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AUDIO FORUMS >> General Discussion and Support >> Zen Triode vs Rachel output comparison
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Message started by Scott M on 02/07/22 at 14:57:01

Title: Zen Triode vs Rachel output comparison
Post by Scott M on 02/07/22 at 14:57:01

I have both of these amps and swap between them using the same preamp and speakers. The volume control on each amp stays set at maximum and volume is controlled with the preamp. Both amps run the same rectifier and input tubes.

Then used an SPL meter in a fixed position to measure Pink Noise on each amp. The Zen Triode measured 74.1 dB. The Rachel measured 68.7 dB. I am surprised the more powerful Rachel measured 5.4 dB quieter when all other variables remained constant. Thoughts on why this might be?

For reference, the Zen Triode is rated at 2 WPC output and the Rachel at 6 WPC.

I've not tried to determine the maximum volume that can be safely achieved with each.

Title: Re: Zen Triode vs Rachel output comparison
Post by thethanimal on 02/07/22 at 15:08:23

The Rachel requires 2.5 volts from the preamp for full output, while the Zen Triode only requires 1.5 volts. I don’t know the gain structure for each, but let’s say you’re putting out 1.5 V from the preamp at that volume control setting: you’ll be getting the maximum watts out of the Zen (~2.3W) but much less than maximum watts out of the Rachel and very likely less than 2.3 W.

Title: Re: Zen Triode vs Rachel output comparison
Post by CAJames on 02/07/22 at 15:20:20

Yes. There is a difference between power and gain. Technically gain is how much the voltage (aka volume) increases. Power is how much current the amp can source to sustain the voltage across your speaker load. What this means in real life is "loud" is not determined by power. What more power gets you is the ability to play louder without clipping.

Title: Re: Zen Triode vs Rachel output comparison
Post by Scott M on 02/07/22 at 15:23:00

OK, I would have guessed an input sensitivity difference but had not seen anything on the web site that referred to that parameter. Thanks.