amplifier questions

[Professor smith]

I have a variety of queries. HOpefully somebody can help me.

Firstly, where does an amplifier such as the F5 compare with in the market place? Is it an extremely high end amp on the level of Krell? Would the f5 be suitable for speakers which are 87db?

Next question is, my speakers are about 87db and I need to build an amp on a low budget but I am thinking of dismantling the old amp then i can use the transformer for example to save costs.
I would even buy something like a trends digital amp but these only put out 15w which might not be enough?

What other choices do i have? It should be powerful enough to drive my speakers and have good bass and be high quality.

Many Thanks.

 

[Babowana]

... Would the f5 be suitable for speakers which are 87db?

Mine (BaboZen, not exactly F5 but approximately the same) drives 84dB speakers (ATC SCM7). It's good enough for my normal home listening. It satisfies my demand and taste.

On my experience, the matching between power amp and speakers is depending on personal demand and taste. How can we answer yes or no to your question without knowing what you exactly want. . .?

Cheers,

🙂

 

[DougL]

QUOTE]Firstly, where does an amplifier such as the F5 compare with in the market place?[/QUOTE]

For an MSRP of $3000 US, there will never be a large "Prestige" following. The Class A, Relieve low power and specialized application is more likely to have a counterculture following.

Here is a link to an F5 review.

http://www.6moons.com/audioreviews/firstwatt7/f5.html

Is it an extremely high end amp on the level of Krell?

I see it as very high end. Who can say about others?

Would the f5 be suitable for speakers which are 87db?

One rule of thumbs is that an amplifier have enough power to deliver 105 db at 1 meter with the target speaker.
Adjust it up or down for room volume, listening taste, and neighbors. Twenty five watts will give about 101 db 1 Meter.
If you listen to classical at 80 db with +30 db peaks, dog don't hunt. Add a powered Sub covering under 100 Hz, about 3 db less power is typically required for your main amp.

I went through collage with a Dynaco ST70 (25 watts/channel) and EPI 100's (89 db speakers) and never got close to needing more power.

What other choices do i have?

Class A amps are limited to about 30W / channel or less simply on the basis of weight. While there are Many other options, to get more power than an F5 in an affordable format is going to require either Class AB or Class D. Horses for courses.

Doug

 

[Professor smith]

thanks for the replies.

The power isn't really the issue, i think about 40 watts upwards... there are many amp kits out there i am sure. The question is which should i go for?

I obviously want it to be an upgrade on my current amp which is worth about 600 bucks.

 

[DougL]

The question is which should i go for?

That I can't answer.
There are some reasons to build an F5.
1: The design has been reviewed as a commercial product. You have an Idea what you will have when you are finished.
2: There will be circuit Boards available.
3. Class A really does sound very good.
4. None of these circuits have been compromised just to test well.

I am more interested in the F1 and the F4 for my personal system.

I obviously want it to be an upgrade on my current amp which is worth about 600 bucks.

My experience says that price is not a good indicator of quality. I would be very surprised if you do not think that the F5 is an upgrade.

Doug

 

[Professor smith]

I have come across this kit of the f5. Can Mr pass tell me if this is a copied version?

Can someone who is experienced tell me if its a good deal?

I think its cheap but I dont know if I should buy it.

 

[Professor smith]

http://cgi.ebay.com/STEREO-AUDIO-POWER-AMPLIFIER-KIT-BASED-ON-PASS-F5!_W0QQitemZ120322637014QQcmdZViewItemQQimsxZ20081024?IMSfp=TL081024103006r16976

I cant post the link but its a chinese seller on ebay anyway..

 

[hifimaker]

Just another sad copy from Asia. Nelson doesn't not authorize kits, especially for current production models.

-David

 

[lineup]

this link may work better
for the kit based on pass F5
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemXitem=120322637014

 

[lineup]

I know Mr. Pass is not into selling Kits 😎

But who could be better to put together a great KIT for diyaudio members
than the designer himself and/or his staff 😉

And who of us would be so stupid go after any kit on eBay
with no security at all of good proper working quality,
if Nelson Pass had a nice Kit out for a fair price?


Lineup 🙂 would not be that stupid

 

[Professor smith]

Well it's not an encouraging reply, but there could be some truth in what you say.

This looks like a convenient way for a beginner such as myself to build this amp because it has all the parts and at an affordable price. However, I have my worries about whether the whole thing will work or sound right etc, this is the problem with diy. I just want a cheap easy amp. It doesn't have to be the best. I just want something decent, because right now, I have no amplifier and no music.

 

[lineup]

Isn't there are Group Buy of F5.
Have a look in the Group Buy forum.

They may have some good offer there, with PCB boards + material
without fear of get bad stuff.

 

[hifimaker]

Forgetting IP and trademark infringements for a moment, I wouldn't buy a parts kit with the mosfets shipped in a plastic bag!

-David

 

[MEGA_amp]

I wouldn't buy a parts kit with the mosfets shipped in a plastic bag!

Ditto!! Additionally, supporting these jokers making a buck off someone else's IP is equally as bad.

Personally I will wait until Nelson puts out a F5 board or a kit, its not like the music is going away any time soon.

-john

 

[Professor smith]

but its not as bad as you make out is it?

The whole idea of Nelson giving out the circuit diagrams is to get people building amps. Kits make it more easier for me. I think he should obtain permission for selling them but its not that bad.

is there any other options for a cheap good amp?