Thanks.
I am running a tube amp and have made inquiries with the manufacturer to explore the possibilities of converting to 16-ohm rating.
Just to clarify: What I hear you saying is that I halve my power output by hooking up a 16-ohm load to 8-ohm taps, but by matchinging the load to the output I can maintain the amp's power rating.
I'll assume I got that right unless you post otherwise.
\mh
I tried using a small integrated PP tube amp on the D5nfs last week. It sounded horrible, small, thin wimpy and very harsh and bright. It has 4 and 8 ohm switchable output taps. This may explain why it sounded bad.
On the other hand, the speakers sound excellent on 100wpc tube monoblocks with a single 5ohm output tap. But they are much more powerful, maybe can overcome the mismatch. But that combo does sound very good.
Also sounds excellent with a ss chip amp, which measured 5w>8ohms at clipping. I would assume it makes less power into 16ohms, but still gives a nice balanced tone. Tere is signs of clipping at high volume though. Now I can understand why, 2-3Watts is likely not enough.
Chris, I do have a pair of speaker autoformers which can increase as well as reduce a speaker's impedance. I will experiment a little with them this week and report back.
Rich
On the other hand, the speakers sound excellent on 100wpc tube monoblocks with a single 5ohm output tap. But they are much more powerful, maybe can overcome the mismatch. But that combo does sound very good.
Also sounds excellent with a ss chip amp, which measured 5w>8ohms at clipping. I would assume it makes less power into 16ohms, but still gives a nice balanced tone. Tere is signs of clipping at high volume though. Now I can understand why, 2-3Watts is likely not enough.
Chris, I do have a pair of speaker autoformers which can increase as well as reduce a speaker's impedance. I will experiment a little with them this week and report back.
Rich
autoformers and more
Chris,
Yes, you could use an autoformer but I'm not aware of anything available as standard stock (but hey, I haven't even looked). Of course you are now subject to two reactive devices and their combined parameters between the output tube(s) and the load. I would also think the cost of a quality autoformer to be pretty close to that of a replacement output transformer. It's no secret that my current favorite line of iron is from Hashimoto and second is MQ. All Hashimoto units ship with standard output taps, ie, 4-, 8- and 16-ohm. MQ also has the Robin-Hood units (good for a single 45 triode) and the TFA-204 if you're running something like a 2A3 or 300B output. Both have a 16-ohm tap and are reasonably priced.
You also have the DIY approach... do a little cheating.... buy one of Mike's parafeed outputs and wire that into the stock amp circuit. Just leave the stock output transformer secondary floating (you sorta turn the stock output into a large choke) and couple to the parafeed output with a high-quality coupling cap.
Figby,
You got it.
Regards, KM
Chris,
Yes, you could use an autoformer but I'm not aware of anything available as standard stock (but hey, I haven't even looked). Of course you are now subject to two reactive devices and their combined parameters between the output tube(s) and the load. I would also think the cost of a quality autoformer to be pretty close to that of a replacement output transformer. It's no secret that my current favorite line of iron is from Hashimoto and second is MQ. All Hashimoto units ship with standard output taps, ie, 4-, 8- and 16-ohm. MQ also has the Robin-Hood units (good for a single 45 triode) and the TFA-204 if you're running something like a 2A3 or 300B output. Both have a 16-ohm tap and are reasonably priced.
You also have the DIY approach... do a little cheating.... buy one of Mike's parafeed outputs and wire that into the stock amp circuit. Just leave the stock output transformer secondary floating (you sorta turn the stock output into a large choke) and couple to the parafeed output with a high-quality coupling cap.
Figby,
You got it.
Regards, KM
Easy as PIE
Probably old news to most but simple calculation of output power:
P=IE where;
P is power in watts
I is current flow int the load in amps
E is EMF (electromotive force) across the load in volts
Re-swizzle the math a bit and you get P = E-squared divided by R where;
P is power in watts
E is EMF (electromotive force) across the load in volts
R is the load in ohms
Examples:
2.83VRMS squared = 8 divided by 8 ohms equals 1-watt
4.00VRMS squared = 16 divided by 16 ohms equals 1-watt
20.00VRMS squared = 400 divided by 8 ohms equals 50-watts
Rich,
Another cheat.... get a high-quality 16-ohm non-inductive resistor (25-watts or more) and put in parallel with the speaker. You still only get half the power to the speaker but you maintain the proper load on the output tube(s). The amplifier will perform more optimally even though your usable power is half.
