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Will changing out the pi tube from an AT7 to an AX7 brighten the amp any?

I need to post my NAD thread its been almost a couple weeks and I love my 105

Hamtone wrote:Will changing out the pi tube from an AT7 to an AX7 brighten the amp any?

My experience is that brightness has more to do with the particular tube (or manufacturer). Running a 12AX7/ECC83 in the PI will drive the power section harder, but I don't know that it'll change the tone characteristics. Only one way to find out, though!

Hamtone wrote:I need to post my NAD thread its been almost a couple weeks and I love my 105

Cool !

Dave

I agree with Dave.
one brand of 12AT7 may sound brighter or darker than another, but it is hard to say that a 12AT7 or 12AX7 of the same make will sound brighter.

I prefer 12AT7 for the PI, but you can certainly try different preamp tubes and tweak to your own liking.

I replace the pi with a nos Jan Phillips 5751 which is awesome then I put another in v1 and holy smokes. There appears to be a lot more volume and it does breakup easier. I think I will put a nos Jan at7 in v1. I have a bunch of these tube kicking around from my fender days.

Amazing how responsive those preamp positions can be! I sure wish prices hadn't skyrocketed on those 5751's. There are times when they're the perfect compromise.

I did snag some JAN 12AT7's off ebay recently. Pretty good prices are still available on those. At least, until someone claims they were Jimi's or Eddie's or Stevie's or _fill_in_the_blank_'s favorite tube .

Dave

Nos at7 is the winner. I wonder why its sooooo much louder now

i wonder if the original tube was bad. Did you try a different 12AX7 in those positions?

---mark

mhuss wrote:i wonder if the original tube was bad.

I shipped it with brand new JJ's . I was working on getting it to the cleanest possible sound. Didn't notice any major volume difference when I was experimenting.

Dave

Nope. I considered it but my NOS stuff just happens to be those 2 types of tubes. I do have ax7's just didnt think to try them out. It was seriously weird though it literally behave like a different amp. I loved it before but now holy %&^* its ridiculous, there isnt any of the same darkness that i had before and string attack is much more apparent. I noticed the biggest change with v1, so maybe the tube was bad. I did notice on v1 that the tube didnt come out very hard or it seemed awfully short coming out of the socket, not nearly as much effort as the PI took.

Maybe that shady guy I bought it from was messing with me (completely joking)

Hamtone wrote: Maybe that shady guy I bought it from was messing with me (completely joking)

All part of my evil plan .

Dave

You know it may have just changed the tone enough to have it be perceived louder, I didnt break out my SPL meter to check it, but it definitely feels louder.

I have been playing it in my living room with the Brill and norm jumped and the volumes at noon and the master on about 9 oclock. I had to take them down to about 10 oclock and the master just off from idle, so it doesnt feedback nothing else changed with my board.

Hamtone wrote:I had to take them down to about 10 oclock and the master just off from idle, so it doesnt feedback

Sounds like she's pretty lively now! Nothing beats vintage glass.

Dave

Interesting.

I do prefer vintage glass in V1 and the PI.

This weekend I went to my buddies house to hard wire my pedal board and get that finished up. We needed some parts that he said he had in some boxes in his basement. Well as it turns out he had a fist full of Great Brittian Mullards (havent checked the codes yet) another handfull of very old still the box telefunkens and some rca black plates, and he gave them to me I told him then, that I would pay for them and he shrugged and said he didnt give a crap about old tubes for what he does.

He used to work for some sound design company in Mass. in the late 80's building amps and repairs and stuff and these were just some things he had for bench testing, and it didnt mean a damn thing to him. He was aware they were worth something, but didnt care. Then we spent the next 8 hours soldering I guess I have a good friend there.

I will report back with the codes, a couple probably are going to be challenging to see but I will snap pictures and post.

Hamtone wrote:I guess I have a good friend there.

I guess I'm a wee bit jealous .

If those dusty old tubes are taking up too much space, just let me know.....friend .

Dave