Re: [AMRadio] 6CA7/EL34 replacements
I've had good luck with J J (tesla) tubes for output tubes, EL34 and EL84. I've had good luck with Sovtek preamp 12AX7s but not 6L6s. I use NOS that I have collected from various sources, especially hamfests. The Electro Harmonix 6L6s seem to be fine, I think that they are picked out Sovteks and the Groove Tubes 6L6s though expensive work well. I think that they are tested Sino or that they are making their own tubes now. There are new Gold Lion and Mullards now as someone is using their designs or even the original tooling. Some are reasonable in cost, some are only for audiofools with more money than sense.The Mullards are supposed to be good and not overpriced. i haven't tried them as I have some NOS units at home. Output tubes last for a few years with regular use, preamp tubes last me for many (10+) years with regular use. Ken Zuercher KC8QO --- jeremy-ca [EMAIL PROTECTED] wrote: My son uses a Koch guitar amp with Ruby EL-34B-STR tubes and they dont hold up well, another one shorted last week. What are the preferred brands? Searching the web gives a lot of conflicting info. Carl KM1H - Original Message - From: Ken Zuercher [EMAIL PROTECTED] To: Discussion of AM Radio in the Amateur Service amradio@mailman.qth.net Sent: Friday, December 07, 2007 12:39 AM Subject: Re: [AMRadio] 6CA7/EL34 replacements I agree about the guitar shop. The Marshall amps use EL34 tubes and are pretty tough on them (like me, I'm a guitar player) I like the JJ tubes as they were the Tesla brand and are made in the Czech Republic. They also have a model with beautiful blue glass envelope. Ken KC8QO --- Mike Sawyer [EMAIL PROTECTED] wrote: John, If you are in a hurry, try checking out your local guitar shop. I'll lay odds that they have them available for about the same price you get for mail order. Mod-U-Lator, Mike(y) W3SLK - Original Message - From: John King [EMAIL PROTECTED] To: amradio@mailman.qth.net Sent: Thursday, December 06, 2007 4:08 PM Subject: [AMRadio] 6CA7/EL34 replacements Please disregard my earlier post requesting information about substituting other numbered tubes for the 6CA7 for testing purposes. I got the transmitter working with the old 6CA7/EL34 tubes. Now to order some!! Has anyone had much luck with the cheaper import 6CA7 tubes such those sold by Antique Radio Supply under the brand names of JJ Electronics and Valve Art ??? Thanks for reading. 73, John, K5PGW __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] 6CA7/EL34 replacements
My son uses a Koch guitar amp with Ruby EL-34B-STR tubes and they dont hold up well, another one shorted last week. What are the preferred brands? Searching the web gives a lot of conflicting info. Carl KM1H - Original Message - From: Ken Zuercher [EMAIL PROTECTED] To: Discussion of AM Radio in the Amateur Service amradio@mailman.qth.net Sent: Friday, December 07, 2007 12:39 AM Subject: Re: [AMRadio] 6CA7/EL34 replacements I agree about the guitar shop. The Marshall amps use EL34 tubes and are pretty tough on them (like me, I'm a guitar player) I like the JJ tubes as they were the Tesla brand and are made in the Czech Republic. They also have a model with beautiful blue glass envelope. Ken KC8QO --- Mike Sawyer [EMAIL PROTECTED] wrote: John, If you are in a hurry, try checking out your local guitar shop. I'll lay odds that they have them available for about the same price you get for mail order. Mod-U-Lator, Mike(y) W3SLK - Original Message - From: John King [EMAIL PROTECTED] To: amradio@mailman.qth.net Sent: Thursday, December 06, 2007 4:08 PM Subject: [AMRadio] 6CA7/EL34 replacements Please disregard my earlier post requesting information about substituting other numbered tubes for the 6CA7 for testing purposes. I got the transmitter working with the old 6CA7/EL34 tubes. Now to order some!! Has anyone had much luck with the cheaper import 6CA7 tubes such those sold by Antique Radio Supply under the brand names of JJ Electronics and Valve Art ??? Thanks for reading. 73, John, K5PGW __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
[AMRadio] 6CA7/EL34 replacements
Please disregard my earlier post requesting information about substituting other numbered tubes for the 6CA7 for testing purposes. I got the transmitter working with the old 6CA7/EL34 tubes. Now to order some!! Has anyone had much luck with the cheaper import 6CA7 tubes such those sold by Antique Radio Supply under the brand names of JJ Electronics and Valve Art ??? Thanks for reading. 73, John, K5PGW Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] 6CA7/EL34 replacements
