neg at high current and pos at low current, but if he ever says that I missed it.

Good Buy at $20. Not sorry I paid $30. Don't pay $120 unless you are very interested and rich.

Yeah 120 is steep for what is there. Nice to have it collected in one place though, even if as you say a lot is app notish stuff.

It's better than Sevin in the TI series, and more up-to-date than the book by Cobbold.