Quote:
Originally Posted by MartyStrat54
Does the EVH use four 12AX7's for Channels 1 and 2 and another set of four 12AX7's for Channel 3? Is that how it is set up? Are you saying your stock OE tubes do not created this problem, only the NOS tubes?
I haven't a clue as to why you are having difficulties getting Channel 3 to respond to known, good tubes. Maybe the problem goes beyond the tubes, that is unless you have certain tubes that will work and all channels respond as they should.
Unless you know what condition the NOS tubes are in, you are just wasting your time. You could have a tube that is 56/78 and another that is 88/94. Which tube would you want in your amp?
It's good to hear info on current production tubes. In fact, I wish others would join and give their opinions on the current production tubes they are using. I sent Josh a gold pin JJ and he didn't like it very much. On the other hand, I am using four EH 12AX7's in an all tube HiFi amp and they sound really good. I've used Sovtek WA's and WB's and didn't like them. However, I ordered some of the LPS's and they aren't bad. I sort of look at Sovtek as the bottom and then everything else is straight up from there.
I'd really like someone to be able to A/B Tung-Sol and Mullard reissue tubes. I've toyed with the idea of getting four each and just trying them in an amp and seeing how it sounds with either the T-S's or the Mullards. I might do that, unless another member can supply feedback.
Marty
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Marty I have Tung Sol and Mullard reissues and both sound really good in the Marshall. The Tung Sols are warm and fat with good frequency response across the board. The Mullards are similar to my ears. These 2 pres are staples for me out of the new production models. JJ pres in my Marshall sounded dull and flat. Frequency response was terrible with dynamics suffering badly.
From what I have picked up you don't want to use a Tung Sol or LPS in a cathode follower stage. LPS make good PI tubes. Here is what I read:
It really depends on the amp with the cathode followers and the voltages on them.
The tube heaters reside inside the cathodes, the cathodes have special coatings on them to insulate them from the heaters.
In typical applications, only 1 to 5 volts is present on the cathodes.
But in cathode follower designs, several hundred volts is present.
On a typical 12AX7 spec. The Heater to cathode voltage difference (difference between the heter voltage and voltage on the cathode) should not exceed 150v to 180v.
On many cathode follower designs like the SLO, almost 200 volts can be seen on the cathode follower stages.
Most of the New Sensor stuff can only handle 100v cathode to heater voltage, and that is why they are not recommended. Too bad they can't even be made to proper specs.