Re: [AMRadio] 4D32 rig testing
Hi Brett I have been following your posts on the 4D32 project with some interest as I too had the same idea. Kind of a coincidense. A few years ago I purchased a couple of mod xfmrs from Fair when the prices were right. The mod xfmrs were rated at 150 watts with a 2400 z , 350ma secondary. I noticed lately some of these have been showing up on ebay for a good price. Anyway, I thought a good final for a 275 to 300 watt rig using that mod xfmr might be a couple of 4D32s at 810 to 840 v. I kicked the idea around with some of the local midwest am'ers and came to the conclusion that so long as the disapation wasn't exceeded that it would be OK. I have collected a bunch of 4D32 spares as I have three rigs (Vik I, HT-20, 32V1) which uses them. Will follow lyour progress with interest . Sounds like fun. Good luck. 73, Wayne, N0TE
Re: [AMRadio] 4D32 rig testing
Thanks for reply Brett. I hear you on 40 meters a lot. Never check in because I cannot wait in line to speak. I just like to listen to you. Very interesting stuff. All my best and I did enjoy the ER article. Dave, W3ST Secretary to the Collins Radio Association Publisher of the Collins Journal www.collinsra.com - Original Message - From: Brett Gazdzinski [EMAIL PROTECTED] To: amradio@mailman.qth.net Sent: Saturday, January 24, 2004 10:46 PM Subject: RE: [AMRadio] 4D32 rig testing Dave, many people run them on low voltage, that is ok with me. I have been running mine on the high voltage for 15 years with no crap outs at all, not a single problem with them. The low voltage transformer frequently went because it was overloaded, and removing the vacuum rectifiers reduces the load a lot. peter Dahl sells replacements, they are likely not cheap, but are good transformers. The only mod transformer I ever blew out was in the 30K1 I had, testing it with 20hz at 100% modulation at full power. Stupid, but I did not know anything then, and the 30K1 cost me less than the peter Dahl 32v3 mod transformer ($200.00). Serial number 9, I wonder if its on the air now, it used to sound very good when I sold it to someone down south. Brett N2DTS -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of David Knepper Sent: Saturday, January 24, 2004 4:10 PM To: amradio@mailman.qth.net Subject: Re: [AMRadio] 4D32 rig testing Please excuse my ignorance among the experts but shouldn't one be careful not to push the voltage rating on the secondary of the modulation transformer when increasing the plate voltage on the RF amplifier? or on the primary winding when pushing higher voltage on the mod. tubes. On all of my 32V's at the Collins Radio Center, I put the toggle switch on the rear to 600 volts, not 700 volts. Know where I can get a replacement mod. transformer for the 32V transmitter? I don't! Inquiring minds would like to know! Why sacrifice a modulation transformer, which are expensive and rare these days. Thank you Dave, W3ST Secretary to the Collins Radio Association Publisher of the Collins Journal www.collinsra.com - Original Message - From: Donald Chester [EMAIL PROTECTED] To: amradio@mailman.qth.net Sent: Saturday, January 24, 2004 3:47 PM Subject: RE: [AMRadio] 4D32 rig testing Collins runs them at over 700 volts in class C plate modulated service (32V series). If they don't arc over, and you don't exceed the plate dissipation, what would be the problem? That's a good point. I recall an article pre-WW2 in QST which described getting high peak audio power from modulator tubes by running unusually high voltage on them, but staying within the rated dissipation rating. A point was made that for example, the 807 is rated for a maximum of 600 volts plate modulated. That means the peak voltage would be at least 1200 volts, and that doesn't hurt them, and is still within factory specified ratings. So for intermittent service, you should be able to run as much as 1200 DC volts on an 807. I think the limit on plate modulated voltage would be the point where arcovers would begin. However, I do recall using a quad of p-p parallel 2A3's in my audio driver. I didn't have a proper driver transformer at the time, so I ran them @ 400 volts/30 m.a. each tube. They are rated at 300 volts/40 m.a. maximum in the RCA manual. That way I could get plenty of peak driving voltage to the class B grids, despite having a driver transformer with too much stepdown, but with exactly the same plate dissipation as per RCA recommended ratings. They worked great, and drove the modulator tubes with very little distortion. But I noticed that within a few months, the 2A3's would get weak. I went through a couple of sets that way. Finally, I obtained a proper driver transformer with the proper turns ratio, and slowered the plate voltage back to 300v, and changed the bias so that each tube would draw 40 m.a., and now I have had the same set of 2A3's for almost 10 years, and they still test good. Maybe just a coincidence, but at the current price of a new 2A3, I don't feel like trying to find out. My conclusion is that some tubes may not take overvoltage very well, while others will not be harmed, and the only way to find out which ones is to try them and see. If your tubes seem to be short lived, go back to the recommended parameters. -K4KYV _ High-speed users-be more efficient online with the new MSN Premium Internet Software. http://join.msn.com/?pgmarket=en-uspage=byoa/premST=1 ___ AMRadio
