| BrianGT |
| quote: | Originally posted by Peter Daniel
I guess Zobel discussion went already to far, so I created a separate thread for it: http://www.diyaudio.com/forums/show...&threadid=34130
Everybody interested in LM4780 board, please be assured that the board will feature a Zobel network. |
Thanks Peter.
--
Brian |
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| neutron7 |
Heres a quick drawing of an idea for "fake class A" using this kit in bridged mode. it does not waste power all the time or need an output capacitor.
I did not calculate the values of the resistors yet, because i was too lazy too look up the gain of the amp, and it may take some experimentation to get it "just right".
I am sure stuff like this has been done before, but i thought i should post my idea anyways.
if the exact same offset is applied to both the non inverted and inverted inputs then both amp outputs should have the same potential relative to each other, so there will be no DC on the speaker. That means no output capacitor. and no current passing.
of course it will have to be very carefully adjusted with the trim to get zero DC on output relative to each other.
I am not an EE , i just make things for DSP, which will not let the smoke go if you make a mistake:) so if there is any bad flaws in this design (besides failure modes, which i believe can be looked after in non obtrusive manner)
if the offset is half of the voltage that would give maximum output, (depending on gain) then you would have "pure class a" but at half of the maximum power of the amp.
I was thinking as a "failsafe" in case of failure of an amp or other bad thing . DC detector , but it just disconnects the +v on the offset circuit and it reverts to"normal" function.
another bonus of this is that there should be good power noise rejection, because the offset voltage will both change at the same time if there is any noise, so the relative difference will be almost nothing. that is why i did not go for a voltage reference rather than just the +v (also if the output power drops on loud passage the offset voltage will drop correspondingly so it is still half)
you might be better off with a EI type transformer If you try this, because the bottom half of the rail will hardly be used, and apparently if you load toroids asymmetrically it can lead to some problem (magnetizing of the core, something bad i forgot)
i could be comletely wrong on this though now i think about it, the rectifier supplies both halves of the power to both rails if it is center tapped, so if you have dual out transformer it might be better to set it up as center tapped, and use 1 bridge. |
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| motherone |
Peter & Brian,
I know it might not mean much from a board lurker, and not to drag things on, but thank you. It definitely shows that you look out for the best interests of the group.
You guys are class acts, and as a beginning audio do-it-yourselfer, your projects make it possible for someone who isn't completely confident in their skills to try out some great stuff. I'm not one for kits, but the PCB's definitely help me out.
Rest assured that I'm sure I'm not the only one on this board that appreciates both of your efforts!
Mike |
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| neutron7 |
| by the way, If you used the 2 boards bridged, how would the onboard zobel work? (if it gets put in) or would it have to be still hardwired if you chose to use one? |
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| jamart821 |
| quote: | Originally posted by motherone
Peter & Brian,
Rest assured that I'm sure I'm not the only one on this board that appreciates both of your efforts!
Mike |
Ditto. Most appreciative and grateful.
jamart |
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| BrianGT |
I am working on finalizing the boards, and will get prototypes made. If all goes well, I will start taking orders in a little over a week, and submit the order for the production boards.
--
Brian |
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| KT |
Hi Brian,
Will the Zobel pads be worked into the LM3875 boards as well, or are you just implementing them on the LM4780 boards?
Just curious.
Thanks,
KT |
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| BrianGT |
| quote: | Originally posted by KT
Hi Brian,
Will the Zobel pads be worked into the LM3875 boards as well, or are you just implementing them on the LM4780 boards?
Just curious.
Thanks,
KT |
I don't feel that it is nearly as big of an issue for the LM3875, since it is only a single channel, not 2 channels being paralleled. Since there are no output resistors, the Zobel could quite easily be attached to the binding posts for the LM3875, something that cannot be effectively with the current LM4780.
It is possible that a future version of the LM3875 will include the Zobel network, but not for now.
--
Brian |
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| BrianGT |
For the recent orders, all of the US ones are shipping out tomorrow (technically today), and half of the international ones are shipping out. I still need to fill out the customs forms and address labels for the other half, but they should go out the next day. US orders should all have received a Delivery Confirmation number.
As for this group order, it seems to have been quite a success with several finished amplifiers so far (see gallery ). I have been donating portions of the proceeds to diyaudio throughout the process, and have donated $500 thus far. I would like to encourage all group orders to be run like this, in order to help out diyAudio. Thank you to all who have participated.
For those who think that they missed out, I am still taking orders for PCB sets, and basic kits on my website:
http://www.BrianGT.com/order
I am hoping to get the rest of the components for the premium kits soon, but it has been quite a task, since I bought out all small inventories from multiple vendors to fill the first batch of orders, leaving everyone to face the 5-8 week leadtimes from the manufacturers.
