A late arrival...

acoustixman · 22nd February 2006, 08:35 PM

Greetings, all! I hope this finds you well.

I don't know what took me so long to "assimilate" as I am a very DIY-hard individual in all areas, especially audio (probably a cheapskate in the minds of some)!! It's good to be here at last! I will admit to collecting a few advisory notes in this forum prior to my joining!! Thanks all!

I've been a D-I-my loudspeaker builder for about a decade; strictly 2-channel music goals... second order all-around; Linkwitz-Riley on the wires, Bessel~Butterworth on the box (control the room: BANG - not BOOM!!)... low fc's and close physical driver placement... ptp wiring; non coupled coils... oblique boxes... VIFA drivers!

Recently, I finally took the plunge and built my first power-amp (in stereo of course); my design has been a bit influenced by W.M.Leach in the front end and G.R.Slone out the back...Full symmetry, 4x-cascode front-end, resistive sources and tails, more diff-gm than low TIM amp, high-beta VA under cascodes, class-A EF buffer, parallelled LMOSFET SF pairs (on 2.73 sq-ft 441K heatsink) in ~class-B... +/-70V rails, 750W / 360Joule supply. The transient response is astonishing (

), and that's of course what I live for in the musical world! I don't mean to seem too proud, but unfortunately none of you can hear it for yourselves at the moment, that is unless you live within about 10 houses of mine

. I intend to give it the full battery (FT/distortion spectra, transient & bandwidth analysis, and whatnot) but I currently lack the means - Tek scope and BKPrecision FG combo proved incapable of resolving any distortion at 1kHz or 10kHz. I'll probably build another or two at 1/2 the power and go with an active crossover.

Vendor Testimonials:
Wakefield Thermal Solutions (TO-3 heatsinks) in NH: excellent, helpful people.
Lansing Instrument Corp (graybox enclosures) in NY: extremely high quality product, helpful advice.
Exicon/Profusion PLC (Lateral MOSFETS) in England: superb product, quick delivery, helpful folks.
ExpressPCB on Internet (ships to me from Oregon): high-quality freeware design package, quick PCB turnaround.
Plitron in Canada: wide variety, custom made at good prices, plan ahead and get order in early, nice folks.
Digi-Key, Allied, Mouser, Newark, McMaster-Carr, Parts Express; always there when you need'em!
Madisound in WI: helpful folks, wide variety, good stock.

Now my question:
I'm seeking a worthy pre-amp design, since my multi-source auditioning system now longs for espousal to my new box. Remote control for source selection and unified volume control are desirable (for improving S.A.F.), not much need for built-in tone controls. I'm thinking about giving it a digital nervous system... Any advice? I might go commercial on a high recommendation... (NAD, etc.?)

b-t-w; how do some users get the graphic ID/handle to the left side of posts?

SY · 22nd February 2006, 08:41 PM

Welcome to the forum!

To get the cool little avatar, size the picture you want, go to the "user cp" button, choose "options," and at the bottom of the control panel, you'll see the button for uploading the pic.

Jonathan Bright · 22nd February 2006, 08:43 PM

Greetings from Australia. BTW waht time is it over there? Your system sounds v.good. You'll enjoy your stay.

acoustixman · 22nd February 2006, 09:43 PM

Jonathan: We're at GMT less 8:00. (Pacific TZ)

Cal Weldon · 22nd February 2006, 09:45 PM

Hi Acoustixman and welcome to the forums. I see you like home brewing. What type of brewing are you doing?

acoustixman · 22nd February 2006, 10:29 PM

Cal: I haven't brewed in a shameful little bit of time. By and large, I'm questing for the perfect IPA recipe. Lots of malt body, flavor & conversion (toast a portion in oven before starting) and heavy on the hops (Fuggles to start / Hallertau to finish). I've always wanted to try a lager version (India Pale Lager?!), but I'm sadly without a spare fridge or consistent cold pantry at this time. I'm pretty seat-of-the-pants in the kitchen and probably won't be able to make the right stuff a second time once I discover it anyway. I think brewing provides the ideal mutual complement for the audio practice (i.e. listen to tunes on good kit while brewing, drink brew while designing, crafting and auditioning the next kit)...

ashok · 24th February 2006, 02:19 PM

Quote:

.....drink brew while designing, crafting ...........

