CrackBerry9000
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That is too cool.
Tube headphone amp kit for $25!?
- Thread starter sunneebear
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- diy headphone-amplifiers
Pricklely Peete
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netsky3 I can't help but think your source may be part of the problem WRT sound stage issues (either in setup or the actual software hardware combination used).
I'm not familiar with the Cowon device but the X-FI card from a notebook without a decent outboard DAC between the amp and the transport can really mess things up (no matter what you do with the amp mod wise). What OS are using ? If it's XP see of if you can upgrade to Win7 since it's audio layer is way way better than the old NT4/5 kernel/HAL interface.
That being said if you have a CDP or DVDP use it with your amp to see if the amp can be better tuned to a standard 2.0V line level source output level. The trim pots if set too high (with the source line level set too low) can cause all kinds of problems (distortion etc) not only that if you lower the level at the computer source (depending on O/S and SC driver) you actually truncate the bit depth of the file rather than attenuate the gain. It's a shortcoming of computer based transports with some hardware configs. That is why I suggest you calibrate the trim pots to a 2.0V line level standard (for a CDP/DVDP) and then transfer the amp to your comp source to see if the problems persist or have been solved. It's best to have the computer set at 100% and adjust the input trimmers on the amp. If the computer output is too hot (well above 2.5V) the input stage of the amp may be clipping causing distortion. The only way to tell if that is the case is to measure the signal level coming from your source using a meter.
It's also possible that the cheap trim pots have been damaged by excessive heating when being installed. It doesn't take much to mess them up since they are very cheap parts. That likelihood is rather remote however although not out of the realm of possibility. Another possible issue is adjusting the trim pots too far in one direction...they sometimes crap out (stick at that setting) from being adjusted too far ...only very small increments should be used. If you have a test tone (say 1Khz) and a SPL meter you can match the L/R levels fairly accurately. Err on the side of caution with the levels.
I agree with the S-Man slow down and take a look at your entire system chain to make sure it's setup optimally for your hardware config/source etc...you may find you have overlooked something (then again maybe not) but it's worth checking it all out anyway while you wait for the amp to mature in it's current revision.
Simplify your system chain down to it's bare essential components and work up from there and worry about the parts quality of the amp later.
Peete.
I'm not familiar with the Cowon device but the X-FI card from a notebook without a decent outboard DAC between the amp and the transport can really mess things up (no matter what you do with the amp mod wise). What OS are using ? If it's XP see of if you can upgrade to Win7 since it's audio layer is way way better than the old NT4/5 kernel/HAL interface.
That being said if you have a CDP or DVDP use it with your amp to see if the amp can be better tuned to a standard 2.0V line level source output level. The trim pots if set too high (with the source line level set too low) can cause all kinds of problems (distortion etc) not only that if you lower the level at the computer source (depending on O/S and SC driver) you actually truncate the bit depth of the file rather than attenuate the gain. It's a shortcoming of computer based transports with some hardware configs. That is why I suggest you calibrate the trim pots to a 2.0V line level standard (for a CDP/DVDP) and then transfer the amp to your comp source to see if the problems persist or have been solved. It's best to have the computer set at 100% and adjust the input trimmers on the amp. If the computer output is too hot (well above 2.5V) the input stage of the amp may be clipping causing distortion. The only way to tell if that is the case is to measure the signal level coming from your source using a meter.
It's also possible that the cheap trim pots have been damaged by excessive heating when being installed. It doesn't take much to mess them up since they are very cheap parts. That likelihood is rather remote however although not out of the realm of possibility. Another possible issue is adjusting the trim pots too far in one direction...they sometimes crap out (stick at that setting) from being adjusted too far ...only very small increments should be used. If you have a test tone (say 1Khz) and a SPL meter you can match the L/R levels fairly accurately. Err on the side of caution with the levels.
I agree with the S-Man slow down and take a look at your entire system chain to make sure it's setup optimally for your hardware config/source etc...you may find you have overlooked something (then again maybe not) but it's worth checking it all out anyway while you wait for the amp to mature in it's current revision.
Simplify your system chain down to it's bare essential components and work up from there and worry about the parts quality of the amp later.
