Running Hot

[tuffy_puppy]

hello all,  being a first time poster i hope i am doing this properly.  about a month ago i purchased on audiogon a s e x 2.1 amp.  liked it so much that i promptly asked shawn to assemble a foreplay 3 with all upgrades.  everything in place and outstanding!!  my concern is the heat buildup in the center transformer of the amp.  several nights ago i noticed that the trannie was too hot to touch.  this seemed wrong and since then i have been paying super-close attention to the heat situation.......at the best of times i can grip the trannie indefinitely.  at other times this gripping must end at the count of 20, or at 15, or at 10, or at some lesser figure.  checked with my audiogon seller and he said that the tubes he included with the amp (6em7) were the tubes he always used.  reminded him that shawn had stated that tube use would require different resistors.  no response.........so, seeing that 6dn7 tubes were intended as original equipt i switched tubes.  situation remains about the same.........just gripped the transformer and got to a count of seven before letting go.........have had two dynacos, one knight, and two decware amps and have seen this heat with some of them.  do i have a problem requiring correction?  i have exactly no skills in the areas for which you guys are famous.  please advise.  don

[Grainger49]

I'm a little confused.  Which product are you having heat problems with the SEX amp or the FP III? 

Heat in Bottlehead transformers is often asked about.  Paul Joppa designed the transformers to run hotter than most guys are used to.  The windings are rated for this heat. 

If you do a search you will find several posts from PJ that will give you an idea how hot they should be.  I found this thread:

http://www.bottlehead.com/smf/index.php/topic,637.0.html

BTW, I checked at Duncan's Amps and the 6EM7 is not listed as a direct substitute for the 6DM7.

Edit: This just became FAQ #4

[Doc B.]

It does get hot, that's the way it is designed. Changing to a 6EM7 requires some resistor changes. Unless those changes have been made it should indeed be running 6DN7s. I think it sounds better with 6DN7s.

[tuffy_puppy]

thank you so much!  love this gear and hoped there were no problems.  sorry grainger,  yes my concern was with the amp.  the heat buildup was significant.  the seller sent 6em7 tubes.  i saw in your info that the 6dn7 tube was correct.  i agree those sounded better.  i come to this product be cause it sounds better than i have experienced not because i have any abilities to tinker;  i do not!!  congrats on a better mousetrap!!  sound is terrific!!.......i now will be ranked among bottlehead devotees!!......don pettit, long beach, washington

[Paul Joppa]

Hey, if you're in Long Beach, keep an eye on the forum - there are periodic local meets, and Bottlehead is on Bainbridge Island - a long drive but not impossible. It's a laid-back but fun community.

[Grainger49]

thank you so much!  love this gear and hoped there were no problems.  sorry grainger,  yes my concern was with the amp.  the heat buildup was significant.  the seller sent 6em7 tubes.  i saw in your info that the 6dn7 tube was correct.  i agree those sounded better.  i come to this product be cause it sounds better than i have experienced not because i have any abilities to tinker;  i do not!!  congrats on a better mousetrap!!  sound is terrific!!.......i now will be ranked among bottlehead devotees!!......don pettit, long beach, washington

Don't worry, we will teach you to be a tinkerer here, tweaking is just too much fun!  Since you are not far from Bottlehead World Headquarters someone will probably be close enough to you to teach you the basics of soldering.  Then you will have enough knowledge to be really dangerous.

[4krow]

Knowing Don, it would be a good idea if you blindfolded him first, and THEN take him to headquarters....could be a Decware spy.

[tuffy_puppy]

hi again,  thank you, paul!  thank you, grainger!  just wait, greg!!

[tuffy_puppy]

thank you so much!  love this gear and hoped there were no problems.  sorry grainger,  yes my concern was with the amp.  the heat buildup was significant.  the seller sent 6em7 tubes.  i saw in your info that the 6dn7 tube was correct.  i agree those sounded better.  i come to this product be cause it sounds better than i have experienced not because i have any abilities to tinker;  i do not!!  congrats on a better mousetrap!!  sound is terrific!!.......i now will be ranked among bottlehead devotees!!......don pettit, long beach, washington

Don't worry, we will teach you to be a tinkerer here, tweaking is just too much fun!  Since you are not far from Bottlehead World Headquarters someone will probably be close enough to you to teach you the basics of soldering.  Then you will have enough knowledge to be really dangerous.

hey again grainger,  my email is [email protected].  would you be comfortable with my using regular email for the questions i have about bottlehead topics? if so shoot me an email that i can reply to.  if not reply here and i will attempt to continue with this method.  i do find this cumbersome as my computer skills are minimal.  thanks, don

[Grainger49]

Don,

You have an email.