Preamp tubes

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BigMesa

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What preamp tubes are you using in your Dual Rectifiers and waht kind of tone change did you experience? Right now I have the MESA 12AX7's in mine but it's time for a retube. Thanks.
 
I've used stock Mesa 12AX7s, Electro-Harmonix 12AX7, Groove Tubes 12AX7-C, JJ's ECC83, and Tung Sol reissue 12AX7.

At the moment my amp is configured with the Tung Sols in V1 and V2, high gain JJ ECC83s in V3 and V4, and a balanced ECC83 in V5.

The JJ's ECC83s have a very dark tone. When I had them in V1 and V2 they absolutely sucked the life out of my clean channel.

The Groove Tube 12AX7-C is Chinese made. It has a much brighter sound than the JJ's. You can expect very dynamic cleans and detailed harmonics.

Currently, the Tung Sol 12AX7 reissue is my tube of choice for the V1 and V2 positions. They are a Russian-made tube, but not nearly as "dark" sounding as the JJ's. It is a very well-rounded tube. I get pristine, 3-dimensional clean tones and excellent crunch and distortion.
 
They make a great deal of difference - I would definitely recommend trying a few different tubes and putting them in different positions - they're relatively cheap to buy but you'll be surprised what a difference they'll make.

I would highly recommend trying them yourself - I agree with what Flashpoint is saying above, however I really liked the JJs in v1 and v2 and I have a Harma Cryo tube in V3 that brought compliments the JJs really well. I personally didn't get on with the Tung Sols at all - like I say it must be down to personal choice and the best way is for you to try it yourself! (-;
 
Yeah, the only thing I can tell you is what I experienced personally. "Good sound" is too subjective to have a right and wrong answer.

Pre-amp tubes are relatively cheap if you want to experiment. Obviously the V1 socket makes the most difference since it is the first stage in shaping your tone. You could buy 2 of each brand that you want to try, then mix and match them in various positions and combinations.
 
I re-tube amps for a living, and right now I'm having the best luck [believe it or not] with the Sovtek 12ax7LPS tubes. The LPS stands for LARGE PLATE, SPIRAL FILAMENT. They are supposed to be quieter in amps with AC heater circuits. I stopped using the EH tubes because I was getting too many of them that were microphonic right out of the box. They also sounded really buzzy to me, not real musical. The Sovteks give a great crunch sound and the cleans are fairly sparkly. I stopped using the JJs in the preamps because they are just BLAH!!! Lifeless sounding!
The durability of the JJ power tubes I have to question as well. I recently had a customer's amp experience a failure that should NOT have happened to 5 month old power tubes.
Everyone has an opinion, this is mine....LOL!!!!
Which ever tube you choose, if you personally like the sound of it, stick with it. That's the right tube for you. :D
 
I agree with these guys. Tone is subjective. You will find your favorite tubes it is certain. But they may not be the same ones that other people like. Get a little stash of various brands and experiment. Just remember that just even though you got one, it might not be a good one. A couple of each is a good idea. Then play musical tubes... :lol: Swap them around in different orders paying close attention to V1 and any other position that you are keying on. Tubes will sound different tonally and have varying amounts of gain. Some will sound good in V1 but may not be your favorite in the later gain stages. Some might even sound terrible but could be a great PI. You might even think a certain type to be the best for all positions. It is all about swapping and really listening to your amp then deciding what sounds best.
 
Yeah what the guy above says! I had 5 different brands of preamp tubes and mixed and matched them into different positions. Some changes can be subtle, but some combinations quite different. I think it also depends on which voicings and which channels you use the most and are most concerned about. I tried some combinations that worked great for one channel and a voicing, and didn't sound good on another channel. I eventually decided to 'voice' the third channel to how I liked it and took the hit on the other channels, as I don't use them quite as much.

Preamp tubes are relatively cheap so I would definitely grab a few and try them - you'll find different levels of brightness, different levels of gain, noise, low end etc. with different brands and even same brand, same model, different tube will be different! The best advice is to try them yourself!!
 
For my two cents...I recommend using preamp tubes that have been tested for microphonics and noise level. The Mesa SPXa7a, any Groove Tube preamp and the High Grade TAD 7025 would fit into this catagory. I have stopped using the EH's as well after too many having noise and microphonic problems. The new Tung Sol has been proving out nicely as well. The Chinese Shuguang tubes are pretty nice as well...your supplier has to be aware as to which factory in china the tubes come from...the shuguang factory has been putting our great tubes.
 
In the 2 channel Dual Recto, V4 is for the loop and V5 is the phase inverter. Am I right?

So that leaves V1, V2 and V3 for laborating with tonal and gain structure changes..?

The first half of V1 is the input stage and the second isn't used at all. V2 is 2nd and 3rd stage. V3 is 4th and 5th stage. So which would affect the gain structure the most V1 or perhaps V2 and wich would do most on the overall tonal character of the amp?
 
what you have to be concerned with regarding the preamp tubes is the gain mutiplication factor...that is v1 is going to be amplified (multiplied) by the next stage...in this case v2..and so on and so on. Therefore, in cascading preamps like boogies, it is critical to have a tube in the v1 position that are extremely low in noise and microphonics. Again, the Mesa SPAX7A fits the bill perfectly, as do other properly tested and selected "brand name" tubes. Each stage does effect the overall tone, but it's the tone stage tube that will have the greatest effect...along with the actual tone stage design. Regarding gain of the tube, the Chinese tubes seem to rule the roost here..and are generally great in other aspects...specifically the Shuguang manufacturer.
 

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