--
Brian |
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| BrianGT |
| quote: | Originally posted by BrianGT
For the recent orders, all of the US ones are shipping out tomorrow (technically today), and half of the international ones are shipping out. I still need to fill out the customs forms and address labels for the other half, but they should go out the next day. US orders should all have received a Delivery Confirmation number.
As for this group order, it seems to have been quite a success with several finished amplifiers so far (see gallery ). I have been donating portions of the proceeds to diyaudio throughout the process, and have donated $500 thus far. I would like to encourage all group orders to be run like this, in order to help out diyAudio. Thank you to all who have participated.
For those who think that they missed out, I am still taking orders for PCB sets, and basic kits on my website:
http://www.BrianGT.com/order
I am hoping to get the rest of the components for the premium kits soon, but it has been quite a task, since I bought out all small inventories from multiple vendors to fill the first batch of orders, leaving everyone to face the 5-8 week leadtimes from the manufacturers.
|
This was supposed to be placed in the LM3875 thread, but I replied to the wrong thread. Sorry for the confusion. I would removed the previous post if I had caught it earlier. This is a reference to the latest batch of LM3875 kits that shipped out. Hopefully, by the end of next month, the first batch of LM4780 kits will have been shipped out. Currently, I am preparing to get prototype pcbs made to test out the design before production. I will post pictures when I get prototype pcbs.
--
Brian |
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| Razorfist |
Hi,
I emailed BrianGT about this already, but maybe some other people here can give their opinion on this too :)
For a first time (chip-)amp I would like to build one of the kits BrianGT distributes. They will be driving my 87dB diy speakers.
What would you choose, being most educational and foolproof ;)? This new 4780 kit or the 3875 kit?
I do have some soldering experience and recently built my own speakers, but no experience whatsoever on amps yet.
Thanks Razorfist |
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| BrianGT |
| quote: | Originally posted by Razorfist
I emailed BrianGT about this already, but maybe some other people here can give their opinion on this too :)
For a first time (chip-)amp I would like to build one of the kits BrianGT distributes. They will be driving my 87dB diy speakers.
What would you choose, being most educational and foolproof ;)? This new 4780 kit or the 3875 kit?
I do have some soldering experience and recently built my own speakers, but no experience whatsoever on amps yet.
|
Let me reiterate my response here for others. I am using the LM3875 gainclone amplifier with my < 90 dB efficient Seas Thor TL speakers (I think they are around 87dB), and I get plenty of power with them. I can turn it up to the point where it makes my ears hurt, without the amplifier clipping. (320VA 2x24vac transformer) It is also a much more proven design than the LM4780. The only hard part about the kit is creating a chassis, and wiring up the power supply (be careful with the AC). I have a manual for the LM3875 kit on my website:
http://www.BrianGT.com (I will add more to it someday when I am not busy)
I also haven't built a LM4780 amplifier yet, and am ordering prototypes soon to try it out, before doing a large order of pcbs.
It will be a month or so before the LM4780 kits start shipping out, since it will take a week to get prototype boards made, some time to test it, then another week to get production boards made.
My intention for the LM4780 is to drive the bottom end of an active crossover system, as this will allow me to use a more inefficient woofer and still match my mids and tweeter.
--
Brian |
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| Razorfist |
Thanks for the reply!
First I'm gonna subscribe to paypal and in the meantime wait for your experience on the new kit. |
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| Jonathan Z |
Being a not too technical newbie, Neutron7's thoughts on this topic seemed interesting. Can someone reply?
I presume another advantage of this would be faster transient response as it should double the slew rate. Is this correct?
Thanks! |
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| Alcaid |
| So, what's the current status on the LM4780 PCB? Have you implemented the Zobels? |
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| theChris |
about the zobels and ect...
every feature requires you place components and then route stuff. granted the board uses 2 sides but doesn't use ALL of both sides...
adding components beyond the caps will prevent clamp-mounting.
this board appears to be a minimalist board -- there are no 10uf or 0.1uf bypass caps, and no zobels.
also, can you phycially move a zobel and maintain good effectiveness? if you move the zobels too far, wouldn't you just defeat the purpose of them becuase there would be too much inductance. |
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| Peter Daniel |
| What do you mean by clamp mounting? Since this board is minimalist approach, the size is also minimal, you can't move Zobel too far;) |
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| chipco3434 |
| I thought this was a Zobel free zone? |
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| SQ Kid |
| hey, i'd be interested in 2 sets. building the parent's a home theater setup for their anniversary, and i have yet to get a sub/amp setup yet. this sounds like it would work (of course they'd be getting my old kenwood combo, this might be too much for them and i want a new sub :)) |
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| Tazzy |
| Think I'm interested in pcbs for 4 channels |
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| peranders |
| quote: | Originally posted by BrianGT
Let me reiterate my response here for others. I am using the LM3875 gainclone amplifier with my < 90 dB efficient Seas Thor TL speakers (I think they are around 87dB), and I get plenty of power with them. I can turn it up to the point where it makes my ears hurt, without the amplifier clipping. |
I have a rather cool VU-meter with 60 dB dymanics, from 0.001 to 100 W. The speakers are Martin Logan SL3 electrostatic ones with not huge efficiency. The power amp itself can deliver around 200 watts/8 ohms.