Regards, KM
Probably old news to most but simple calculation of output power:
P=IE where;
P is power in watts
I is current flow int the load in amps
E is EMF (electromotive force) across the load in volts
Re-swizzle the math a bit and you get P = E-squared divided by R where;
P is power in watts
E is EMF (electromotive force) across the load in volts
R is the load in ohms
Examples:
2.83VRMS squared = 8 divided by 8 ohms equals 1-watt
4.00VRMS squared = 16 divided by 16 ohms equals 1-watt
20.00VRMS squared = 400 divided by 8 ohms equals 50-watts
Rich,
Another cheat.... get a high-quality 16-ohm non-inductive resistor (25-watts or more) and put in parallel with the speaker. You still only get half the power to the speaker but you maintain the proper load on the output tube(s). The amplifier will perform more optimally even though your usable power is half.
Regards, KM
Rich,
It's just a very general statement but I think some 8-ohm valve amplifiers will sound just fine with the Feastrex drivers, depending on the particulars of the amp.
To be honest, although they are nominally 16-ohm drivers, I don't know just what their impedance curve is doing . . . .
Again as a general rule, within reason, solid state amps are pretty much not going to gripe about the impedance of the Feastrex drivers.
Chris
It's just a very general statement but I think some 8-ohm valve amplifiers will sound just fine with the Feastrex drivers, depending on the particulars of the amp.
To be honest, although they are nominally 16-ohm drivers, I don't know just what their impedance curve is doing . . . .
Again as a general rule, within reason, solid state amps are pretty much not going to gripe about the impedance of the Feastrex drivers.
Chris
We are listening to the Red Rcok Amps
Al Steiffel of RMAF drove from Denver to Marin this weekend and delivered his $40,000 50 watt push pull amps, http://www.redrockaudio.com/), and a prototype pre-amplifier which are now installed in the system. We listened for a bit to the D5nf/PB9 speaker yesterday and then switched over to the D9e Type II. Listening to the D5nf/PB9 was something of a revelation on this equipment (BTW the output is 8 ohm). The highs are sparkly and transparent. The overall response of the small speaker was smooth smooth smooth - very nice. The D9e really took until today to warm up. At no point yesterday were the flanges warm, but by this morning they were cooking nicely, and the sound - Holy S**t. BTW did I say Holy S**t. My room is 22 feet wide in front, takes a jog inward just behind the listening position on the right side to 15' wide and is 28 feet deep. The ceiling tapers up at the front wall from 8' to 22' just behind the listener and then down to 8' again at the back wall - modified A-frame. There's lots of volume in this room. The backmost corners of the speakers are 4' 5" from the front wall. The bass is almost, not quite, but almost, too much. This speaker does not play the bottom most octave such as an organ pedal tone completely, but anything else in the acoustic instrument realm is completely well served. I have never heard bass anywhere near as transparent as the D9e can deliver. It is just breathtaking. We didn't get this level of performance at RMAF due to shoddy power delivery, but here we hear the full glory.
Judging by the position of the volume knobs on the pre we have to think that Mr. Teramoto's rating of 106db might be a bit optimistic, but that in no way detracts from the sound. OMG
Al Steiffel of RMAF drove from Denver to Marin this weekend and delivered his $40,000 50 watt push pull amps, http://www.redrockaudio.com/), and a prototype pre-amplifier which are now installed in the system. We listened for a bit to the D5nf/PB9 speaker yesterday and then switched over to the D9e Type II. Listening to the D5nf/PB9 was something of a revelation on this equipment (BTW the output is 8 ohm). The highs are sparkly and transparent. The overall response of the small speaker was smooth smooth smooth - very nice. The D9e really took until today to warm up. At no point yesterday were the flanges warm, but by this morning they were cooking nicely, and the sound - Holy S**t. BTW did I say Holy S**t. My room is 22 feet wide in front, takes a jog inward just behind the listening position on the right side to 15' wide and is 28 feet deep. The ceiling tapers up at the front wall from 8' to 22' just behind the listener and then down to 8' again at the back wall - modified A-frame. There's lots of volume in this room. The backmost corners of the speakers are 4' 5" from the front wall. The bass is almost, not quite, but almost, too much. This speaker does not play the bottom most octave such as an organ pedal tone completely, but anything else in the acoustic instrument realm is completely well served. I have never heard bass anywhere near as transparent as the D9e can deliver. It is just breathtaking. We didn't get this level of performance at RMAF due to shoddy power delivery, but here we hear the full glory.