Re: [AMRadio] 4D32 rig testing
Brett, I just get nervous about overextending my 32V transmitters. I have 4 at the Collins Radio Center and no spare transformers in the event one of them breaks down. So you can see why I am hesitant about switching the toggle on the rear to 700 volts. Take care and continue to experiment/homebrew. Great to see someone is doing what others only talk about!! Dave, W3ST Secretary to the Collins Radio Association Publisher of the Collins Journal www.collinsra.com - Original Message - From: Brett Gazdzinski [EMAIL PROTECTED] To: amradio@mailman.qth.net Sent: Saturday, January 24, 2004 10:39 PM Subject: RE: [AMRadio] 4D32 rig testing Don, I was in qso with Jay, n2wwl today, and we were talking about the 32v3, and the voltage it runs at, Jay runs his on the low voltage position, about 600 volts on the plates. I run mine on the 700 volt tap, 180 to 200 ma. The panel meter says 800 volts high voltage, but I put my DMM on it and was very surprised to find 940 volts on the plates. I have been running them that way for 15 years with the same tubes in them, and used to use them quite a lot. I get 100 watts out, and 350 watts pep. I have solid stated the power supplies, which explains the high voltage. I think, as long as you don't exceed the plate dissipation, you are likely ok with most tubes. Brett N2DTS Collins runs them at over 700 volts in class C plate modulated service (32V series). If they don't arc over, and you don't exceed the plate dissipation, what would be the problem? That's a good point. I recall an article pre-WW2 in QST which described getting high peak audio power from modulator tubes by running unusually high voltage on them, but staying within the rated dissipation rating. A point was made that for example, the 807 is rated for a maximum of 600 volts plate modulated. That means the peak voltage would be at least 1200 volts, and that doesn't hurt them, and is still within factory specified ratings. So for intermittent service, you should be able to run as much as 1200 DC volts on an 807. I think the limit on plate modulated voltage would be the point where arcovers would begin. However, I do recall using a quad of p-p parallel 2A3's in my audio driver. I didn't have a proper driver transformer at the time, so I ran them @ 400 volts/30 m.a. each tube. They are rated at 300 volts/40 m.a. maximum in the RCA manual. That way I could get plenty of peak driving voltage to the class B grids, despite having a driver transformer with too much stepdown, but with exactly the same plate dissipation as per RCA recommended ratings. They worked great, and drove the modulator tubes with very little distortion. But I noticed that within a few months, the 2A3's would get weak. I went through a couple of sets that way. Finally, I obtained a proper driver transformer with the proper turns ratio, and slowered the plate voltage back to 300v, and changed the bias so that each tube would draw 40 m.a., and now I have had the same set of 2A3's for almost 10 years, and they still test good. Maybe just a coincidence, but at the current price of a new 2A3, I don't feel like trying to find out. My conclusion is that some tubes may not take overvoltage very well, while others will not be harmed, and the only way to find out which ones is to try them and see. If your tubes seem to be short lived, go back to the recommended parameters. -K4KYV _ High-speed usersbe more efficient online with the new MSN Premium Internet Software. http://join.msn.com/?pgmarket=en-uspage=byoa/premST=1 ___ AMRadio mailing list AMRadio@mailman.qth.net http://mailman.qth.net/mailman/listinfo/amradio ___ AMRadio mailing list AMRadio@mailman.qth.net http://mailman.qth.net/mailman/listinfo/amradio
RE: [AMRadio] 4D32 rig testing
