Since that is a prototype board the holes may not be plated through. If that is the case you need to solder both sides of the components where the hole serves as a via between layers.
Thanks Grimberg,
I did realize that while I was soldering the board and made sure that the components were soldered to the pad they were to conduct to and if it was possible I soldered both sides.
HINT on the build. Pop your heatsink on right away. Capacitors get in the way of screwdrivers 🙂
Uriah
I did realize that while I was soldering the board and made sure that the components were soldered to the pad they were to conduct to and if it was possible I soldered both sides.
HINT on the build. Pop your heatsink on right away. Capacitors get in the way of screwdrivers 🙂
Uriah
Just running a little checklist for anyone watching. LM318 and all caps are in properly. Rechecked all wiring to/from amp and it is connected in all cases correctly. LED is in correctly. All zeners and diodes are in correctly.. Just about everything else is bipolar. Oh man now I have to check resistances. What a pain 🙂
Uriah
Uriah
Resistors are fine. Maybe and hopefully the problem is inbetween the source and the amp. I will just wire a pot in there.
Uriah
Uriah
If you think the problem might be the preamp, swap the channels rather than use a pot. Much easier.
If the output relay engaging when you power it up? If not, check the two transistors for continuity between the pins. If you find a short, you have found the dead transistor.
If it is engaging, then we can think about it some more.
If the output relay engaging when you power it up? If not, check the two transistors for continuity between the pins. If you find a short, you have found the dead transistor.
If it is engaging, then we can think about it some more.
I swapped earlier. I will try testing transistors and I may have to replace the relay as I am not getting a click. LED comes on. But thats it.
Well we are decorating the tree so I have to get back to that. Hopefully I can try these fixes later tonight.
Uriah
Well we are decorating the tree so I have to get back to that. Hopefully I can try these fixes later tonight.
Uriah
Have you thought of re-doing the boards again?
May be keep the traces to one side and use a ground plane on top if it's going to be a double sided board
May be keep the traces to one side and use a ground plane on top if it's going to be a double sided board
No 🙂 The thought never crossed my mind. This is Mauro and Twisted Pear's design and not mine to change. It works, it just doesnt work right now. So I am investigating what might have gone wrong. Right now it appears a relay may be faulty.
Uriah
By the way, if anyone wants to know more about AndrewT's lightbulb safety test its also called a Poor Man's Variac and a great little intro to it is found here
http://antiqueradio.org/dimbulb.htm
Uriah
By the way, if anyone wants to know more about AndrewT's lightbulb safety test its also called a Poor Man's Variac and a great little intro to it is found here
http://antiqueradio.org/dimbulb.htm
Transistors are fine. Fired it up with potentiometer in line.
Still nothing but the LED. Guess we are on to the relay. I had my ear right up near it and no click.
By the way it takes a few seconds after power on for the LED to light up. Normal?
Uriah
Still nothing but the LED. Guess we are on to the relay. I had my ear right up near it and no click.
By the way it takes a few seconds after power on for the LED to light up. Normal?
Uriah
Replaced relay. AndrewT's safety circuit still in place. It lights up for a split second and then the LED comes on. No click from the new relay either. I left it on for about 15 seconds and put my finger on the LM3886. No heat. Turned it off. Going to bed.
Uriah
Uriah
BOARD WORKS! I am THRILLED 🙂
In an embarrassing turn of events I... well I'll leave out the details. Something to do with not enough voltage to the amp.
The GOOD NEWS is that I got sound tonight!
Now to get a proper preamp going to this thing which means simply rewiring the junker I threw together a few weeks ago that works on and off when its not shorting. Probably tomorrow I will rewire that thing Or maybe just finish the enclosure with dual 25k pots coming out the front.
Well I am really happy about this guys and glad to report that Peter and I will be getting the group buy under way in a few days. He is on a business trip and we want to verify a few end details before everything is solidified so that you all get a PERFECT kit but I can tell you right now the BOARD WORKS!
So, good night and I will probably update tomorrow once I get the pots wired in or my preamp redone.
Uriah
In an embarrassing turn of events I... well I'll leave out the details. Something to do with not enough voltage to the amp.
The GOOD NEWS is that I got sound tonight!
