I'm not sure why you would want XLR connectors for this amp, but, if you do, Vampire makes a better plug than Neutrik. Believe me, I've listened to them and inspected them with a magnifier. Vampire is better, without a doubt. I'm not sure they offer a jack for chassis mounting. I don't know how Neutrik became the standard, but that's what everyone uses. They're good quality and will work fine, but they're simply not the best.
Apex Jr offers some cheaply made parts at a low price. If that's what interests you after all your hard work and expense, go ahead and compromise performance to save a few bucks.
Regarding higher price and "snake oil": the two factors are not directly coupled. Some things that cost more are worth more in that they do sound better. If you haven't figured that out by building this amp compared to the low cost initial offering, then nothing I can write here will persuade you.
The best aspect of DIY is being able to ultimately control the quality of your equipment. If you want it to be the best you can make it, you will need to spend more money. The most expensive parts are not always the ones that sound the best, but there is a very strong correlation between cost and performance. A $1.50 Chinese jack will most likely not sound as good as a $12 copper base jack. Of course, it is your choice to make, but there is a difference. More money does not necessarily buy mere "snake oil", unless you cannot hear or don't care about that difference.
If you're more interested in a pretty case than the sound that comes out of it, then by all means blow your dough on an expensive box and skimp on the parts that actually improve what you're hearing. I am not suggesting you don't buy Uriah's nice looking chassis. But don't spend $165 on it and then try to save $20 by using crappy parts. Then you might as well buy a commercial product, because that's exactly what they do!
Peace,
Tom E
Apex Jr offers some cheaply made parts at a low price. If that's what interests you after all your hard work and expense, go ahead and compromise performance to save a few bucks.
Regarding higher price and "snake oil": the two factors are not directly coupled. Some things that cost more are worth more in that they do sound better. If you haven't figured that out by building this amp compared to the low cost initial offering, then nothing I can write here will persuade you.
The best aspect of DIY is being able to ultimately control the quality of your equipment. If you want it to be the best you can make it, you will need to spend more money. The most expensive parts are not always the ones that sound the best, but there is a very strong correlation between cost and performance. A $1.50 Chinese jack will most likely not sound as good as a $12 copper base jack. Of course, it is your choice to make, but there is a difference. More money does not necessarily buy mere "snake oil", unless you cannot hear or don't care about that difference.
If you're more interested in a pretty case than the sound that comes out of it, then by all means blow your dough on an expensive box and skimp on the parts that actually improve what you're hearing. I am not suggesting you don't buy Uriah's nice looking chassis. But don't spend $165 on it and then try to save $20 by using crappy parts. Then you might as well buy a commercial product, because that's exactly what they do!
Peace,
Tom E
1. I totally agree on both accounts. a) Why XLR's it's a single ended amp? b) Vampire makes some great products at reasonable prices.
2. Consistency and value over a long period. You can count on Neutrik to work as expected.
3. You get what you pay for but some items like RCA's can start off on the cheap side and be "upgraded" as funds allow. Where as PCB components are much more challenging to change out later to improve.
My next DIY project will be some high efficiency speakers so I thought it would make that job much easier if I used a Behringer DCX to model the crossover in the digital domain and then proceed to passive.
Maybe I am wrong,
rick
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I am not sure how I came across as an uber mizer, but I like to shop for value which is usually about 60-75% up the cost schedule. A good valued RCA connector could easily cost 12 -20 dollars. Those connectors Dario pointed out seemed to be a good value. Those connectors would have no snake oil attached. The sound is why we're doing it, right?
rick
For $20 you could go with top end RCAs...
connectors_rca_cardas
But yes the Neutriks are a GREAT value and will be better than "average" connectors.
EDIT: BTW I got the link on the bottom of THIS page so they are also a DIYAudio supporter!!
Rick,
I didn't mean to imply you're a miser, but you mentioned value and snake oil in the same sentence. In these forums, that frequently means the poster is not interested in more expensive parts because they believe the parts are more expensive for no good reason. At the parts level, there are very good reasons for something to cost more. At the level of, say, cables, I agree that higher cost can be pure marketing nonsense, or snake oil.
About connectors: you certainly can add XLR connectors on your amps, but you will need to connect them internally in single-ended mode, which is quite simple. That will enable you to use balanced line level equipment and cables, but the signal will be single-ended. I'm not sure building speakers with digital xover/EQ will translate directly to a proper passive xover. A correctly designed xover does more than simply separate highs from lows. Do more research about xover design before taking the plunge on that digital gizmo. Also, you'll need more than one stereo amp if you plan to trial a digital xover, as it filters the signal before the amp, not between the amp and speaker. Hence, you need an amp for each portion of the filtered signal and the appropriate driver(s).
