OT question

[shreditup]

Hey,
1) I'm planning to buy a new OT for my Carvin Legacy clone. The one i have right now is a OT42PP from ebay(OT42PP Output Transformer Push Pull 45VA 4K2 to 2 4 8 16 Ohm | eBay).
Now at the time that i was buying it i thought my Legacy with 2 EL34's will probably put out 50-60w, so with the transformer, being 45W, will only overdrive at around max volume, which i'll probably will never play at anyway. I didn't do any calculations for that assumption, and it showed: in reality the OT started clipping at around 2-3/10 on MV. By clipping I mean the more MV i set, the more treble and less bass it was putting out(and the overall sound was very weird). Then i also experimented with different speaker configs, and might have damaged it even more, since it overdrives earlier now. Also, at higher volumes the OT gets pretty hot.
So now I'm looking at the Hammond 1750P(http://www.hammondmfg.com/pdf/EDB1750P.pdf). The question is this: since judging from specs it's only 5w more than the OT42PP(don't know why it's 42 then), will it handle the Legacy? I run it around 430V on plates and 420V on screens biased at around 70% if i remember correctly, but plan to pump it up to ~480V on plates and 445v on screens. And by handling i mean that the OT won't clip at any volume.
2) I'm also planning to buy a 2nd speaker, and make a 212 cab. Now i've come across a Celestion G12L-35 for cheap, but it's 8ohms and 35w. Will the Celestion, wired in parallel with my Eminence JCA12, not blow up with the Legacy at high volume? How much wattage will the cab be rated for if wired in parallel?
Also, since the resulting impedance will be 5,(3) ohms, is it a good practice to use the 2ohm tap on the Hammond as the common to give 6ohms with the 8ohm tap?

[Jazz P Bass]

I think you have your logic wrong.
The wattage of an output transformer has nothing to do with it breaking up early (at least not a 5 watt discrepancy)
And you don't want the Hammong to clip at any volume.
Again, that is not the OT's job.
You may have amplifier problems that are making the output break up early.
Then again the OPT may be bad.
I would try to sort it out before I plunked down money for a Hammond.
The speaker thing, Celestion & Eminence in parallel is also confusing.
What is the DC resitance of the Eminence.
If it is 16ohms, forget mixing it with an 8 ohm Celestion.

[shreditup]

Well i think i did sort it out. I borrowed a friends Marshall DSL100 amp and used it's output transformer, and the top end harshness was out, and the sound was better overall(then again that also might have to do something with the fact the ot42pp was designed for fender amps so has more treble response or something), so I'm assuming my OT's bad after the experimenting I did to it.

The wattage of an output transformer has nothing to do with it breaking up early (at least not a 5 watt discrepancy)

Then what does? Why does a transformer overdrive if not that it's wattage rating is smaller than what the Legacy's putting out?

And you don't want the Hammong to clip at any volume.
Again, that is not the OT's job.

Yes, i know, hence the question of will the Hammond clip with my Legacy?

The speaker thing, Celestion & Eminence in parallel is also confusing.
What is the DC resitance of the Eminence.
If it is 16ohms, forget mixing it with an 8 ohm Celestion.

Yes, the Eminence is 16ohms. Why can't i mix them? In parallel the Eminence will get more current, if i remember my electronics basics correctly, which will result in it being louder, but other than that, why can't I?

[Steve Conner]

Output transformers don't "clip", they saturate. The difference is that saturation is only triggered by low frequencies, so an undersized OT gives the effect of thin, constricted bass when driven hard. From your description of the symptoms I think the OT you bought was most likely bad.

If you connect a 16 ohm and an 8 ohm speaker in parallel, two-thirds of the power will go to the 8 ohm driver. So the power rating of the combination will be 3/2 the power of the 8 ohm speaker, or 3x the power of the 16 ohm one, whichever is smaller.

The impedances of transformer windings are proportional to the square of the number of turns, so they don't add and subtract. The section between the 8 ohm tap and the 2 ohm tap is just 2 ohms again.

[shreditup]

Well the thin bass thing was also there, but wasn't as annoying as the overbearing treble. And judging by your explanation i suppose i can use any wattage transformer and the only difference(well apart from tone and other smaller factors) I'll hear is less or more bass?

Speakers: And how will the power distribute if i connect them in series?

Transformer: So i can still use the approach, but as a resulting impedance i should use the sqrt(x-y) formula instead of just x-y(x=8ohms and y=2ohms in my case). I actually used the 2nd formula, that explains why i have weird sound right now.

[Steve Conner]

If you connect an 8 ohm speaker and a 16 ohm one in series, the 16 ohm one will get two-thirds of the power.

No, the square root of (8-2) is not 2. You have to take the square roots of the impedance values to get voltages, then take the difference, then square again.

[shreditup]

Ok. Then the g12l35's out.
Then there's a g12h30 16ohm that's pretty cheap. It's 30w though. So the power get's divided evenly between them in parallel: how much power can the Legacy put out at max volume with 70% bias at 430 plate voltage? 50w? I'm safe taking this h30 then?

Btw just rewired the secondaries, the sound at max volume lost it's treble spike. I cannot believe i fcked up like that lol.