2015/04/17 18:19:45
ampfixer
Part 2 of 3 is now online for those of you that like to tinker,
 
http://blog.thetubestore.com/if-you-cant-find-it-build-it-diy-amp-part-two/
 
2015/04/19 10:10:46
michaelhanson
Wow, very informative, John. This is an awesome lesson even for those of us that feel it is way beyond our current capabilities to build an amp.

I shop at The Tube Store for tubes, though it's been a while since I have bought any. I've got a new H&K 18w head that I will eventually start tweaking with tube changes. I may have to hit you up for recommendations. I have seen that you review the tubes as well.
2015/04/19 10:46:01
Paul P
 
John, great part II.  Sure makes me anxious to open up my amp again and get my hands dirty.
 
I won't have the time to give proper consideration to what you've done before June (and I'm pretty rusty) but one thing that stands out to me is your use of a pentode for your preamp.  I've never seen this.  Is it a personal innovation of yours or have there been commercial amps that did the same ?  Also, you say the EF86's output is strong enough to drive a tone control without the need for a makeup stage, but your current design does have a two-tiered makeup stage ?
 
2015/04/19 11:00:10
fireberd
Excellent.  I'm an old amp tech and ham radio op (general).  I've done a lot of "home brew" equipment (and built a lot of Heathkits).
 
 
2015/04/19 14:09:19
ampfixer
I realize that the article doesn't really give enough information for a noob to build an amp but I think it's enough to provide some entertainment and give some insight into what's involved.
 
@Paul P - The EF86 will easily drive a simple tone control. The 3 band tone stack requires more signal than a one knob tone control. The cathode follower circuit for the tone stack does not add significant gain to the circuit but will ensure that the signal passes through without loss.
 
My various recommendations for tubes are posted on the net but I'm always happy to chime in here or answer PM's for specific questions.
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