I'll continue to explore this configuration, but I won't be surprised if the Mosfet version has sweeter highs (not to mention how easy--because of their size--to configure). This has been my observation, thus far.
The Jfet is smooth, but when you load up the power mosfet with plenty of current (just enough to get a good power curve) you discover a very remarkable sound. Better than anything I've ever heard!
It's not the voltage that makes this amp sound so good; there isn't much. It's the current.
An interesting point, I'm testing my bread-boarded version with a pair of cheap full range, single driver, JVC bookshelf speakers (I looked the 4" Onkyo driver up on Madisound: $3.50 on sale) and can't believe my ears. These fellows sound fantastic--I can only imagine what a decent pair of Tang Bang, or Fostex full range drivers would sound like.
Nelson wrote a beautiful piece on current amps and how special they are with full range systems. I'm here to attest, he wasn't pulling our leg. I'll never go back to voltage amps.
What's really interesting is the heat in my power supply and connecting wires. I'm running my current configuration with a net of 6.4 volts through an LCLC filter (extremely quiet!) and if I up the output voltage to 7 volts, the insulation on the power feed wires becomes quite warm--I'm using fourteen gauge, but will convert to ten gauge in the final product.
This has been a very amusing adventure. 😀
The Jfet is smooth, but when you load up the power mosfet with plenty of current (just enough to get a good power curve) you discover a very remarkable sound. Better than anything I've ever heard!
It's not the voltage that makes this amp sound so good; there isn't much. It's the current.
An interesting point, I'm testing my bread-boarded version with a pair of cheap full range, single driver, JVC bookshelf speakers (I looked the 4" Onkyo driver up on Madisound: $3.50 on sale) and can't believe my ears. These fellows sound fantastic--I can only imagine what a decent pair of Tang Bang, or Fostex full range drivers would sound like.
Nelson wrote a beautiful piece on current amps and how special they are with full range systems. I'm here to attest, he wasn't pulling our leg. I'll never go back to voltage amps.
What's really interesting is the heat in my power supply and connecting wires. I'm running my current configuration with a net of 6.4 volts through an LCLC filter (extremely quiet!) and if I up the output voltage to 7 volts, the insulation on the power feed wires becomes quite warm--I'm using fourteen gauge, but will convert to ten gauge in the final product.
This has been a very amusing adventure. 😀
Speaking of these JVC drivers, I'm running them in parallel off the mono channel (summed stereo into the amp) and sat them up just like you would stereo speakers about three feet away from me ears. The artist is projected ten feet away. Everyone who's listened so far thinks the effect is eerie.
BTW, my "golden ears" wife says the Mosfet version of this amp gives her chills. She was smiling in a good way when she offered the compliment. 😀
Thanks for the time, folks. 🙂
BTW, my "golden ears" wife says the Mosfet version of this amp gives her chills. She was smiling in a good way when she offered the compliment. 😀
Thanks for the time, folks. 🙂
carpenter said:
Carpenter - Do those JVC's have the Onkyo driver in them, or you just looking for alternative 'shop speakers'? I need a pair, as I blew out one of my older 5" radio shack full rangers. Nice find.
This design is Constant Current Source IN/OUT, like F1?
My bad: I double checked the driver in my JVC cabinet. It's not Onkyo, after all. Sorry.
It is a cheap little pincushion style unit with a small motor. You can bet it isn't too far off from the Onkyo speaker.
I'm going to replace them with nice 4 inch Tang Bangs, probably the W4-1337SA 4 inch Titanium Drivers.
It is a cheap little pincushion style unit with a small motor. You can bet it isn't too far off from the Onkyo speaker.
I'm going to replace them with nice 4 inch Tang Bangs, probably the W4-1337SA 4 inch Titanium Drivers.
carpenter said:
John, you might want to double check the phase of your drivers. Are they both the same?
😀
Phase is the same, and they're being fed by a monoblock. It's just cool to hear center channel imaging to such a great degree from stereo placement. 🙂
Hi Carpenter!
Which VDS graph curves asks for 8 or 9 amps at this voltage diff?
Greets:
Tyimo
Could you show me that "triode curve on the LU1014 VDS graph" ?
Which VDS graph curves asks for 8 or 9 amps at this voltage diff?
Greets:
Tyimo
Sorry Tyimo,
This thread is so old, and I haven't a clue where that graph is located. I looked at some of the pics I posted in this thread -- boy that stuff seems old.
This thread is so old, and I haven't a clue where that graph is located. I looked at some of the pics I posted in this thread -- boy that stuff seems old.
Hi!
Yes this thread is realy old.
I have only this datasheet:
LD1014D datasheet(4/5 Pages) ETC1 | High Performance N-Channel POWERJFET with PN Diode
Greets:
Tyimo
Yes this thread is realy old.
I have only this datasheet:
LD1014D datasheet(4/5 Pages) ETC1 | High Performance N-Channel POWERJFET with PN Diode
Greets:
Tyimo
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How do you calculate the size choke for a given low frequency cutoff ?
I might try building one just for use above 200hz and assume I could get
by with much smaller chokes.
I might try building one just for use above 200hz and assume I could get
by with much smaller chokes.
Hi Tyimo. You can find all that information on Nelson's tutorial regarding the ZV9 (I think... maybe ZV8) He has a graphic like that in your post and describes where the sweet spot is located on the graph.
Woody: I don't have the formula, and most of the time, I use Simetrix to determine how much choke I require for a particular project. If you use a 100mH choke, you'll have ample support at 200hz. To be quiet honest, you could probably get away with 50mH. I believe Magura uses 80mH hand wound air core chokes for full range performance -- probably keeps the phone number for a tow-truck in case he ever wants to move the amp to which it's attached. 😉
Woody: I don't have the formula, and most of the time, I use Simetrix to determine how much choke I require for a particular project. If you use a 100mH choke, you'll have ample support at 200hz. To be quiet honest, you could probably get away with 50mH. I believe Magura uses 80mH hand wound air core chokes for full range performance -- probably keeps the phone number for a tow-truck in case he ever wants to move the amp to which it's attached. 😉
Hi Carpenter!
Thanks! I found it!
How long worked your amp? Did you have any thermal problem?
Tyimo
Thanks! I found it!
How long worked your amp? Did you have any thermal problem?
Tyimo
Hi Tyimo,
I'm currently using the choke loaded, class A amp I describe on my web site. It creates a fair amount of heat, but is rather efficient (all things considered), and sounds quite pleasant to the ear. I'm using it as my computer amp. Needless to say, my computer sounds out of this world.
There's something very special about the sound of a choke in a differential, follower amp. It may never create huge power, but when the speaker is only two feet away, it's not a problem at all.
A friend of mine gave me a center channel speaker (which I'm using in mono mode for my computer), but not just any ordinary speaker. This fellow has a powered subwoofer that taps into the Class A amp's output for its signal. The combination is stunning -- powerful and crisp. I think that perhaps a choke loaded pre-amp is an interesting way to put some "spring" into recorded music.
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