Topic: different input tubes?

[jmz93]

I use a Decware SE84C-S amp as the heart of my system... 5 watts class A single-ended triode.
Output tubes are SV83's, it's self-biasing, and the input tube is currently a 6N1P which to my untrained eye, looks just like the 12AX7 preamp tubes in my guitar amps.
Can I swap it for a 12AX7 or 12AAT7 without frying anything? What about 6922's?  Has anybody else experimented like this
and what did you find the characteristics were of various input tubes?

[Nick Culbreth]

There has been a lot of discussion of tube rolling in the past and I think in most cases swapping the input tubes can have a huge impact on sound quality.  While most 9-pin tubes have a similar construction, they are not drop in replacements and putting the wrong type of tube can do a lot of damage to your equipment.  In your case the 6N1P is a Russian tube with similar specs to the 6DJ8 / 6922 family.  The 6N1P draws a bit more current than the 6922s so you should probably contact the manufacturer to find out if a 6922 is a suitable replacement.  Provided that your amp is fine with 6922s I'd look into the NOS 6H23 (Russian equivalent of 6922) military grade tubes, in my experience they're significantly better than the current production 6922s and are far more budget friendly than most of the NOS 6922 tubes.

[Church-Audio]

I use a Decware SE84C-S amp as the heart of my system... 5 watts class A single-ended triode.
Output tubes are SV83's, it's self-biasing, and the input tube is currently a 6N1P which to my untrained eye, looks just like the 12AX7 preamp tubes in my guitar amps.
Can I swap it for a 12AX7 or 12AAT7 without frying anything? What about 6922's?  Has anybody else experimented like this
and what did you find the characteristics were of various input tubes?

12AX7 Is a higher gain version of the 12AT7 So if you want less gain use the AT7 if you want more use the AX7 You should check out this place www.tubestore.com

Chris

[Tim]

There has been a lot of discussion of tube rolling in the past and I think in most cases swapping the input tubes can have a huge impact on sound quality.  While most 9-pin tubes have a similar construction, they are not drop in replacements and putting the wrong type of tube can do a lot of damage to your equipment.  In your case the 6N1P is a Russian tube with similar specs to the 6DJ8 / 6922 family.  The 6N1P draws a bit more current than the 6922s so you should probably contact the manufacturer to find out if a 6922 is a suitable replacement.  Provided that your amp is fine with 6922s I'd look into the NOS 6H23 (Russian equivalent of 6922) military grade tubes, in my experience they're significantly better than the current production 6922s and are far more budget friendly than most of the NOS 6922 tubes.

TS.com's resident Tube Master

[Frank in JC]

I use a Decware SE84C-S amp as the heart of my system... 5 watts class A single-ended triode.
Output tubes are SV83's, it's self-biasing, and the input tube is currently a 6N1P which to my untrained eye, looks just like the 12AX7 preamp tubes in my guitar amps.
Can I swap it for a 12AX7 or 12AAT7 without frying anything? What about 6922's?  Has anybody else experimented like this
and what did you find the characteristics were of various input tubes?

FYI, the "6" in a designation like 6N1P or the "12" in 12AX7 refers to the heater voltage.  You can't use a tube with a 12-volt heater in a circuit that only provides 6-volts without modification.  That's a major tip-off right there, and it's probably the least significant way in which tubes can vary!  DO NOT go by looks, as the electrical characteristics between two very similar looking tubes can be wildly different. 

You can also check with Upscale Audio or Parts ConneXion for recommended alternatives.  Both are retailers I've had excellent experience with.