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Hi all, great forum Steve! I'm using a power tranny, choke, ect... salvaged from a Hammond organ similar to what Steve used on his Lightning prototype. My secondary voltages measure 335,0,335 compared to the Lightning's 285,0,285.
1. What are the effects of higher voltages on the Lightnin's sound?
2. Would this be to much voltage to try to drop to get in the needed range?
3. Would maybe a 5y3 rectefier help tame down the voltages?

Maybe I should just buy a more suitable PT before I go cutting a hole in my chassis.
Thanks for any help and insight anyone can provide.
Denny

The matchless amps all run very hot by design, very hard on the EL84s. But I don't think you'll be able to drop enough with a 5y3 or 5r4. I'd recommend saving your PT for another project (perfect for the Atlas w/6V6s) and get the lightning PT for this project. CraigB

Matchless designed their circuit to use a 4K impedance for the output tubes. In comparison, the 18 uses 8K.

I found that working into an 8K load, the Lightning has a smoother sound. You might want to try it.

If you want to Tone Test Tranny Impedences or if you just want to use a non standard Matchless transformer try this:

If you are using an original Matchless OT, then they are designed to provide the "mismatch", out of the box. If you connect an 8 ohm speaker to the 8 ohm tap on that OT it will put a 4K load on the power tubes.

If you have a 4K Impedance output transformer and want to effectively increase the 4K impedance to 8K, use a 8 ohm speaker on the 4 ohm secondary (or 16 ohm speaker on 8 ohm secondary). That will make the primary load 8K, which should smooth out the sound, plus run the output tubes in a safer zone.

However, if you are using a non-Matchless OT, such as an 8K Impedance output transformer and want to effectively decrease the 8K impedance to 4K, use a 4 ohm speaker on the 8 ohm secondary (or 8 ohm speaker on 16 ohm secondary). That will make the primary load 4k, which can emulate the Matchless design and sound.

I know this get confusing because it seems opposite. Just remember, to reduce the reflected OT impedance, increase the speaker impedance while remaining connected to the same tap.

Clear?

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

CraigB., what is an Atlas with 6v6's. I've heard mention of a Tweed Atlas but don't really know all the details. Can you fill me in?

Coco, thanks for the info on output trannies, I was going to use a non Matchless 4K primary into an 8 ohm speaker load but it looks from what you describe this would be the wrong way to go.

Also Coco, do you have any opinions on the power tranny I have with higher voltages on the secondary 335,0,335 than a Matchless type power tranny.

Thanks,
Denny

Denny,

IMO, the tranny voltage is just too high. You need to step that down by 30 volts which will take a big hi power dropping resistor.
A 5AR4 and the 5Y3 woud drop the voltage more than 5AR but not enough I don't think.

You should try Duncan amps voltage simulator and see what you would need to make this deliver B+ of 340 volts to the tubes. Go to www.duncanamps.com

See if you can find an old A035 or A039 Hammond reverb and use that tranny.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps