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In the Forum: Audio Discussions
In the Thread: SET amplifiers

Post Subject: ResumingPosted by noviygera on: 3/24/2016

After planning out the exit strategy for my DSP crossover, I am resuming my first Single Ended Pentode 307a tube amp project, the one mentioned earlier. I'd like to approach this with a certain degree of understanding so I have re-read carefully all posts and comments and this time I feel I have less stupid questions to ask. As I understand, choosing the proper transformers for a dedicated SEP will give me ability to tune the amp-speaker relationship (and this is what I want). But I want to lay down, what I feel, may be constants in the context of this project so that I can wisely narrow down the variables.The schematic shows 5K primary impedance on OPT. My mid horn is used between 220hz and 1.9Khz and in this freq range it's impedance sweep curve is between 25 and 14 ohms.Does this info help me select a proper OPT? Is it safe to assume that secondary should have single tap 14-16ohm and primary may have, perhaps, three taps 4.5K, 5K, 5.5K that will leave me with the single variable necessary to tune the amp-speaker relationship? Am I missing additional variables that will be used to further adjust OPT-speaker relationship?Who makes re-mappable OPT?I found SILK transformers are reasonably priced and will make custom. But to order custom I need to have a good idea of how to specify "custom".
Gera

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