Peete.
netsky3
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Quote:
Actually the only source that i have is my pc with the x-fi as output where i connect directly my Akg (i'm waiting for my dac arrives from canada) and where i use also the amp between pc and cans
Maybe next week end i can use the amp with a CDP as source but i don't think that is the problem because the headphones on the x-fi sounds well.
The only things a little damaged are 2-3 holes where are soldered the caps 7-8 (but still working) and the jack for the output (that will be soon changed with a new piece)
Desolder everything and re-do the amp will be a solution??
Thanks again for your patience
| Originally Posted by Pricklely Peete /img/forum/go_quote.gif netsky3 I can't help but think your source may be part of the problem WRT sound stage issues (either in setup or the actual software hardware combination used). I'm not familiar with the Cowon device but the X-FI card from a notebook without a decent outboard DAC between the amp and the transport can really mess things up (no matter what you do with the amp mod wise). What OS are using ? If it's XP see of if you can upgrade to Win7 since it's audio layer is way way better than the old NT4/5 kernel/HAL interface. That being said if you have a CDP or DVDP use it with your amp to see if the amp can be better tuned to a standard 2.0V line level source output level. The trim pots if set too high (with the source line level set too low) can cause all kinds of problems (distortion etc) not only that if you lower the level at the computer source (depending on O/S and SC driver) you actually truncate the bit depth of the file rather than attenuate the gain. It's a shortcoming of computer based transports with some hardware configs. That is why I suggest you calibrate the trim pots to a 2.0V line level standard (for a CDP/DVDP) and then transfer the amp to your comp source to see if the problems persist or have been solved. It's best to have the computer set at 100% and adjust the input trimmers on the amp. If the computer output is too hot (well above 2.5V) the input stage of the amp may be clipping causing distortion. The only way to tell if that is the case is to measure the signal level coming from your source using a meter. It's also possible that the cheap trim pots have been damaged by excessive heating when being installed. It doesn't take much to mess them up since they are very cheap parts. That likelihood is rather remote however although not out of the realm of possibility. Another possible issue is adjusting the trim pots too far in one direction...they sometimes crap out (stick at that setting) from being adjusted too far ...only very small increments should be used. If you have a test tone (say 1Khz) and a SPL meter you can match the L/R levels fairly accurately. Err on the side of caution with the levels. I agree with the S-Man slow down and take a look at your entire system chain to make sure it's setup optimally for your hardware config/source etc...you may find you have overlooked something (then again maybe not) but it's worth checking it all out anyway while you wait for the amp to mature in it's current revision. Simplify your system chain down to it's bare essential components and work up from there and worry about the parts quality of the amp later. Peete. |
Actually the only source that i have is my pc with the x-fi as output where i connect directly my Akg (i'm waiting for my dac arrives from canada) and where i use also the amp between pc and cans
Maybe next week end i can use the amp with a CDP as source but i don't think that is the problem because the headphones on the x-fi sounds well.
The only things a little damaged are 2-3 holes where are soldered the caps 7-8 (but still working) and the jack for the output (that will be soon changed with a new piece)
Desolder everything and re-do the amp will be a solution??
Thanks again for your patience
Pricklely Peete
Franken modder
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Quote:
Sit tight until the DAC arrives is my advice for now. The difference in SQ from your current source to an outboard DAC will likely surprise you by a quite a fair margin. No use in doing anything until it arrives.
Peete.
| Originally Posted by netsky3 /img/forum/go_quote.gif Actually the only source that i have is my pc with the x-fi as output where i connect directly my Akg (i'm waiting for my dac arrives from canada) and where i use also the amp between pc and cans
Maybe next week end i can use the amp with a CDP as source but i don't think that is the problem because the headphones on the x-fi sounds well. The only things a little damaged are 2-3 holes where are soldered the caps 7-8 (but still working) and the jack for the output (that will be soon changed with a new piece) Desolder everything and re-do the amp will be a solution??
Thanks again for your patience
|
Sit tight until the DAC arrives is my advice for now. The difference in SQ from your current source to an outboard DAC will likely surprise you by a quite a fair margin. No use in doing anything until it arrives.
