Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id w3CLdHWX004458 for ; Thu, 12 Apr 2018 23:39:18 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1f6jr5-0007rk-FS for rs_out_1@blacksheep.org; Thu, 12 Apr 2018 22:34:07 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1f6jr4-0007rb-OR for rsgb_lf_group@blacksheep.org; Thu, 12 Apr 2018 22:34:06 +0100 Received: from mail-wm0-x232.google.com ([2a00:1450:400c:c09::232]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1f6jr0-0005iP-NI for rsgb_lf_group@blacksheep.org; Thu, 12 Apr 2018 22:34:05 +0100 Received: by mail-wm0-x232.google.com with SMTP id r82so837467wme.0 for ; Thu, 12 Apr 2018 14:34:01 -0700 (PDT) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=kXFh5hb8wGHCNJVFiHu23y0k0eZkYbeKiWeFbmPJh1Q=; b=Oz7bAN08QkioC9QFIUSt/PbGvOkPajbbQYi0YeE2wZWf7xQDdgTLUDNAbStLbEPJay I4LuepszQWLq+4/lt8VSQlU/zc+bWCYpeR4uKHzqPFMm1E6QuMRqrLXcNnndaoSMzCif hOswzjdyjl2j/dGjQZmKrO3O69f8h0Q7KSvGvmhbRhLYDmRsSR3fR1nFqkXnGtTVqXSM L7nVMDiXEt7CHrX8ekXAlQezAx7jWRBA0LYFFxZqEObBCC7pfkv2W3U4oN1hyJbUzCtw v7GU4EoaT97UrLPCCDJAxkaF3kdfnLvZDHGvlgSx/PqOe5oXC8EJG/BIbF8mxMR268g7 /N7Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=kXFh5hb8wGHCNJVFiHu23y0k0eZkYbeKiWeFbmPJh1Q=; b=JmPVifdaZATUYniBMcfOLEKC0trETakEak4BMN3nxaG1+jHHd2mkdN5BW1/Tnr/iu1 88um/f2hYQo8IEFVJhAHhHVT14oTpFdL8w3rodXid9LhOv9Rn17ClB8ztkBPjrLZBfHB QBLJlO7UkO0a9+oAW3jr6k60gLwL3gmsLobgKTg8dUk1TZvMCzeBsY6+4iCd3hfZvFLG 7F9/fMq/0PzziRvIDPtK4y9oXOduPTw0Szqm8Zli5uJYu6GjaanZ/R6RrGfg+dFYd3l7 MAZZiNL/bvVXzqFYYOZpvZgQeV5h9RETXRpl8KRfV02EpeiJlI3V15A/I0/sqlu2F1O4 wuFw== X-Gm-Message-State: ALQs6tBfJ39VWxEkoPpA3EsOPgOZCINC6FFrurcKTZ/ffWgnFAH4/5MI 7bc1grm/ZtSD0AjlO8RrZF3qiYUhCxvswArzPFqCFerd X-Google-Smtp-Source: AIpwx49x7TOS19tXp1DvMBq7XFOmQ31q8BkJ31FN/FYLBJ5/CDVDR8N+I3eWwJRmVig1KaEHu4/ExCi9FeCi4xfnxws= X-Received: by 10.80.212.213 with SMTP id e21mr17208781edj.205.1523568840527; Thu, 12 Apr 2018 14:34:00 -0700 (PDT) MIME-Version: 1.0 Received: by 10.80.154.195 with HTTP; Thu, 12 Apr 2018 14:34:00 -0700 (PDT) In-Reply-To: <8D5E7536EB86447B920A6B0C99E2BA88@gnat> References: <1UQRRBrZ33.5N62o0UWd72@optiplex980-pc> <1b2b034a-404d-8b95-220c-5568950a1918@n1bug.com> <1523452469895.92892@kuleuven.be> <8c1acac6-e271-6398-2768-481298344387@n1bug.com> <1523457751831.88599@kuleuven.be> <612685899.20180411225537@gmail.com> <968686644.20180411232838@gmail.com> <7950E881690348FB8A48C42DD2735F8D@StevePC> <1UQRSH98Tx.2IrTZ1ue7L6@optiplex980-pc> <7FBAA3A0B6C84158BA005CFF09A5A7EA@DELL4> <4d214d82-a112-84c7-f9ab-c71941f6689a@n1bug.com> <277967114.20180412191941@gmail.com> <8D5E7536EB86447B920A6B0C99E2BA88@gnat> From: Andy Talbot Date: Thu, 12 Apr 2018 22:34:00 +0100 Message-ID: To: LineOne X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Yes, I agree with Alan and fail completely to see why the driver should have any effect on the ringing. It just cannot. As I keep saying, such ringing is commonplace in SMPSUs and is due to leakage inductance in the transformer. I don't like torroids as they don't allow you to enclose the winding nearly as much as as ETD or pot core type of construction does and I'm sure contribute more leakage L than more enclosed core types. There is more wire facing outer-space than there is facing ferrite when you have windings of only a couple or turns. . [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (andy.g4jnt[at]gmail.com) 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 94a3ffcd3903efbf0b2b811b1b1cc0bf Subject: Re: LF: W1VD amp help - more waveforms Content-Type: multipart/alternative; boundary="94eb2c1afb6e87d2600569ad8324" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.1 required=5.0 tests=HTML_FONTCOLOR_UNSAFE, HTML_MESSAGE autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false --94eb2c1afb6e87d2600569ad8324 Content-Type: text/plain; charset="UTF-8" Yes, I agree with Alan and fail completely to see why the driver should have any effect on the ringing. It just cannot. As I keep saying, such ringing is commonplace in SMPSUs and is due to leakage inductance in the transformer. I don't like torroids as they don't allow you to enclose the winding nearly as much as as ETD or pot core type of construction does and I'm sure contribute more leakage L than