While on the subject, Scott, do you mind letting on whether you have any preferred output devices, and if so, which and why?
Also, one personal question - can you list a few AD op amps you would recommend for audio use (general amp purposes, no specials)? I ask because I have been programmed with the following line: if aopm, then AD. I am extremely partial to AD op amps simply because I have excellent experience with 825, 826, and a few others. Never ever even hiccuped, let alone let me down.
Also, one personal question - can you list a few AD op amps you would recommend for audio use (general amp purposes, no specials)? I ask because I have been programmed with the following line: if aopm, then AD. I am extremely partial to AD op amps simply because I have excellent experience with 825, 826, and a few others. Never ever even hiccuped, let alone let me down.
I don't consider it an exact science. Two power MOSFET's per side that's only 12.5 Watts per device. This is not my expertise anyway. As I said before I'm not much of an op-amp roller, AD823's, ADA4841-1's have worked for me, you might want to try some of the low noise parts with linearized inputs from our Santa Clara group.
Interesting excursion yesterday, a local festival with plenty of real sounds, and PA variants - nice to get some perspective again on what currently is considered the sound "to have". Many of the PA efforts had classic "bloop, bloop" bass, which drowned out most of the midrange and treble, you had to work at trying to identify what the underlying music was about, tiny munchkin noises which were the melody lines. The standout was a school big band, running through just a pair of new, active QSC K8 PA satellites, bookshelf sized speakers you could use as PC monitors. Using just an 8" mid/bass unit, these produced an intensity of sound which made a mockery of the normal mega huge "high end" amplifier/ speaker combos - a very clean sound, easily able to do a saxophone justice, while also handling 20 or so other instruments with no significant distortion. Was it audiophile sound? No, of course not, the detail of each individual instrument's contribution was not clear, or "refined" shall we say, and the true high frequency, high harmonics sparkle was missing. But in its ability to produce SPLs which were fully coherent, were not disturbing by having far too many irritating artifacts, and truly matched the bite of natural sound it made normal audiophile sound quite pathetic in comparison - all from a speaker box size and drivers that would be laughed at in audio circles ...
On the other side of the coin there were plenty of drums, real whack with a huge mallet drums that you could feel from half a block away - a plethora,
, of the things. A million miles away from the PA "bass", the transient cracks of a fleet of these being walloped a few feet away were a delight to hear - and guess what? No ear protection!! - I must have been mad ... ,!!
On the other side of the coin there were plenty of drums, real whack with a huge mallet drums that you could feel from half a block away - a plethora,
, of the things. A million miles away from the PA "bass", the transient cracks of a fleet of these being walloped a few feet away were a delight to hear - and guess what? No ear protection!! - I must have been mad ... ,!!
Last edited:
I 'm currently running a Pr of these at my main desk , 4 yrs old now decent sound for what they are perfect for mp3 you tooob music ..
Altec Lansing VS2521 Computer Speakers - GadgetGrid
Altec Lansing VS2521 Computer Speakers - GadgetGrid
Keep up with me, a.wayne,
... the point is that properly engineered PA speakers, with minimally sized drivers and cabinets, have no trouble produceed the SPLs, and more, of the real thing. So, why were they able to do it? Simple, they used class D amplification, and proudly displayed the wattage on the cabinets, 1 kW of grunt per side. So, the "simple" drivers had no trouble pumping out the dBs, but they were driven by electronics that could control the cones with authority - job done.My current PC speakers are driven by mosquito power at the moment, hence no real wallop - but I have used other speakers of comparable calibre in previous systems with extra drive, and to the limits of the voltage rails were able to "do" big brass bands - not to the volume of the QSC, but to a much higher standard of 'transparent' detail than the pro units.
Last edited:
I'll be interested in whether I get a decent answer from you on this ... put these behind a curtain, along with your main system, run them at the same volume: what do the little 'uns do wrong?I 'm currently running a Pr of these at my main desk , 4 yrs old now decent sound for what they are perfect for mp3 you tooob music ..
Altec Lansing VS2521 Computer Speakers - GadgetGrid
Thanks for the reply, Scott.
Agreed, selecting power devices is not an exact science, I think our choices are ruled partly by our requirements, and partly by our experience. I've been using Motorola/ON Semi power devices since the very first amp I made way back in 1975 and in all that time, not one has ever let me down (that didn't turn out to be my fault in the end). Same for Toshiba devices, notably their 2SC3281/2SA1302. Sanken, on the other hand, gave me much grief, so I stay away from them like the Devil avoids the cross and garlic.
As opposed to many people here, I'm no fan of MOSFETs. FETs can be nice, but I find MOSFETs to lack that "oomph!" some BJT power devices have. Obviously, a very personal view.
You design op amps, but are not an op amp guy? A bit odd, don't you think? Anyway, thanks for the tip.
You both own the same make of car?
BTW, if the pause had been real, it wouldn't have been pregnant.
Anyone found that simulators for port loaded speaker designs don't agree? I have asked for a square plate to allow various ports to be used and do it by ear. That seems rather easy. My friends seem to be like on a tightrope without a net when I say it. Don't they realize the computer makes only one version and if we are honest a good port loaded design verges on the oxymoron. I am suggesting a restricted port or flared port as something to try. The computer seems to accelerate the work. Then is grinds it to a permanent halt.70% I love the computer. I love the 30% by ear also. Wouldn't want to go backwards when we couldn't check assumptions. Just think if choosing Cider was so difficult.
The specific problem is the upper bass seems week . This wasn't so when OB. I know why. At least I know it should be possible somehow.
If I can get 4 speakers of the same type I am going to try a back to back dipole. Then filter the rear bass to see what I get. I have a hunch some of what I hate about box speakers is less the box and more cardioid output. 4 Dynaco's would suit fine. Had a shoot out between Dynaco and Magneplanars . Both are great. Dynaco's are 3/4 hour speakers ,then I feel slightly fatigued. Maggie's do not match the 12Lta OB for drama. They sound rough at times but do not fatigue. Funny thing is the Dynaco's have a similar roughness and do fatigue.
The specific problem is the upper bass seems week . This wasn't so when OB. I know why. At least I know it should be possible somehow.
If I can get 4 speakers of the same type I am going to try a back to back dipole. Then filter the rear bass to see what I get. I have a hunch some of what I hate about box speakers is less the box and more cardioid output. 4 Dynaco's would suit fine. Had a shoot out between Dynaco and Magneplanars . Both are great. Dynaco's are 3/4 hour speakers ,then I feel slightly fatigued. Maggie's do not match the 12Lta OB for drama. They sound rough at times but do not fatigue. Funny thing is the Dynaco's have a similar roughness and do fatigue.
- Status
- Not open for further replies.