When I have the TV on, 0.01-1 W is normal. 10 W is nearly party level. 100W the neighors complains. You must multiply the power with 10 in order to get a real change in sound level. |
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| theChris |
| quote: | Originally posted by Peter Daniel
What do you mean by clamp mounting? Since this board is minimalist approach, the size is also minimal, you can't move Zobel too far;) |
i call it clamp mounting for lack of better words. i know for a fact that you've done it even. a metal plate or bar is used to clamp the IC to the heatsink, thus ensureing no tilting of the IC. obviously the 4780 wouldn't require this feature unless you wanted to easily isolate the IC from the heatsink -- the metal tabs on the IC touch the default mounting points, thus requireing extra hardware or nylon screws. i guess some insulative material could be moulded there, but its not my suggestion that you would ever think that it was truely safe.
oh, that reminds me -- brian, in my experience with mininal sized boards with this chip, i found that mounting the caps isn't just about where they are on the board, but where they are with respect to the IC mounting points. on my board, with caps in place, it took 30 minutes to mount the ICs because i counld't get any tools into place to mount the chip. even now it is marginal, though the amp works fine. |
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| Peter Daniel |
It would have been probably easier to remove caps, mount the chip and then mount the caps again.
With this board, I checked into the proper access for installing the mounting hardware, so I think it shouldn't present a problem.
As to the components beyond the caps, if they are flat on the PCB, I don't see how they would prevent using the clamping bar. I understand you are talking about zobel parts, and in this case a resistor can be closer to chip and capacitor further away, so it won't be in a way.
I'm not using clamp anymore. I don't like it's influence on a sound. |
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| theChris |
i meant if the bar was placed horizontally, it would hit the caps if the caps were placed by the heatsink... vertically placed clamping would work.
hmm, what influence did the clamp have on sound? |
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| Peter Daniel |
I'm not saying it is for sure, but it seems like the sound becomes less open, more dull, simply, not enough air.;)
I would go with just 2 screws, no clamp, although with chip that wide, the clamp has a definite appeal. |
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| jamesjung21 |
I'm sick of waiting for this group order to happen... :dead:
Brian & Peter Daniel, what's the current status of this group order?:sleep: |
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| cdoggy81 |
jeeezzz, take a powder dude........
I would rather wait till the cows come home & get good boards than rush into something. Last time I checked they were doing me a favor since I can't design these. |
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| BrianGT |
| quote: | Originally posted by jamesjung21
I'm sick of waiting for this group order to happen... :dead:
Brian & Peter Daniel, what's the current status of this group order?:sleep: |
I am still finalizing the details of the order, due the the recent discussions over the zobel network. I should have the revised board done soon, and will post pictures of it here.
--
Brian |
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| rabstg |
Hey Brian-
Nice of you for being polite but don't let the pressure from one individual influence or compromise your work.
The majority appreciate the work and effort you have done.
If someone is in a hurry they can design/commission their own boards.
You are doing top notch work and offering phenomenal products virtually free. I can wait and be patient for that!
Thanks again for fabulous products,
Troy
ps- I'm eager for the new ones also, but I would never rush the design out of impatience.
Edit: spelling. |
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| BrianGT |
| quote: | Originally posted by rabstg
Nice of you for being polite but don't let the pressure from one individual influence or compromise your work.
The majority appreciate the work and effort you have done.
If someone is in a hurry they can design/commission their own boards.
You are doing top notch work and offering phenomenal products virtually free. I can wait and be patient for that!
Thanks again for fabulous products,
|
I am glad that you enjoy the products. I am not rushing the LM4780 boards. I am going to get prototypes made first, and try out the design.
I am actually anxious myself to get some boards in my hands to try out. The design has been looked over many times, and is almost ready for ordering prototypes.
There is also a revised LM3875 layout, which I will get made soon, as I am out of pcbs currently (all past orders have been fulfilled)
--
Brian |
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| rabstg |
By the way, I see you(Brian) and Peter working allot on these together.
I don't want to exclude/ignore Peter’s VERY hard work but being somewhat new to this forum I don't know the working relationship between you two.
I have also come to respect and trust Peter's judgment quite quickly after seeing his work here too!
Thanks Peter!
