I thought this is the key too... Now the last cap is small siemens sikorel,but i think good MKP should have positive influence,as i know allready, with these a-class transistor amps ANY mod in PSU are noticable.
I really hope that F5 can give suzuki superbike like performance with my titan dioxide tweeters,more "being there" felling.Now it's just amp that dont involve me much in the music.With harsh cd,speakers,maybe it would be very good.
Yes, I guess one pr device would work
But they dont seem very practical to use, with tricky mounting
HEATSINK ALUMINUM EXTRUSION 10.08 WIDE 1-12" PC. - eBay (item 170471042670 end time Apr-17-10 05:06:27 PDT)
There is no sibilance? that's good, not bad, unless you can measure a rolloff at HF....
_-_-bear
Personally, I would not use these heatsinks because you will need a considerable distance between the PCB and the mosfets... the flat back with fins type extrusion is much easier to use with this type of amp.
There may be tricks to be able to make a flat attachment to the type of heatsink you showed, but they're not worth the effort, nor the machining especially for used ones with holes in them, or unless you have some cosmic styling aesthetic.
There are flat backed ones on ebay, someone mentioned the vendor earlier in this thread, iirc.
_-_-bear
The flat back heatsinks make a good base for the PCB.
The only problem i had was because the ehatsink had fins on the other side was I had to tap all the holes for the output transistors and pcb.
Of course I missed a bit of swarf and punctured one of the insulators !
Luckily I checked with a meter first before powering it up.
It was my first time using a tap and of course I broke two before looking up that you need cutting oil for them to work OK.
LOL...I had no cutting oil when I tapped mine...ended up using extra virgin olive oil...worked great!
There is no sibilance? that's good, not bad, unless you can measure a rolloff at HF....
_-_-bear
It's not good when there are too much or too little simbliliance
But in some recordindgs it must be.Now i have a feeling of some kind of rollof,but there isn't, when different amp is connected Vocals ,instruments arent "very" sharp.Ok i try do not bother with my subjective opinion,will bypass psu,some other upgrades and write my final subjective decision some day
we have a separate thread for listening impressions and discussions, fwiw... but most folks equate "sibilance" or similar effects with "highs"... I prefer to compare to natural sound, which tends to not have the same sort of "electronic" or mechanical sounding effect.
Otoh, I have heard the F5 vary all over the map in terms of "sound" depending on all sorts of rather minor seeming things. So, wazzup wit dat?
_-_-bear
Otoh, I have heard the F5 vary all over the map in terms of "sound" depending on all sorts of rather minor seeming things. So, wazzup wit dat?
_-_-bear
LOL...I had no cutting oil when I tapped mine...ended up using extra virgin olive oil...worked great!
The absolute best lube for tapping aluminum I have ever used is Anchorlube
You won't believe how easy the tap goes through, first time you use it you will wonder if you drilled the hole too big.
And someone is selling it on E-bay so it is easy to get.
eBay.com.sg: ANCHORLUBE TAP CUTTING FLUID G-771 ECOFRIENDLY 4 FL OZ (item 220540873893 end time Apr 06, 2010 00:38:57 SGT)
I've been running F5 for close to 4 months every day, the sound has change several times over that period and only in last month has it good to where id called burnt in, during that period I've tried different types of speaker cable and interconnects, so if you want sibilance go to QED silver Anniversary's, once its burnt in I think you will find Ant-cables work best. You could put some 8 - 10 ohm resistors in place of speakers and let it run 24/7. But leave it 2 or 3 months before final adjustments.
and Thank you Nelson, and my neighbours thank you, Music Reference valve pre, 91db Tannoys, means plenty of volume. thanks to all contributors as well.
and Thank you Nelson, and my neighbours thank you, Music Reference valve pre, 91db Tannoys, means plenty of volume. thanks to all contributors as well.
Listening to this approach of F5, I agree with Tee-bag's description:
http://www.diyaudio.com/forums/blog...-current-limiting-thermistors.html#comment387
http://www.diyaudio.com/forums/blog...-current-limiting-thermistors.html#comment387
I havent yet heard the F5, but I doubt very much it would lack resolution
I trust it enough to blame the speakers
Well, I probably would in almost any case....speakers are mostly the problem
Anyway, I usually need some time to get accustomed to new gear
Goes for anything, a different car, new bike, etc
A new stove may take up to a year
Lets talk again in a year, and you might say the opposite
I trust it enough to blame the speakers
Well, I probably would in almost any case....speakers are mostly the problem
Anyway, I usually need some time to get accustomed to new gear
Goes for anything, a different car, new bike, etc
A new stove may take up to a year
Lets talk again in a year, and you might say the opposite
This has all what you'd expect from a moderately high end amp, so its worth the rest of your system being up to that standard to hear it at its best, and other High Fi buffs that have listened agree.There's been nothing fancy added like extra mosfets etc, its just as the master designed it.
The sound of the F5 can vary all over the map.
NP already said that the bias setting alone will change things.
The brand of resistors seems to change it.
I have heard the very same amp go from stunningly clean and clear to rather fat, recessed and somewhat dull... just some seemingly minor changes made that happen!
Break-in? Roll the dice.
_-_-bear
NP already said that the bias setting alone will change things.
The brand of resistors seems to change it.
I have heard the very same amp go from stunningly clean and clear to rather fat, recessed and somewhat dull... just some seemingly minor changes made that happen!
Break-in? Roll the dice.
_-_-bear
@prooptiki: Thank you! That is just what I have been looking for.
I am building my first F5 exactly to the masters original design (updated w/22K current limiters) with IRFP240/FQA12P20, but I have a set of Toshibas for a second set of monoblocks. I was not going to use them unless a saw some well-explained mods to the original circuit, or, a revised schematic. Prooptiki's schematic matches my notes for the most part. I plain to do direct A/B comparisons when finished.
Anyone else have experience/comments on prooptiki's Toshiba implementation?
From my notes:
I am building my first F5 exactly to the masters original design (updated w/22K current limiters) with IRFP240/FQA12P20, but I have a set of Toshibas for a second set of monoblocks. I was not going to use them unless a saw some well-explained mods to the original circuit, or, a revised schematic. Prooptiki's schematic matches my notes for the most part. I plain to do direct A/B comparisons when finished.
Anyone else have experience/comments on prooptiki's Toshiba implementation?
From my notes:
I got these Wild Burro 8" fullrange and my plan is to mate them with a 35mm TB, in a floor based omni design
In my experimental setup the small TB sounds pretty good, with lots of resolution, when carefully adjusted
When I get around to build my F5 I will know if its a good match
Maybe next year
In my experimental setup the small TB sounds pretty good, with lots of resolution, when carefully adjusted
When I get around to build my F5 I will know if its a good match
Maybe next year
I would also like to share that in my set up , the addition of a pre transforms the sound for lethargic, lacking drive to' being there " with the musician experience . The treble in my ribbon tweeter is very detail and precise . The varying force of the drummer on the hat could be appreciated.
kp93300
Bias is important, but also the F5 depends on a specific "sweet
spot" or nulling effect where the positive and negative halves
are just right. It takes a distortion analyzer to find it quickly
or a very good ear to find it slowly. Go off the balance and it
fattens right up, and some like that.
Personally I find it to be partly a function of the loudspeaker
driver. With something like the Feastrex D9nf, a little fat
doesn't hurt, or you can switch to an F3, or perhaps a nice
glass of cabernet.