Ace Tone 301 Speaker Information

[Aerostoon]

Hi all
I purchased an Ace Tone 301 amp. One of the speakers is missing and I believe the one installed is not original (Sony brand). I don't have a schematic for this amp so I am not sure what ohm speakers to use. The output transformer has 2 ohms written on it. Would this imply (2) 4 ohm speakers?

[Aerostoon]

Should I trust the 2 ohm marking on the output transformer?

[52 Bill]

Should I trust the 2 ohm marking on the output transformer?

Sometimes the primary side will also be marked with an impedance, is it?

If it is and if the impedance matches the expected impedance of the output tubes, then yes it would be looking for a 2 ohm load.

[Aerostoon]

It indicates 2k ohms. Does that help?

It uses two 12AX7's in the preamp and a 50HB26 power tube.

[g1]

That helps, at least we know the ratio is 1000. The other thing that would help is the plate and screen voltage on the output tube.
According to a post elsewhere, it is around 300V: Print Page - some help with a compatible tube in an acetone amp
Attached is the data sheet for the 50H-B26, perhaps 52Bill or someone could interpolate the data for what the Z would be at around 300V.

[Aerostoon]

I found a bit of information relating to the 50HB26 tube. I found a wiring diagram for a different amp with two 12AX7's and two 50HB26 on a foreign website. It was written in Chinese but I could see a link to the wiring diagram and a little info on the tube.

[52 Bill]

Not being able to read Japanese makes it difficult to get much info from the data sheets.

I looks like the load resistance for a single tube at 150v is 800 ohms. I would guess that at 300v the load could rise to 2K, so the speaker load could be 2 ohms. The amp has two 8" speakers? It could have been loaded with two Champ type speakers, 8" at 4 ohms.

[Aerostoon]

Thanks for your help! I will go with two 4 ohm speakers hooked in parallel. I'm pretty certain that will work ok.