Hi, I would like to access (and maybe change) the preamp tubes (2 x 12ax7 and 1 x 12at7) of my newly acquired 2011 AD200 MKIII. I gave it a try by unscrewing the back panel. I cannot access to preamp tubes since the power tubes (4 x 6550) block the way. Simple question: can I safely remove the power tubes and replace them afterward without any particular precaution? Or is it another way (that I can't figure out by myself) to access the preamp tubes without touching the power tubes? Thanks in advance
yes that's how you do it, remove the power tubes. doesn't matter which order they go back in (although keeping them in the same order is a good idea if you want). i found the AD200 dark for my tastes so NOS telefunken or Slyvania helped to brighten it up some.
Thank you very much Mark! I had in mind some NOS Telefunken too (or 5751 Tung-Sol) for the 12ax7s and RCA or Mazda for the 12at7. But definitely something clearer with more top.
Thanks for the tip Mr. Foxen. I don't have the head with me right now, but I guessed that the screws are in the feet of the head, right?
I followed your advice. Screws were in the plastic feet. Four screws, chassis out. Pretty easy. Thanks again for the advice.
Don't know yet. I am still waiting for the new tubes: 2 12ax7 Philips-Miniwatt (Bugle Boy) and 1 12at7 RCA black plates. I will let you know
After few weeks of use, I would say that the sound is clearer and more articulated. Now maybe there is no objective difference and I am completely projecting the kind of difference I was expecting by putting in the 12AX7 Phillips Miniwatts and the 12AT7 RCA.
Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products. Browser not compatible