Tube headphone amp kit for $25!?
Nov 23, 2009 at 5:43 AM Post #31 of 216
Did you adjust your potentiometers up. Mine sounded rough the first couple of hours But I burned it in for about 30 hours and it got so loud I had to turn the potentiometers down. I'm using a ipod for a source
 
Nov 23, 2009 at 5:55 AM Post #32 of 216
I've tried adjusting everything I can find. I've got the onboard potentiometers the highest they can be without distorting (which is actually pretty low, they're just a little above nothing). Any more and the sound is dirty and distorted.

So it gets louder after some hours running? I'll leave it running then and hope to see some improvement.
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Nov 23, 2009 at 6:02 AM Post #33 of 216
Quote:

Originally Posted by mattcalf /img/forum/go_quote.gif
Just a FYI: postage is $7 all over Australia for up to 5 kits.
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Matt, you gonna start smelling like solder fumes
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Looks a nice project, thanks sunneebear for bringing this to light
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Nov 23, 2009 at 6:05 AM Post #34 of 216
Hey I'm sorry I did not notice that you added a volume knob. I use my potentiometers for the balance and my ipods Volume control for the volume. I am running the potentiometers pretty low or i'm sure I could blow my earbuds.Could it be your volume knob itself ,did you put the volume knob in line before or after the amp. My volume adjustment is before the amp
 
Nov 23, 2009 at 6:10 AM Post #35 of 216
I'm suspecting it's the potentiometer I used for the volume knob, but I checked to make sure it's wired properly and all. My volume control on the amp is after. It's wired between the output on the board and the headphone out. Would it work better if I wired it between the rca inputs and the input on the board?
 
Nov 23, 2009 at 6:21 AM Post #38 of 216
ok i'm using my ipods out jack (no lod) into the amp input and I plug my earbuds into the amps output
If you hook yours up like this try to jumper out (or bypass)the volume knob and try to adjust the volume with your ipod If this works the problems with your amps volume knob
 
Nov 23, 2009 at 6:29 AM Post #39 of 216
well yes, when I use the headphone out from my iPod, then the iPod dictates the volume of the output. I may try to put the volume knob before the amp tomorrow or when I have time. Or maybe not, it still gets loud enough for me as it is now, it's more just an annoyance. I appreciate your help though hipcat.
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Nov 23, 2009 at 8:22 AM Post #42 of 216
Quote:

Originally Posted by johnwmclean /img/forum/go_quote.gif
Matt, you gonna start smelling like solder fumes
tongue.gif
Looks a nice project, thanks sunneebear for bringing this to light
smile_phones.gif



I think this'll be a project that'll be a warm-down after the current AMB and Jaycar onslaught. I'll probably use it a pre-amp for my tiny amp for my DIY speakers.
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Nov 23, 2009 at 9:14 AM Post #43 of 216
Hey Squid+, I'll take my amp home tomarrow and hook my ipod lod to it to see if I get the same results. I've seen several of these amps now and I have'nt seen one with a volume control. I don't think this amp is designed to work with a line level signal. If I understand it right the line level signal has no "power" it's just a signal. I think this amp needs a amped signal to boost it. Theirs no power to really boost a line level signal if you see what I mean I think that why you need to turn up your volume so high.If I'm wrong I hope someone will set me straight. Any way I'll see what happens tomarrow and let you know.
 
Nov 23, 2009 at 6:08 PM Post #45 of 216
Quote:

Originally Posted by hipcat /img/forum/go_quote.gif
Hey Squid+, I'll take my amp home tomarrow and hook my ipod lod to it to see if I get the same results. I've seen several of these amps now and I have'nt seen one with a volume control. I don't think this amp is designed to work with a line level signal. If I understand it right the line level signal has no "power" it's just a signal. I think this amp needs a amped signal to boost it. Theirs no power to really boost a line level signal if you see what I mean I think that why you need to turn up your volume so high.If I'm wrong I hope someone will set me straight. Any way I'll see what happens tomarrow and let you know.


I believe it's usually preferable to use line level signals, to reduce coloration and distortion or something. I guess it could be the opposite in this case, but I'd be surprised.

I was thinking about it last night, and it seems to make good sense that the volume would reach higher levels if the volume pot was installed before the amping stage. I probably won't bother fixing it on this amp, since it's just for personal use and still reaches volumes loud enough that I wouldn't listen at. The space is small and I don't want to risk messing up something else to get this normal.

Thanks again for the help though, guys. Next amp I build, I'll put the volume control on the input side of the amping.

[edit: just thought I'd add that I moved the volume pot before the amp stage earlier today. That fixes the low volume problem, but it seems like I hear tube ringing more than before (it was nonexistant before). It's very quiet though and I can't really hear it with music on. Maybe I just need some more grommets or something.]
 

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