VER2923 looks like it'll work beautifully - it's through hole, and it's deliciously overkill. Check out the L versus frequency curve:
http://www.coilcraft.com/images/ver2923c.gif
http://www.coilcraft.com/images/ver2923c.gif
How so? The more you start separating grounds from each other, the more likely you'll create potential differences between the various different grounds.
Separating audio negative (ground in unbalanced systems) from the board ground on the existing design created enough frustration for people.
Ask Lo_Tse if he used metal standoffs with your ampboard and what happened when he did with two PBTL ampboards in same enclosure with metal standoffs and SMPS powersupply. He can tell you first hand. others might tell you you get free groundloop.
There is potential difference front side pcb and backside pcb too btw, reason why some designers claim neatly looking classd ampboard with connections on each end can not be good. Going real compact like some do is one solution for that classd problem probably
*yawn*... was up late last night working on the PBTL Wiener. Started with the stereo design, ripped out the left channel input. The right hand 'input' side of the board looks great now.
I'm hoping to keep the same 5x10 card dimensions, and keep all the same test points in the same locations allowing me to use my existing bed of nails test jig to test everything. But damn, the VER2933's are huge
Two VER2933s take up the entire area of the existing output filter, leaving me no room to place the output C's.
I might go looking through the Wurth/etc catalogs for comparable inductors that are still way overkill but slightly smaller, or if I keep the Coilcrafts the card will probably end up being 6x10cm. Got a bunch of drywall to do tonight but I'll get back at it on the weekend.
I'm hoping to keep the same 5x10 card dimensions, and keep all the same test points in the same locations allowing me to use my existing bed of nails test jig to test everything. But damn, the VER2933's are huge
Two VER2933s take up the entire area of the existing output filter, leaving me no room to place the output C's.I might go looking through the Wurth/etc catalogs for comparable inductors that are still way overkill but slightly smaller, or if I keep the Coilcrafts the card will probably end up being 6x10cm. Got a bunch of drywall to do tonight but I'll get back at it on the weekend.
http://www.micrometalsarnoldpowdercores.com/upload/ArnoldDesigns.exe.zip
Fluxsan FS-106060-2 core with thick litz wire ...
Fluxsan FS-106060-2 core with thick litz wire ...
*yawn*... was up late last night working on the PBTL Wiener. Started with the stereo design, ripped out the left channel input. The right hand 'input' side of the board looks great now.
I'm hoping to keep the same 5x10 card dimensions, and keep all the same test points in the same locations allowing me to use my existing bed of nails test jig to test everything. But damn, the VER2933's are huge
I might go looking through the Wurth/etc catalogs for comparable inductors that are still way overkill but slightly smaller, or if I keep the Coilcrafts the card will probably end up being 6x10cm. Got a bunch of drywall to do tonight but I'll get back at it on the weekend.
Any plans of making more BTL stereo amps? Some of my friends are impressed with the first version, and are waiting for the same to be made available again. Listening to Genesis' remastered "Lamb Lies Down on Broadway," and the sound is so three dimensional.
Yeah, I'll keep making the stereo amp.
Might make a small change - changing the 30K resistors to ground on the negative inputs to 22 ohms or so. This should get rid of the whole having to strap the negative to ground thing, while still providing a tiny bit of common mode rejection.
Spent the weekend hanging 28 sheets of drywall, I'll put some good hours into this project in a few days or so.
Might make a small change - changing the 30K resistors to ground on the negative inputs to 22 ohms or so. This should get rid of the whole having to strap the negative to ground thing, while still providing a tiny bit of common mode rejection.
Spent the weekend hanging 28 sheets of drywall, I'll put some good hours into this project in a few days or so.
I understand what you speak of!I don't mind hanging drywall at all. It's the whole plastering thing I despise, and that's why I get someone else to do it
I finished up my office/media room last summer, and while I had hung all the DW, I was wise enough to know the limitation of my 'weekend-warrior' skills. I hired a local DW contractor to do the mudding, corner bead, and taping. It came out much, much better than I could have ever done. I was/am a happy camper with the job and the finished project now.I have done enough taping to know better.
The trick and not too many use it because it is quick set, is to use Duarbond 90 for the first coat over the self adhesive fibre tape/corner bead etc. If you put too much on you're a rookie because it is hard to sand it, I chisle it if i screw up. Follow by sheetrock 90 = no cracks, popped screws, unless you get an earthquake like in "San Andreas" movie we saw last night
I have since moved on to bodywork on my '95 Chev 4x4 that I am now renaming my 3M GM, for all the fibreglass holding that strong GM steel from deteriorating
Short strand fibreglass resin is like Durabond 90 = Tough as steel
Happy sanding.
