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[195.171.43.25]) by mx.google.com with ESMTP id k6si2469186wjr.130.2013.12.29.12.39.06 for ; Sun, 29 Dec 2013 12:39:07 -0800 (PST) Received-SPF: neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) client-ip=195.171.43.25; Authentication-Results: mx.google.com; spf=neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) smtp.mail=owner-rsgb_lf_group@blacksheep.org Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1VxMS2-0000DI-Hm for rs_out_1@blacksheep.org; Sun, 29 Dec 2013 19:55:06 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1VxMS2-0000D5-0b for rsgb_lf_group@blacksheep.org; Sun, 29 Dec 2013 19:55:06 +0000 Received: from blu0-omc1-s18.blu0.hotmail.com ([65.55.116.29]) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1VxMS0-0003sP-3w for rsgb_lf_group@blacksheep.org; Sun, 29 Dec 2013 19:55:04 +0000 Received: from BLU180-W43 ([65.55.116.8]) by blu0-omc1-s18.blu0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Sun, 29 Dec 2013 11:55:02 -0800 X-TMN: [0P5kW87glvi5QC+XOgU0baa31nc7zsqs] X-Originating-Email: [rjraide@hotmail.com] Message-ID: From: Bob Raide To: "rsgb_lf_group@blacksheep.org" Date: Sun, 29 Dec 2013 14:55:01 -0500 Importance: Normal In-Reply-To: <52C06C71.1090300@freenet.de> References: <20C550A7D07741688C6A26E73CBCF741@White> <52BF4895.8080502@iup.uni-heidelberg.de> <52BF7E2A.9000002@iup.uni-heidelberg.de> <52BFD963.8020300@freenet.de> <8C09023FA2074CB380BC9CF1E7A514E3@White> <52C00514.4030805@freenet.de> <52C04A0A.5070101@iup.uni-heidelberg.de> <52C05731.3060401@freenet.de> <52C0630C.8090407@iup.uni-heidelberg.de>,<52C06C71.1090300@freenet.de> MIME-Version: 1.0 X-OriginalArrivalTime: 29 Dec 2013 19:55:02.0359 (UTC) FILETIME=[DCA53670:01CF04CF] X-Spam-Score: 2.2 (++) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Stefan; Now that's an amp! 73-Bob > Date: Sun, 29 Dec 2013 19:39:45 +0100 > From: dl4yhf@freenet.de > To: rsgb_lf_group@blacksheep.org > Subject: Re: LF: MF PA > > Hi Stefan, > > Hi Wolf, > > > > What type of FETs are you using? The standard IRFPs? Many of them have > > internal Z diodes, so no addional RC network or Z idode is needed. The > > losses are there anyway, of course. > > > I'm using HUF 75343 P3 : 75 A, 55 V, 9 mOhm RDs on, and a hefty gate > input capacitance. > Just for historic reasons (on LF), and because I still have a tube with > over a dozen of them. > But the TC4452 has sufficient driving power to switch them rapidly > enough, even at 470 kHz (and presumably more). > > For the DC modulator (with 0.1 V ... 13 V output, depending on the PWM > duty cycle), there is another HUF 75343, and one IRF 4905, working > together as a complementary push-pull stage at 100 kHz with a PWM DC of > "almost" zero (due to the limited speed of the comparator + driver) to > 100 percent. After a simple choke, and a few microfarads (ceramic), this > provides the 0... 13 Volts for the MF final stage. > In case of mismatch or excessive drain current (actually measured as > source current in the PA), the PWM DC is gradually reduced in a control > loop... and the control loop design turned out quite tricky, because the > loop gain depends on the load, and the loop has a dead time (due to the > 100 kHz switching-mode modulator) which can cause the loop to oscillate > under certain conditions. This is actually the reason why the PA is not > "on air" yet... > > Cheers, > Wolf . > [...] Content analysis details: (2.2 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [65.55.116.29 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (rjraide[at]hotmail.com) 1.6 SUBJ_ALL_CAPS Subject is all capitals -0.0 SPF_PASS SPF: sender matches SPF record -0.4 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 0.0 HTML_MESSAGE BODY: HTML included in message 1.0 FREEMAIL_REPLY From and body contain different freemails X-Scan-Signature: 2ee80849a5d572dbc974bb207a527753 Content-Type: multipart/alternative; boundary="_27a53811-cbe9-4609-8c1c-e5013b558c24_" Subject: