Exciting new line of fullrange drivers from Feastrex

[nicoch58]

Ot

hyperacusis in one ear

HI bvan,same unlucky but my analog stuff and fullrange solved this problem, probabily I have all dinamic that I need, at low pressure

If I remenber well, John Curl speaks about one AES study found that digital music can do problem ....

 

[bvan]

The First Watt does look promising on paper. Thanks for that.

Interesting what you say about hyperacusis and vinyl. I'm having a GTG at my place on the weekend and might for the first time ever get to hear vinyl playing in my home A bit worried to find out what I might have been missing (and what I cant yet afford)

 

[bvan]

Just wondering about the current-source First Watt amps, seems from the FR graphs to bring down the mid-treble region, which is a useful flattening out of most fullragers. But if the fullranger were to be flattish to begin with, could this cause an unwanted roll off towards the top?

 

[kmaier]

16 ohm taps

Just in case a few folks forgot....

OPTs simply reflect the load from one winding to the other. If you have an OPT with a 5K primary impedance and an 8 ohm secondary, loading the secondary with an 8 ohm load results in a 5K primary impedance. Drop the secondary load to 4 ohms and the primary drops to ~2.5K, raise the secondary load to 16 ohms and the primary increases to ~10K.

As a result, not having the proper matching of load to OPT can offset the loading by a large amount and alter the operating specs of the amp by a fair amount. Having a 20 ohm secondary will result in a "lower than rated" primary impedance with the Feastrex drivers (and vary somewhat as the actual impedance of the Feastrex driver does versus frequency). You can also get much less power in a tube amp when the matching is off and distortion can suffer quite a bit.

For what little it's worth, I've done extensive testing with the 45 and 2A3 (over 100 samples). My preferred loads for these are 5K and 3.5K respectively. With good driver circuitry and proper operating voltage/bias, I generally get 2.25-watts from the 45 and 4.5-watts from the 2A3 with very low distortion and very good linearity.

Regards, KM

PS - the EL84 is not specifically a guitar amp tube... nor are any others that I'm aware of... they're popular of course.... as are 6L6GCs in guitar amps.

 

[rcdaniel]

Re: 16 ohm taps

For what little it's worth, I've done extensive testing with the 45 and 2A3 (over 100 samples). My preferred loads for these are 5K and 3.5K respectively. With good driver circuitry and proper operating voltage/bias, I generally get 2.25-watts from the 45 and 4.5-watts from the 2A3 with very low distortion and very good linearity.

OT - I really appreciate your sharing of knowledge and experience on the various forums. I'd like to know more about your testing, chosen operating points, and preferred sonics. If you have the time and inclination, would it be possible to start a thread in Tubes or PM me? Thank you.

Now, back to regular programming.

 

[dzzmiller]

The First Watt does look promising on paper. Thanks for that.

Interesting what you say about hyperacusis and vinyl. I'm having a GTG at my place on the weekend and might for the first time ever get to hear vinyl playing in my home A bit worried to find out what I might have been missing (and what I cant yet afford)

Until you've heard The Monkies on vinyl you haven't lived.

 

[bvan]

Anyone got a FR graph of D5nf they could send me?

Cheer
B

 

[Scottmoose]

I have to admit, I'd be intrigued to see one myself. As Feastrex don't appear to measure the electrical / mechanical parameters of their drivers however, one assumes that they don't take an FR curve either. Exactly what one is supposed to make of that, I don't know. I can think of five possible reasons, but which is / are correct is open to question.

 

[bvan]

Yeah, I'm hoping someone has taken some at home, pref out in the garden.

They sound flat enough to my ear, but I'm about to try digitally high pass them with a DEQ2496 (upstream of my dac) so I figured I might try correcting whatever irregularities the driver might have and see if its an improvement.

(if the above sounds like an impossible setup it's not too far off - plan is to high pass the entire signal, 80hz 2nd order, and from the DEQ feed SPDIF to dac to SET amp to D5nf, and at the same time from DEQ to DCX to SS amp to subs. In the DCX I'll dial back the missing bass with a 24db bump at 20hz. Volume control via DEQ. I'm guessing there could be some loss of low freq resolution by attenuating in the digital realm, and maybe excessive phase shift. It seems a better bet than using only the DCX and its inbuild dacs, or using passive components, or running D5nf unfiltered in OB. We'll see...)

 

[cdwitmer]

. . . Feastrex don't appear to measure the . . . FR curve . . . Exactly what one is supposed to make of that, I don't know. I can think of five possible reasons, but which is / are correct is open to question.

If it's any help, I would venture to say that whichever of those five possible reasons is the most charitable, that's the one that is probably closest to the truth.