more enclosed core types. There is more wire facing outer-space than there is facing ferrite when you have windings of only a couple or turns. . But everyone else just seems to have accepted torroids are the best thing, so carry on. Someone must have originally said they're the way forward but I'd love to know why no one just uses standard SMPSU cores. I'll just tootle along with switching power amps built with tank circuits and only then into a transformer, and let everyone else go their own way. It just seems such a simple and obvious route, I cannot understand the need to generate a square wave, force it though an unwilling transformer then use a complicated low pass filter to clean up. The only LF amp I've built where push-pull FETs go straight into a transformer is a linear (well, almost linear) one - just to see if it could be done. About 40 - 50 Watts from a 28V supply, 60 - 70 watts saturated with scope for improving it with better FETs http://www.g4jnt.com/Linear_LF_PA3.pdf . The output transformer for that was just an RM10 sized pot core of F44 material. I suspect that if pushed hard into saturation, and the feedback CR removed from each drain-gate it would also show ringing on the edges. But there's little call for linear amps on the LF bands. Andy G4JNT On 12 April 2018 at 21:43, Alan Melia wrote: > Paul, Chris, Jay et al > Just a wild thought....Jays LPF is not inside the PA box. The filter is > giving a frequency dependent load on the PA. Could it be possible that some > reflected impedance is exagerating the ringing. As Andy said unwanted > resonance somewhere. For accurate efficiency measurement you need to know > what you are actually measuring but from the stability point of view the > filter is not necessary. Is it possible (and worth trying) taking the > filter out of circuit and putting the transformer straight into the load > ?? Then see if the ringing is more controlled?? > > I honestly cant see why the driver would affect this. As far as I can see > there is no sign of a ring on the gate waveform. As it goes off it drops > straight to ground, starting before the other phase switches on. My naive > though is that the filter may not be damping the ring but the wide band > load might. Filters need treating with care theycan behave oddly when not > terminated with resistive loads. Then there is the coupling that might be > occuring inside the case. > > Probably rubbish but I think its an angle we have not considered yet. :-)) > > Alan > G3NYK > > ----- Original Message ----- From: "Chris Wilson" > To: "N1BUG" > Sent: Thursday, April 12, 2018 7:19 PM > Subject: Re: LF: W1VD amp help - more waveforms > > > >> >> Hello Paul, >> >> I am looking at your photo of the LPF. The specs say L1 and L3 should >> have 52 turns, and L2, the centre one, should have 73 turns. i was >> unable to get 73 turns on the toroid without winding on top of a lower >> layer, and insulated with Kaptan tape. This made the overall depth >> quite a bit deeper than L1 and L3. In the photo it looks like the >> centre toroid overall is no deeper than the end ones, and the amount >> of bolt thread protruding *LOOKS* the same as the end ones. Your build >> is so painstakingly neat though, it may be that you have aesthetically >> made all the toroids look identical. >> >> http://www.chriswilson.tv/paul-lpf.jpg >> >> Thursday, April 12, 2018, 5:42:13 PM, you wrote: >> >> Jay, >>> >> >> When the package arrives I will swap out the caps and the IR2110. If >>> that doesn't do it I will order a new 74F74 and swap out the >>> resistors. If all of that fails I don't see anything else I can do. >>> Realistically at my level of expertise if it doesn't work at that >>> point I will have reached the end of the road. :-( >>> >> >> The caps I have are KEMET part # R82EC1100Z350J >>> >> >> Here is a link to the datasheet: >>> >> >> https://www.mouser.com/datasheet/2/212/KEM_F3101_R82-1103738.pdf >>> >> >> Paul >>> >> >> >> >> >> >> -- >> Best regards, >> Chris mailto:dead.fets@gmail.com >> >> >> > > --94eb2c1afb6e87d2600569ad8324 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Yes, I agree with Alan and fail completely to see why the = driver should have any effect on the ringing. It just cannot.