No..No... ... Not if you are into tubes ...

You could end up in a box .

Be very careful if you handle high voltages....... have no hooch around.

Welcome to the forum !

acoustixman · 24th February 2006, 03:19 PM

ashok: Agreed and thanks for the *sound* advice!! I haven't exceeded +-70V rails, and while that's no tube-caliber, I do treat volts (and coulombs) with respect and resistance. I don't think my wife would be too happy otherwise no matter how great my life insurance is... I do tend to imbibe a little more freely when listening and conceiving [in the circuitry sense] than when soldering and testing.

Personal note on the tubes; I highly revere them (they are a beautiful and magical component of audio electronics), but I think their best place is in creating sound (guitar and bass amps), not reproducing it. Let's see what arguments that instigates...

Happy listening and thanks for the welcome!

Bobken · 24th February 2006, 03:35 PM

Hi JW,

Welcome from me too.

I once accidentally grabbed +/- 75v rails (i.e. total 150v DC) and I don't recommend it!

Take care!

acoustixman · 24th February 2006, 05:25 PM

Thanks Bobken;

I've touched 140VDC with dry hands and it worked out OK...my calluses must be highly ohmic... I couldn't give the same testimony when I accidentally touched a rail-bound resistor lead and GND with one voltmeter probe... Bright flash in my face (always wearing eye protection at the test bench!!), loud bang, and one vaporized resistor. I'm not sure where all the metal went, but I move more slowly at any rate...

I think a part of my joy in audio is the thrill of [coming close to] being in command [at times] of these large quantities of electrical energy.

22nd February 2006, 08:35 PM	#1
acoustixman diyAudio Member Join Date: Feb 2006 Location: Boulder City, Nevada	A late arrival... Greetings, all! I hope this finds you well. I don't know what took me so long to "assimilate" as I am a very DIY-hard individual in all areas, especially audio (probably a cheapskate in the minds of some)!! It's good to be here at last! I will admit to collecting a few advisory notes in this forum prior to my joining!! Thanks all! I've been a D-I-my loudspeaker builder for about a decade; strictly 2-channel music goals... second order all-around; Linkwitz-Riley on the wires, Bessel~Butterworth on the box (control the room: BANG - not BOOM!!)... low fc's and close physical driver placement... ptp wiring; non coupled coils... oblique boxes... VIFA drivers! Recently, I finally took the plunge and built my first power-amp (in stereo of course); my design has been a bit influenced by W.M.Leach in the front end and G.R.Slone out the back...Full symmetry, 4x-cascode front-end, resistive sources and tails, more diff-gm than low TIM amp, high-beta VA under cascodes, class-A EF buffer, parallelled LMOSFET SF pairs (on 2.73 sq-ft 441K heatsink) in ~class-B... +/-70V rails, 750W / 360Joule supply. The transient response is astonishing ( ), and that's of course what I live for in the musical world! I don't mean to seem too proud, but unfortunately none of you can hear it for yourselves at the moment, that is unless you live within about 10 houses of mine . I intend to give it the full battery (FT/distortion spectra, transient & bandwidth analysis, and whatnot) but I currently lack the means - Tek scope and BKPrecision FG combo proved incapable of resolving any distortion at 1kHz or 10kHz. I'll probably build another or two at 1/2 the power and go with an active crossover. Vendor Testimonials: Wakefield Thermal Solutions (TO-3 heatsinks) in NH: excellent, helpful people. Lansing Instrument Corp (graybox enclosures) in NY: extremely high quality product, helpful advice. Exicon/Profusion PLC (Lateral MOSFETS) in England: superb product, quick delivery, helpful folks. ExpressPCB on Internet (ships to me from Oregon): high-quality freeware design package, quick PCB turnaround. Plitron in Canada: wide variety, custom made at good prices, plan ahead and get order in early, nice folks. Digi-Key, Allied, Mouser, Newark, McMaster-Carr, Parts Express; always there when you need'em! Madisound in WI: helpful folks, wide variety, good stock. Now my question: I'm seeking a worthy pre-amp design, since my multi-source auditioning system now longs for espousal to my new box. Remote control for source selection and unified volume control are desirable (for improving S.A.F.), not much need for built-in tone controls. I'm thinking about giving it a digital nervous system... Any advice? I might go commercial on a high recommendation... (NAD, etc.?) b-t-w; how do some users get the graphic ID/handle to the left side of posts?