Collins runs them at over 700 volts in class C plate modulated service (32V series). If they don't arc over, and you don't exceed the plate dissipation, what would be the problem? That's a good point. I recall an article pre-WW2 in QST which described getting high peak audio power from modulator tubes by running unusually high voltage on them, but staying within the rated dissipation rating. A point was made that for example, the 807 is rated for a maximum of 600 volts plate modulated. That means the peak voltage would be at least 1200 volts, and that doesn't hurt them, and is still within factory specified ratings. So for intermittent service, you should be able to run as much as 1200 DC volts on an 807. I think the limit on plate modulated voltage would be the point where arcovers would begin. However, I do recall using a quad of p-p parallel 2A3's in my audio driver. I didn't have a proper driver transformer at the time, so I ran them @ 400 volts/30 m.a. each tube. They are rated at 300 volts/40 m.a. maximum in the RCA manual. That way I could get plenty of peak driving voltage to the class B grids, despite having a driver transformer with too much stepdown, but with exactly the same plate dissipation as per RCA recommended ratings. They worked great, and drove the modulator tubes with very little distortion. But I noticed that within a few months, the 2A3's would get weak. I went through a couple of sets that way. Finally, I obtained a proper driver transformer with the proper turns ratio, and slowered the plate voltage back to 300v, and changed the bias so that each tube would draw 40 m.a., and now I have had the same set of 2A3's for almost 10 years, and they still test good. Maybe just a coincidence, but at the current price of a new 2A3, I don't feel like trying to find out. My conclusion is that some tubes may not take overvoltage very well, while others will not be harmed, and the only way to find out which ones is to try them and see. If your tubes seem to be short lived, go back to the recommended parameters. -K4KYV _ High-speed usersbe more efficient online with the new MSN Premium Internet Software. http://join.msn.com/?pgmarket=en-uspage=byoa/premST=1
Re: [AMRadio] 4D32 rig testing
Please excuse my ignorance among the experts but shouldn't one be careful not to push the voltage rating on the secondary of the modulation transformer when increasing the plate voltage on the RF amplifier? or on the primary winding when pushing higher voltage on the mod. tubes. On all of my 32V's at the Collins Radio Center, I put the toggle switch on the rear to 600 volts, not 700 volts. Know where I can get a replacement mod. transformer for the 32V transmitter? I don't! Inquiring minds would like to know! Why sacrifice a modulation transformer, which are expensive and rare these days. Thank you Dave, W3ST Secretary to the Collins Radio Association Publisher of the Collins Journal www.collinsra.com - Original Message - From: Donald Chester [EMAIL PROTECTED] To: amradio@mailman.qth.net Sent: Saturday, January 24, 2004 3:47 PM Subject: RE: [AMRadio] 4D32 rig testing Collins runs them at over 700 volts in class C plate modulated service (32V series). If they don't arc over, and you don't exceed the plate dissipation, what would be the problem? That's a good point. I recall an article pre-WW2 in QST which described getting high peak audio power from modulator tubes by running unusually high voltage on them, but staying within the rated dissipation rating. A point was made that for example, the 807 is rated for a maximum of 600 volts plate modulated. That means the peak voltage would be at least 1200 volts, and that doesn't hurt them, and is still within factory specified ratings. So for intermittent service, you should be able to run as much as 1200 DC volts on an 807. I think the limit on plate modulated voltage would be the point where arcovers would begin. However, I do recall using a quad of p-p parallel 2A3's in my audio driver. I didn't have a proper driver transformer at the time, so I ran them @ 400 volts/30 m.a. each tube. They are rated at 300 volts/40 m.a. maximum in the RCA manual. That way I could get plenty of peak driving voltage to the class B grids, despite having a driver transformer with too much stepdown, but with exactly the same plate dissipation as per RCA recommended ratings. They worked great, and drove the modulator tubes with very little distortion. But I noticed that within a few months, the 2A3's would get weak. I went through a couple of sets that way. Finally, I obtained a proper driver transformer with the proper turns ratio, and slowered the plate voltage back to 300v, and changed the bias so that each tube would draw 40 m.a., and now I have had the same set of 2A3's for almost 10 years, and they still test good. Maybe just a coincidence, but at the current price of a new 2A3, I don't feel like trying to find out. My conclusion is that some tubes may not take overvoltage very well, while others will not be harmed, and the only way to find out which ones is to try them and see. If your tubes seem to be short lived, go back to the recommended parameters. -K4KYV _ High-speed users-be more efficient online with the new MSN Premium Internet Software. http://join.msn.com/?pgmarket=en-uspage=byoa/premST=1 ___ AMRadio mailing list AMRadio@mailman.qth.net http://mailman.qth.net/mailman/listinfo/amradio
