A question for technically astute


I have recently repurchased a Sophia Baby amp on A'gon at a really cheap. I suspect the cheap price the result of it being a 220 model. I think somebody move back from Europe with it. They bought a step transformer so it would work on 110. Anyway when I listened to it , I could swear that it had much better dynamics and slam than the first one I had. It seems like it can get much louder before compressing. The speakers might be a little more sensitive than before but not much. Is this my imagination or could this power arrangement make a difference?
128x128larryrx7
Hmmmm.Could it be the step transformer is feeding the amp a very clean, very constant 110? In other words, it is, by default, acting as a (seemingly successful) power line conditioner?
I don't think you can make any meaningful comparisons between 2 amps with different tubes played through 2 different speakers and going from memory on the sound of the first set up.
Thanks for the response..the step up transformer is boosting the voltage to 220 so I guess it could be producing a cleaner 220. As to my memory of the prior amp. It had the exact same tube complement. The only difference is the first was a 110 and this one is 220. Your right it is difficult to draw a comparison, but the difference particularly in bass slam seems noticeable for whatever reason. I wonder if the 220 produced by the step up transformer is giving the amp better juice to draw on? Does that sound reasonable?
Hi Larry. Yes, it could be your step up transformer. When using a transformer, you need to over spec the transformer otherwise it will effect the sound in ways you mention. While this may be totally overkill, I wouldn't consider using one unless its capacity is 9 to 10 times that required by the amplifier. When over spec like that, they do not restrict the amp and serve to reduce the noise on the power lines.

You could could try a larger capacity xformer and see if it sound better or you could contact the vendor and see if the amplifier power transformer could be wired to 110v. I suggest you do the latter. Many amplifier transformers have multiple wiring options to accept 100, 115 and 220 volts.

Regards
Paul
Hi Paul...I am really happy with the sound right now..I think it sounds better than the 110 version..I was just trying to find out if that's possible and why.
Hi Larry. Sorry - misread your post.

The transformer is filtering out noise in the power lines. The short of that is that it translates to a B+ voltage in your amp with less noise and ripple.

That would not (to my knowledge) give you more dynamics or slam though, but it would allow the amp to resolve low-level detail a lot better.

I think the better dynamics and slam is probably due to your speaker presenting an easier load to the amp. Tube amps really come into their own when they drive speakers with benign impedance curves and good sensitivity. The difference between a well match tube amp/speaker setup vs. a not so good match is startling.

Regards
Paul
Paul ..you probably have a point with the speaker thing..I have them playing thru a pair of Ref 3A Decappos which already really like tube amps.. but they seem to like this amp especially well
I have lived in countries using all voltages and it is a commonly known fact between amp designers that 220-240V regions perform better with most of their designs.

In addition, transformers that can cover the full requirement of the amp (hard to do, by the way) can provide more stable electricity and importantly de-couple it from the rest of the electrical installation in your home. I use transformers even at unchanged voltage to good results.
Thanks Mihalis....your explanation makes sense... I am also wondering if this holds true more for tube electronics than SS?
Mihalis, would you expand on "it is a commonly known fact between amp designers that 220-240V regions perform better with most of their designs"

thanks
Paul
Gents I cant expand because I dont know why. But for some reason higher voltage seems to benefit the amps. This was told to me by the designers of Tenor, Lyra Connoisseur and I think BAT if I remember correctly. I keep in touch with the LC guys who are great. I will drop them an email and see.
When you consider electrical conductors (as in AC power cables), the ability to pass lots of current is directly related to the diameter(cross-section). If you need to be able to pass lots of current, you need fat conductors. But if the voltage can be increased, you don't need to pass so much current (again for the same amount of power), and you therefore don't need such fat cables.

This means that the power-handling capability of the same power cable will be increased by running it at 220~240V AC, as compared to 100~117V AC. The same applies inside the power amp (for the power supply input wiring and circuitry up to the power transformer). By running it at 220~240V AC, it is effectively "getting an upgrade."

The limitation on voltage handling of electrical conductors concerns physical spacing and insulator material (and thickness). Usually, the wiring inside a modern power cable (and also the power supply input wiring and circuitry up to the power transformer inside a modern audio component) should be able to handle 240VAC without difficulty.
Worn tubes may cause lower voltage drive. Worn outputs would reduce output power. Try some fresh output tubes to see if you would get more power and headroom.

Baby Amp is well design and excuted amplifier. User modification and tube rolling are no different than DIY your perfect working BMW cars without any professional training.

A tune up to factory specification would bring your Baby Amplifier back to its designed power rating and bring back to its Sophia voiced sound.