12au7 vs 12ay7

[BenPerkins]

Hi guys,

I have an Orange Micro Dark, which comes with a 12ax7. I wanted to increase the amount of clean headroom available, and make it so I really had to turn up the Gain in order to get the full amount of dirt. I found a late 60’s Mullard 12au7 and it sounds amazing in this capacity.

I also have an OR15 and would like to do the same thing. But before I go searching for more Mullard 12au7’s, how much different would a 12ay7 sound? Or should I stick with 12au7?

Thank you

 

[Lake Placid Blues]

Re: 12au7 vs 12ay7

Amplification factor,

12AX7=100
12AT7= 60
12AY7 = 44
12AU7 =17 and 19.5
12DW7 = 100 and 17-20

The 12AY has a little more than twice as much gain as a 12AU7, but a little less than have as much gain as the common 12AX7. The 12AY7 was used for V1 in Tweed Bassmans but a 12AX7 is often substituted for more gain in guitar applications. The 12AY7 seems to work better as a AX sub possibly because it has similar cathode bias needs. I think its better as an AX sub than a 12AT which is often used as a PI in Fenders. Each of these 9 pins are actually two triodes in one bottle. In the case of the 12DW7 one triode is a 12AU and the other is a 12AX.

 

[BenPerkins]

Re: 12au7 vs 12ay7

Awesome! Thank you for this info

 

[JollyRoger523]

Re: 12au7 vs 12ay7

I think I have a 5751 in my Micro Terror. The gain is a little less, but the biggest difference is it eliminated a harsh sizzle I was hearing with the stock 12ax7

 

[BenPerkins]

12au7 vs 12ay7

I think I have a 5751 in my Micro Terror. The gain is a little less, but the biggest difference is it eliminated a harsh sizzle I was hearing with the stock 12ax7

Which brand are you using? I was looking at a 5751 Tung Sol. JJ seems a little noisy.

https://www.tubedepot.com/products/tung-sol-5751-new-production-preamp-vacuum-tube

 

[JollyRoger523]

Re: 12au7 vs 12ay7

Which brand are you using? I was looking at a 5751 Tung Sol. JJ seems a little noisy.

https://www.tubedepot.com/products/tung-sol-5751-new-production-preamp-vacuum-tube

I don't remember if it's a JJ or EH. It's been a while since I swapped it out.