Troy, you make an excellent point about being able to upgrade connectors after completing the build more easily than you can change circuit components. The only exception is C13, which can and should be changed until you find one you like more than any other. Cheap connectors will not ruin the sound of this amp, but better connectors will make it sound better. It's a good idea to initially build it as best you can, then upgrade as funds allow.
Peace,
Tom E
I didn't mean to imply you're a miser, but you mentioned value and snake oil in the same sentence. In these forums, that frequently means the poster is not interested in more expensive parts because they believe the parts are more expensive for no good reason. At the parts level, there are very good reasons for something to cost more. At the level of, say, cables, I agree that higher cost can be pure marketing nonsense, or snake oil.
About connectors: you certainly can add XLR connectors on your amps, but you will need to connect them internally in single-ended mode, which is quite simple. That will enable you to use balanced line level equipment and cables, but the signal will be single-ended. I'm not sure building speakers with digital xover/EQ will translate directly to a proper passive xover. A correctly designed xover does more than simply separate highs from lows. Do more research about xover design before taking the plunge on that digital gizmo. Also, you'll need more than one stereo amp if you plan to trial a digital xover, as it filters the signal before the amp, not between the amp and speaker. Hence, you need an amp for each portion of the filtered signal and the appropriate driver(s).
Troy, you make an excellent point about being able to upgrade connectors after completing the build more easily than you can change circuit components. The only exception is C13, which can and should be changed until you find one you like more than any other. Cheap connectors will not ruin the sound of this amp, but better connectors will make it sound better. It's a good idea to initially build it as best you can, then upgrade as funds allow.
Peace,
Tom E
Only slightly off topic, please be patient
I haven't found a simple way to get the balanced to single ended accomplished. The best choices I have come up with are shown in the following link from Jensen Transformers:
http://www.jensen-transformers.com/as/as012.pdf
Further info, especially Figure 3.2 is here:
http://www.jensen-transformers.com/an/an003.pdf
Elsewhere on their site, they say that the JT-10KB is the best choice where a bit of signal attenuation is desired. I probably fit here as I'd use the Behringer DCX which uses a digital volume control which means loss of signal fidelity. I'd prefer to keep that volume control as high as possible to avoid data loss. Anyway, the schematic shows grounds on the primary side of the transformer at the XLR connector and on the secondary side at the single ended side. Given this amp, in a case, has 3 different grounds, case, signal, and virtual, I am not sure what goes where.
If one were to use an input transformer, then is it proper to bypass the input cap (obligato) for the balanced input and still be safeguarded against DC? No input cap would be a plus. In this case, the lowest frequency I'd be looking to amplify would be around 50 hz or so with another amp, maybe a DIY class D (T), powering subs so I don't think the transformer is a real downer. Opinions appreciated.
Anyone have comments on getting balanced to single ended, methods to get there, or thoughts on this Jensen transformer technique? I am still trying to maximize this amps performance.
TIA,
rick
I haven't found a simple way to get the balanced to single ended accomplished. The best choices I have come up with are shown in the following link from Jensen Transformers:
http://www.jensen-transformers.com/as/as012.pdf
Further info, especially Figure 3.2 is here:
http://www.jensen-transformers.com/an/an003.pdf
Elsewhere on their site, they say that the JT-10KB is the best choice where a bit of signal attenuation is desired. I probably fit here as I'd use the Behringer DCX which uses a digital volume control which means loss of signal fidelity. I'd prefer to keep that volume control as high as possible to avoid data loss. Anyway, the schematic shows grounds on the primary side of the transformer at the XLR connector and on the secondary side at the single ended side. Given this amp, in a case, has 3 different grounds, case, signal, and virtual, I am not sure what goes where.
If one were to use an input transformer, then is it proper to bypass the input cap (obligato) for the balanced input and still be safeguarded against DC? No input cap would be a plus. In this case, the lowest frequency I'd be looking to amplify would be around 50 hz or so with another amp, maybe a DIY class D (T), powering subs so I don't think the transformer is a real downer. Opinions appreciated.
Anyone have comments on getting balanced to single ended, methods to get there, or thoughts on this Jensen transformer technique? I am still trying to maximize this amps performance.
TIA,
rick
Shielding
I am just about ready to start laying out the 'bits' in the case for my amp.
I am curious... I saw Lazarus quote above and thought that's a good idea! I'll do that.
Now I am wondering if a big aluminium heat sink actually has more shielding effect than the power supply caps would? In that case I would be better with toroids one side of the heat sink and amp boards the other?
I have a strip of suitable heat sink long enough to take two amp boards comfortably.
Does anyone have any thoughts on this?