RE: [AMRadio] 4D32 rig testing
Don, I was in qso with Jay, n2wwl today, and we were talking about the 32v3, and the voltage it runs at, Jay runs his on the low voltage position, about 600 volts on the plates. I run mine on the 700 volt tap, 180 to 200 ma. The panel meter says 800 volts high voltage, but I put my DMM on it and was very surprised to find 940 volts on the plates. I have been running them that way for 15 years with the same tubes in them, and used to use them quite a lot. I get 100 watts out, and 350 watts pep. I have solid stated the power supplies, which explains the high voltage. I think, as long as you don't exceed the plate dissipation, you are likely ok with most tubes. Brett N2DTS Collins runs them at over 700 volts in class C plate modulated service (32V series). If they don't arc over, and you don't exceed the plate dissipation, what would be the problem? That's a good point. I recall an article pre-WW2 in QST which described getting high peak audio power from modulator tubes by running unusually high voltage on them, but staying within the rated dissipation rating. A point was made that for example, the 807 is rated for a maximum of 600 volts plate modulated. That means the peak voltage would be at least 1200 volts, and that doesn't hurt them, and is still within factory specified ratings. So for intermittent service, you should be able to run as much as 1200 DC volts on an 807. I think the limit on plate modulated voltage would be the point where arcovers would begin. However, I do recall using a quad of p-p parallel 2A3's in my audio driver. I didn't have a proper driver transformer at the time, so I ran them @ 400 volts/30 m.a. each tube. They are rated at 300 volts/40 m.a. maximum in the RCA manual. That way I could get plenty of peak driving voltage to the class B grids, despite having a driver transformer with too much stepdown, but with exactly the same plate dissipation as per RCA recommended ratings. They worked great, and drove the modulator tubes with very little distortion. But I noticed that within a few months, the 2A3's would get weak. I went through a couple of sets that way. Finally, I obtained a proper driver transformer with the proper turns ratio, and slowered the plate voltage back to 300v, and changed the bias so that each tube would draw 40 m.a., and now I have had the same set of 2A3's for almost 10 years, and they still test good. Maybe just a coincidence, but at the current price of a new 2A3, I don't feel like trying to find out. My conclusion is that some tubes may not take overvoltage very well, while others will not be harmed, and the only way to find out which ones is to try them and see. If your tubes seem to be short lived, go back to the recommended parameters. -K4KYV _ High-speed usersbe more efficient online with the new MSN Premium Internet Software. http://join.msn.com/?pgmarket=en-uspage=byoa/premST=1 ___ AMRadio mailing list AMRadio@mailman.qth.net http://mailman.qth.net/mailman/listinfo/amradio
RE: [AMRadio] 4D32 rig testing
Dave, many people run them on low voltage, that is ok with me. I have been running mine on the high voltage for 15 years with no crap outs at all, not a single problem with them. The low voltage transformer frequently went because it was overloaded, and removing the vacuum rectifiers reduces the load a lot. peter Dahl sells replacements, they are likely not cheap, but are good transformers. The only mod transformer I ever blew out was in the 30K1 I had, testing it with 20hz at 100% modulation at full power. Stupid, but I did not know anything then, and the 30K1 cost me less than the peter Dahl 32v3 mod transformer ($200.00). Serial number 9, I wonder if its on the air now, it used to sound very good when I sold it to someone down south. Brett N2DTS -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of David Knepper Sent: Saturday, January 24, 2004 4:10 PM To: amradio@mailman.qth.net Subject: Re: [AMRadio] 4D32 rig testing Please excuse my ignorance among the experts but shouldn't one be careful not to push the voltage rating on the secondary of the modulation transformer when increasing the plate voltage on the RF amplifier? or on the primary winding when pushing higher voltage on the mod. tubes. On all of my 32V's