Troy |
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| BrianGT |
| quote: | Originally posted by rabstg
By the way, I see you(Brian) and Peter working allot on these together.
I don't want to exclude/ignore Peter’s VERY hard work but being somewhat new to this forum I don't know the working relationship between you two.
I have also come to respect and trust Peter's judgment quite quickly after seeing his work here too!
Thanks Peter!
Troy |
Peter and I have been passing ideas back and forth for a few months with these designs. Before his input, I initially wanted to make a simple gainclone pcb, since I had a few friends who wanted gainclones, and I didn't want to wire them point-to-point for them. I showed him my initial pcb, and he helped me refine it into what it is now.
--
Brian |
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| Peter Daniel |
| A member, who is modest enough (to pass Fred's scrutinity) sent me those pics, giving me permission to post them (in case I liked them). Well, it's a total opposite to what we try to achieve here, yet I find the layout and design quite interesting and carried out very well. It is a full implementation of LM4780, without any shortcuts taken. |
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| Peter Daniel |
Here's another pic. Now, that's the board one can be proud of;)
Well done, Upupa Epops. |
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| peranders |
Very nice work indeed, Upupa Epops. :up: :nod:
You have used my "industrial" approach, using "normal" parts. :up:
I especially like those Wago 256 connectors which creates the necessary pain (sharp springs into the wire) to the music, a real blues connector! I also like the nice looking coils, nice craftmanship. |
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| rabstg |
Hey Peter-
In your post you stated the following:
"Well, it's a total opposite to what we try to achieve here"
May I ask you to throw out a few reasons for that statement?
Is it size, component type/brand, circuit layout....?
It does look stunningly meticulous, but also somewhat complicated. There are a lot of components on the board for a "chip amp".
Thanks in advance,
Troy |
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| Peter Daniel |
| quote: | Originally posted by rabstg
Hey Peter-
In your post you stated the following:
"Well, it's a total opposite to what we try to achieve here"
May I ask you to throw out a few reasons for that statement?
Is it size, component type/brand, circuit layout....?
It does look stunningly meticulous, but also somewhat complicated. There are a lot of components on the board for a "chip amp".
|
"Circuit is quite universal, you can connect it in all modes ( stereo, bridge, parallel and two modules as parallel / bridge for output power 200 W ). It has DC protection, delayed output and on input connector is taked + / - 15 V for prewiew stages ( electronic crossover, preamp etc. )"
The design that we try to finalise in this thread is aimed at minimalistic approach. That means only 1000u caps are used (as to me they sound better than 5,600 I tried already, and I wouldn't even dare to go with 22,000;)). Also, we concentrate on basic implementation, so no stereo or bridged mode, just parallel. Stereo can be still achieved, but components have to be raised from the board.
We use separate board for rectifiers, and we will provide the option to mount it piggy back style, directly attached to the amp's board. This reduces the size and allows more creativity with chassis design and most any style and chassis box can be used.
We also prefer to use more exotic components (as regretably over the months, they still prove to provide better sound than your military grade stuff) and direct connection of wires to the board. Although those fancy connectors look nice, direct solder joint certainly isn't any worse.
We not concentrate on fuses and output protection, leaving this option to end user. I also don't want to be limited by a heatsink choice as with this amps I prefer to use the chassis wall as heat disipating surface.
So basically the design philosophy is completely different, and I can't say that one is necessary better than other, it just brings different results;) |
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| carlosfm |
| quote: | Originally posted by BrianGT
I am still finalizing the details of the order, due the the recent discussions over the zobel network. I should have the revised board done soon, and will post pictures of it here.
--
Brian |
Brian, what's the final conclusion of that zobel network discussion?
My suggestion of two paralleled 0.47 ohm resistors in series with the output?:cool:
BTW Peter sent me a board, very nice.
Thanks, Peter.:angel: |
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| karma |
minimalistic approach is good:D i to have been playing around with caps and i find it does change the sound allot;)
but i am still learning i find it easyer to fix than to build:)
i look forward to geting the lm4780 pcbs:smash: :smash: :smash: :drink: |
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| Alcaid |
What about the bridging board, how is that going?
I've drawn one quickly, but I'm not sure about the decoupling. The datasheet doesn't mention it, and on the drawings, they only have 1uF(doesn't mention if it's electrolytic, film or tantalum). On this PCB I have put 100nF ceramics and 120uF elecrolytics. No PSU on the PCB.
Wouldn't it be a good idea to implement the PSU for this one on the rectifying bridge boards?
But how are we going to get the +/-18V? By using adjustable regulators like LM3x7, linear regulators like LM7x18, zener, series resistors or anything else? |
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| Peter Daniel |
| quote: | Originally posted by Alcaid
Wouldn't it be a good idea to implement the PSU for this one on the rectifying bridge boards?
