20070725.ba v04_n073.bam.20070725 >From ???@??? Wed Jul 25 18:37:59 2007 -0500 Date: Wed, 25 Jul 2007 23:36:53 GMT From: Old Tube Radios To: Old Tube Radios Subject: BOATANCHORS digest 4073 Message-Id: <20070725233653.CEFF647015F@srvr1.theporch.com> BOATANCHORS Digest 4073 Topics covered in this issue include: 1) Re: Capacitor Question by Scott Robinson 2) Re: Capacitor Question by "Arden Allen" 3) Re: Capacitor Question by "Tom Rauch" 4) Re: Capacitor Question by w1id@comcast.net 5) Re: Capacitor Question by "Marty Reynolds' debris field" 6) RE: Capacitor Question by "James C. Garland" <4cx250b@muohio.edu> 7) Re: Capacitor Question by "John K9UWA" 8) More Russki Radio... by "David Stinson" 9) Correction: More Russki Radio... by "David Stinson" 10) Re: Capacitor Question by wb3fau@att.net 11) Re: More Russki Radio... by Richard Loken 12) More info on PM-2 Transformers by W6cds@aol.com 13) Re: More Russki Radio... by "Arden Allen" 14) Question: B & K 707 Tube Tester by Mike 15) RE: Question: B & K 707 Tube Tester by "Brian Goldsmith" ---------------------------------------------------------------------- Mime-Version: 1.0 Message-Id: Date: Tue, 24 Jul 2007 18:56:21 -0700 To: Old Tube Radios From: Scott Robinson Subject: Re: Capacitor Question Content-Type: text/plain; charset="us-ascii" ; format="flowed" >Tom wrote: > >I looked into the piezo effects of ceramic caps a few times over the >past few years, largely because of claims they add significant audio >distortion. Even the caps with the highest piezo effects only >produce fractions of a millivolt distortion when the dielectric is >twisted with a few dozen volts of change. > >The only place I can think of that happening to the extent it would >affect a system would be in the frequency determining components of >a low-distortion audio oscillator, or in a high-Q filter of some >type where the cap is in a critical response shaping position. > >In all our good old boatanchors with 2% or more distortion and >virtually no current through the caps from the high impedance >systems, and hundreds of stable volts on the caps, I would bet money >the distortion is immeasurable. > >It would take someone who can hear the difference between >oxygen-free cotton covered matched impedance speaker wires and >regular old zip cord on a HiFi system to hear the difference between >a ceramic disk and a mylar in a radio. > >Or it might be that lady who bitched so much about her picture in >her Muntz TV I rolled the vertical and told her to pick one she >liked. She did, I left it there, and she was happy. Now I bet she >could hear the difference. and Scott comments: The effect I'm talking about is due to the voltage coefficient of capacitance of type X7R ceramic dielectric material. It was measured in a shelving equalizer, and gave several tenths of a percent distortion in a circuit that should have 0.00x % THD. It ain't audiophoole stuff, it's real. I do analog audio design for a living and deal in real, repeatable measurements, not smoke and mirrors. A coupling cap would only do this at the low end of the intended frequency range, where LF rolloff starts. To be sure, a few tenths of a percent in a 1 to 10% THD circuit isn't much, but why not use a better cap and have no extra? Distortion is an enemy of intelligibility! Peace, Scott ------------------------------ Message-ID: <004801c7ce70$ac4f36c0$5da1480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Subject: Re: Capacitor Question Date: Tue, 24 Jul 2007 21:02:46 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit > ..... Distortion is an enemy of intelligibility! Ya'd think it was distortion was the enemy of intelligence. ;-) Arden Allen KB6NAX ------------------------------ Message-ID: <00ea01c7cea3$fcbaa530$640fa8c0@radioroom> From: "Tom Rauch" To: Old Tube Radios Subject: Re: Capacitor Question Date: Wed, 25 Jul 2007 06:10:03 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit > >Tom wrote: >> >>I looked into the piezo effects of ceramic caps a few >>times over the past few years, largely because of claims >>they add significant audio distortion. Even the caps with >>the highest piezo effects only produce fractions of a >>millivolt distortion when the dielectric is twisted with a >>few dozen volts of change. >> >>The only place I can think of that happening to the extent >>it would affect a system would be in the frequency >>determining components of a low-distortion audio >>oscillator, or in a high-Q filter of some type where the >>cap is in a critical response shaping position. > and Scott comments: > > The effect I'm talking about is due to the voltage > coefficient of capacitance of type X7R ceramic dielectric > material. It was measured in a shelving equalizer, and > gave several tenths of a percent distortion in a circuit > that should have 0.00x % THD. Bingo. Exactly the kind of circuit and dielectric I described above where a measurable piezo effect could occur. The problem is the general population exaggerates or extrapolates factual behavior in one or two specific applications into the idea it's a problem in typical bypassing or coupling systems or that all types of ceramics are bad. The NAACP (National Association for Advancement of Ceramic Parts) needs to get involved! 