Bottlehead Forum
Bottlehead Kits => Sublime Subwoofer Amplifier kit => Topic started by: benzxc on July 17, 2024, 06:51:47 AM
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So my build passed the voltage test and the LED lights are all working, and all connections appear to me solid, but there is no sound to the subwoofer at all, even when I crank up the volume and crossover on the sub amp.
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Photo
https://i.imgur.com/sEbt1eM.jpeg
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Are you using this Sublime with a Subette subwoofer? Have you tested the subwoofer with another amp to make sure it is working properly? That would probably be a good thing to verify before diving into the amp.
Also, the Sublime binding posts can be a little finicky. If you are using spade lugs on your speaker cable you might need to adjust the way they sit around the posts to make good contact with them.
The first thing to check in the amp is that all of the screw terminal connections are good. It is possible to have the wire in the hole in such a way that it isn't making good contact. You might just wiggle each connection a little bit to verify that they are all snug.
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Yes, I used the subette with a dayton plate amp with no issues. I checked all the screw terminal connections and all are solid. I might need to pull the whole thing apart and rebuild it because I can't find where the issue is. Thanks!
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Don't do that. A better approach is to use a little detective work. You said all the LEDs light up so it seems the circuit is working, and the wiring all looks good in the picture. So it is most likely an issue somewhere in the signal path. First try connecting the subwoofer up again and see if you hear a slight pop or tick when you turn the amp on. Let us know the result and then we will go to the next step.
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Did you get any whare with this amp?
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Thanks for the help. I've been super busy with life and have not yet followed doc's advice. Will let everyone know once I go fix it. Thanks again!
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Don't do that. A better approach is to use a little detective work. You said all the LEDs light up so it seems the circuit is working, and the wiring all looks good in the picture. So it is most likely an issue somewhere in the signal path. First try connecting the subwoofer up again and see if you hear a slight pop or tick when you turn the amp on. Let us know the result and then we will go to the next step.
Finally got the chance to get into this project. Turned the amp up, all connected (speaker wire to the subette; spades from amp speaker connector to RCA on sublime), blue LED lights glowing.
No pop or tick. Still no sound from the subette. I've double checked all connections and they appear fine...
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I'm at home but when I get in to the office later I can come up with a test procedure if you would like to try it. Not to harp on it but we do find that the binding posts we use can be a little tricky to get good contact. Every once in a while when I am swapping gear I have to fiddle with the position of the speaker cable ends on the posts to get sound out.
The modular nature of this kit and every board seemingly getting power (all LEDs lit) leaves just a couple of options.
We could trace signal going through the amp to see where it stops. That would localize the issue precisely, but it requires the use of a signal source and a meter to track the signal thru the circuit. I'm thinking we would simply test at the output of each board and at the bindng posts.
The second approach would be to send out a new amp board and see if that solves the probem. Pretty easy to swap. If it did not fix it we would need to perhaps try replacing the preamp/filter board. If that doesn't do it we would need to figure out what connections are bad., which kind of takes us back to the first approach.
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Doc, I'd greatly appreciate a test procedure for this. At this point, I am thinking of sending the sublime back to you guys for repair, although the shipping/repair costs would probably cost as much as the amp itself, but I just can't stand having an idle amp sitting around.
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Hi Ben,
OK, a test/signal trace procedure is where we will start. Please bear with me for a bit, a tree fell on our house on Friday and took down our power line. We've been living in a hotel over the weekend and working to get things fixed. I'm a bit tied up with the electrician and inspector this morning (assuming they will show up in the snow that is falling this morning!) but should be able to get into the office this afternoon.
UPDATE - so sorry, I have been tied up trying to get our power back on all day and currently still waiting for the PSE truck to show up. Should be in the office tomorrow and will post what you need to do to start tracing the signal.
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Oh no! No rush, Doc. Take your time. Hope all is well with you both. Stay safe.
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It took longer on the phone with the power company to get a reenergize order going than it did to do the actual repair. Power finally restored at 5 p.m. Life is getting back to normal pretty quick. Will definitely be back at work tomorrow.
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Glad to hear that all is well!
It occurred to me if my connections from the Stereomour II outputs to the Sublime inputs are the issue? I am currently connecting it as Stereomour II output (spade) to Sublime input (RCA). I was reading online that the amp output is high level and the RCA input is low level. Is this perhaps the issue?
This might be a dumb question but I thought it worth asking given the circumstances!
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While that can be an issue, the output level of a small SET amp like the 2A3 is roughly on par with line level signal.
The binding posts we use aren't always agreeable with spades though, so you could try slipping a bit of extra bare wire through the hole in the binding post to help make that connection.
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Do you have a level control on the source that feeds the Stereomour? If you do, you might try setting the source level low and connecting it directly to the sublime input to see if you get sound. That would help determine if the interconnect from the Stereomour is the issue.
Unfortunately we are still sorting our power issue at the house today. Looks like we are close to getting it all the way fixed. Hope to head to the office this afternoon.
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OK, I finally made it to the office! Our cable modem got smoked at home when they turned on the power with no neutral wire connected to the house (smh) and my hot spot setup is dismal. Here is what I will suggest -
Connect a source to your Sublime RCA input jacks. Ideally you would put a tone thru, like maybe a 100Hz sine wave. But a music signal with good bass will work too.
Make sure you have the knobs on the sublime turned up at least one third of the way so signal can pass thru. What you want to do is flip your sublime over and turn it on. Turn on your sound source. Then take your meter set to AC volts and test at the following points as pictured in the attachment (I have labeled them on the amp board with a black sharpie)
First measure at the RCA jacks (red led to center pin, black lead to ground tab) to determine the signal level coming into the amp. If you see no signal check your setup and your cables. If you are sure you have signal coming in thru the cables you can move on to the next step.
Next move the test leads to the amp board terminals labeled I + (red lead) and I - (black lead) Verify that you see some AC voltage. If you do not you know the problem is ahead of that point, that is, it's a problem with the preamp/control board or its connections.
If you do see signal voltage move your leads to O + (red lead) and O - (black lead). Again look for signal voltage. If you see none the issue is with the amp board or its connections.
If you do see signal at the amp output it's likely that the issue is at the binding posts as mentioned in previous posts.
Let us know how it goes and we'll see if you need to fix a connection or we need to send a replacement board out.