I'm just thinking aloud....
Cheers
Bill
I am just about ready to start laying out the 'bits' in the case for my amp.
I am curious... I saw Lazarus quote above and thought that's a good idea! I'll do that.
Now I am wondering if a big aluminium heat sink actually has more shielding effect than the power supply caps would? In that case I would be better with toroids one side of the heat sink and amp boards the other?
I have a strip of suitable heat sink long enough to take two amp boards comfortably.
Does anyone have any thoughts on this?
I'm just thinking aloud....
Cheers
Bill
radio tells us that the screen must completely enclose the aerial to become effective, in either direction, transmit or receive.
The amplifier would need to be completely enclosed in the screen to attenuate radio signals (electrical radiation).
You are dealing here with magnetic radiation. The rules might be different, certainly the wavelengths are very different. The gaps allowed to stop 50Hz passing are quite enormous compared to the gap allowed to prevent 50MHz passing.
A partial barrier may be quite effective. Are you prepared to build two versions and tell us the results?
The amplifier would need to be completely enclosed in the screen to attenuate radio signals (electrical radiation).
You are dealing here with magnetic radiation. The rules might be different, certainly the wavelengths are very different. The gaps allowed to stop 50Hz passing are quite enormous compared to the gap allowed to prevent 50MHz passing.
A partial barrier may be quite effective. Are you prepared to build two versions and tell us the results?
I'm not sure what kind of noise you're concerned about shielding against. If it's noise from the traffo and AC, there is no need to take any extraordinary precautions. My amps are mounted only a couple inches away from the traffo, and they are stone silent. All that lies between the amps and their traffo is the power supply caps. You do not need to arrange heatsinks to block anything. In fact, having to route AC around heatsink, past the amplifier to the traffo may cause more noise from cabling than it helps avoid. Use the simplest, most direct routing of ALL internal wiring, especially signal input, and you need take no further precautions.
Attachments
This GB is finished.
Another may start up, but be prepared to wait.
This or it's sister thread may come sooner:
http://www.diyaudio.com/forums/chip-amps/175937-myref-revd-successor-revc.html#post2342433
Another may start up, but be prepared to wait.
This or it's sister thread may come sooner:
http://www.diyaudio.com/forums/chip-amps/175937-myref-revd-successor-revc.html#post2342433
I just wanted to say what a gem this amp turned out to be. The ref C biamping mono's have been going strong for a couple months now. I built them for my brother, both he and I are very happy with them.
I Want to say thanks to all the people who put a lot of hard work into the group buy, as well as to the people who spent a lot of time swapping parts, tuning the sound. The Ref C is just an awesome amplifier, It puts my "regular" chip amp to shame.
Thanks everyone,
Ben
I Want to say thanks to all the people who put a lot of hard work into the group buy, as well as to the people who spent a lot of time swapping parts, tuning the sound. The Ref C is just an awesome amplifier, It puts my "regular" chip amp to shame.
Thanks everyone,
Ben
Re... Shielding
Dear Andrew, Regi and Madisonears, thanks for your posts.
Helpful ideas, and comments! I wish I had the wherewithal two build two amps Andrew... but I can as Regi suggests try a few different layouts and watch for AC noise on a scope at the output.
Madison ears the simple practical advice is very welcome and sounds good. Nice looking amp you built there! Can you ID the cap you appear to be using across the mains switch?
They should be safety rated shouldn't they? I was looking for a suitable cap for 100V AC mains switches and getting confused by too much information on the intrawebular thingy.
I'm easily confused I fear!
Thanks again
Bill
Dear Andrew, Regi and Madisonears, thanks for your posts.
Helpful ideas, and comments! I wish I had the wherewithal two build two amps Andrew... but I can as Regi suggests try a few different layouts and watch for AC noise on a scope at the output.
Madison ears the simple practical advice is very welcome and sounds good. Nice looking amp you built there! Can you ID the cap you appear to be using across the mains switch?
They should be safety rated shouldn't they? I was looking for a suitable cap for 100V AC mains switches and getting confused by too much information on the intrawebular thingy.
I'm easily confused I fear!
Thanks again
Bill
I bought a few kits at the beginning of this project with good intentions of building a multi-channel. At the same time I also started a new business which has consumed all of my time so I've made very little progress on the amp.
I know that I have a few kits and extra boards somewhere, just can't remember what. As much as I'd like to build the amp I simply don't have the time so there's no point in me keeping the kits. I'll dig them out later and let you know what is available.
I know that I have a few kits and extra boards somewhere, just can't remember what. As much as I'd like to build the amp I simply don't have the time so there's no point in me keeping the kits. I'll dig them out later and let you know what is available.
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