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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
hilde45's avatar
hilde45 OP
5,453 posts
 

@atmasphere I'll convey that to Mike and see what he says. Thank you.

hilde45's avatar
hilde45 OP
5,453 posts
 

@atmasphere Here's what Mike said: "It will almost certainty raise both the harmonic and intermodulation distortion in triode mode and drastically reduce the power, but it may be pleasant distortion."

It will be switchable, so if it doesn't sound nice on the speakers, we'll switch it back. Gotta experiment, right?

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.  

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