-- Chris

 

[BTW]

In the DCX I'll dial back the missing bass with a 24db bump at 20hz. Volume control via DEQ. I'm guessing there could be some loss of low freq resolution by attenuating in the digital realm, and maybe excessive phase shift. It seems a better bet than using only the DCX and its inbuild dacs, or using passive components, or running D5nf unfiltered in OB. We'll see...)

Whatever electronic means you use to filter/flatten the curve.. etc.. Always reference back to the unloaded D5nf.... We have tried the D5nf with an electronic crossover to a subwoofer... It compromised the dynamics , details too much.. I didn't like the effect..

The better Feastrex implementations I've heard with subwoofers are ....... Feastrex in their recommended cabinets run fullrange and subs like the REL... rolled in at 40 Hz or so..

Have fun D5nf........

 

[Scottmoose]

TBH Chris, I was simply considering some generalised situations that regularly crop up in manufacturing as a whole, rather than anything exclusive to drivers, or to Feastrex. Anyway, I daresay you're right, on the charitability front.

 

[nicoch58]

HI BTW

yes is the only way , FR must run free ....

But in OB can be a problem ....the only hi-end alternative that I know http://www.borbelyaudio.com/eb1102215b.asp

as I have phono and amp ,sure are good , no caps on signal path

sorry the DEQ2496 work well, but are for midi hifi..

 

[Nelson Pass]

For what it's worth, I have previously posted curves of my D9nf's,
and if my experience is any indication, the D5's will be flatter than
those. All told, there's nothing particularly remarkable about the
frequency response curves of the Feastrex - they tend to resemble
those of similar high sensitivity cones. I don't think Feastrex has
anything in particular to hide, so I go with the charitable viewpoint.

Addressing another issue, the use of EQ and crossover filters can work
very well with these drivers, but getting the right sound is not a
trivial thing. You should be prepared for considerable trial and error
in finding the right characteristics, and for me they have been very
simple low Q curves.

 

[cdwitmer]

. . . I daresay you're right, on the charitability front.

And I dare say that when it comes to charity you know of what you speak, given the many DIY audiophiles in your debt for the excellent enclosure designs you have helped make available -- not that you're one to keep a tally sheet about such things, of course. (I'm tempted to borrow a quote from Jesus about the left hand not knowing what the right hand is doing, except that in the context of DIY that might be misinterpreted to sound like I'm dissing your DIY skills . . . )

-- Chris

 

[bvan]

HI BTW

Hi nicoch,

Would you also consider DEQX for mid-fi applications only? If not, what do you see as the difference between the two units, used as I intend? cheers

B.

 

[Scottmoose]

... (I'm tempted to borrow a quote from Jesus about the left hand not knowing what the right hand is doing, except that in the context of DIY that might be misinterpreted to sound like I'm dissing your DIY skills . . . )

It'd probably be deserved though -I'm not exactly God's gift to speaker design, and I'm learning all the time, thank goodness. Hasn't stopped me yet of course... I relate to the bloke on the cover here... (good album BTW)

 

[dpaws]

Hi nicoch,

Would you also consider DEQX for mid-fi applications only?

B.

I'm not expert (and Guys, please chip in and correct me) but... as I understand it you can not boost a frequency digitally, you can only lower the volume of all those frequencies around it in order to create a relative peek. The way this seems to be done is to dispose of data bits, which also contain a load of information such as harmonics, spatial clues etc. I suppose its the same as an mp3 against a lossless recording. It's music, but somehow lacking its soul.

So, by using digital EQ you can effectively reduce the remaining frequncies to mp3 quality for the sake of a 12db "boost"....

It's importance depends on the ability of your system to resolve this extra information, hence the reference to "mid-fi". I'm happy with compressed radio streams and mp3's on my factory fitted car stereo, but play them on my (very good) hifi and they sound awful....

As far as I'm aware only dCs have got digital volume contol sorted... Help me out Guys!!! Romy... ???

 

[cdwitmer]

I'm no expert on that subject but I would suggest that common sense dictates "less is more" when using equalization to correct frequency response anomalies. In the past I have used a combination of adjustments in both the digital domain and the analogue domain to get what I considered to be good results. Red Book CD can make for excellent listening but only when it is at its absolute best, and I would think twice before making the decision to do anything that would degrade the already borderline signal that you get from CD format recordings . . . one can't afford to drop very much from that signal before the effort becomes counterproductive. How far one can go will vary from one situation to another -- how good the rest of your system is, how good your ears are, the frequencies you're working on, etc.

Judicious use of analogue domain equalization can be a good thing . . .

-- Chris

 

[nicoch58]

beringer is pro hardware not hiend psu -dac-clock-output stage are ......