73 Tom ------------------------------ From: w1id@comcast.net To: Old Tube Radios Cc: Scott Robinson Subject: Re: Capacitor Question Date: Wed, 25 Jul 2007 11:59:33 +0000 Message-Id: <072520071159.18081.46A73B250003973E000046A122007636920B07CE99@comcast.net> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="NextPart_Webmail_9m3u9jl4l_18081_1185364773_0" --NextPart_Webmail_9m3u9jl4l_18081_1185364773_0 Content-Type: text/plain Content-Transfer-Encoding: 8bit Audio coupling applications aside, the piezo electric effect is significant mainly in bypass applications. For example, we never use Y5V dielectrics at full rated voltage. For example, a .1uf/100V Y5V ceramic would be usable up to 50 volts maximum because its capacitance might be halved at 100 volts. Just how significant this effect may be can only be determined by looking up the manufacturer's data sheets. Some of them are not that forthcoming because after all, they are trying to make their sales quota, the Engineers be damned. We try to use only X7R dielectrics whenever and wherever possible and then use X5R dielectrics as a last resort. -------------- Original message -------------- From: Scott Robinson > >Tom wrote: > > > >I looked into the piezo effects of ceramic caps a few times over the > >past few years, largely because of claims they add significant audio > >distortion. Even the caps with the highest piezo effects only > >produce fractions of a millivolt distortion when the dielectric is > >twisted with a few dozen volts of change. > > > >The only place I can think of that happening to the extent it would > >affect a system would be in the frequency determining components of > >a low-distortion audio oscillator, or in a high-Q filter of some > >type where the cap is in a critical response shaping position. > > > >In all our good old boatanchors with 2% or more distortion and > >virtually no current through the caps from the high impedance > >systems, and hundreds of stable volts on the caps, I would bet money > >the distortion is immeasurable. > > > >It would take someone who can hear the difference between > >oxygen-free cotton covered matched impedance speaker wires and > >regular old zip cord on a HiFi system to hear the difference between > >a ceramic disk and a mylar in a radio. > > > >Or it might be that lady who bitched so much about her picture in > >her Muntz TV I rolled the vertical and told her to pick one she > >liked. She did, I left it there, and she was happy. Now I bet she > >could hear the difference. > > and Scott comments: > > The effect I'm talking about is due to the voltage coefficient of > capacitance of type X7R ceramic dielectric material. It was measured > in a shelving equalizer, and gave several tenths of a percent > distortion in a circuit that should have 0.00x % THD. It ain't > audiophoole stuff, it's real. I do analog audio design for a living > and deal in real, repeatable measurements, not smoke and mirrors. > > A coupling cap would only do this at the low end of the intended > frequency range, where LF rolloff starts. To be sure, a few tenths of > a percent in a 1 to 10% THD circuit isn't much, but why not use a > better cap and have no extra? Distortion is an enemy of > intelligibility! > > Peace, > > Scott > --NextPart_Webmail_9m3u9jl4l_18081_1185364773_0 Content-Type: text/html Content-Transfer-Encoding: 8bit
Audio coupling applications aside, the piezo electric effect is significant mainly in bypass applications. For example, we never use Y5V dielectrics at full rated voltage. For example, a .1uf/100V Y5V ceramic would be usable up to 50 volts maximum because its capacitance might be halved at 100 volts. Just how significant this effect may be can only be determined by looking up the manufacturer's data sheets. Some of them are not that forthcoming because after all, they are trying to make their sales quota, the Engineers be damned. We try to use only X7R dielectrics whenever and wherever possible and then use X5R dielectrics as a last resort.
 
-------------- Original message --------------
From: Scott Robinson <spr@earthlink.net>

> >Tom wrote:
> >
> >I looked into the piezo effects of ceramic caps a few times over the
> >past few years, largely because of claims they add significant audio
> >distortion. Even the caps with the highest piezo effects only
> >produce fractions of a millivolt distortion when the dielectric is
> >twisted with a few dozen volts of change.
> >
> >The only place I can think of that happening to the extent it would
> >affect a system would be in the frequency determining components of
> >a low-distortion audio oscillator, or in a high-Q filter of some
> >type where the cap is in a critical response shaping position.