But how are we going to get the +/-18V? By using adjustable regulators like LM3x7, linear regulators like LM7x18, zener, series resistors or anything else? |
I would be tempted to get the supply voltage from filter capacitors on amp's board (1000u). All you need then is regulators on a bridging board, providing +/-15V and some small bypass caps after regulators (10-100u would be fine). I would use the low dropout type reg, I mentioned somwhere else on the forum.
The connection points on bridging board should match connection points on amops boards (to create compact module). |
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| peranders |
| quote: | Originally posted by Peter Daniel
Here's another pic. Now, that's the board one can be proud of;)
Well done, Upupa Epops. |
His excellent piece of work can be downloaded here
It's only schematics and pcb layout, partslist will come. |
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| joensd |
| quote: | | Here's another pic. Now, that's the board one can be proud of |
Although I rather like simplisitc approaches the board looks really well designed.
Only thing that I don´t like is the position of the heatsink, the weight and the actual size causing a lot of stress on the PCB.
(Even on the pictures you can see it´s bend)
Working in the repair business and knowing that these chips are almost indestructable I´d almost bet my butX on what´s defect first...
You´d at least have to screw the PCB where the heatsink sits with more screws and the heatsink itself to the chassis although I´d rather plan it different or use flanged heatsinks and mount the PCB to the heatsink, not the other way round. |
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| Upupa Epops |
| To joensd : If you look below this heatsink, you will see there 6 holes :cool: . This profile is standard 100*100*40 mm. If you turn it 90 degrees, you can use all holes. Also as heatsink you can use an " U " profile, square pipe or " jackel " pipe. All this heatsinks you can on oposite side screw on to cassis or another bigger heatsink. Belive me, I was thinking about honestly :cool: and this amp is quite universal. |
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| peranders |
| quote: | Originally posted by joensd
Only thing that I don´t like is the position of the heatsink, the weight and the actual size causing a lot of stress on the PCB.
(Even on the pictures you can see it´s bend) |
The biggest stress at his board is caused by the eminent Wago connectors when you connect. These new Wago's with levers reduces the bending forces a lot. If you use Wago 236 without levers and use a screwdriver you will create huge stress and even huger stress if you have SMD parts. No, this rather small board can take this heatsink if the pcb is not mobile, at home like. |
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| joensd |
| quote: | | To joensd : If you look below this heatsink, you will see there 6 holes |
I didn´t have a look at P-A´s pdf-file that´s why I obviously haven´t seen the 2 screws going through the heatsink.
That´s what I meant with attaching the heatsink to the chassis.
2 screws through the chassis, PCB and heatsink which should be enough to take any stress from the PCB.
Congratulation on a job well done.
What do you think about your project and the chips used?
Any comparisons with discrete amps?
Regards
Jens |
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| Upupa Epops |
| To joensd : If you can and some of others guys too, I can write about this project more, but I mean, that should be better do it on new thread, 'cos this is Brian's battlefield ;) , isn't truth ? |
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| peranders |
| quote: | Originally posted by Upupa Epops
To joensd : If you can and some of others guys too, I can write about this project more, but I mean, that should be better do it on new thread, 'cos this is Brian's battlefield ;) , isn't truth ? |
Check here
http://www.diyaudio.com/forums/show...1485#post411485 |
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| tool49 |
Hi, I just wanted to know if BrianGT had had a chance to evaluate the prototypes of the board yet. Is there an ETA for the final boards?
Thanks,
Sébastien |
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| karma |
| last time i asked a few day's ago he was ordering em the prototypes that is brian and peter are still working on it;) |
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| agent.5 |
Brian,
any update on this project? Is there any plan to incorporate Nelson Pass's super symmetry GC into the schematic? |
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| BrianGT |
| quote: | Originally posted by agent.5
Brian,
any update on this project? Is there any plan to incorporate Nelson Pass's super symmetry GC into the schematic? |
There are no plans to incorporate NP's SuSy stuff into the GC, as it is patented technology. I wouldn't want to infringe upon his patent. It is also an unproven design, that so far, only looks good on paper.
Here is a screenshot of the current layout, which I still have delayed making the prototypes, as I have been busy with the LM3875 kits. I will work hard to get the prototype boards ready to order tomorrow.
--
Brian |
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| kestrel200 |
| quote: | Originally posted by BrianGT
There are no plans to incorporate NP's SuSy stuff into the GC, as it is patented technology. I wouldn't want to infringe upon his patent. It is also an unproven design, that so far, only looks good on paper.
Here is a screenshot of the current layout, which I still have delayed making the prototypes, as I have been busy with the LM3875 kits. I will work hard to get the prototype boards ready to order tomorrow.
