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Hi All , I have recently replaced the 3x12AX7's with AY7's (cleaner tone at higher volume), would this cause any problems (2003 BJ) ?

No it would give no problems apart from the amp having less gain but more headroom (as you said).

Thanks Roger, I had been told to only use a AY7 in the V1 position, but i think it would only be beneficial for 'blues players', I'll trust your knowledge and leave the 3 AY7's in, Regards Keith

Hi Keith

As far as I know the popular thing is to put a lower gain replacement in the V1 pos only and that makes it a more bluesy sound I understand I do not think anything to be gained replacing all 12AX7s with lower gain types as you will lose volume in the end. Popular one is a 5157 Jan in V1 reduces gain to about 70% on a 12AX7. This is what a lot of people tend to do. However having all 3 valves changed will not affect the amp at all just a lot less gain in the stages and therefore less volume output as Roger Allcock stated.

HTH

Hi Rog, I've put Ay7's in V1 and V3 phase inverter, on the Billm site it says these 2 will give cleaner darker tone than a AX7 at higher volume and should cause no problems

Keith is it a balanced triode valve for the inverter ? these are usually the ones to get for that V3 pos.

According to Billm the std 12AY7 or 5171 can be used in the P/i position, The E/Harmx EL84's are balanced, I did try it as you advised with just 1 AY7 in V1 but i couldn't really say there was much difference (deafness has this effect) so will have to wait for next hankies meet for good ears to comment !!. It also states half the gain (AY7) valves does not mean half the volume, just that distortion doesn't kick in until much higher vol, ie level 8 AY7 level 4 AX7