ONO + D1 @ B2 + F5 @ Duetta 3-Way (all Eton incl. ER 4)

[martinschki]

Good Day everybody!

I'm thinking of building the above mentioned to slowly replace my current (not worth mentioning) system.
In the end I'm "only" looking for a really nice system for my passion, listening to music.

I'd like to do small rather easy reproducable projects which I can finish one at the time.

The Duetta is a 3-Way Loudspeaker based on Eton Chassis including the AMT ER4 with 89dBm sensitivity. I was thinking of Bi-Amping it. Is the F5 the right amp for this speaker? Or can I even build a smaller one. (I'm not really crazy about huge capacitor arrays and high voltages...)
Can I even do Bi-Amping with the maybe coming B2? How about active Cross-Overs?? Questions over questions...

So please, if someone would be so kind helping me out here if my thinking makes any sense?

Thanks a lot!!!
m.

[lineup]

start with building
one F5
and maybe one other for the other channel

then you see if you like the performance
and if you would want to move on
with biamping and/or B2 and Ono

89 dB SPL is a bit lower than www.firstwatt.com amplifiers were thought for, I think
but if you have not too large room,
it may work like a charm, anyway

my personal favourite would be FristWatt F4
but that is only me,
Lineup

[Tolu]

I have heard the Duetta many times in a 45m² room with a tube amp (2x30W) and that is all you need. The F5 is more than enough for the Duetta (which is the best speaker I have heard so far!).

I have the parts for an Aleph J in my tinker room in order to drive a Minuetta with 87dB/W.

[martinschki]

Thanks for your answers!

I think I will start building the B1 to get started and warmed up

Just for clarification since Lineup mentioned the F4:
Are B1 and F4 a good match? It looks like I would need a very strong signal out of my CD player or Phono stage to drive it.
Isn't the F5 in combination with the B1 a better fit? On the other hand, if I want to do biamping one day which one (F4 or F5 or ??) fits better?

Thanks!
m.

[juma]

Both F4 and F5 have high input impedance so they don't need B1 which is a buffer stage with no voltage gain.
F4 is power buffer with no voltage gain. You need a mighty preamp to drive it to full power.
F5 needs approximately 4V peak (2.8V rms) on its input for full output.
You can find detailed readings about these amps on firstwatt.com (articles/downloads)

[martinschki]

So what would I do then for a Preamp?

I currently have a Pro-ject Phono Tube stage and a CD Player and a Audiolab 8000P Power Amp.
I'd like to start with a pre amp and maybe the D1 DAC. Which simple, high quality preamp would you recommend? I also like the idea of using a shunt attenuator instead of a pot. Good? Bad?

Thanks!

[juma]

Preamp for F4 or for F5 ?

[martinschki]

yes

or, what it probably is: source switcher with volume control

[juma]

You asked:

Originally posted by martinschki
So what would I do then for a Preamp?
......

I wanted to know what amp you want to build:

Originally posted by juma
Preamp for F4 or for F5 ?

and you answer:

Originally posted by martinschki
Yes
......

If you want to build both amps it's unlikely that same preamp will do. F5 can be satisfied with 6 dB gain preamp - assuming that you have 1.5-2V rms output from your source device, but F4 will need 16-20dB gain from preamp under same conditions. Of course you can build a preamp with adjustable gain but it should be able to swing +/-20V on output (for F4). Ok?

[juma]

Preamp shown in attachment will do a great job for F4. Q5 and Q6 need heatsink. R4 sets DC offset on output and changing the R3 will set the desired gain (lower R3 -> higher gain and vice versa).
I tried it p2p with F4 and it sounded very, very good. +/- 36V can be derived from F4's power supply by means of voltage doubler and added regulators.
Anyway, F5 sounds better to my ears and this thing is history - although a nice one !