--
Brian |
Brian,
Any progress on these? |
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| karma |
| :yinyang: :whacko: :magnify: |
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| jmateus |
Just a question:
Are the boards ready to order?:bawling: |
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| BrianGT |
Sorry for the long delay. I have been really busy. I just finished buying my first house last week, and have been busy with this and mailing out LM3875 kits over the last couple of months. I have the board files ready to go for ordering prototypes, and haven't mailed them out yet. I will do this very soon, and once I verify that the boards work good, I will order the production boards. Another reason for the delay is that I had been planning to submit the board files for both the tda1543 dac and LM4780 at the same time, and got delayed with that project as well.
I will try hard to make these kits a reality soon.
--
Brian |
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| garbage |
no worries Brian.
we'll wait patiently with anticipation. :)
btw, the dac, those are not kits? |
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| Peter Daniel |
No, those DACs are not kits yet, and I have serious doubts if they ever become kits, seeing the current attitude from certain forum members.
I developed that DAC over a period of one year and lots of tweaking went into final design. The components layout has been finalized, and the whole thing fits into 2 x 3 aluminum tubing as enclosure. I'm still uncertan about grounds layout, that's why we decided, with Brian, to go with 3 diffferent versions and compare which one is best.
Recently I had a chance to listen to AckdAck, and my prototype, although run from AC, was a fair contender (actually was preferred by the guy who brought me the AckdAck for comparison). |
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| fedde |
Interesting Peter! Keep up the good work ;-)
I also have plans to design a small DAC pcb. I want to try some ideas I have. Though I am not yet sure if it will ever see the light...
Fedde |
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| SS1 |
Hey Brian,
are you going to have battery powered dac kit version?
how's the performance for the gc lm3870 with the zobel? any chance i can get an upgrade deal (instead of the entire kit) only need the newer pcb and the resistor + cap for the zobel. i have the first gc kits.
:) |
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| BrianGT |
| quote: | Originally posted by SS1
Hey Brian,
are you going to have battery powered dac kit version?
how's the performance for the gc lm3870 with the zobel? any chance i can get an upgrade deal (instead of the entire kit) only need the newer pcb and the resistor + cap for the zobel. i have the first gc kits.
:) |
As for the dac, I have no solid plans to offer kits at this time. I will work with Peter and see how the prototypes work out. I also wouldn't want to upset Scott Nixon and offer a cheaper kit...
As for the LM3875 boards: Sure, this is possible. Drop me an e-mail. I will include the zobel components for free, along with the pcb set. The resistor will be a 3w resistor, as seen in the picture here:
http://www.diyaudio.com/forums/show...9711#post439711
so it won't fit the spacing, but it seems fine as it is in the picture of my board that I posted. In the future, I will offer the components as an upgrade to the kits, along with the 2w resistor.
As for the zobel performance, I am in the process of moving now, so I won't be able to do some comparisons for a couple of weeks, after I get settled in.
As for the LM4780 boards, I still haven't ordered them, but will work on it soon. I have been extremely busy with my job, shipping out the LM3875 kits, and I also just finished buying my first house, which has taken up a lot of my time over the last 2 months. I am moving into the house this weekend, so once I get settled in, I will start working on making this project a reality. house pics
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Brian |
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| Jamh |
| Nice views. Congradulations. |
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| chipco3434 |
Nice house.
Doesn't need any work at all.
Here's a little bit of advice for marital bliss. Don't sail any week long regattas during the moving days.
Please get back to 4780 and the DAC. :-)
Congratulations! |
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| rabstg |
Brian-
DOAH! When I moved into this house I set up my walkman with my Cambridge SoundWorks PC speakers for music while I worked.
I expect to see picture of a Gainclone set up before ANYTHING is moved in.....
Of course I moved us in while my wife stayed back and closed the sale on the old house. Be happy if she lets you have a "space" for your audio stuff. :cannotbe:
Troy
Edit: Oh and congrats on the new place. I think she would appreciate photo 87 being removed. The cheek rub(?) looks misleading. :-) |
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| SS1 |
hey brian,
your house is spaced out so you can play your music without disturbing your neighbors. or is it your neighbor disturbing your music. haha
what's with dac=scott? nevermind jk |
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| fcel |
Brian,
Congratulation on the new house. Are all those pictures of one house? I counted - there are more than 10 bedrooms!
By the way, what City and State do you live in? Somewhere on the East Coast? I'm not used to seeing houses with no fence. |
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| BrianGT |
| quote: | Originally posted by fcel
Brian,
Congratulation on the new house. Are all those pictures of one house? I counted - there are more than 10 bedrooms!
By the way, what City and State do you live in? Somewhere on the East Coast? I'm not used to seeing houses with no fence. |
Just north of Atlanta, GA. I don't see too many fences around here. The subdivision was started in 1997 for the phase I, and they are doing phase II now, with a few houses left.
