Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: teletubbie on March 24, 2013, 08:23:42 pm

Title: EL90 alternatives
Post by: teletubbie on March 24, 2013, 08:23:42 pm

Dear Forum,

I have a small custom tube amp (for low volume practice) which consists of a 12ax7 pre-amp and a single EL90 (6005) power.  Having had trouble finding quality tube replacements for the EL90 I was wondering if it would be advisable to switch the EL90 for a 6V6, 6L6, EL84.  I was wondering if anyone might have an opinion regarding the following 3 questions:

1. Any recommendations for good sounding quality EL90, 6AQ5, 6005 power tubes suitable for a guitar amplifier?

2. Is there another tube type that would be fairly easiest to adapt to?  I realize that this would require changing at least the socket... and possibly the transformer.

3. What would be the optimum approach to enhancing this 2 tube circuit for a low volume guitar practice amp?  What would I need to consider given my current arrangement?

Thanks!

Thanks for all the great advice... can anyone direct me to information about converting a 6aq5 socket to a 6v6?

Title: Re: EL90 alternatives
Post by: tubenit on March 24, 2013, 08:29:30 pm

Check out just the pentode side of the 6BM8 tube.  You don't have to use the triode side.  Push/pull will be around 7-9 watts.  It's a nice sounding tube.   Check out Geezer's  mini-bassman.  6BM8 is a current manufacture, IIRC. 

http://www.el34world.com/Forum/index.php?topic=562.0 (http://www.el34world.com/Forum/index.php?topic=562.0)

& the 56T  6BM8 reverb

http://www.el34world.com/Forum/index.php?topic=6176.0 (http://www.el34world.com/Forum/index.php?topic=6176.0)

With respect, Tubenit

Title: Re: EL90 alternatives
Post by: Geezer on March 24, 2013, 08:53:48 pm

I have several amps running 6AQ5/6005 tubes.

The best NOS that are still readily available and affordable are the JAN GE 6005W...did a quick search of eBay and sleeves of 5x go for about $25 to $30

I have also purchased used Tung Sol 6AQ5's that still sound good....those are tough as nails and last a long time!

G

Title: Re: EL90 alternatives
Post by: PRR on March 25, 2013, 07:35:55 pm

EL90 *IS* 6AQ5.

NOS 6AQ5 are still readily available.

6AQ5 is a small 6V6. If you have a big drill, you can bodge an octal socket in and run 6V6.

Title: Re: EL90 alternatives
Post by: HotBluePlates on April 04, 2013, 09:27:20 pm

Quote from: drgonzonm on April 04, 2013, 06:43:56 pm

Aren't the pin placements on the 6aq5 and 6v6 a little different?  If so, don't forget to rewire.

The 6AQ5 is a 7-pin mini tube, while the 6V6 is an octal tube. So a different socket is needed.

The EL90 and 6AQ5 have identical sockets and pinouts.