resend... John King Said: Thu, 06 Dec 2007 13:08:48 -0800 Please disregard my earlier post requesting information about substituting other numbered tubes for the 6CA7 for testing purposes. I got the transmitter working with the old 6CA7/EL34 tubes. Now to order some!! Has anyone had much luck with the cheaper import 6CA7 tubes such those sold by Antique Radio Supply under the brand names of JJ Electronics and Valve Art ??? Thanks for reading. 73, John, K5PGW Reply by Jim Candela, WD5JKO: John, I have one of my QRO Central electronics 20A projects where I tried a EL-34 for RF Ab1 linear use for 160-20m. I tried the Svetlana, Sovtek, and an old vintage KT-77. None of them did as well as a Teslovak E34LS (this is not a typo, the tube number changed). This tube is carried by the Penta Laboratory folks. This tube is more robust with a higher Pd rating than the plane Jane 6CA7 / EL-34 (30w instead of 25w Pd). You will find these hi-fi tubes a little finicky because the high Gm means high gain, and variations in grid 1 bias and/or screen voltage really move the idling current a bunch. Having provision to vary the static G1 voltage is really a must, and regulating the both G1 and G2 voltages are both very desirable. In my main QRO 20a I use a pair of 7591's (get 60w PEP out) and I had to regulate the G1 bias and G2 screen to maintain a stable DC operating point for these tubes. The 7591 is kind of a baby 6550 and both are very high Gm Hi-Fi tubes. Tubes like the 6L6/5881 have lower gain, and therefore require considerably more peak grid swing. Here is the link to Penta Labs: http://www.pentalaboratories.com/Audiophile.aspx?dept_id=1516 My vote is to pay a little more and buy from Penta Labs, Regards, Jim JKO __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
RE: [AMRadio] 6CA7/EL34 replacements
John King Said: Thu, 06 Dec 2007 13:08:48 -0800 Please disregard my earlier post requesting information about substituting other numbered tubes for the 6CA7 for testing purposes. I got the transmitter working with the old 6CA7/EL34 tubes. Now to order some!! Has anyone had much luck with the cheaper import 6CA7 tubes such those sold by Antique Radio Supply under the brand names of JJ Electronics and Valve Art ??? Thanks for reading. 73, John, K5PGW Reply by Jim Candela, WD5JKO: John, I have one of my QRO Central electronics 20A projects where I tried a EL-34 for RF Ab1 linear use for 160-20m. I tried the Svetlana, Sovtek, and an old vintage KT-77. None of them did as well as a Teslovak E34LS (this is not a typo, the tube number changed). This tube is carried by the Penta Laboratory folks. This tube is more robust with a higher Pd rating than the plane Jane 6CA7 / EL-34 (30w instead of 25w Pd). You will find these hi-fi tubes a little finicky because the high Gm means high gain, and variations in grid 1 bias and/or screen voltage really move the idling current a bunch. Having provision to vary the static G1 voltage is really a must, and regulating the both G1 and G2 voltages are both very desirable. In my main QRO 20a I use a pair of 7591's (get 60w PEP out) and I had to regulate the G1 bias and G2 screen to maintain a stable DC operating point for these tubes. The 7591 is kind of a baby 6550 and both are very high Gm Hi-Fi tubes. Tubes like the 6L6/5881 have lower gain, and therefore require considerably more peak grid swing. Here is the link to Penta Labs: http://www.pentalaboratories.com/Audiophile.aspx?dept_id=1516 My vote is to pay a little more and buy from Penta Labs, Regards, Jim JKO __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] 6CA7/EL34 replacements
John, If you are in a hurry, try checking out your local guitar shop. I'll lay odds that they have them available for about the same price you get for mail order. Mod-U-Lator, Mike(y) W3SLK - Original Message - From: John King [EMAIL PROTECTED] To: amradio@mailman.qth.net Sent: Thursday, December 06, 2007 4:08 PM Subject: [AMRadio] 6CA7/EL34 replacements Please disregard my earlier post requesting information about substituting other numbered tubes for the 6CA7 for testing purposes. I got the transmitter working with the old 6CA7/EL34 tubes. Now to order some!! Has anyone had much luck with the cheaper import 6CA7 tubes such those sold by Antique Radio Supply under the brand names of JJ Electronics and Valve Art ??? Thanks for reading. 73, John, K5PGW __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
Re: [AMRadio] 6CA7/EL34 replacements
I agree about the guitar shop. The Marshall amps use EL34 tubes and are pretty tough on them (like me, I'm a guitar player) I like the JJ tubes as they were the Tesla brand and are made in the Czech Republic. They also have a model with beautiful blue glass envelope. Ken KC8QO --- Mike Sawyer [EMAIL PROTECTED] wrote: John, If you are in a hurry, try checking out your local guitar shop. I'll lay odds that they have them available for about the same price you get for mail order. Mod-U-Lator, Mike(y) W3SLK - Original Message - From: John King [EMAIL PROTECTED] To: amradio@mailman.qth.net Sent: Thursday, December 06, 2007 4:08 PM Subject: [AMRadio] 6CA7/EL34 replacements Please disregard my earlier post requesting information about substituting other numbered tubes for the 6CA7 for testing purposes. I got the transmitter working with the old 6CA7/EL34 tubes. Now to order some!! Has anyone had much luck with the cheaper import 6CA7 tubes such those sold by Antique Radio Supply under the brand names of JJ Electronics and Valve Art ??? Thanks for reading. 73, John, K5PGW __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body. __ Our Main Website: http://www.amfone.net AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