Now to get a proper preamp going to this thing which means simply rewiring the junker I threw together a few weeks ago that works on and off when its not shorting. Probably tomorrow I will rewire that thing Or maybe just finish the enclosure with dual 25k pots coming out the front.
Well I am really happy about this guys and glad to report that Peter and I will be getting the group buy under way in a few days. He is on a business trip and we want to verify a few end details before everything is solidified so that you all get a PERFECT kit but I can tell you right now the BOARD WORKS!
So, good night and I will probably update tomorrow once I get the pots wired in or my preamp redone.
Uriah
That's great news. You can sleep soundly tonight. Looking forward to more "dailey" updates.
Peace,
Tom E
Peace,
Tom E
I have to say it sounds, with only one channel going so far, really really really good. Mauro claims it sounds better than some class A amps. Well, who knows I have yet to finish my F5 so that comparison is a ways off for me, but right now Bruce Springsteen is in my basement and I get a private concert 🙂
That was the first improvement I noticed. His voice was definitely more 'real' than with my LM3886 'regular' chip amp, which I love dearly and is way more easy to build than this thing, and cheaper to.
I really like this amp for a few reasons. Obviously right now on the first ten minutes of real listening the voices are improved. I would like to add a roll off to the highs though. The thing is a beast. I have really really screwed with it and screwed up a few things that by all rights should have killed it. I smelled smoke 5 minutes before I got it all right and it is still playing well. It waits before turning on so that I dont get that 'bump.' I like that a lot. It has speaker protection. Some of you may know from my past mishaps that this is, in my case, a big bonus.
I used a safety circuit in all my testing and the circuit is in place right now. I will NEVER, I repeat NEVER build another amp without using it. It may have saved this baby several times from cooking or maybe the amps own circuitry would have saved it, but nevertheless the safety lightbulb in my poor mans variac has lit many times and the time I smelled smoke the lightbulb lit and either saved the amp or gave the amp time to save itself. I dont know which but I am grateful to AndrewT of DIYaudio for promoting this circuit in almost every other post when he is helping newbs or pros.
You can find that little gem here: http://www.antiqueradio.org/dimbulb.htm
That was the first improvement I noticed. His voice was definitely more 'real' than with my LM3886 'regular' chip amp, which I love dearly and is way more easy to build than this thing, and cheaper to.
I really like this amp for a few reasons. Obviously right now on the first ten minutes of real listening the voices are improved. I would like to add a roll off to the highs though. The thing is a beast. I have really really screwed with it and screwed up a few things that by all rights should have killed it. I smelled smoke 5 minutes before I got it all right and it is still playing well. It waits before turning on so that I dont get that 'bump.' I like that a lot. It has speaker protection. Some of you may know from my past mishaps that this is, in my case, a big bonus.
I used a safety circuit in all my testing and the circuit is in place right now. I will NEVER, I repeat NEVER build another amp without using it. It may have saved this baby several times from cooking or maybe the amps own circuitry would have saved it, but nevertheless the safety lightbulb in my poor mans variac has lit many times and the time I smelled smoke the lightbulb lit and either saved the amp or gave the amp time to save itself. I dont know which but I am grateful to AndrewT of DIYaudio for promoting this circuit in almost every other post when he is helping newbs or pros.
You can find that little gem here: http://www.antiqueradio.org/dimbulb.htm
Wowww!!! 😱 That's very encouraging comments! You're making me so impatient now to receive my boards and try it myslef. 
Jcon-jcon2 said:
I asked this same question....
Apparently the group buy is closed- I'm in the same boat as you (but a couple of days ahead in line) so we are out of luck this time around unless somebody 'on the list' doesn't follow through with their purchase.
It does look like a nice project, doesn't it?
Cheers
John
Judging of the human nature here, it's most likely that more than one has signed up for more boards than needed => just wait in see. 
Judging from the low number of responses so far I am thinking Peranders is right 🙂 You guys may be in luck! We will soon see.
Peter gets back from his business trip in 2 days and then we will hammer out whatever the last things are that we need to, well, hammer out.
Uriah
Peter gets back from his business trip in 2 days and then we will hammer out whatever the last things are that we need to, well, hammer out.
Uriah
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