RE: LF: MF PA X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=FORGED_HOTMAIL_RCVD, HTML_MESSAGE,SUBJ_ALL_CAPS,TO_ADDRESS_EQ_REAL 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 Status: O X-Status: X-Keywords: X-UID: 1539 --_27a53811-cbe9-4609-8c1c-e5013b558c24_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Stefan=3B Now that's an amp! 73-Bob =20 > Date: Sun=2C 29 Dec 2013 19:39:45 +0100 > From: dl4yhf@freenet.de > To: rsgb_lf_group@blacksheep.org > Subject: Re: LF: MF PA >=20 > Hi Stefan=2C > > Hi Wolf=2C > > > > What type of FETs are you using? The standard IRFPs? Many of them have= =20 > > internal Z diodes=2C so no addional RC network or Z idode is needed. Th= e=20 > > losses are there anyway=2C of course. > > > I'm using HUF 75343 P3 : 75 A=2C 55 V=2C 9 mOhm RDs on=2C and a hefty gat= e=20 > input capacitance. > Just for historic reasons (on LF)=2C and because I still have a tube with= =20 > over a dozen of them. > But the TC4452 has sufficient driving power to switch them rapidly=20 > enough=2C even at 470 kHz (and presumably more). >=20 > For the DC modulator (with 0.1 V ... 13 V output=2C depending on the PWM= =20 > duty cycle)=2C there is another HUF 75343=2C and one IRF 4905=2C working= =20 > together as a complementary push-pull stage at 100 kHz with a PWM DC of=20 > "almost" zero (due to the limited speed of the comparator + driver) to=20 > 100 percent. After a simple choke=2C and a few microfarads (ceramic)=2C t= his=20 > provides the 0... 13 Volts for the MF final stage. > In case of mismatch or excessive drain current (actually measured as=20 > source current in the PA)=2C the PWM DC is gradually reduced in a control= =20 > loop... and the control loop design turned out quite tricky=2C because th= e=20 > loop gain depends on the load=2C and the loop has a dead time (due to the= =20 > 100 kHz switching-mode modulator) which can cause the loop to oscillate=20 > under certain conditions. This is actually the reason why the PA is not=20 > "on air" yet... >=20 > Cheers=2C > Wolf . >=20 = --_27a53811-cbe9-4609-8c1c-e5013b558c24_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Stefan=3B
Now that's an amp! = 73-Bob
 =3B
>=3B Date: Sun=2C 29 Dec 2013 19:39:45 +0100>=3B From: dl4yhf@freenet.de
>=3B To: rsgb_lf_group@blacksheep.org=
>=3B Subject: Re: LF: MF PA
>=3B
>=3B Hi Stefan=2C
>= =3B >=3B Hi Wolf=2C
>=3B >=3B
>=3B >=3B What type of FETs a= re you using? The standard IRFPs? Many of them have
>=3B >=3B inter= nal Z diodes=2C so no addional RC network or Z idode is needed. The
>= =3B >=3B losses are there anyway=2C of course.
>=3B >=3B
>=3B= I'm using HUF 75343 P3 : 75 A=2C 55 V=2C 9 mOhm RDs on=2C and a hefty gate=
>=3B input capacitance.
>=3B Just for historic reasons (on LF)= =2C and because I still have a tube with
>=3B over a dozen of them.>=3B But the TC4452 has sufficient driving power to switch them rapidly=
>=3B enough=2C even at 470 kHz (and presumably more).
>=3B
= >=3B For the DC modulator (with 0.1 V ... 13 V output=2C depending on the= PWM
>=3B duty cycle)=2C there is another HUF 75343=2C and one IRF 49= 05=2C working
>=3B together as a complementary push-pull stage at 100= kHz with a PWM DC of
>=3B "almost" zero (due to the limited speed of= the comparator + driver) to
>=3B 100 percent. After a simple choke= =2C and a few microfarads (ceramic)=2C this
>=3B provides the 0... 13= Volts for the MF final stage.
>=3B In case of mismatch or excessive d= rain current (actually measured as
>=3B source current in the PA)=2C = the PWM DC is gradually reduced in a control
>=3B loop... and the con= trol loop design turned out quite tricky=2C because the
>=3B loop gai= n depends on the load=2C and the loop has a dead time (due to the
>= =3B 100 kHz switching-mode modulator) which can cause the loop to oscillate=
>=3B under certain conditions. This is actually the reason why the P= A is not
>=3B "on air" yet...
>=3B
>=3B Cheers=2C
>= =3B Wolf .
>=3B
= --_27a53811-cbe9-4609-8c1c-e5013b558c24_--