at the Collins Radio Center, I put the toggle switch on the rear to 600 volts, not 700 volts. Know where I can get a replacement mod. transformer for the 32V transmitter? I don't! Inquiring minds would like to know! Why sacrifice a modulation transformer, which are expensive and rare these days. Thank you Dave, W3ST Secretary to the Collins Radio Association Publisher of the Collins Journal www.collinsra.com - Original Message - From: Donald Chester [EMAIL PROTECTED] To: amradio@mailman.qth.net Sent: Saturday, January 24, 2004 3:47 PM Subject: RE: [AMRadio] 4D32 rig testing Collins runs them at over 700 volts in class C plate modulated service (32V series). If they don't arc over, and you don't exceed the plate dissipation, what would be the problem? That's a good point. I recall an article pre-WW2 in QST which described getting high peak audio power from modulator tubes by running unusually high voltage on them, but staying within the rated dissipation rating. A point was made that for example, the 807 is rated for a maximum of 600 volts plate modulated. That means the peak voltage would be at least 1200 volts, and that doesn't hurt them, and is still within factory specified ratings. So for intermittent service, you should be able to run as much as 1200 DC volts on an 807. I think the limit on plate modulated voltage would be the point where arcovers would begin. However, I do recall using a quad of p-p parallel 2A3's in my audio driver. I didn't have a proper driver transformer at the time, so I ran them @ 400 volts/30 m.a. each tube. They are rated at 300 volts/40 m.a. maximum in the RCA manual. That way I could get plenty of peak driving voltage to the class B grids, despite having a driver transformer with too much stepdown, but with exactly the same plate dissipation as per RCA recommended ratings. They worked great, and drove the modulator tubes with very little distortion. But I noticed that within a few months, the 2A3's would get weak. I went through a couple of sets that way. Finally, I obtained a proper driver transformer with the proper turns ratio, and slowered the plate voltage back to 300v, and changed the bias so that each tube would draw 40 m.a., and now I have had the same set of 2A3's for almost 10 years, and they still test good. Maybe just a coincidence, but at the current price of a new 2A3, I don't feel like trying to find out. My conclusion is that some tubes may not take overvoltage very well, while others will not be harmed, and the only way to find out which ones is to try them and see. If your tubes seem to be short lived, go back to the recommended parameters. -K4KYV _ High-speed users-be more efficient online with the new MSN Premium Internet Software. http://join.msn.com/?pgmarket=en-uspage=byoa/premST=1 ___ AMRadio mailing list AMRadio@mailman.qth.net http://mailman.qth.net/mailman/listinfo/amradio ___ AMRadio mailing list AMRadio@mailman.qth.net http://mailman.qth.net/mailman/listinfo/amradio
RE: [AMRadio] 4D32 rig testing
Don, Well, so what? Collins runs them at over 700 volts in class C plate modulated service (32V series). If they don't arc over, and you don't exceed the plate dissipation, what would be the problem? I am also running 812A's and 811A's at 1700 volts or more without any problems, and some run them at 2000 volts! Cant say I have had any tube failures in the last 20 years, or had any go soft/weak. Brett N2DTS -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of [EMAIL PROTECTED] Sent: Friday, January 23, 2004 10:43 AM To: amradio@mailman.qth.net Subject: Re: [AMRadio] 4D32 rig testing Brett, The 4D32 is rated for 750 volts max plate volts for class C telegraphy and 600 volts max for class C plate modulated AM. Don ___ AMRadio mailing list AMRadio@mailman.qth.net http://mailman.qth.net/mailman/listinfo/amradio
Re: RE: [AMRadio] 4D32 rig testing
In a message dated 1/23/4 9:59:58 AM, [EMAIL PROTECTED] writes: Collins runs them at over 700 volts in class C plate modulated service (32V series). If they don't arc over, and you don't exceed the plate dissipation, what would be the problem? Brett, I have a 32V-3. I can't find anywhere in the manual where they specifically say wherher to use 600 or 700 volts except to use 600 volts for initial adjustments. They do say in the description of the HV supply The tube manufacturer recommends no more than 600 plate volts for phone operation, but this is for CCS rating. So without saying it I guess they are implying that 700 volts is allright for amateur use. The 4D32 is probably pretty conservatively rated. I have been running mine at 600 volts, but perhaps now I will try the 700 volt position. Still, I would not run the 4D32 at over 700 volts. Don
