How to know if GAN-fet amp and Lyngdorf 2170 (as a Pre and Dac) are compatible

A two volt output on a DAC means.....two volts at 0db on a CD. This is the industry standard. If your amp has 26db of gain.....like the LSA Voyager does....then that means it has 20 times gain. There are practically no CDs that put out 0db on the CD. Usually peaks are around -6db.....so that means a 2 volt source is really only putting out 1 volt peaks on the highest recorded CDs. One volt times 20 times gain = 20volts......divided by an 8 ohm speaker that is 2.5 amps....times 20 volts = 50 watt peaks. If your speaker is 87db sensitive (this would mean maybe 83 at listening position then one watt gives 83......10 watts gives 93 and 100 watts gives 103db. 50 watts would be under 100db. This would be for the highest recorded discs. If the disc were recorded very low then you would not get anywhere near as much level of sound.......so it depends on the sensitivity of the speaker, how loud you listen and the recorded level of the recording. This is why I like to see at least 3 volts (1.5 in reality) on the output of a DAC or DAC pre to run straight into an amp. Another advantage for high sensitivity speakers. If you use a separate preamp then you usually have plenty of gain as most preamps have at least 6 db of gain......but the Lyngdorf?....you need to get a spec from the manufacturer. If I was a manufacturer of such a product I would have 4 volts as my standard. This way it can drive most speakers with most digital sources.

There are ways to increase the gain of an amp. The input buffer on some Class D amps is simply a buffer set for whatever gain the manufacturer wants. If you change a couple of resistors in the first buffer you can increase the gain 6 db or more......a no brainer on some amps. Some amps come with variable gain setting.....like the Premium-Audio amp has a choice of 26, 28 and 32 db gain.

Thanks Ric.  Very much.

I clarified my text to the factory rep based on the details in your post and when he replies I should have what I need to determine compatibility between the two pieces.

I have no experience matching separates but have been advised to confirm compatibility between amp and pre to avoid performance issues.

While this is certainly important, the other crucial factor is if the individual components provide the sound characteristics you’re looking for.  Just because components work together doesn’t mean they’ll necessarily sound good to you.  Just to state the obvious. 

Here is the reply from Lyngdorf:

“….1. The maximum output level of the analog output is 4V but you can reduce the level in the output setup to match the connected power amplifier.
2. The amplifier gain is dependent on the level setting in the output, so you have the option to match the max output level - or the gain if you prefer to call it that - to the power amp in use.

The volume control in the TDAI amplifiers is working in extremely small steps which means that even if you use only a fourth of the volume wheel scale there is very good resolution. Still it makes sense to match the output level to the power amp in use.”

Ricevs:

I can connect and go or I can play around adjusting the pre output.  But it seems to have your stated preference of 4v.