The Dude Posted November 7, 2012 Share Posted November 7, 2012 I had built a pre amp kit from tubes4hifi.com One of the last parts is to install the phono preamp, for this I need a bigger chassis. I have a aluminum case that is the same width, and depth. But it is over twice as tall, so if the cards have the same bolt patteren could I stacked them. Would this cause any sound issues, or heat issues with the 12ax7 tubes. Thanks Nick Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted November 7, 2012 Share Posted November 7, 2012 Does the preamp use a solid state or tube rectifier? If the latter, putting the phono board above the preamp board would subject the components to fairly excessive amounts of heat which is not a good idea (and would also restrict the ventilation of heat generated by the rectifier.) Also, rectifiers such as a 6X4 would require very tall standoffs for the phono board since the tube is around 2.5" high. So, the point is that it isn't a good idea to stack them in that fashion. Otoh, if you can place the phono board under the preamp board you may be ok as the 12AX7s generate very little heat. And the enclosure needs to be very well ventilated of course. Good luck! Maynard Quote Link to comment Share on other sites More sharing options...
Don Richard Posted November 7, 2012 Share Posted November 7, 2012 Heat is the enemy of electronic components and you want to keep them as cool as you can. Heat can shorten the life of electrolytic caps and cause resistance values to drift with the varying temperatures. Of course this affects performance. Heat management is an important aspect of circuit design. Mil-spec caps are available with high temp ratings, along with resistors with different temperature compensation curves. They are more expensive so it would be cheaper to get another chassis or case. Adequate ventilation is a must, as was mentioned before. Quote Link to comment Share on other sites More sharing options...
The Dude Posted November 7, 2012 Author Share Posted November 7, 2012 Does the preamp use a solid state or tube rectifier? If the latter, putting the phono board above the preamp board would subject the components to fairly excessive amounts of heat which is not a good idea (and would also restrict the ventilation of heat generated by the rectifier.) Also, rectifiers such as a 6X4 would require very tall standoffs for the phono board since the tube is around 2.5" high. So, the point is that it isn't a good idea to stack them in that fashion. Otoh, if you can place the phono board under the preamp board you may be ok as the 12AX7s generate very little heat. And the enclosure needs to be very well ventilated of course. Good luck! Maynard I uses the 12x4, and has a separated power supply. I was just going to stack the phono card and line stage card. Quote Link to comment Share on other sites More sharing options...
The Dude Posted November 7, 2012 Author Share Posted November 7, 2012 Heat is the enemy of electronic components and you want to keep them as cool as you can. Heat can shorten the life of electrolytic caps and cause resistance values to drift with the varying temperatures. Of course this affects performance. Heat management is an important aspect of circuit design. Mil-spec caps are available with high temp ratings, along with resistors with different temperature compensation curves. They are more expensive so it would be cheaper to get another chassis or case. Adequate ventilation is a must, as was mentioned before. I understand what you are saying. I just come across some boxes sometimes that just aren't the right size. I can put all three cards in the chassis I have now, and put the transformer in a separate box, which I might do for now. I have my eye on a chassis its just having the funds. Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted November 8, 2012 Share Posted November 8, 2012 Some pictures of the arrangement you are currently using would be very helpful in coming up with a workable solution. Quote Link to comment Share on other sites More sharing options...
The Dude Posted November 8, 2012 Author Share Posted November 8, 2012 Ok I will take some this evening, I don't have the phono stage yet as I am trying to plan for when I do get it. I have a idea what might work for now. I will pick up some supplies this evening on my way home. I know I have been down this road before but just couldn't decide how to tackle it. But for now to have a phono section something needs to be done. Quote Link to comment Share on other sites More sharing options...
The Dude Posted November 12, 2012 Author Share Posted November 12, 2012 Here are some pics, but over the weekend. I came across a Bozak C-305 component cabinet, so I guess you can say I lost interest in project and am now more focused on one for now. Quote Link to comment Share on other sites More sharing options...
The Dude Posted November 12, 2012 Author Share Posted November 12, 2012 Sorry forgot to post the pics Quote Link to comment Share on other sites More sharing options...
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