> >
> >In all our good old boatanchors with 2% or more distortion and
> >virtually no current through the caps from the high impedance
> >systems, and hundreds of stable volts on the caps, I would bet money
> >the distortion is immeasurable.
> >
> >It would take someone who can hear the difference between
> >oxygen-free cotton covered matched impedance speaker wires and
> >regular old zip cord on a HiFi system to hear the difference between
> >a ceramic disk and a mylar in a radio.
> >
> >Or it might be that lady who bitched so much about her picture in
> >her Muntz TV I rolled the vertical and told her to pick one she
> >liked. She did, I left it there, and she was happy. Now I bet she
> >could hear the difference.
>
> and Scott comments:
>
> The effect I'm talking about is due to the voltage coefficient of
> capacitance of type X7R ceramic dielectric mate rial. It was measured
> in a shelving equalizer, and gave several tenths of a percent
> distortion in a circuit that should have 0.00x % THD. It ain't
> audiophoole stuff, it's real. I do analog audio design for a living
> and deal in real, repeatable measurements, not smoke and mirrors.
>
> A coupling cap would only do this at the low end of the intended
> frequency range, where LF rolloff starts. To be sure, a few tenths of
> a percent in a 1 to 10% THD circuit isn't much, but why not use a
> better cap and have no extra? Distortion is an enemy of
> intelligibility!
>
> Peace,
>
> Scott
>
--NextPart_Webmail_9m3u9jl4l_18081_1185364773_0-- ------------------------------ Message-ID: <4127.66.56.28.127.1185367859.squirrel@fracas.netboobie.org> Date: Wed, 25 Jul 2007 08:50:59 -0400 (EDT) Subject: Re: Capacitor Question From: "Marty Reynolds' debris field" To: Old Tube Radios Cc: "Old Tube Radios" , "Scott Robinson" MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit Yo W8ZR We had the same silver mica problems on our KWM-1s 2 yrs ago. Leaky component in the phase-shift audio osc. CW tone-maker. W8JI take note of application. Seems the silver migrates around the mica edges & produces the leak. Physical process is, I think, still a mystery that only turns up after a half century. Especially evident on AA5 IFTs of the Miller K-tran type. Also the coupler to a 75A4's AVC amp. is ofter in the tank (plate-to-grid 455kc coupler) Perhaps the acronym RMOD will someday stand shoulder-to-shoulder with BBOD. Red micas of death 'rm aka Marty ------------------------------ From: "James C. Garland" <4cx250b@muohio.edu> To: Old Tube Radios Subject: RE: Capacitor Question Date: Wed, 25 Jul 2007 07:15:59 -0600 Message-ID: <07ea01c7cebd$f1d64240$09e83586@Garland> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Yep, I remember well the red micas of death in my KWM-1. They'd work for awhile when the rig was turned on, but after a half hour or so I'd start to get signal loss and lots of popping. It was the grid-plate caps that was the problem. The cathode bypass ones were okay, presumably because there wasn't much DC voltage across them. Jim ********************** Jim Garland W8ZR Santa Fe, NM www.w8zr.net ********************* Yo W8ZR We had the same silver mica problems on our KWM-1s 2 yrs ago. Leaky component in the phase-shift audio osc. CW tone-maker. W8JI take note of application. Seems the silver migrates around the mica edges & produces the leak. Physical process is, I think, still a mystery that only turns up after a half century. Especially evident on AA5 IFTs of the Miller K-tran type. Also the coupler to a 75A4's AVC amp. is ofter in the tank (plate-to-grid 455kc coupler) Perhaps the acronym RMOD will someday stand shoulder-to-shoulder with BBOD. Red micas of death 'rm aka Marty ------------------------------ From: "John K9UWA" To: Old Tube Radios Date: Wed, 25 Jul 2007 08:17:44 -0500 MIME-Version: 1.0 Subject: Re: Capacitor Question Message-ID: <46A70728.29336.174BBEF0@k9uwa.arrl.net> Content-type: text/html; charset=US-ASCII Content-transfer-encoding: 7BIT Content-description: Mail message body

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> Especially evident on AA5 IFTs of the Miller K-tran type.  Also the
> coupler to a 75A4's AVC amp. is ofter in the tank  (plate-to-grid
> 455kc coupler)
>
>   'rm aka Marty
>

I repaired one of these yesterday in a consumer radio. We call it
Silver Mica Disease. In these radios it sounds like a thunderstorm
is going on .... inside the radio.... the mica is molded into the base
of the IF can ... cure is... take dremel tool and grind it out... add
external on the can leads new silver mica cap...
