Low gain valves?

[Johnny Competent]

Hi there,

Ive got a Grainger valve 5 (Epi valve junior) and i gigged with it a couple of weeks ago.
It was great but broke up a little too early for my liking.

I heard that replacing the 12AX7 pre-amp valve with a 12AT7 or 12AY7 would give a little more clean headroom.

I'm not convinced that it will make much of a difference, is it worth it?
Does anyone know which is the lowest gain valve?

Cheers!

[Ratrod]

Someone wil correct me if I'm wrong but I think the 12AU7 is the lowest gain.

[kellar]

If you want a great lower gain tube, go with the JJ 12AU7 (ECC81) valve. Fantastic clean tones and it suits the EVJ very well.

[Johnny Competent]

Oh right, i forgot about the 12AU7.
Thanks for the tip.
I just ordered one, cant wait.

On a similar note, i also heard that EL34's give more volume than EL84's.
Is that true? And would it require replacing other components to cope with the extra oomph?

[kellar]

Can't really comment on the EL34 but here is a very informative site about tube substitutions that may help.

http://www.eurotubes.com/euro-j.htm

 :)

[HTH AMPS]

I always find that using lower gain valves in the preamp sounds dull and lifeless - YMMV.

In a 5w amp, you're never gonna get headroom for gigging - its an amp designed for cranking the sh*t out of to get natural amp overdrive.

You won't be able to swap in any other output stage valve as the EL84 uses a 9-pin base while every other popular valve used in guitar amps uses an 8-pin base.  Additionally, almost every other output stage valve requires more heater current (0.45A 6V6, 0.76A EL84, 0.9A 6L6, 1.5A EL34) so you'd need a new PT to deliver the required current and a new OT to deliver the extra volume.

All in all, you'd be better off getting another one of those amps and running them together if you want more volume.

Lastly, what speakers are you using? - more efficient speakers and a 4x12 will make those 5 watts go further.

[Johnny Competent]

Its 100% stock at the moment.

Ha Ha, right i'll not bother with that then!

You're absolutely right and to be honest i'm not that fussed, its a cheap amp that more or less does what i want it to - just thought if theres some simple things i can try out for now then i'd give them a go. Maybe get into modding it later

I thought about trying to cram in a 10" 8 ohm speaker, maybe jensen, as im not convinced by 8" inch speakers.
A cab would be great but i'm all about the portability at the moment.

Ill just save up for a more powerful amp i think!

[Elliot]

Most of the 5 watt amps benefit from a slightly lower powered pre-amp valve - but nothing too drastic: try a 5751 - they work at about 75% of 12AX7 and that slight drop gives you a sweeter OD, especially if you use a OD/distortion pedal as part of your gain stage.

They also have more clean headroom using a E84L rather an EL84.

[Fourth Feline]

Most of the 5 watt amps benefit from a slightly lower powered pre-amp valve - but nothing too drastic: try a 5751 - they work at about 75% of 12AX7 and that slight drop gives you a sweeter OD, especially if you use a OD/distortion pedal as part of your gain stage.

They also have more clean headroom using a E84L rather an EL84.

Another lover of the JAN/Philips 5751 valve here  :D  I keep a stock in - as they are for me a real part of making that mellow clean sound.