[KTS]

Good Evening,
I am test driving a First Watt F3 that was a DIY amp, I believe it is around 15 watts class A. I have been switching between a Shiit Vidar and the First Watt. I absolutely love the First Watt’s sound stage and really just its sound signature very smooth, my only concern is I must turn my pre amp (Shiit Freya+) to around 80% to hit 70-75 db max. Here come the questions-

Will a low pass filter rolling off the bottom octave help the first watt play louder up to 80-90 db range?
Will it hurt anything to continue to put more volume on it?


The speakers are NX Studio with Double Trouble subs.

Thank you, Kelly

[richidoo]

Sounds fun! 

Freya can be run with either 0dB voltage gain in passive mode, or 12dB gain in differential tube mode.
F3 is only 13dB gain.
NX Studio is 87dB sensitive.
You just don't have enough voltage gain to drive the amp to full power, which you need to get the speaker to play loud enough.

F3's 15W is enough current to play NX Studio up to about 90+dB comfortably, that's pretty loud in a small room.
But F3 is low voltage gain, so it needs a preamp with enough voltage gain to drive it to full power, which Freya isn't doing.
Freya has two modes, passive and tube. Passive is 0dB gain, maybe that's what you're using and only have 13dB voltage gain from the F3. That would keep you in the 70dB range. In "differential tube" setting Freya makes +12dB gain. Manual doesn't state the voltage gain on RCA outputs. It might be only 6dB. You need  a traditional 20+dB preamp to drive F3 to the volume level you want.

Using a XLR/RCA  adapter on the balanced outputs may only get you 6dB signal level, not the 12dB you would get if you used both legs of the balanced output.

Vidar is 27dB gain, which is traditional gain for power amp so it may be able to play loud enough because it has 14dB more voltage gain.

To answer your question about harming anything, once you get the gain raised high enough, then the only harm that could happen will be pushing the amp beyond 15 watts, causing clipping, which can damage planar ribbon tweeters.

It should be safe to turn Freya up to max, but do so carefully, listening for any clipping, which can damage tweeters. If the RCA outputs are playing passive mode with no gain, then try to use the tube mode. The manual is not clear if RCA jacks can have any tube gain, but seems like they shoulda, but it might only be 6dB, not 12. 

If you were to keep the F3, I think you'd need to get a hotter preamp, with the traditional 20dB voltage gain. Since most amps are 26+ now and most people use strong sources the traditional 20dB preamp has gone out of style. It was needed when phono was king and that needs more gain.

A high pass filter will filter out the lows, but won't add any voltage gain to your electronics to make them play louder.

[poseidonsvoice]

Too bad there isn’t a like feature for AC.

richidoo hit all the nails on all the heads with that post

Enjoy the LU1014 Jfet in single ended Class A!

Best,
Anand.

[KTS]

Thank you, it sound like I will need to switch pre amps or pass on the amp. I am running it in tube mode using RCA, I do believe to get the full 12db of gain I will need to use the XLR and the amp is not XLR.

Thank you again, much appreciated!

Kelly,

[Hafgrim]

Will a low pass filter rolling off the bottom octave help the first watt play louder up to 80-90 db range?

Hello Kelly,
A "high" pass filter will not make the speaker louder at a given volume, if that's what you wanted.
But I recommend still getting a filter for your nx-studios. Most of the power in amps is used only to play low bass notes.
Human hearing is less sensitive in the bass than the mids so a lot of music will Have the bass level at 10 -20db louder that the mids and highs. That means if even you like to listen at around 90 db your amp may still see up to 100-110 db in dynamic and percussive music. That's anywhere from 15 to 100 watts at peaks!
Removing that load on your low wattage amp will give it much more current headroom and massively reduce distortion. You might pervice a more fluid and relaxed presentation.
You also remove a lot of stress from the mid woofer as Danny has stated in his videos on the subject.

[KTS]

Hello Kelly,
A "high" pass filter will not make the speaker louder at a given volume, if that's what you wanted.
But I recommend still getting a filter for your nx-studios. Most of the power in amps is used only to play low bass notes.
Human hearing is less sensitive in the bass than the mids so a lot of music will Have the bass level at 10 -20db louder that the mids and highs. That means if even you like to listen at around 90 db your amp may still see up to 100-110 db in dynamic and percussive music. That's anywhere from 15 to 100 watts at peaks!
Removing that load on your low wattage amp will give it much more current headroom and massively reduce distortion. You might pervice a more fluid and relaxed presentation.
You also remove a lot of stress from the mid woofer as Danny has stated in his videos on the subject.

Understood and I appreciate the recommendation.