2. amps-preamps
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Transformer coupled outputs/inputs in preamplifiers.

I have been a big fan of VAC preamplifiers, both for their musicality and their ability to optimally mate with all solid state and tube amplifiers I’ve owned. I believe this is strongly related to use of transformer coupling at output and input. Are there many any other tube preamplifier companies that use transformer coupled outputs (+/- input transformers). I am aware of the SE preamplifiers recently from BAT with transformer coupled outputs and a recent offering from Prima Luna, I believe. Any thoughts on these preamplifiers or others. Yes, I am aware that transformer coupling has its strengths and weaknesses, but I am convinced (after 15 years using VAC preamplifiers) that output transformers are generally the answer for compatibility issues. Thanks so much for all your kind input.
audiobrian
antigrunge2
1,366 posts
 
Best case in point are Wavac pre- and power amps: all transformer coupled with nary a capacitor in sight. Sheer audiophile bliss, conveying an immediacy and colour saturation that in my estimation hasn‘t been bettered.
atmasphere's avatar
atmasphere
11,640 posts
 
Its possible to direct-couple preamp outputs too.
Transformers need to be loaded correctly; if loaded too lightly (impedance they are driving is too high) they can express more of the inter-winding capacitance and less of the turns ratio. This can result in a peak somewhere in its response curve. If loaded too heavily you can get a bit of a roll-off at higher frequencies. This might not be much of an issue since its pretty easy to get good bandwidth at line levels. But you might want to ask Kevin what impedance he regards as ideal for them to drive.
cey's avatar
cey
206 posts
 

@larryi, do you have ea build thread with pics and schematics somewhere? 

 

 

ceylon

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