my issue is how to reduce the power without reducing the tone. in the old days, bands would demand more and more power to take their acts to bigger and bigger audiences. a lot of these amps sounded, and still sound, great, but aren't very practical for the home. that hundred watt combo amp that served pete townshend so well will shake your walls and have the police in your driveway. and it will make you deaf.
so the problem is along the lines of how can we reduce that amp from 100 watts to, say, a more living room manageable 5 watts so we can overdrive those tubes just like our favorite rockers did and not suffer the consequences listed above. a quality attenuator is an quick answer, but now you've got this solid state box messing with your all tube bliss. a somewhat more time consuming method is the make changes to the tubes to bring about this radical power demise. there's a lot of help out there to do this job. i'm glad this amp is circuit boards as i'd otherwise probably have the chassis out and mess with the innards, which is never a good thing for me to be doing when i'm done, i'll take it down to the real amp guy and have him go over it and fix all my messups, where the dialog goes from "that could work, i guess, but i don't know anyone who would do it that way" to "this is how people end up burning their house down". as an aside, there is only one full time dedicated profesional guitar tube amp guy left in the entire atlanta metro and i fear he will not be able to hold on too much longer. if anybody is interested in helping him out by buying a guitar amp made entirely by hand and by one individual, google "andrews amp atlanta." only about 1500 bucks or so. On Fri, Mar 13, 2009 at 10:25 PM, OK Don <okd...@gmail.com> wrote: > Well, crap - I used to know that stuff, can't remember which one my HH > Scott > amp used anymore. > Had to go to the other end of the house to look them up. > The AT7 is a high mu tube and the AU7 is a medium mu tube. The input > capacitances are higher in the AT7, the grid bias is higher in the AT7, the > plate current is higher in the AU7, the plate resistance and transductance > are higher in the AT7, but probably most inportant, the "amp factor" is 60 > for the AT7, and 17-19.5 for the AU7. > > >From the 40th edition of the ARRL handbook, 1963. > > > > > that will make it certain i don't forget about it while thinking hard on > > the > > differences between a 12AT7 and a 12AU7 and which one needs to go where. > > > > > -- > OK Don > W124 Diesels > Ubuntu 8.10 > KD5NRO > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://okiebenz.com/pipermail/mercedes_okiebenz.com/attachments/20090313/8d627c36/attachment.html > > > _______________________________________ > http://www.okiebenz.com > For new and used parts go to www.okiebenz.com > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://okiebenz.com/pipermail/mercedes_okiebenz.com/attachments/20090313/0d2e54c5/attachment.html> _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
