[TheChairGuy]

 aa   

[topround]

Sounds good... somebody post something

[WGH]

Welcome to AC Roger !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Wayne

[Whitese]

i have a hard time finding 6EM7's...

Roger, can I trade an Atma-Sphere amp?

I have a customer who goes through 2 dozen 6AS7's a year in his bigg Atma-Sphere. It's a fine amp if one doesn't mind the operating cost. BTW I have made up a tube matcher and can supply those tubes to any owner.


As far as EM7's go, do you need the 6 volt version for any particular reason. I have them and the 13 in matched pairs for $60.

[launche]

Welcome Roger,

Can the original 6EM7 units be upgraded to these newer versions?
If so what would the cost?

Thanks

I am looking into that.

Roger

[jeffreybehr]

Can the original 6EM7 units be upgraded to these newer versions?
If so what would the cost?

WHICH new versions?  Roger, you holding out on me?

[MikeyMouse]

Hi Roger,

Welcome to the forum.  My original RM9 MkII is still sounding great after all these years.

-Mike

[kyyuan]

Roger...Welcome.  How about adding an integrated product to your lineup?  aa

[Whitese]

i have been told that the 6EM7's had a different sound...I honestly cant even remember what was said to me. 

The Atma-Sphere sounds great..best voices I have heard, but for some reason, I rather have 2 tubes than 16. I am also getting some Edgarhorns, and 30 watts OTL seems overkill...

i might sell it to finance an RM  245.1

[Roger A. Modjeski]

Roger...Welcome.  How about adding an integrated product to your lineup?  aa

We already do that on a custom basis as long as its one or two inputs.  So far we have made an EM7 and a 245.1 with one pair of inputs and a volume control. We can accommodate 2 sources on the EM7. For more than that we have "Pot in a Box" with up to 6 inputs.

Most integrateds are just power amps with a volume control in front. CD players have 2 volt output which is more than needed to drive a power amp to full output. So all we need it to attenuate and we call that's what we do in "Pot in a Box"

[Roger A. Modjeski]

i have been told that the 6EM7's had a different sound...I honestly cant even remember what was said to me. 

The Atma-Sphere sounds great..best voices I have heard, but for some reason, I rather have 2 tubes than 16. I am also getting some Edgarhorns, and 30 watts OTL seems overkill...

i might sell it to finance an RM  245.1

The EM7 tube is gem and unlike any other power triode I have encountered. BTW the 6AS7/6080 and 6C33 were both designed to be pass tubes in a power supply where bias stability is a non-issue. It also explains why those tubes have very low Mu (2.0). In my experience with they drift all over the place. Their internal structure is very different also, with the EM7 being the more traditional one.

The 45 is a gem of another age and has equally interesting properties that I explored in the 245.1 design. I felt it could benefit from a new application (there are only 3 SE applications in the RCA manual).

[Whitese]

what are the differences between the 6EM7 and 13EM7?

[pubul57]

bump

[Roger A. Modjeski]

what are the differences between the 6EM7 and 13EM7?

Just the filament voltage. 6.3 volts vs. 13 volts at half the current. Lots of tubes have several filament voltages for use in series string TV sets where the filament currents have to be equal (series circuit) so they pick odd voltages to get the filament power the same as the 6 volt version which is often the original. The smaller tubes in the tuner end up with 3 volt filaments and the big power tubes are often 36-40 volts. It all adds up to 120 volts. There were just a few currents chosen and the 13EM7 goes in the 450 mA string. There was also a 150 mA string for table radios and a 300 mA and 600 mA string for color TV.

The EM7 amp is supplied with 13 volt types in parallel which can easily be arranged in series for the 6 volt type. I hope to make the amplifier available again soon. In the meantime I have one new one for sale and the prototype which has a volume control and a headphone jack.