ampage Tube Amps / Music Electronics	For current discussions, please visit Music Electronics Forum.

ampage archive

Vintage threads from the first ten years

previous: Tailpiece I've got these strange tubes, 8417 ... -- 8/26/1999 3:59 AM

Re: Weird Tubes

8/26/1999 12:56 PM
Doc	Re: Weird Tubes These tubes were used in some Bogen amps (as GW mentioned) and also in some high power HiFi amps. Dynaco's largest mono tube amp used 8417s. Look for a Dyna schematic for the Mark IV amplifier for typical circuit voltages. Also, there are some mono amps built in the last ten years by Quicksilver that are based on 8417s. Nice score! You know how to maker a guy jealous. It's a shame this tube, or another with similar characteristics, isn't made anymore. It had high power dissipation rating, was ruggedly built using good materials, had high transconductance and a low plate resistance for a pentode. The low plate resistance means that the output transformer can be wound with a lower primary impedance, thus a relatively low inductance results which is great for low distortion high power at low (bass) frequencies. They appeared toward the end of the big HiFi tube era, and only a few manufacturers built them. I guess in the big picture, demand was low.

8/26/1999 12:56 PM

Doc

Re: Weird Tubes

These tubes were used in some Bogen amps (as GW mentioned) and also in some high power HiFi amps. Dynaco's largest mono tube amp used 8417s. Look for a Dyna schematic for the Mark IV amplifier for typical circuit voltages. Also, there are some mono amps built in the last ten years by Quicksilver that are based on 8417s. Nice score! You know how to maker a guy jealous.

It's a shame this tube, or another with similar characteristics, isn't made anymore. It had high power dissipation rating, was ruggedly built using good materials, had high transconductance and a low plate resistance for a pentode. The low plate resistance means that the output transformer can be wound with a lower primary impedance, thus a relatively low inductance results which is great for low distortion high power at low (bass) frequencies. They appeared toward the end of the big HiFi tube era, and only a few manufacturers built them. I guess in the big picture, demand was low.

Replies:

Ken Check out the Svetlana incarnation ... -- 8/26/1999 4:28 PM