John k9uwa
John Goller, K9UWA & Jean Goller, N9PXF
Antique Radio Restorations
k9uwa@arrl.net
Visit our Web Site at:
http://www.JohnJeanAntiqueRadio.com
4836 Ranch Road
Leo, IN 46765
USA
1-260-637-6426
 
------------------------------ Message-ID: <001201c7cec6$68453140$6401a8c0@boudreaux> From: "David Stinson" To: Old Tube Radios Subject: More Russki Radio... Date: Wed, 25 Jul 2007 09:16:31 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit At the local surplus outlet (Tanner Electronics in Carrolton; NICE people), I found these 18-inch log AT&T line cards with a dandy little DC/DC converter on the end. These were like my first, but smaller and less current, being rated at only 170 mils out. That was fine by me, since at the tip-top, the radio is drawing less than 20 mils: http://home.netcom.com/~arc5/usp/USP034.JPG I pulled three of the converters and built a shield box just for them, with some surplus EMI filters and feed-thru caps in and out of the box. I'm only using two of the converters, but can jump up to 90 volts out by simply adding two jumpers: http://home.netcom.com/~arc5/usp/USP%20032.JPG I took the old converter mess out of the power/audio chassis and installed the shield box in that place: http://home.netcom.com/~arc5/usp/USP051.JPG I know- I could compress everything into a much smaller box and put the speaker in there, too, but have you priced metal project boxes lately? Yeow! That one with the converters in it was over eight bucks. Anyone got a better price on boxes? Anyways- during bench tests, the converter ran for hours at 25 mils out without even breaking a sweat. Input current at 13.5 volts was 180 mils. I installed it and have run it all night and all this morning. 99% of my birdies have flown away. The very few left (none in the ham bands) are so low level; you have to hunt for them to find them. It was well worth the extra work. It's so darn rare that I get the time to build anything, and I'm pleased how this turned out. I'll compact it all into one small power/speaker box one of these days. It'll have to do as-is for now- duty calls. On another note: the quality of the radio build. I've have time to look deeper since I first opened the radio, and the problems with the old Soviet system and it's broken work ethic have begun to show. Band Two was dead when I got the radio. I finally got around to trouble-shooting that and found that a wire to the antenna coil was pinched between the coil shield and the chassis, shorting out the antenna. When the worker screwed the shield down, he didn't take the time to check his work. Band Two could never have operated; it was shipped like this. Works now :). Another: The top coil deck is screwed to the chassis with several short, counter-sunk screws, then the coil shields are placed over the coils and screwed to this deck, partially covering the countersunk screw heads. Well, the deck is connected to the chassis with exactly *one* countersunk screw. The other holes are empty and it had to have been shipped in this condition. I'll fix that later. Pity that such nice, functional engineering would be tripped-up by the corrosion of worker's attitudes and societal decay that is inevitable under Socialism. I still like the radio, though. 73 Dave S. ------------------------------ Message-ID: <001b01c7cec7$5b15af30$6401a8c0@boudreaux> From: "David Stinson" To: Old Tube Radios Subject: Correction: More Russki Radio... Date: Wed, 25 Jul 2007 09:23:18 -0500 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit Here's the correct link for the insides of the high voltage converter: http://home.netcom.com/~arc5/usp/USP032.JPG ------------------------------ From: wb3fau@att.net To: Old Tube Radios Subject: Re: Capacitor Question Date: Wed, 25 Jul 2007 14:49:20 +0000 Message-Id: <072520071449.24326.46A762F0000565C200005F0621602807489A0E00CC0D99@att.net> you need some bumble-bee caps and a some Amprex Bugle-boy 12AX7s in there... ------------------------------ Date: Wed, 25 Jul 2007 09:40:37 -0700 From: Richard Loken Subject: Re: More Russki Radio... To: Old Tube Radios Cc: Old Tube Radios MIME-version: 1.0 Content-type: TEXT/PLAIN; charset=US-ASCII On Wed, 25 Jul 2007, David Stinson wrote: > Pity that such nice, functional engineering would be tripped-up > by the corrosion of worker's attitudes and societal decay > that is inevitable under Socialism. I still like the radio, though. I think there is more blame to be laid on totalitarian brutality and beaurocatic incompitence/mismanagement. Sweden was run by the socialist hordes but L.M.Erickson, Volvo, and SAAB seemed to be viable companies. Now Sweden has a government that leans more to the right and SAAB is owned by GM, Volvo cars has been spun off to Ford, and L.M.Erickson have moved their corporate headquarters to Great Britain. hell, even excessive government control is not an adaquate answer to problems of quality control and worker attitute, Singapore very tightly controls the hehaviour of their population (but they do not try to