2. amps-preamps
  3. 1399439075

25 watts Class A or 70 watts Class A/B ?

I understand these days there are many good examples of both Class A and Class A/B amps. To the point that a well designed Class A/B can beat a similar pedigree Class A amp. However my question is in particular related to these two amps:

1. First Watt F5 (Pass Labs)
2. Naim NAP 300

The speaker to be driven is a Tannoy dual concentric Turnberry SE. It is a 93 db sensitive 8 ohm load and in general considered to go well with both high powered and low powered amps.

F5 is a highly purist class A 25 watts design with a robust power supply. It is a push-pull design so it can generally drive difficult loads better than typical single ended first watt models (F3, F4 etc). I have heard the F5 on an Altec horn system and I loved its pure and direct sound.

Naim amps in general has always appealed to me, again because of their very direct presentation. Music has a certain excitement and bounce through them. The NAP 300 is one of their top models and I am sure it will be a very refined amp.

However I will only buy one. Both these amps must be having few fundamental differences in the way they present music considering they are coming from very different designers. Even the topology is different here.

The first question here is, can a 25 watts F5 drive the Tannoys well ? My room size is 200 sqft and I listen to music at reasonably medium to loud levels. I dont play very loud though. I listen to all kinds of music from Mozart to Metallica.

Qualitatively, sound per sound, how do these two amps compare ?
pani
bombaywalla's avatar
bombaywalla
1,958 posts
 
Abhi,
from my experience it is not correct to think that just because a speaker is of high(er) efficiency that a low(er) power amplifier will do the job.
I have a Tannoy studio monitor that is 94dB SPL/W/m & I use it with a 120W/ch class-AB amp with very good effect. This studio monitor is, well..........., used in studios where the power amplifiers are of 100s of watts & often even 1000s of watts. The max wattage handling capacity of my speakers is 350W/speaker even tho' it's rated a 94dB SPL/W/m. To me this in itself is a huge hint from Tannoy to me that my speaker will do very well with a high power amp despite its high efficiency.
A higher power amp with a Tannoy will give you more control over the music & a lot more dynamic headroom. You music will sound alive as there will be plenty of wattage on-tap for dynamics.
I would try to find an excellent 100W/ch power amp for this Turnberry SE speaker. Maybe Pass' own offerings or some well regarded 100W tube amp.....

I tend to agree with Chayro - NAIM gear seems to sounds its very best with associated NAIM components. The magic falls off the cliff once you put a NAIM component with some other brand. IMHO. YMMV. Have you heard NAIM gear mixed-matched with other non-NAIM gear? If yes, did it have the same magic as with all-NAIM gear?

atmasphere's avatar
atmasphere
12,105 posts
 
Just a FWIW: 93 db is not considered high efficiency. It is a moderate efficiency. You are transitioning from moderate to high efficiency about 97 or 98 db.

If the room is small enough or lively enough, I would go with the F5 in a heartbeat- it is one of the best transistor amps made and by that I mean best-sounding. But if you keep running it out of gas it will be frustrating in the long run. Any chance to do an audition?
mapman's avatar
mapman
22,754 posts
 
Obviously the Pass has a lot of upside if it is up to the task in your specific setup and room. So there is some risk with this option, possibly worth taking.

The Naim is a safer bet, and will still likely sound very good!

So if it were me, I would only buy the Pass if I knew I could change afterwards without taking a financial hit. You could buy used, not overpay and resell if needed, or buy from a source with a good return policy. Then if does not work out, you still have good options and little downside other than extra work to change and perhaps a small financial hit, depending.
pbnaudio's avatar
pbnaudio
1,615 posts
 
Don't know where your located, if here in the US you could try one of these out.

Liberty B2B-100

Theres a few reviews out

Good Sound Review

Don't forget to click on the measurement tab, Bascom King performed the technical test of the B2B-100

Positive Feedback Review

And yes I do make them

Good Listening

Peter
bombaywalla's avatar
bombaywalla
1,958 posts
 
So, Peter, what's the deal here (just trying to understand this for myself) - you have PBN Audio manuf loudspeakers & also several amplifiers & then you have Liberty Audio also manuf some power amps??
How does Liberty Audio compare to PBN Audio? Is Liberty Audio the down-market brand?
Thanks.
More to discover