Is There A Big Difference?

[Jazzbo]

Good morning all,

Is there a big difference between the EF86 and 12AX7 tube in terms of quietness, excellence of sound and use in MC/microphone pre amps? Thanks for all input.

jazzbo

 

[treitz3]

Hello, Jazzbo. I noticed that you haven't received any response yet and unfortunately, I can not answer your question due to not having any direct experience with the comparison of the two tube types. I have many 12AX7's and I've heard a plethora of them in different gear and applications but I don't recall ever hearing an EF86 yet. Since no one has chimed in, please allow me to offer some friendly advice if you are up for it. I have created a tube supplier thread from years of gathering information and this link can be seen below.

http://www.whatsbestforum.com/showthread.php?5438-Tube-Supplier-and-cross-reference-thread

On that thread, there is contact information to some very knowledgeable folks when it comes to tubes. To just narrow your search down to two reliable and extremely knowledgeable sources off of that list, both Andy at http://www.vintagetubeservices.com/Default.htm and Jim McShane http://www.mcshanedesign.net can definitely help you out with your inquiry. They are both basically a walking encyclopedia of tube knowledge, have probably forgotten more about tubes than I'll ever know and both come highly recommended. My suggestion to you would be to start with the both of them, until someone here hopefully chimes in. One other friendly bit of advice. If you do contact them, do it by phone. It'll be worth your time.

I know it's not much but it's the best that I can offer right now. I hope this helps.

Tom

 

[DonH50]

I've never used an EF86 that I can recall. The ECC83 is a replacement for the 12AX7. I have found more variation among manufactureres and tube-to-tube than whether it was a 12AX7 or ECC83. Many have both labels on them (though there are, or used to be, some internal differences).

Is the EF86 pin-compatible? I am pretty sure the specs are a little different...

I actually used a small metal-cased Nuvistor in my last tube MC preamp design, IIRC.

 

[treitz3]

Is the EF86 pin-compatible?

I didn't even bother to check on that one, Don. Apparently, it isn't without some modification. Just ran across this http://www.dougcircuits.com/EF86.html

Tom

 

[Jazzbo]

Good Saturday Evening all,

I want to thank you all for your input and any suggestions. I am not sure what the difference if any, between the 12AX7 and EF86. I am just wanting to know which would/might provide and quieter/low noise pre amp circuit. The pre amp tech/builder will start out with the 12AX7 which he is intimately familiar with. I am sure that as popular as the 12AX7 is and it's use in a number of high quality phono pre amps. Thanks all for chiming in with your time and attention. I do appreciate.

jazzbo