plan and manage tbe economy as far as I know) and their economy is doing very well even though China and Hong Kong get all the attention these days. How about corruption, incompetence, mismanagement? Yeah that helps to explain a lot of stuff that happens no matter where you look. With any luck the corruption, incompetence, and mismanement stuff will bite China very hard on the ass one of these days. One can always hope. The tales about how the Kremlin mismanaged the economy are legion but the one that would affect your radio is beaurocrats demanding outrageous quotas out of factories at certain times (like just before the reports had to go in) so that the workers were slamming machines together as fast as (and indeed faster) than was humanly possible so that a lot of the output was inoperative when shipped. There was a Soviet joke that the government pretends to pay us and we pretend to work. Somebody should complie a book of Soviet gallows humour before it is all forgotten. -- Richard Loken VE6BSV, Systems Programmer - VMS : "Anybody can be a father Athabasca University : but you have to earn Athabasca, Alberta Canada : the title of 'daddy'" ** richardlo@admin.athabascau.ca ** : - Lynn Johnston ------------------------------ From: W6cds@aol.com Message-ID: Date: Wed, 25 Jul 2007 15:27:23 EDT Subject: More info on PM-2 Transformers To: Old Tube Radios MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1185391643" -------------------------------1185391643 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Hi all! I never expected to get so many inquires on my PM-2 Transformers & Chokes. 15 so far. So here's more info for you. I have 2 of each and they are band new military surplus. The transformers weight over 7 lbs each and the chokes over 2 lbs each. Combined shipping weight over 10 lbs plus packing. The exact cost of shipping depends on where you live unless we go priority mail. Shipping cost for a pair runs about $20 for regular mail and about $25 for priority mail, my first choice including insurance. Sorry guys, but I will only ship to the USA. Too much trouble to ship overseas. I have no idea what they are worth, a lot, I would guess but I'm not greedy. I want to sell them as a set of transformer and choke and since some people wanted both sets, will entertain that idea too. You will decide the price. Make an offer. Charles D Simmons, W6CDS, Buena Park, CA 90622, 714-994-6843 ************************************** Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour -------------------------------1185391643 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * -------------------------------1185391643-- ------------------------------ Message-ID: <002701c7cf00$0a89c860$689f480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Cc: "Old Tube Radios" Subject: Re: More Russki Radio... Date: Wed, 25 Jul 2007 14:08:39 -0700 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit > .....How about corruption, incompetence, mismanagement? ..... Secrecy is the signature of corruption and incompetence. While they blame each other neither wants anyone to know about what goes on. Does that pass the sniff test????? Arden Allen KB6NAX ------------------------------ Date: Wed, 25 Jul 2007 15:13:43 -0700 From: Mike Subject: Question: B & K 707 Tube Tester To: Old Tube Radios Message-id: <000801c7cf09$1036ca70$6501a8c0@m0a1da7d341114> MIME-version: 1.0 Content-type: text/plain; format=flowed; charset=iso-8859-1; reply-type=original Content-transfer-encoding: 7bit It looks like the sensitivity control in this tester has been replaced by a previous owner. The pot is described as "1K Ohm 5 Watt W.W. Pot (Spec. Taper)". I'm assuming "Spec. Taper" means special taper, anyone know what the taper is? Is it possible to have a wire wound pot that is not a linear taper? Mike VE7MMH ------------------------------ From: "Brian Goldsmith" To: Old Tube Radios Subject: RE: Question: B & K 707 Tube Tester Date: Thu, 26 Jul 2007 09:37:37 +1000 Message-ID: <000001c7cf14$c8d53520$0a00a8c0@pcbriang> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit -----Original Message----- From: Mike It looks like the sensitivity control in this tester has been replaced by a previous owner. The pot is described as "1K Ohm 5 Watt W.W. Pot (Spec. Taper)". I'm assuming "Spec. Taper" means special taper, anyone know what the taper is? Is it possible to have a wire wound pot that is not a linear taper? ****** I don't know about the B & K,however in the AVO CT160,the Grid Bias pot is indeed a 5 Watt wire wound with a "special" taper.The actual construction consists of four linear sections of the winding in series,the necessary change in resistance being accomplished by increasing the gauge number (and turns) of the resistance wire used.In this pot the coarse part of the winding is at the anticlockwise end of the winding.The pot is described as having a Log taper. Brian Goldsmith. ------------------------------ End of BOATANCHORS Digest 4073 ******************************