New transformer/speaker hot Rod Deluxe

[NanooMan]

Alright, I know some folks replace stock transformers in Hot Rods with higher quality transformers like Mercuries, but my question is two-fold. I'm thinking of adding a 10" speaker to the mix, so should I just match the impedance with new speakers, or should I just go ahead and upgrade the transformer and have a match?

Nanoo Man

[ChrisK]

You need to match the speaker(s) to the transformer or the transformer to the speaker(s).

If you find Mercury's to be somewhat dear, consider Allen Amps.

www.allenamps.com/

New transformers link at the top right.

[NanooMan]

well, I was asking which was the better idea.

[humanbn]

This is a little off topic but it relates to the premise of the question. As far as people who simply change their transformer, why is this done? What effect does it have on the amp sound, power, or anything?

[sumgai]

humanbn said:

As far as people who simply change their transformer, why is this done? What effect does it have on the amp sound, power, or anything?

None, none, and nothing else.

An amp's power output is dependent on it's power transformer. If the output transformer is "upgraded" to something with a magical property (perhaps the equivalent of Monster's "oxygen-free copper" cables ), then it will take better ears than mine to discern such an increase in tonal quality. If it's simply replaced to handle more wattage, it'll be a waste, until the power transformer is also upgraded to supply those higher voltages.

If you burn down the power transformer, and replace it, you could conceivably up the voltage available to the tubes. If you do this, then you really should upgrade the output transformer to handle the additional capacity. I advise my customers to change the output transformer only if they are increasing the power (a new power transformer), or when it is obviously bad...... and that's pretty darn rare. If they wanna do it for the sake of the Mythical Tone Quest, I'll oblige them, but only after getting their signature in blood that they won't bad-mouth me when the magic fails to come gushing out of their new, and un-needed, output transformer.


Now, to address your original question........
Aside from my placing Mercury transformers in the same class as Monster cables, you have two courses of action........ 1) keep the stock speaker, and replace the tranformer with the exact same specifications; or 2) plan on replacing the speaker at the same time, and therefore needing to match the planned new transformer to the new speaker's impedance. If you go for lower impedance (meaning, on both the speaker and the transformer), you'll get more apparent power. But you also loose headroom, so don't get too smug about your leapfrogging the horsepower race. As with anything else, there are design trade-offs. Ask around for folks who've done what you're contemplating, and avoid the pitfalls of re-inventing the wheel.

HTH


sumgai

[ChrisK]

well, I was asking which was the better idea.

I wasn't trying to be facetious, regardless of which course you take, things must match.

Now, I tend to side with sum gai on this whole meta-physical stuff. There are those that swear by Mercury, even to the point of buying the $289 kit to upgrade the $139 street Epi Valve Junior. I'm not going to say that this is feldergarb, just that I can't tell much of a difference. When/if I upgrade mine, I'll be trying the Allen stuff.


If you are adding a third speaker to the Hot Rod (I don't know what one comes with anyway), this makes stuff interesting since not only do you have to effect a total impedance that matches the output transformer's available taps, but you also need to mind the rated power of EACH speaker as well. It's simple, just not trivial, to do.


I can't tell you which is the better path to follow. One has to be careful not to "improve" the amp too much. For instance, the 35 watt under-sized output transformer is what makes a Vibrolux a Vibrolux. Putting in a better 40+watt rated one makes it a Twin/Reverb (well, sort of). Leo's way of protecting the weak 10" speakers of the day was to choke the amp's bottom end. The Bassman was a 4 x 10". The Vibrolux has only a 2 x 10". Hmmm.....