My F5 Lives!!!!!!!

[dantwomey]

First of all, Many, many thanks to Father Pass for sharing and inspiring such an interesting hobby.

Now to my first impressions. In my system the F5 has a warm and liquid midrange that gives this amp a very lifelike smoothness. But this smoothness comes at a price. The high end is softened and less detailed and lacks the sparkle of my gainclone. If I could restore this sparkle and detail without any accompanying glare this would take the F5 up a notch for me. I can also tell that the soundstage is deeper with the F5 with artists sounding farther back. All in all a very rewarding amp that is well worth the effort.

Now for something that puzzles me. After running the F5 for a few hours I realized I was running out of power. I find this very odd because I'm running line arrays that are about 95db efficient. Time for an F5 Turbo V3 or an F6?

Regards,
Dan

 

[AudioSan]

the sound will change over the next few days.
but run out of power? i have never run out of power. on 88db speakers.

 

[6L6]

After running the F5 for a few hours I realized I was running out of power.

Check your bias. It might not be stable once things get all warm and toasty.

 

[ra7]

Running out of power means you need to provide a higher input signal. What preamp are you using? You need a whole 2.5V to drive it to full power, if you built it to spec. 95 db speakers should be no problem for the F5.

 

[6L6]

I thought it was 4v to full output... I could be wrong.

 

[AudioSan]

thats a lack of gain. when you run out of power, your amp has started clipping.

 

[oneplustwo]

No pictures?! How are we to know you actually joined this elite club?

 

[a.wayne]

the sound will change over the next few days.
but run out of power? i have never run out of power. on 88db speakers.

Standard f5 or v2 .......?

 

[AudioSan]

thats a standar F5 with 30% higher bias. but stil +/-24V rails.

EDIT: F5v2. CViller boards. (not turbo v2)

 

[juma]

I thought it was 4v to full output... I could be wrong.

There are volts and... volts
4V_peak = 2.8V_RMS

 

[a.wayne]

thats a standar F5 with 30% higher bias. but stil +/-24V rails.

EDIT: F5v2. CViller boards. (not turbo v2)

36 watts rms@8 , sounds like you are using 4 ohm speakers , small room and listen moderately (82db avg din) ...

 

[AudioSan]

8ohm. not to big room.

 

[fab]

...Now to my first impressions. In my system the F5 has a warm and liquid midrange that gives this amp a very lifelike smoothness. But this smoothness comes at a price. The high end is softened and less detailed and lacks the sparkle of my gainclone. If I could restore this sparkle and detail without any accompanying glare this would take the F5 up a notch for me. ...

Hi

I have built a Gainclone LM3886.
I have built a standard F5 (no input cascode).

If you want the soundstage, smoothness and sparkles, try:
http://www.diyaudio.com/forums/pass-labs/162042-f5-meets-buzquito.html#post2097690

You can run this amp with about up +/- 30 Vdc to get a little more voltage swing.

The bass is not as tight as the Gainclone though but you are right about the missing soundstage of GC compared to F5.

Fab

 

[dantwomey]

Check your bias. It might not be stable once things get all warm and toasty.

Once assembled my amp has no room to check anything. I setup bias using a spare heatsink and the PS from this amp. The heatsinks get nice and toasty with myself only being able to leave my hand on for the required ten seconds!

Regards,
Dan

 

[dantwomey]

thats a lack of gain. when you run out of power, your amp has started clipping.

It's probably my preamp. At full power things are very smooth with no clipping or 'bad sounds'.

Regards,
Dan

 

[AudioSan]

then it is lack of gain.

 

[dantwomey]

36 watts rms@8 , sounds like you are using 4 ohm speakers , small room and listen moderately (82db avg din) ...

Actually my speakers are 10 ohm in a very large (18' x 27') room.

 

[bear]

ur room is a bit live...

the F5 has no strain in the sound of highs...so you may be playing it much louder than you think...

_-_-bear

 

[oneplustwo]

I don't see a F5 in those pictures...

 

[Russellc]

Once assembled my amp has no room to check anything. I setup bias using a spare heatsink and the PS from this amp. The heatsinks get nice and toasty with myself only being able to leave my hand on for the required ten seconds!

Regards,
Dan

If I understand you correctly, that's a problem. Bias will vary with whether or not the top is on, and you cant check it on the assembled amp? Time to start over. You need to be able to get to and measure bias with the amp assembled, and be able to get to the adjustment pots. This is probably why your amp has no "sparkle"......Should be clear and transparent with plenty of sparkle, some complain of too much...Hopefully I misunderstood?

Russellc