Preamp ideas for F5

[Rixsta]

Originally Posted by billyk

The B1 "buffer" being unity gain, may work just fine with those sources, others may need more gain, that's what being discussed here. Personally I will be using this or something like it for a bit more gain than the B1 has to offer.

Ok thanks i need to properly look into what the B1 actualy does then.

[McQuaide]

Originally Posted by AndrewT

If you want to take advantage of the peak voltage levels available from the F5 then you need a source that can push out ~2.6Vac (~3.5Vpk)
Very few, if any, domestic sources can achieve that.

A Pearl 2 built stock with a 4mv+ moving magnet cartridge can drive the stock F5 just fine. Lower output cartridges or quieter CDs just don't have enough oomph.

[kcray]

Originally Posted by AndrewT

If you want to take advantage of the peak voltage levels available from the F5 then you need a source that can push out ~2.6Vac (~3.5Vpk)
Very few, if any, domestic sources can achieve that.

Hello, what is the maximum allowable input Vpk for F5, disregarding the output clip?

Thanks

[Zen Mod]

with goal that semis are surviving ......... or not ?

if later - rock it babe ....... with MV !!

[kcray]

Originally Posted by Zen Mod

with goal that semis are surviving ......... or not ?

if later - rock it babe ....... with MV !!

sorry ZM, my question was not clear , of course with goal that the semis are surviving.
may be this one is more clearly:

What is the maximum allowable input Vpk for F5 without clipping the input stage's output, but disregarding the output stage clip.

[Zen Mod]

tough question , really , only because there is no exact moment when input stage is going from linear to saturation/starving mode

why is that info really important ?

[Rixsta]

Ok, finaly understood what the B1 is and does, say i integrated a B1 into same chassis as F5, but later on decided i wanted to add a pre-amp.
would it be possible to Pre-amp -> B1 -> F5
or is B1 supposed to be used alone ?

[Zen Mod]

B1 is redundant , if using proper preamp

if preamp is having highish output impedance , then ( input-volume-less) B1 is welcome addition

[AndrewT]

Each Source in the chain must be capable of driving the combined load of the Receiver and the cable connection to that Receiver.

If a Source can drive that complex load then a Buffer is not required.

Any equipment in the middle of the chain acts as both Receiver and transmitter.
For example a passive volume control has an input impedance value that equals the resistance of the track and to a smaller extent the upstream impedance of the next link/Receiver in the chain.
That same passive volume control also has an output impedance. This output impedance varies depending on the attenuation of the control. It can vary from zero ohms to approximately one quarter of the track resistance. Here too the Source feeding the passive pot has a small influence on the output impedance.

Now let's expand that Passive Pot.
Use a 100k dual track log law potentiometer.
Zin <= 100k This is an easy load for just about any Source. Add in a cable from Source to Vol pot. That cable has capacitance. The Source must drive both the cable capacitance and the 100k resistive load. There is a limit to how long that cable can be.

Now looking at the output side. Zout is 25k when the attenuator is set to -6dB.
Feed that into a 100k Zin of the next Receiver. No Problem if there is no cable and parasitic capacitance is designed to be very low.
Add in a cable interconnection and HF attenuation steps in to ruin the performance of the vol pot to receiver link.
High source impedance cannot properly drive cable capacitance of audio cables.

When the Source cannot properly drive the complex load of Zin+Cable then you must use a Buffer to improve the audio performance of the audio link.

From all of the above it should now dawn on you that the F5 does not need a Buffer in front of it. Read that again. If necessary read this whole post and it should become obvious.

[Rixsta]

Originally Posted by Zen Mod

B1 is redundant , if using proper preamp

if preamp is having highish output impedance , then ( input-volume-less) B1 is welcome addition

Thankyou, i see a couple of Pre's mentioned here, anyone have a favored one or is there a favored one for the F5? i think i will need a little more gain.

Thanks AndrewT, i need to read your post couple times and take it in is making sense tho!