Gain and volume and hFE's and how they relate

[ridgeback]

I'm experimenting with swapping transistors in a Mudbunny (BMP).  Everyone talks about 2n5133's vs xyz tranny and so forth and also about the mystical hFE ratings.  Does a higher hFE rating imply that its effect in the pedal will make it sound more saturated / distorted?  OR does it relate to the overall loudness in terms of volume?

For example, I put 4 BC239C's in the Mudbunny and the distortion was sweet but I had to dime the volume on the pedal to get the volume where I needed.  Unity was probably at 3 o'clock.  Conversely I had some 2n2088's in there that sounded saturated (but not as nearly as sweet) AND unity volume was at about 10 o'clock on the volume knob.

Testing the hFE's on a digital multimeter with a hFE meauring feature put the 239's around 520 hFE across the 4 trannys.  I realize this doesn't probably doesn't account for leakage.  Perhaps this is the key element?  For reference the 5088's were in the 450 hFE range.

Can anyone shed some light?  Perhaps it's way more complex. 

[maysink]

I seem to remember reading you want the highest hfe transistor in Q1 and then second highest in Q2 and so on for a BMP build.

[ridgeback]

Thanks maysink, that answers another question I had about the order of placement but I'm still wondering if the transistor hFE rating is more about it's distortion characteristics or more about overall volume output.

[maysink]

I've always associated higher hfe = more gain but I have no imperial evidence to support that!

wikipedia sez:

Etymology of hFE
The 'h' refers to its being an h-parameter, a set of parameters named for their origin in a hybrid equivalent circuit model. 'F' is from forward current amplification also called the current gain. 'E' refers to the transistor operating in a common emitter (CE) configuration. Capital letters used in the subscript indicate that hFE refers to a direct current circuit.

Also, I further remember reading that Q1 & 4 are all about boosting whilst Q2 & 3 add 'flavor' to the clipping section. Most BMP schems have Q1 boosting the signal, Q2 & 3 driving the diode clipping sections and Q4 boosting the signal after the passive tone section (to make up for the passive tone = signal loss)...

[oldhousescott]

The pinouts for the BC239C and the 2n5088 are exactly backwards. Unless you rotated all of the BC239Cs 180 degrees in their sockets, you would not get anything near their full potential gain. Otherwise, there's enough local NFB in all but the output stage that the relative difference in hFE between the two types shouldn't have mattered much when correctly inserted.