Judging by the position of the volume knobs on the pre we have to think that Mr. Teramoto's rating of 106db might be a bit optimistic, but that in no way detracts from the sound. OMG
talawalla said:
Indeed -- somewhat akin to the trauma of an afternoon of very kinky play with Scarlett Johansson. It's enough to scar a guy for life.
An externally hosted image should be here but it was not working when we last tested it.
-- Chris
cdwitmer said:
With all due respect to Feastrex, I'd imagine that even though the price might be higher, the line up of potential customers for that kind of play-date is longer than that for introductory pre-orders for these drivers.
Those would be scars you'd get some good mileage bragging over.
Heck, I'd take Kristen Bell as a low rent alternative if Scarlett was busy that weekend.
(is that who the life model was for the magnet housings?)
Stuffing the Feastrex Box
Yesterday I removed the back of the Freddy Box and stuffed it.
I measured out 31 grams of silk for each box. Thats about an ounce of sil. My wife had some arts and crafts paper glue so I used that to stick the silk to the inside.
The silk is stuck to the back of the box.
Screwed the back back on and fired it up.
It seems to have worked just fine. The box is better...so far it will take some time for me to see if the 31 grams is to much or to little.
At first blush I would say it may be to much...maybe 15 grams would be better.
Time will tell but its a start.
I like the way it sounds with the stuffing. The female voices seem less edgy.
I didn't notice a loss of bass and maybe the bass is better as a result. Not more bass but cleaner and clearer.
I swapped out the Feastrex boxes with my Lowthers while doing the stuffing...The Lowthers are a sad replacement.
I do love the Feastrex drivers.
Best single drivers I have ever heard hands down.
West of the Pecos and
East of the Rio Grande
Phil
Santa Fe
Yesterday I removed the back of the Freddy Box and stuffed it.
I measured out 31 grams of silk for each box. Thats about an ounce of sil. My wife had some arts and crafts paper glue so I used that to stick the silk to the inside.
The silk is stuck to the back of the box.
Screwed the back back on and fired it up.
It seems to have worked just fine. The box is better...so far it will take some time for me to see if the 31 grams is to much or to little.
At first blush I would say it may be to much...maybe 15 grams would be better.
Time will tell but its a start.
I like the way it sounds with the stuffing. The female voices seem less edgy.
I didn't notice a loss of bass and maybe the bass is better as a result. Not more bass but cleaner and clearer.
I swapped out the Feastrex boxes with my Lowthers while doing the stuffing...The Lowthers are a sad replacement.
I do love the Feastrex drivers.
Best single drivers I have ever heard hands down.
West of the Pecos and
East of the Rio Grande
Phil
Santa Fe
Sorry guys. Lauren Laverne does it for me. 
Ideally, the box wants lining to kill any standing waves. Top, one side-wall, & back, making sure the throat is clear will be ~ideal. Stuffing is a viable alternative -I doubt the difference between the two would be audible. My fault -I didn't really mention this before because I made the assumption that everyone would automatically apply standard BR cabinet construction details like that (& add any bracing etc that they wished) as a matter of course.
Ideally, the box wants lining to kill any standing waves. Top, one side-wall, & back, making sure the throat is clear will be ~ideal. Stuffing is a viable alternative -I doubt the difference between the two would be audible. My fault -I didn't really mention this before because I made the assumption that everyone would automatically apply standard BR cabinet construction details like that (& add any bracing etc that they wished) as a matter of course.
That's typically a good starting point. What you want is to supress any possible standing waves with the minimum possible damping materials (of course you can add more to suit your individual requirements). Lining opposite faces with a light layer of your favourite material sorts that out, especially if you've used golden / some other acoustic ratio (like the old H = 1.414 x W & W = 1.414 x D), or close to it, which ensures for all practical purposes a ~uniform air particle density within the cabinet & minimises potential standing waves.
Hi Phil,
I'm probably not alone having some personal experience with Lowther but none with Feastrex. Can I ask you to characterize for us some of the differences you hear between the two, especially now that you've got some more hours on the latter.
