The Burning Amp Festival-Burning Gadgets Preview

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seems that I must do all hard work here ..........
where is official Mod when you need it most ?
:devilr:

MOD EDIT: Please post schematics as Zen Mod asks, also construction plans and crossovers of speaker projects, also where and on what threads circuit boards are available, photos are shown, etc, etc. That way people who get inspired at the show can come here to find out about the projects that they got inspired by....
END MOD EDIT


anyway - let's try that this became "official" technical preview thread for BAF .

do not post your ugly faces - post nice pics and schematics of space shuttle you think to bring to SF happening ......


hehe - don't expect that Papa will reveal here what Fx he'll bring in da trailer .........

:clown:
 
may I........ ?

let's see ..... there is Papa-like product , well buried in "official" thread about :Pumpkin:

position: Preamp

cause : why not

I'll send main pcbs , tested , on Monday to Mr. Simovic , AKA Ar2 , hoping that they will arrive to SF in time for BAF.

unfortunately , reg pcbs can't be finished for this occasion , and that will be main reason why :pumpkin : will certainly sound awful , and soon I'll be just one of many ex members of this board...... I'll not survive that public humiliation .......
anyway...... there is main schmtc
 

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SY

diyAudio Moderator Emeritus
2002-10-24 10:19 pm
Chicagoland
www.SYclotron.com
I have an F4-compatible preamp featuring a CV1988 purloined from Morgan Jones's collection. Balanced-only output, gain of 26dB. No loop feedback. All triode. Pretty impressive linearity. Now if it all goes together in the case... all the things magura is good at, I'm bad at.

John Curl tells me that he's got an interesting historic gadget or two to show.

This is gonna be fun.
 
OK, I'm bringing an open loop (no global feedback) preamp with RIAA stage and unity gain line driver. The schematic for the overall preamp is shown below. This is housed in a humble Ten-Tec box and serves as a test bed for various RIAA preamp and output buffer experiments. The box is powered with a +40VDC external supply which also contains a 25A relay for switching all my other audio components. The single 40V supply intentionally limits what I try to fairly simple single-ended circuits, which is the whole brief of this line of experimentation, about 2 years old now.

Some of the past and present occupants of this box are described in the threads "Open Loop Follies" and "JFET SRPP". The box currently uses a pair of Bourns 100k conductive plastic pots with 19k metal film law-fake resistors for volume/balance controls.

The RIAA amp currently in use is the JFET SRPP preamp described in the aforementioned thread, and the output buffer is a heavily biased NMOSFET/PNP Darlington "super Gm" follower with current sink loading.

Before I show up at Burning Amp, I'm swapping the SRPP preamp for an open loop single-ended discrete JFET/MOSFET amp, pieces of which are described in the threads mentioned. I just finished tweaking the bias on all stages Friday afternoon, and will be testing gain on Monday using the HP gain-phase analyzer at work. As soon as I'm satisfied, I'll post a schematic and picture. The JFETs/Mosfets used are very intentionally ones that can be easily found at Mouser, to prove a point....

The conductive plastic controls will be swapped for a pair of of NOS Clarostat 75k, 2W wirewound pots with a pair of Micro-Ohm 35k precision bobbin-wound resistors in parallel each for law-fake. The combination scans very flat on the impedance analyzer at work. I'm looking forward to hearing an all-metal volume control.

I may keep the super-Gm buffer, or swap it out for a cascaded MOSFET follower circuit. It would be interesting to bring an assortment of pieces along, as the RIAA and buffer modules I have built so far are interchangable and only require about 10-15 min of soldering to swap.
 

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:smash:
Please guys, I believe the Zen Mod was sincere in asking that posts here be on topic and include information about projects being presented at Burning Amp '07. This will allow attendees to easily find out more about project that they see at the show- Actually I guess it will allow anyone to find out more..
 
I have an F4-compatible preamp featuring a CV1988 purloined from Morgan Jones's collection. Balanced-only output, gain of 26dB. No loop feedback. All triode.

And I 'm making the F4 for it and other high output preamps such as that absolutely smashing :smash: Pumpkin Preamp


Here's the photo of just the power supply. I'm making one for each F4 stereo amp, BUT I'm running each stereo amp balanced 'cause I've always wanted a balanced system and the 100w/ch couldn't hurt.. ;)

http://www.diyaudio.com/forums/showthread.php?postid=1316742#post1316742

You'll have to see the rest of the amp at the show- or in the after show photos.. It's big!

ere are links about the F4

http://www.passlabs.com/np/f4-power-amp.pdf
http://www.diyaudio.com/forums/showthread.php?s=&threadid=99351&perpage=25&pagenumber=1
http://www.diyaudio.com/forums/showthread.php?s=&threadid=97540&perpage=25&pagenumber=1
http://www.diyaudio.com/forums/showthread.php?s=&threadid=103891&perpage=25&pagenumber=1
 
Variac said:


............