22nd February 2006, 08:41 PM	#2
SY diyAudio Moderator Join Date: Oct 2002 Location: Chicagoland Blog Entries: 1	Welcome to the forum! To get the cool little avatar, size the picture you want, go to the "user cp" button, choose "options," and at the bottom of the control panel, you'll see the button for uploading the pic. __________________ If there's a sucker born every minute, where do the rest of them come from?

22nd February 2006, 08:43 PM	#3
Jonathan Bright diyAudio Member Join Date: Feb 2004 Location: Queensland	Greetings from Australia. BTW waht time is it over there? Your system sounds v.good. You'll enjoy your stay. __________________ "It was the Springtime of the year when aunt is calling to aunt like mastodons bellowing across primeval swamps." P.G. Wodehouse.

22nd February 2006, 09:43 PM	#4
acoustixman diyAudio Member Join Date: Feb 2006 Location: Boulder City, Nevada	Time in Boulder City Jonathan: We're at GMT less 8:00. (Pacific TZ)

22nd February 2006, 09:45 PM	#5
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	Hi Acoustixman and welcome to the forums. I see you like home brewing. What type of brewing are you doing? __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

22nd February 2006, 10:29 PM	#6
acoustixman diyAudio Member Join Date: Feb 2006 Location: Boulder City, Nevada	Cal: I haven't brewed in a shameful little bit of time. By and large, I'm questing for the perfect IPA recipe. Lots of malt body, flavor & conversion (toast a portion in oven before starting) and heavy on the hops (Fuggles to start / Hallertau to finish). I've always wanted to try a lager version (India Pale Lager?!), but I'm sadly without a spare fridge or consistent cold pantry at this time. I'm pretty seat-of-the-pants in the kitchen and probably won't be able to make the right stuff a second time once I discover it anyway. I think brewing provides the ideal mutual complement for the audio practice (i.e. listen to tunes on good kit while brewing, drink brew while designing, crafting and auditioning the next kit)...

24th February 2006, 03:19 PM	#8
acoustixman diyAudio Member Join Date: Feb 2006 Location: Boulder City, Nevada	ashok: Agreed and thanks for the sound advice!! I haven't exceeded +-70V rails, and while that's no tube-caliber, I do treat volts (and coulombs) with respect and resistance. I don't think my wife would be too happy otherwise no matter how great my life insurance is... I do tend to imbibe a little more freely when listening and conceiving [in the circuitry sense] than when soldering and testing. Personal note on the tubes; I highly revere them (they are a beautiful and magical component of audio electronics), but I think their best place is in creating sound (guitar and bass amps), not reproducing it. Let's see what arguments that instigates... Happy listening and thanks for the welcome!

24th February 2006, 03:35 PM	#9
Bobken diyAudio Member Join Date: Dec 2002 Location: UK	Hi JW, Welcome from me too. I once accidentally grabbed +/- 75v rails (i.e. total 150v DC) and I don't recommend it! Take care! __________________ Bob

24th February 2006, 05:25 PM	#10
acoustixman diyAudio Member Join Date: Feb 2006 Location: Boulder City, Nevada	Thanks Bobken; I've touched 140VDC with dry hands and it worked out OK...my calluses must be highly ohmic... I couldn't give the same testimony when I accidentally touched a rail-bound resistor lead and GND with one voltmeter probe... Bright flash in my face (always wearing eye protection at the test bench!!), loud bang, and one vaporized resistor. I'm not sure where all the metal went, but I move more slowly at any rate... I think a part of my joy in audio is the thrill of [coming close to] being in command [at times] of these large quantities of electrical energy.

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