Parkie37's Audio Note System

**petrat** · 06-10-2016, 08:45

Totally different valves, with different pin-outs, I believe ... so, not just a case of substituting the valves. The 6SN7 is a double triode (presumably with both halves used for the high gain version you have), whereas the 6J5 is a single triode ... so almost certainly the circuit will be different for the low gain version, meaning re-wiring and different pins connected on the valve base.

**Firebottle** · 06-10-2016, 11:36

I wonder if you could bypass one half of the 6SN7 in the high gain version?

I don't know the circuit so it's just a guess.

**petrat** · 06-10-2016, 16:55

Yeah, Don, go for it! All you need is a pair of wire clippers, a reel of hook-up wire, some crocodile clips, and a pair of rubber gloves.

I mean, how hard can it be? ... it's a lot less complicated than an aeroplane, you know

**The Black Adder** · 06-10-2016, 16:58

skzzzzzzzt!

**Lee Henley** · 06-10-2016, 18:08

If I were you Don I'd give AN a call or drop them an email in the UK

**Parkie37** · 07-10-2016, 04:17

Originally Posted by petrat

Totally different valves, with different pin-outs, I believe ... so, not just a case of substituting the valves. The 6SN7 is a double triode (presumably with both halves used for the high gain version you have), whereas the 6J5 is a single triode ... so almost certainly the circuit will be different for the low gain version, meaning re-wiring and different pins connected on the valve base.

I wasn't that interested in experimenting but I ran across two articles that said that the 6J5 was the half strength signal tube compared to the 6SN7 - and that they had the same tube pins. I ordered. a pair and will check them out. The good news is that theyRe only 13.95 each. If they aren't right, then no problem!

**Parkie37** · 07-10-2016, 04:20

Originally Posted by petrat

Yeah, Don, go for it! All you need is a pair of wire clippers, a reel of hook-up wire, some crocodile clips, and a pair of rubber gloves.

I mean, how hard can it be? ... it's a lot less complicated than an aeroplane, you know

That's the winning attitude that allowed us to win the war! What could possibly go wrong?! I am currently enjoying Blue Train with my younger daughter. Holy cow, it sounds magnificent!

**Parkie37** · 07-10-2016, 04:23

Originally Posted by Parkie37

That's the winning attitude that allowed us to win the war! What could possibly go wrong?! I am currently enjoying Blue Train with my younger daughter. Holy cow, it sounds magnificent!

So...we continued to listen to the MM version of Blue Train on vinyl. Wow!

**Firebottle** · 07-10-2016, 06:09

Hi Don,
Don't plug the 6J5 into your amp, it will not work, it may even cause damage.

The valve base may be the same but the connections are totally different. If there are articles out there that suggest you can just substitute then they are plain WRONG.

Just a heads up.

**petrat** · 07-10-2016, 07:03

Alan is correct!!! DO NOT DO IT, YOU MAY WELL DAMAGE THE AMPLIFIER.

Each 6SN7 has two triodes in it, the 6J5 has only one ... so they are different internally and use different pins to connect their various bits to the valve base. Putting the 6J5 straight into your amplifier as it is will result in the wrong pins being connected. The amplifier will need to be re--wired before you can use the 6J5s.

Also in the interests of accuracy, the 6J5 is not 'half-strength', it actually has more gain than one triode of the 6SN7, the latter only having more gain in this application because AN use both of the triodes in its tube, doubling up.

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