=C2=A0As I keep saying, such ringing is commonplace in SMPSUs and is = due to leakage inductance in the transformer.=C2=A0 =C2=A0I don't like = torroids as they don't allow you to enclose the winding nearly as much = as as ETD or pot core type of construction does and I'm sure contribute= more leakage L than more enclosed core types.=C2=A0 =C2=A0There is more wi= re facing outer-space than there is facing ferrite when you have windings o= f only a couple or turns.=C2=A0 .

But everyone els= e just seems to have accepted torroids are the best thing, so carry on.=C2= =A0 =C2=A0Someone must have originally said they're the way forward but= I'd love to know why no one just uses standard SMPSU cores.=C2=A0=C2= =A0

I'll just tootle along with switching powe= r amps built with tank circuits and only then into a transformer,=C2=A0 and= let everyone else go their own way.=C2=A0 =C2=A0It just seems such a simpl= e and obvious route, I cannot understand the need to generate a square wave= , force it though an unwilling transformer then use a complicated low pass = filter to clean up.

The only LF amp I've b= uilt where push-pull FETs go straight into a transformer is a linear (well,= almost linear) one - just to see if it could be done.=C2=A0 =C2=A0About 40= - 50 Watts from a 28V supply, 60 - 70 watts saturated with scope for impro= ving it with better FETs=C2=A0 =C2=A0http://www.g4jnt.com/Linear_LF_PA3.pdf=C2=A0=C2=A0=C2=A0.= =C2=A0 =C2=A0 The output transformer for that was just an RM10 sized pot co= re of F44 material.=C2=A0=C2=A0=C2=A0I suspect that if pushed hard into sat= uration, and the feedback CR removed from each drain-gate it would also sho= w ringing on the edges.

But there's little cal= l for linear amps on the LF bands.

Andy G4JNT<= /div>

On 12 April = 2018 at 21:43, Alan Melia <alan.melia@btinternet.com> wrote:
Paul, Chris, = Jay et al
Just a wild thought....Jays LPF is not inside the PA box. The filter is giv= ing a frequency dependent load on the PA. Could it be possible that some re= flected impedance is exagerating the ringing. As Andy said unwanted resonan= ce somewhere. For accurate efficiency measurement you need to know what you= are actually measuring but from the stability point of view the filter is = not necessary. Is it possible (and worth trying) taking the filter out of c= ircuit and putting the transformer straight into the load ??=C2=A0 Then see= if the ringing is more controlled??

I honestly cant see why the driver would affect this. As far as I can see t= here is no sign of a ring on the gate waveform. As it goes off it drops str= aight to ground, starting before the other phase switches on. My naive thou= gh is that the filter may not be damping the ring but the wide band load mi= ght. Filters need treating with care theycan behave oddly when not terminat= ed with resistive loads. Then there is the coupling that might be occuring = inside the case.

Probably rubbish but I think its an angle we have not considered yet. :-))<= br>
Alan
G3NYK

----- Original Message ----- From: "Chris Wilson" <dead.fets@gmail.com> To: "N1BUG" <rsgb_lf_group@blacksheep.org>
Sent: Thursday, April 12, 2018 7:19 PM
Subject: Re: LF: W1VD amp help - more waveforms




Hello Paul,

I=C2=A0 am looking at your photo of the LPF. The specs say L1 and L3 should=
have=C2=A0 52=C2=A0 turns,=C2=A0 and=C2=A0 L2, the centre one, should have = 73 turns. i was
unable to get 73 turns on the toroid without winding on top of a lower
layer,=C2=A0 and=C2=A0 insulated=C2=A0 with=C2=A0 Kaptan tape. This made th= e overall depth
quite=C2=A0 a=C2=A0 bit=C2=A0 deeper=C2=A0 than=C2=A0 L1 and L3. In the pho= to it looks like the
centre=C2=A0 toroid=C2=A0 overall is no deeper than the end ones, and the a= mount
of bolt thread protruding *LOOKS* the same as the end ones. Your build
is so painstakingly neat though, it may be that you have aesthetically
made all the toroids look identical.

http://www.chriswilson.tv/paul-lpf.jpg

Thursday, April 12, 2018, 5:42:13 PM, you wrote:

Jay,

When the package arrives I will swap out the caps and the IR2110. If
that doesn't do it I will order a new 74F74 and swap out the
resistors. If all of that fails I don't see anything else I can do.
Realistically at my level of expertise if it doesn't work at that
point I will have reached the end of the road. :-(

The caps I have are KEMET part # R82EC1100Z350J

Here is a link to the datasheet:

https://www.mouser.com/datashee= t/2/212/KEM_F3101_R82-1103738.pdf

Paul





--
Best regards,
Chris=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 mailto:dead.fets@gmail.com





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