A 6L6 has an octal base, 8 pins. Looking at the bottom with keyway toward you pin #1 is on the left. This pin needs to be grounded if you have a metal shell base.
You mentioned these are large tubes. Very possible without the metal shell grounded the amp may go into oscillation.
Norm
:I just realized I was writing while you were responding. Please forgive me I'm obviously an amateur. I really do appreciate your help. One important thing though, I have no idea how to hook up a shell base, or 6L6 metal. My only experience is with old farm radios and guitar amps. Thanks for letting me pick your brain.
Here is information on metal 6L6. If you have any metal around the base it needs to be grounded. Notice pin #1 has "S", shield.
http://www.mif.pg.gda.pl/homepages/frank/sheets/021/6/6L6.pdf
Norm
:I just realized I was writing while you were responding. Please forgive me I'm obviously an amateur. I really do appreciate your help. One important thing though, I have no idea how to hook up a shell base, or 6L6 metal. My only experience is with old farm radios and guitar amps. Thanks for letting me pick your brain.
I had the idea your tubes have a metal shell base. If not, pin #1 doesn't have to be grounded as there isn't anything to connect to chassis.
What is the problem you are having with these tubes?
You mentioned earlier tubes are large? Are these original? Could they be larger than original types? Although different versions of 6L6 have the same electrical characteristics, capacity can cause problems. I've seen cases where input wires close to output tubes caused oscillation. If tubes were smaller or metal this would be less likely to happen.
Norm
:Hey Norm! Sorry to bother you again, but.......after visiting the web sites you've offered, I'm still not satisfied. So far, after all the people and places I've contacted, you are still the only one who knows what I'm talking about. Though I am quite ignorant on this subject, I did know what JAN meant as well as the "s" for the #1 pin. As you stated earlier, this valve does have a yellow ( tan ) base, but no visible metal. Does this matter? Should I just connect the #1 from the socket to the chasis ground ( for guitar amps, farm radios, Hi-Fi stereos, etc.... ) without any special alterations ? Please indulge me this last inquiry and I promise to leave you alone! P. S., you were absolutely right about the effect these tubes created while left ungrounded. I have every confidence in you! Thanks again for everything! Hope to pick your brain again some day, or just chat. Signed, a very appreciative amateur, Todd
As for the tube itself. It has the classic urn shape with a tan bakelite base. Also, unlike other 6L6's that I'm familar with, this one has 7 pins. All plastic base models I've ever used have only 6 pins. Again this is a large tube that some people refer to as "coke-bottle" shaped ( the classic urn, not the more modern "T" ). Please ask around. Thanks for all your time!
:Hi Todd
:
: I had the idea your tubes have a metal shell base. If not, pin #1 doesn't have to be grounded as there isn't anything to connect to chassis.
:
: What is the problem you are having with these tubes?
:
: You mentioned earlier tubes are large? Are these original? Could they be larger than original types? Although different versions of 6L6 have the same electrical characteristics, capacity can cause problems. I've seen cases where input wires close to output tubes caused oscillation. If tubes were smaller or metal this would be less likely to happen.
:
:Norm
:
:
:
::Hey Norm! Sorry to bother you again, but.......after visiting the web sites you've offered, I'm still not satisfied. So far, after all the people and places I've contacted, you are still the only one who knows what I'm talking about. Though I am quite ignorant on this subject, I did know what JAN meant as well as the "s" for the #1 pin. As you stated earlier, this valve does have a yellow ( tan ) base, but no visible metal. Does this matter? Should I just connect the #1 from the socket to the chasis ground ( for guitar amps, farm radios, Hi-Fi stereos, etc.... ) without any special alterations ? Please indulge me this last inquiry and I promise to leave you alone! P. S., you were absolutely right about the effect these tubes created while left ungrounded. I have every confidence in you! Thanks again for everything! Hope to pick your brain again some day, or just chat. Signed, a very appreciative amateur, Todd
:Hey Norm! Thanks again for your response. First off, the problem I'm having is heavy oscilation. During the first few moments of warm-up, the tone and volume are noticeably greater, but then, within seconds, that large grind associated with oscilation begins.
