Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: clayman on June 28, 2021, 01:02:11 pm

Title: Cheap nos tubes
Post by: clayman on June 28, 2021, 01:02:11 pm

6by7 pentode. Can this be used as a preamp tube?

Title: Re: Cheap nos tubes
Post by: PRR on June 28, 2021, 02:36:09 pm

Almost any tube can be "a preamp". But is it still "cheap" if you have to experiment to find a happy-point?

Title: Re: Cheap nos tubes
Post by: kagliostro on June 28, 2021, 04:28:29 pm

From the pages of Heinz, a friend of the forum

(https://i.imgur.com/PlAOhvy.jpg)

http://jschem.bplaced.net/t7/ (http://jschem.bplaced.net/t7/)

--

As you can see here EF85 in equivalent to the 6BY7

http://tdsl.duncanamps.com/show.php?des=6BY7 (http://tdsl.duncanamps.com/show.php?des=6BY7)

Franco

Title: Re: Cheap nos tubes
Post by: clayman on July 04, 2021, 02:48:01 pm

Has anyone used 6aq5 in place of 6v6? I know I would have to use 7pin socket, rewire.

Title: Re: Cheap nos tubes
Post by: sluckey on July 04, 2021, 02:58:34 pm

yes     http://sluckeyamps.com/smoky/smoky.pdf

Title: Re: Cheap nos tubes
Post by: clayman on July 04, 2021, 03:11:17 pm

Steve, your link doesn't work. Fixed, thanks

Title: Re: Cheap nos tubes
Post by: kagliostro on July 06, 2021, 07:01:09 am

To me the link works correctly

Franco

Title: Re: Cheap nos tubes
Post by: Latole on July 06, 2021, 07:40:11 am

Quote from: kagliostro on July 06, 2021, 07:01:09 am

To me the link works correctly

Franco

To me too.