For the house, there is one pretty big master bedroom (with the tray ceiling), and then 3 small bedrooms, once which I will make my office.
The basement will be my long term project, providing all the room that I need for my audio projects. :)
Anyway, got to get back to packing. I have a good deal of the small stuff moved already, and am renting a moving truck tomorrow for the big stuff.
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Brian |
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| Jim Karr |
Brian.....I'd be interested in at least one 4780 kit. I've built one of Rod Elliot's 3786 'Clones, and am putting together final touches on his P3A amp. Two solder bridges, an unsoldered leg on a component, and six blown fuses later, I've got replacement drivers on order and I'm ready to make it play.
I want to get my son Ben and some of his 4-H companions started on some diy projects. Your Gainclone kit would probably be perfect, due to your excellent website instruction.
Please let me know when the 4780's will be ready. My PayPal account is waiting! :D |
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| planet10 |
| quote: | Originally posted by rabstg
I expect to see picture of a Gainclone set up before ANYTHING is moved in..... |
1st thing moved in and set up at a new place is the hifi!! Gotta have tunes.
dave |
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| BrianGT |
| quote: | Originally posted by planet10
1st thing moved in and set up at a new place is the hifi!! Gotta have tunes.
dave |
I actually let my friend borrow my Seas Thor TL speakers, and my gainclones for a week or so, while I am moving in. It will keep me from getting distracted with projects. I might hook up my other speakers and my old leach amp, which I still have here.
As for my first task, I am going to have to finish painting the inside of the house, as the previous owner painted all the walls an awful pink color. I have 2 bedrooms masked off, and ready to go, and another room painted. The hardest part will be painting the room with the 20+ ft tall ceilings, which painters quoted me $1500 to just paint the 2 areas with the tall ceilings (http://sites.darg.net/mere/House/house_059). I found a friend who would let me borrow scaffolding for free, and my parents found me a $500 pickup truck (late 80s ford f150), so I figured that I would try to do it myself :) It will cost me about the same, including the pickup truck and 6 months insurance, which will help me out with my other projects.
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Brian |
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| rabstg |
Brian-
So that was your WRX in the driveway...
STi?
Nice car.
Troy |
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| cjd |
First thing I thought... that house needs some color! You painting it all boring white(ish)?
Congrats on the purchase though. You have kids to fill up all those rooms?!
C |
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| jajabin |
Brian-
Is the LM4780 group buy finish yet?
Can I place order now?
Thanks
Wing |
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| pinkmouse |
| I think my entire 2 bedroomed house would fit in your garage...:) |
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| BrianGT |
Had a long weekend of moving, and almost everything is moved out of my old apartment except for the internet router and my laptop.
| quote: | Originally posted by rabstg
So that was your WRX in the driveway...
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Nope, that is my wife's car. I am still driving my 1998 Honda Civic CX hatchback, which I will keep on driving for quite a while. My wife's car is a 2004 regular WRX. It is a fun car, but she doesn't let me drive it too often.
| quote: | Originally posted by cjd
First thing I thought... that house needs some color! You painting it all boring white(ish)?
Congrats on the purchase though. You have kids to fill up all those rooms?! |
Nope, no kids. I just turned 24 yesterday, and don't foresee having kids for quite a while. Being married with dual income and no kids seems like a good choice for a while. As for the colors, the walls are currently a pinkish-white color, and we painted one room bluish-gray, and picked out a sandstone color, and a light brown-grey color for other rooms.
| quote: | Originally posted by jajabin
Brian-
Is the LM4780 group buy finish yet?
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The order is not finished yet, and I will post details in this thread when it is ready.
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Brian |
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| rabstg |
Brian-
Woman in a WRX, nice...
Married two children and one income... I can't complain, but I remeber dual income and no kids. It was a life time ago for me, I suggest you not rush it.
I have a similar entry way in my home that is still white. Been 3.5 yrs now and every other room in the house has been painted. Good choice on the scafolding and getting it done quickly.
Congrats and good luck on the home,
Troy |
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| kestrel200 |
Brian,
Is this project still alive? I'll be in Atlanta 10-18 Sept. Any chance you'll be selling them by then and if so would it be possible I could pick some up from you? I built a 4 channel amp using your boards now I'd like to try the LM4780s.
Mike |
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| SheldonD |
Brian/Peter:
What is the status of this project?
This has been asked a number of times by a number of different people but there has been only deafening silence in reply.
I know Brian was going to get some PCBs made, and I know he has had a lot on his plate in the last several months, but perhaps I missed it but have not heard anything since early June or so.