Which Lowther driver are you comparing to the D5?
TIA
Mark
I'm probably not alone having some personal experience with Lowther but none with Feastrex. Can I ask you to characterize for us some of the differences you hear between the two, especially now that you've got some more hours on the latter.
Which Lowther driver are you comparing to the D5?
TIA
Mark
Lowther DX3
Lowther DX3 was a total revelation about two years ago when I swapped out the Fostex 206E. Granted I did lose bass since the Fostex was well endowded in that department. But the midrange of the Lowther was sooo nice (after the required breakin)(To be fair however the 206 are still in use in my woodshope hooked up to a nice NAD receiver. Lots of bass...
But I digress...This is about Lowther and Feastrex.
Lowther and Feastrex
A story of two drivers searching for the meaning of life.
They are standing over there, in the corner, Lowther and friend, with their faces against the wall. Kinda like two bad children, separated from the flock. I feel their neglect. Guilty? well yes, a bit now that I think of it. After all they were my best friends and I loved the way they would push the music into the air. Not much bass but I simply did... not... care. We have tools to help with this problem. Subs.
I was happy.
Lowther DX3 was a total revelation about two years ago when I swapped out the Fostex 206E. Granted I did lose bass since the Fostex was well endowded in that department. But the midrange of the Lowther was sooo nice (after the required breakin)(To be fair however the 206 are still in use in my woodshope hooked up to a nice NAD receiver. Lots of bass...
But I digress...This is about Lowther and Feastrex.
Lowther and Feastrex
A story of two drivers searching for the meaning of life.
They are standing over there, in the corner, Lowther and friend, with their faces against the wall. Kinda like two bad children, separated from the flock. I feel their neglect. Guilty? well yes, a bit now that I think of it. After all they were my best friends and I loved the way they would push the music into the air. Not much bass but I simply did... not... care. We have tools to help with this problem. Subs.
I was happy.
Attachments
Lowther and Feastrex
Yes I was happy...but little did I know that that was about to change with a chance visit to Mr Olshers web site while searching for Open Baffle drivers. I placed an order for Dicks paper about BassZilla etc. I read the booklet. Then this popped up.
http://www.blackdahlia.com/html/tip_59.html
I looked over the site and Dick talks about this driver he used... A Feastrex... what the heck is a Feastrex? Sounds like a mid east fast food operation.
I called the number on the screen and talked to a guy named Joe.
Joe said the driver was good...actually he said it was unbelievable. So was the price. I hung up.
Later that week I placed my order. Let the credit card fell the pain.
So after about 200 plus hours on the DIQ (driver in question) I say this.
If you think you have heard midrange magic...You have not.
I can not compare Lowther vs Feastrex...I am not an audio pile writer with a golden ear or a gift for golden text. I will say, the Feastrex has made an impression on me like no other loudspeaker I have ever heard in my 63 years. (I started building amps and stuff at the age of 12)(Knight Kits, Heathkits, Eico etc etc)
And for the very first time in my life, as I was sitting listening, last week, This thought came to mind.
This is as far as I need to go...It's done, I can enjoy the music... at last.
Yes I was happy...but little did I know that that was about to change with a chance visit to Mr Olshers web site while searching for Open Baffle drivers. I placed an order for Dicks paper about BassZilla etc. I read the booklet. Then this popped up.
http://www.blackdahlia.com/html/tip_59.html
I looked over the site and Dick talks about this driver he used... A Feastrex... what the heck is a Feastrex? Sounds like a mid east fast food operation.
I called the number on the screen and talked to a guy named Joe.
Joe said the driver was good...actually he said it was unbelievable. So was the price. I hung up.
Later that week I placed my order. Let the credit card fell the pain.
So after about 200 plus hours on the DIQ (driver in question) I say this.
If you think you have heard midrange magic...You have not.
I can not compare Lowther vs Feastrex...I am not an audio pile writer with a golden ear or a gift for golden text. I will say, the Feastrex has made an impression on me like no other loudspeaker I have ever heard in my 63 years. (I started building amps and stuff at the age of 12)(Knight Kits, Heathkits, Eico etc etc)
And for the very first time in my life, as I was sitting listening, last week, This thought came to mind.
This is as far as I need to go...It's done, I can enjoy the music... at last.
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