F5 Listening Impressions & Discussion

Hi Attila,
i know about the qualities and problems of feedback. Obviously it is not so helpful for open mids but sometimes necessary for a clean bass response. That depends on the amount of bass given by the speaker. very dry sounding speakers go better with less damping. Papa is telling us about in the current source amp article. As long as the resulting bass frequency response is even the lower damping sounds fine. But for the most of the frequency band a flat impedance of the speaker is no problem. you can even use the impedance curve to equalise the frequency response wit a very low damping amp.
The F5 is a fine example for good bass with quite low damping and not so low distortion.
I think a lot of his art and science is the "shape" of damping and distortion. A friend of mine who builds tube gear was surprised by the "high" distortion he measured from the f5. The nice bass response in combination with the open top end makes me think that the feedback/damping is changing with frequency?
 
....A friend of mine who builds tube gear was surprised by the "high" distortion he measured from the f5.

How much distortion numbers is at 1Watt@1kHz from Your friend tube amp ?
Damping factor 40 ~ 60 is plenty and 0.001~0.005% distortion is low as well.
Source : FIRST WATT F5
 

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... A friend of mine who builds tube gear was surprised by the "high" distortion he measured from the f5. The nice bass response in combination with the open top end makes me think that the feedback/damping is changing with frequency?
Distortion in F5 is dependent on interaction of characteristic of the fets in use, selection and matching of parts considerably affect resulting distortion. Since your F5 is a diy unit, there is no clue of the characteristic of the parts in use.
However, in the F5 Turbo article, there is a P3 potentiometer that may help adjust distortion amount and characteristic closer to user requirement/taste. Jim (member 6L6) explain this nicely on a video discussed in his Adjusting P3 - a video thread.
 
Should the F5 be the next build?

Most amps take me a long time to make. I like to lay out and etch my own PCBs, and build the chassis from scratch. Not to mention the limited time. For me it's been important to pick the 'right' next amp.

I am really enjoying the M2. It is perfect for the music I listen to most. I spend a lot of time listening to different types of Jazz and vocalists. For this the M2 has been unparalleled to anything I've had here. If I had to stop, I'd stop on the M2. 98db speakers.

Rock is a different story. Usually I am happier with an Adcom or some other thingy.

For those that have had both, or heard both - what do you think? The ~25w output doesn't bother me due to speaker efficiency. I think I know the answer, but...

Should the F5 be the next build? Does it have a better 'character' for rock?
 
Great video! Thank you very much for the link. My friend is doing something like it when seaching the point where the sinewave is changing and looking for frequency range and distortion. He is old but taking a few measures and calculating instantly in mind what he is interested in. So in this video it is visible and understandable what 6l6 is telling. I ll look for P3 in my f5 and take a listen...
 

PKI

Member
Joined 2011
Paid Member
Most amps take me a long time to make. I like to lay out and etch my own PCBs, and build the chassis from scratch. Not to mention the limited time. For me it's been important to pick the 'right' next amp.



I am really enjoying the M2. It is perfect for the music I listen to most. I spend a lot of time listening to different types of Jazz and vocalists. For this the M2 has been unparalleled to anything I've had here. If I had to stop, I'd stop on the M2. 98db speakers.



Rock is a different story. Usually I am happier with an Adcom or some other thingy.



For those that have had both, or heard both - what do you think? The ~25w output doesn't bother me due to speaker efficiency. I think I know the answer, but...



Should the F5 be the next build? Does it have a better 'character' for rock?



F6.
 
Member
Joined 2003
Paid Member
Most amps take me a long time to make. I like to lay out and etch my own PCBs, and build the chassis from scratch. Not to mention the limited time. For me it's been important to pick the 'right' next amp.

I am really enjoying the M2. It is perfect for the music I listen to most. I spend a lot of time listening to different types of Jazz and vocalists. For this the M2 has been unparalleled to anything I've had here. If I had to stop, I'd stop on the M2. 98db speakers.

Rock is a different story. Usually I am happier with an Adcom or some other thingy.

For those that have had both, or heard both - what do you think? The ~25w output doesn't bother me due to speaker efficiency. I think I know the answer, but...

Should the F5 be the next build? Does it have a better 'character' for rock?

Aleph J

Russellc
 
Hi mpmarino,

did you ever compare your listening experiences with the distortion "habits" of your amps?
despite the question of sheer power this is a hint for enjoyment.
Unfortunately my f5 does not have the P3 option, but to change the distortion from second to third harmonic is one of the simplest methods to get a different sound. its not a question of quality but of taste.
I prefer my push pull with 20 watts over my single ended with 6 watts with led zeppelin.
its not the power...my horn speakers make nearly 100 db from one watt and the sub is helped individually, but the first sounds involving and challenging while the second tends to sound nice and relaxt. i prefer both sometimes. f5 and f7 are capable of both, sweet and bitter but with P3 you can decide about the weather...

regards arndt
 
Thanks for the suggestions. It seems that F5 would not be suggested for rock n' roll :)

with the exception of 'P3' in the F5 - moving to 3rd harmonic for some more 'sizzle' - interesting. Sorta seems like avoiding AB just for the sake of being A.



ZM - the only thing I blame the M2 for, is being the best amp yet ever :D