Thanks |
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| Philo |
| Easy guys. Peter and Brian both have lives and families outside this forum. Brian now has a new handicap, er... wife, a new house and a relatively new job that he has to schedule around his free time :D . They'll get to it as soon as they can. You can always P2P their layout until then. It is doable with this chip, believe it or not. |
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| wytco0 |
I think this is a case where we have to draw our own conclusions. I am sure Brian and Peter are both very busy and have proper lives unlike some of us (Me!). However they both use these forums frequently and I think they have both posted today.
The fact that they have not answered questions about this project, despite being asked on several occasions, has led me to the conclusion that they have deliberately chosen not to answer these questions, and I would guess that they are working on it as commercial project. In some ways this is understandable following the fuss about commercial project earlier.
What I do not understand is why they don't just say so. A short comment saying whats happening would be very easy and whatever they have chosen to do is completely their choice, I don't have any complaints they have already produced some great stuff that I and many other have benefited from. After all this thread was started by Brian :) |
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| Peter Daniel |
Sorry for not answering. As you know, Brian takes care of ordering the boards. I was talking with him last week over the phone and we decided that this should be taken care of as soon as possible.
You should see something coming out of it pretty soon. |
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| SheldonD |
Peter:
Thank you for the update.
The concern is not to rush you and/or Brian but simply to find out if it was a dead project or not. People can then decide what they want to do.
Now that it is not dead we can wait, for as long as is needed.
Thank you again |
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| Peter Daniel |
| Now that some of you are showing that the interest in that project didn't die either, I will make it my priority that it will see the light of a day;) |
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| kestrel200 |
Thaks Peter! I for one am happy to hear that the project will see the light of day and will wait patiently to place my order(s).
Mike |
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| bzdang |
| Me too, waiting patiently, still interested, have a new speaker design to try it with. |
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| karma |
| same here im Sitting on a hand full of em :D would like to see if thay sound as good as thay look;) |
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| brentw |
I too am waiting as hundreds probably are :)
If you are board waiting and haven't heard what the LM3886 sounds like then do what I did and jam one into on of Brian's LM3875 boards. The pinout of the chips is not that different. I only had to cut one trace on the board with a utility blade. Simple if you compare the pinouts of the two chips at the National.com site. I even unsoldered a chip and put in a new one so changing chips is posible if you want to try it bad enough.
The only thing new you have to know is that there is a mute pin. Put a 68K to 10K resistor from the Mute pin to V- to keep the mute off.
By defalt the mute is on.
How does it sound? Very different! Currently I like it more then the LM3875 and that is after a couple days of breakin. I would say LM3886 has more power and is quicker, the bass seems the same. My speakers are weak in the bass, so I may not be a good judge of bass.
Since I found a big diffence between these two chips I am wondering what the rest of the chips sounds like.
When multi-amping speakers one chip may do one frequency range better then another. Giving us even more DIY control over the music we hear.
For those who have heard the LM4780 how does it sound compared to the LM3875?
Can anyone describe how all the chips sound? Sorry I had to ask on the off chance that someone knows and is willing to share. |
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| rabstg |
Hey brentw-
I have a handful of the Alesis amp modules Steve @ Apex.jr was selling for $5!!
Those have an LM 3886 and an LM 3876 crossed over at 1.5K with a 48 dB(not a typo !!) electronic crossover. All SMD components.
60 wpc for bass/mid, 40 wpc for tweeter. I made a set of self powered surround speakers, 6.5" two way, with some and they work really well.
I will be changing another sets x-over freq to about 100 Hz and making a sat/sub computer speaker shortly.
Best of luck on your project,
Troy |
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| tool49 |
| quote: | | Now that some of you are showing that the interest in that project didn't die either, I will make it my priority that it will see the light of a day |
Hi Peter, do you have a timeframe established for this project?
Thanks,
Sébastien |
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| Peter Daniel |
Let's say I would be really happy to see some number of those boards (either beta or prototype version) going into production early next week.
I was talking to Brian, and he also seems to be keen on the idea ;) |
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| bg40403 |
| Lest there be any doubt as to the interest in this project, may we PROVIDE a show of hands of those interested? :up: :up: :up: :up: :up: |
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| BrianGT |
Alright, I will work with Peter to make this project a reality.
I am considering doing a beta run of 25 boards or less, relatively soon.
Sorry for the long delay with this project. I didn't imagine that I would be so busy with the rest of the stuff in my life for the last 4 months, new house, new married life, along with keeping busy with my full-time job. I am finally getting settled in my house, and will put effort into this project again.
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Brian |
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| JoeBob |
| Quick question, there are still 3875 pcbs left, right? I was thinking of picking up a few. |
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| Peter Daniel |
| quote: | Originally posted by JoeBob
Quick question, there are still 3875 pcbs left, right? I was thinking of picking up a few. |
Yes, they are still available. |
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