:
:As for the tube itself. It has the classic urn shape with a tan bakelite base. Also, unlike other 6L6's that I'm familar with, this one has 7 pins. All plastic base models I've ever used have only 6 pins. Again this is a large tube that some people refer to as "coke-bottle" shaped ( the classic urn, not the more modern "T" ). Please ask around. Thanks for all your time!
:
:
:
:
:
::Hi Todd
::
:: I had the idea your tubes have a metal shell base. If not, pin #1 doesn't have to be grounded as there isn't anything to connect to chassis.
::
:: What is the problem you are having with these tubes?
::
:: You mentioned earlier tubes are large? Are these original? Could they be larger than original types? Although different versions of 6L6 have the same electrical characteristics, capacity can cause problems. I've seen cases where input wires close to output tubes caused oscillation. If tubes were smaller or metal this would be less likely to happen.
::
::Norm
::
::
::
:::Hey Norm! Sorry to bother you again, but.......after visiting the web sites you've offered, I'm still not satisfied. So far, after all the people and places I've contacted, you are still the only one who knows what I'm talking about. Though I am quite ignorant on this subject, I did know what JAN meant as well as the "s" for the #1 pin. As you stated earlier, this valve does have a yellow ( tan ) base, but no visible metal. Does this matter? Should I just connect the #1 from the socket to the chasis ground ( for guitar amps, farm radios, Hi-Fi stereos, etc.... ) without any special alterations ? Please indulge me this last inquiry and I promise to leave you alone! P. S., you were absolutely right about the effect these tubes created while left ungrounded. I have every confidence in you! Thanks again for everything! Hope to pick your brain again some day, or just chat. Signed, a very appreciative amateur, Todd
Did original tubes cause the same problem? These might have higher gain or frequency response and go into oscillation easier.
You probably have 2 tubes as push-pull output. Add a small cap between pin #3 of each tube and see if this helps. This cap will remove very high frequencies. You might try .001 mfd @ 600 volts or more. Radios sometimes use .005 or .01 mfd.
Norm
:Hey Norm! Are you out there? I forgot to include that these tubes are NOS-NIB, and continually test out just fine on all my tube testers as well as my Westmore tube anylizer. Pease read hte last message I left for further info. Thanks agian!
:
:
::Hey Norm! Thanks again for your response. First off, the problem I'm having is heavy oscilation. During the first few moments of warm-up, the tone and volume are noticeably greater, but then, within seconds, that large grind associated with oscilation begins.
::
::As for the tube itself. It has the classic urn shape with a tan bakelite base. Also, unlike other 6L6's that I'm familar with, this one has 7 pins. All plastic base models I've ever used have only 6 pins. Again this is a large tube that some people refer to as "coke-bottle" shaped ( the classic urn, not the more modern "T" ). Please ask around. Thanks for all your time!
::
::
::
::
::
:::Hi Todd
:::
::: I had the idea your tubes have a metal shell base. If not, pin #1 doesn't have to be grounded as there isn't anything to connect to chassis.
:::
::: What is the problem you are having with these tubes?
:::
::: You mentioned earlier tubes are large? Are these original? Could they be larger than original types? Although different versions of 6L6 have the same electrical characteristics, capacity can cause problems. I've seen cases where input wires close to output tubes caused oscillation. If tubes were smaller or metal this would be less likely to happen.
:::
:::Norm
:::
:::
:::
::::Hey Norm! Sorry to bother you again, but.......after visiting the web sites you've offered, I'm still not satisfied. So far, after all the people and places I've contacted, you are still the only one who knows what I'm talking about. Though I am quite ignorant on this subject, I did know what JAN meant as well as the "s" for the #1 pin. As you stated earlier, this valve does have a yellow ( tan ) base, but no visible metal. Does this matter? Should I just connect the #1 from the socket to the chasis ground ( for guitar amps, farm radios, Hi-Fi stereos, etc.... ) without any special alterations ? Please indulge me this last inquiry and I promise to leave you alone! P. S., you were absolutely right about the effect these tubes created while left ungrounded. I have every confidence in you! Thanks again for everything! Hope to pick your brain again some day, or just chat. Signed, a very appreciative amateur, Todd