The trick and not too many use it because it is quick set, is to use Duarbond 90 for the first coat over the self adhesive fibre tape/corner bead etc. If you put too much on you're a rookie because it is hard to sand it, I chisle it if i screw up. Follow by sheetrock 90 = no cracks, popped screws, unless you get an earthquake like in "San Andreas" movie we saw last night
I have since moved on to bodywork on my '95 Chev 4x4 that I am now renaming my 3M GM, for all the fibreglass holding that strong GM steel from deteriorating
Short strand fibreglass resin is like Durabond 90 = Tough as steel
Happy sanding.
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Having lived with this amp for a number of weeks it seemed like a good time to give a brief review.
The short version: this is a really fine sounding and behaving amp that is worth the premium over Chinese boards.
I have been consistently impressed with the quality of this amp from the get go. It is quiet on turn on and turn off. I hear no hiss when placing my ear next to the tweeter. It runs cool.
In terms of sound quality, two things stand out most. First is that the bass is both strong and detailed. It is very easy to pick out bass lines as individual notes. I am using the amp on my three-season porch, which could be of firmer construction. It is very noticeable to me that the amp is making the room shake in a way that previous versions did not.
Secondly, the amp seems very dynamic. On more than a few occasions sudden increases in volume surprised not only me, but my cats, who shot me the hairy eyeball in the way only a cat can do. The amp seems very fast.
I have played with switching frequencies, but not gain. It is still at 26db gain.
To my ear the amp sounds best in the 500/600 khz modes. I need to play with the higher switching frequencies. My non-scientific impression is that the treble sounds more natural at lower frequencies.
Would I buy another or recommend it to a friend? Yes and without hesitation.
Thanks to Gary for producing such a fine amp.
The short version: this is a really fine sounding and behaving amp that is worth the premium over Chinese boards.
I have been consistently impressed with the quality of this amp from the get go. It is quiet on turn on and turn off. I hear no hiss when placing my ear next to the tweeter. It runs cool.
In terms of sound quality, two things stand out most. First is that the bass is both strong and detailed. It is very easy to pick out bass lines as individual notes. I am using the amp on my three-season porch, which could be of firmer construction. It is very noticeable to me that the amp is making the room shake in a way that previous versions did not.
Secondly, the amp seems very dynamic. On more than a few occasions sudden increases in volume surprised not only me, but my cats, who shot me the hairy eyeball in the way only a cat can do. The amp seems very fast.
I have played with switching frequencies, but not gain. It is still at 26db gain.
To my ear the amp sounds best in the 500/600 khz modes. I need to play with the higher switching frequencies. My non-scientific impression is that the treble sounds more natural at lower frequencies.
Would I buy another or recommend it to a friend? Yes and without hesitation.
Thanks to Gary for producing such a fine amp.
Supposedly the modulation switch has an effect on the THD content of the output of the amp. I can't recall from memory which mode (BD or 1SPW) has more THD. That THD as I have read is mostly even-order, which makes the amplifier sounds warmer. I haven't been able to observe this on my crappy speakers with the Wiener amp, but perhaps you may hear something ?
I couldn't recall hearing a difference between 500 to 600 khz for the modulation frequency.
Oh, and absolutely thanks to Gmarsh for his wonderful work. I am looking forward to the PBTL version.
Hammett: Thanks for the review!
PBTL board is in the queue. Drywall's mostly done, doing a side job right now for a Burning Man art project which I'll be clear of in a couple days, then I'm back on the next Wiener card. Rather than a monoblock, I've decided I'll do a "big wiener" stereo card with two PBTL TPA implementations on it.
Existing Wiener design will still be available. Just ordered a metal stencil from Elecrow for the existing PCB, gonna give the toaster oven reflow method a try this time around, thanks to bk856er for all the tips.
PBTL board is in the queue. Drywall's mostly done, doing a side job right now for a Burning Man art project which I'll be clear of in a couple days, then I'm back on the next Wiener card. Rather than a monoblock, I've decided I'll do a "big wiener" stereo card with two PBTL TPA implementations on it.
Existing Wiener design will still be available. Just ordered a metal stencil from Elecrow for the existing PCB, gonna give the toaster oven reflow method a try this time around, thanks to bk856er for all the tips.