You'll have to see the rest of the amp at the show- or in the after show photos.. It's big!


you can shoot me with as many photos of that beauty you can ;

I love wallpapers like these , and just looking this Marine style is ,well, .........joy.

please - use my PM addy

hehe- and that just because you are :captain:


ps - :Pumpkin: package sent few hours ago
 
here's another package that will soon be on its way.

The Twisted Pear people are finishing up the Opus DAC demo box with switchible inputs- S/PDIF or USb, Balanced or single ended. Even some filters to switch in and out.


http://www.diyaudio.com/forums/showthread.php?postid=1320147#post1320147

Threasd starts here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=79456&perpage=25&pagenumber=1

I can't wait to hear it plugged into a laptop and run uncompressed files and see if it matches expensive CD players...

If it does, then my whole collection goes on a Hard drive. At Costco the other day I saw a 500 gig external HD for $160 :eek:
 
Ok, schematic for RIAA section of preamp I'm bringing. I'll call it the "All American Preamp" for lack of any other name, as it uses all US made JFETs/ Mosfets in the signal chain. There's a few Japanese-made transistors in the bias and power supply circuits, but they could be replaced with MPSW05/W56.

I was looking for 40 dB gain at 1 kHz - I got ~42 dB, which is close enough for the time being. The circuit is a fairly radical alteration of the Pacific preamp, with followers for each stage, cascoding, and extra current source biasing to allow the gain FETs to run at fairly high quiescent current and also to be able to more independently choose the load resistor values, as not all the bias current is flowing in the load resistors.

When all is said and done, I'll probably go back to using a simple cascoded 2SK170 in the first stage, as performance is adequate at the low signal levels there. However, the use of a heavily biased MOSFET and the extra current source appears to have a big advantage at higher signal levels, with about 1/10 the THD of a simple JFET source follower, according to simulation. This time around, though, I was feeling cantankerous and wanted to do the whole preamp with domestic FETs that could be purchased locally.

The schematic shows one channel and the common discrete regulator for both channels.
 

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ashok

Member
Paid Member
2002-06-06 4:43 am
3RS
my whole collection goes on a Hard drive. At Costco the other day I saw a 500 gig external HD

I always worry about the old saying " If your hard drive ai'nt broke it just about to !".

So I guesss all those who put all their music on a HDD will keep their original discs and not throw them out the window or dispose them ?

A friend I know gets around the HDD crash by sharing a copy of his drive with several close friends ( with music from other friends also ). That way he is sure that at least one good drive will be available to recopy if disaster strikes.

Cheers.
 

reshippie

Member
2007-08-17 12:20 am
ashok said:


I always worry about the old saying " If your hard drive ai'nt broke it just about to !".


With the price of hard drives these days, I go for the 2 for 1 model. Using a technique called RAID (Redundant Array of Inexpensive Drives) you can mirror all info across both drives. When 1 dies, simply replace that one and then the data syncs to the new one.

I know there are tools to let you do this under Linux (and other unix-y OSes) as well as Windows. I'm willing to bet Mac has something like that built in. Something to the effect of RAID-1, or mirroring.

To me, an extra $100-$150 is worth not ripping CDs again, or getting off the couch to change one. :)
 

anatech

Administrator
Paid Member
2004-06-06 8:31 pm
Georgetown, On
Hi reshippie,
Sadly, OS/2 Advanced Server 4 (more than 10 years ago) supported drive mirroring and multiple processors! It's taken u$soft this long to catch up.

Another technology from IBM OS/2 was the Journaled File System (JFS) available to server for E Business versions of OS/2 Warp 4. See this link or look at the IBM website. These were Unix offerings originally. I used these features and they delivered.

If I were someone who wanted high reliability in their system, I'd be looking at some flavor of Linux. Nothing for u$oft to break with an update. They are their own worst enemy and you are the victims.

-Chris
 
reshippie said:

I'm willing to bet Mac has something like that built in. Something to the effect of RAID-1, or mirroring.

Yes you are right - it is part of standard utilities under OS X - comes with a system.
I remember in the old days I was using a nifty app - Hard disk tool kit, with systems 6, 7, 8 and 9. I do not know if they still exists.
 
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