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Your journey with lower-watt tube amps -- Can a kit be good enough?

Looking for stories about your low-watt amp journeys.

Here's the situation: I have new speakers, 97 db. Trying them with lower watt tube amps (45/211, 300b, etc) seems generally wise. I am attempting to borrow some from audiophiles in the area. 

The horizon beyond trying these things involves actually buying some. I'm looking at a budget limit of about $5k.

Curious as to folks' experience with lower-watt amp kits vs. those of good makers (e.g. Dennis Had, etc.).

If you have any thoughts about the following, I'd be interested:

Did you start out with a kit and then get dissatisfied? Why?

Did you compare kits vs. pre-made and find big differences?

Did you find you could get the equivalent level of quality in a kit for much less than the same pre-made version? How about kit vs. used?

Also: did you find there was a difference between "point to point wiring" vs. "PCB" in these various permutations?

I realize that there are good kits and bad ones, good pre-made amps and bad ones. I'm hoping you'll be comparing units which seem at comparable levels of quality and price-points.

Thanks.

hilde45
atmasphere's avatar
atmasphere
12,180 posts
 

@hilde45 I applaud your interest in experimentation. Triodes will give a pleasant distortion. But if you want to maintain the feedback you'll need another stage of gain. 

Another consideration is the tube in triode mode will want to see a different plate load for which the transformer isn't designed. 

 

hilde45's avatar
hilde45 OP
5,453 posts
 

@atmasphere My tech said this about the ST-35 mods we're discussing:

"The datasheet lists a 10k plate-to-plate load for the tubes in triode mode and 8k plate-to-plate in ultra linear, so it's not that far off. Per the Mullard datasheet, power drops to about 5W, which is expected. Full power distortion is ~2.5% vs 1.17, but probably lower at lower power levels. Required grid voltage is about the same, so the feedback probably won't be completely borked. As for more gain, short of building a new amp on a new chassis, that is not an option and of course it would no longer be an st-35."

atmasphere's avatar
atmasphere
12,180 posts
 

@hilde45 The Z-565 is the output transformer.

Its ultralinear taps are supposed to be at 25%.

It might be worth measuring their impedance to see if that would work better as a plate to plate load. Off the top of my head I can't say since the impedance varies by the square of the turns ratio.  

hilde45's avatar
hilde45 OP
5,453 posts
 

@atmasphere Thanks, Ralph. My tech understands those facts and appreciates the reminder. We're going in fully eyes open (he has an ST-35, also) and will report back if you're curious.

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