Mini-A to a Mini-F2?


2005-08-05 6:27 am
I could have sworn that I read a thread over the last coupleof days where Mr. Pass suggested some changes to an Aleph amp to make it more F2-like. Or did I imagine that? Seems that you can not search for the term "F2" and get any results. Is something like a Mini-A to a Mini-F2 even possible , and/or possible using the premade boards for the Mini?

Thanks guys.


2005-08-05 6:27 am
Well, these will mainly be for use in the car on my compression drivers active XOed from 700 and up.

But, I will build a Mini-A or A30 for my Edgarhorn Slimlines just to play with. Have a small SET on them now.

It should be fun either way. The Mini-A is already leaps and bounds better than any car amp on the market now.
winslow said:
The F2 is more SET-like, correct?

I would agree in general that the F2 sounds more like a SET with the following qualification. Yes, that SET like harmonic richness is there. But in addition, with highly transparent speakers, the F2 delivers PRAT. This amp has a 200kHz bandwidth and is plenty fast on my Lowther DX55 speakers.

Fuling said:
Let your speakers decide. F2 is an high output impedance amp, suitable for fullrange drivers in horn enclosures.
Aleph on the other hand is suitable for...everything!

I agree that in the end the speakers decide. Because the F2 is a transconductance amp, its output impedance of 16 ohms may seem high when compared to traditional voltage sourced amps. However, both the F1 and F2 can be used effectively with high sensitivity speakers of any bandwidth. Just as both amps can extend the frequency range of full range drivers by altering their Q, they can also extend the range of other drivers as well. Both amps work well with closed box designs, and by adjusting the input network of Leap 5, I have been able to simulate some promising vented box enclosure designs. The Abbey is an example of a MLTL design that works very well with the F1. Perhaps the limiting factor of the F1 and F2 are their output power (10 and 5 watts) and the need for a serial crossover for multiple driver designs. So I understand your comment that the Aleph is suitable for everything. However, the ablitiy of a transconductance amp to adjust the driver Q is special and very useful for extending low frequency responses.
Tweeker said:
If your using F1 or F2 amps and multiple drivers, biamping really seems to be the way to go budget allowing. Takes care of the crossover and gives more power too boot.

Hi Tweeker. Yep, that's the route I'm following. F2 on the top, F1 or Aleph type on the bottom. Simulation goes only so far. Then its cut, listen and try again. Simulations suggest that a 24 ft^3 closed box will get my woofer to about 31 Hz with the F1. This is a big box.