Peete.
netsky3
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Quote:
I hope that you're right
even if the Dac is only a hotaudio destroyer and the x-fi sounds well imho (less gap quality
)
| Originally Posted by Pricklely Peete /img/forum/go_quote.gif Sit tight until the DAC arrives is my advice for now. The difference in SQ from your current source to an outboard DAC will likely surprise you by a quite a fair margin. No use in doing anything until it arrives. Peete. |
I hope that you're right
sennsay
1000+ Head-Fier
Quote:
Yes Cal, there is a drop-in board with two OPA627s on it - one over, one under, since an OPA627 is a single channel opamp, you need two of them, meaning you get an 627 for each channel on the one drop-in board. I use the same system but with two AD825s on a drop-in board instead, it sounds magic with my Denon cans. So does the OPA627 board, though I prefer it when using the FrankenZero DAC from the lappy, rather than from the dock outlet of the iPod, where the AD825 is a better match.
The 2134 has less current output than the other two, which is why it is recommended for using the amp as a preamp where the extra drive isn't needed, it sounds ok with the Denons though, it just doesn't draw me into the music as effortlessly as the other two do.
| Originally Posted by calico88 /img/forum/go_quote.gif Sennsay, are you saying that this board can just use Opa627.. just drop in ? I have mine but I thought is not working at all. how is the sound compare to 2134 for Headphone Amplifier ? you have not tried that as a headphone amp ? Cal |
Yes Cal, there is a drop-in board with two OPA627s on it - one over, one under, since an OPA627 is a single channel opamp, you need two of them, meaning you get an 627 for each channel on the one drop-in board. I use the same system but with two AD825s on a drop-in board instead, it sounds magic with my Denon cans. So does the OPA627 board, though I prefer it when using the FrankenZero DAC from the lappy, rather than from the dock outlet of the iPod, where the AD825 is a better match.
The 2134 has less current output than the other two, which is why it is recommended for using the amp as a preamp where the extra drive isn't needed, it sounds ok with the Denons though, it just doesn't draw me into the music as effortlessly as the other two do.
sennsay
1000+ Head-Fier
Netsky3, I have to agree with PP, you will get a much improved soundstage with a decent DAC! Heck, even the iPod's dock port gives me an excellent s/s with the Denons, in some ways it's the best I've heard them as far as out-of-head s/s is concerned. You're not so much hearing the failings of your amp, but that of your source, hadn't quite thought of it like that until PP mentioned it
In comparison to a perfectly fine Corda 2Move, it is less visceral while being more spacious in it's soundstaging, yet is easily as tuneful. You hear deep bass in a different way too, not as immediate and upfront, yet it is still there and once you get used to it, it is just as engaging.
PS: BTW, I do use a more than half decent cable from the iPod dock to the amp, an Audioquest Mini 3 solid core copper cable, it's excellent for this sort of thing and doesn't cost a pile of $$$$.
In comparison to a perfectly fine Corda 2Move, it is less visceral while being more spacious in it's soundstaging, yet is easily as tuneful. You hear deep bass in a different way too, not as immediate and upfront, yet it is still there and once you get used to it, it is just as engaging.
PS: BTW, I do use a more than half decent cable from the iPod dock to the amp, an Audioquest Mini 3 solid core copper cable, it's excellent for this sort of thing and doesn't cost a pile of $$$$.
sennsay
1000+ Head-Fier
Sorry, pushed a wrong button somewhere - sheepish
sennsay
1000+ Head-Fier
Okay, play time
I have upped the voltage to 18V with two 9V batteries in series, this with the AD825 opamps in the output. Certainly it improves the dynamic abilities of the bass, the taut kick drum in Regina Spektor's superbly recorded album doesn't feel a bit overloaded any more, tight as. The AD825s certainly need more than 9V to perform at their best, though they are still wonderfully musical at 9V.
Surprisingly, I felt that I preferred the sound of the AD825s with 9V, regardless of any gains in the bottom end, they just sounded a little harder in the mids and I was a little less engrossed in the overall sound.
So I thought to try the OPA627s again and immediately cooked the little board! DOH, I had it in around the wrong way, after so many ins and outs, I made a booboo. Sigh. Well, I knew I had another one or two and I spotted a new pair of full sized OPA627BPs on a Black Dog board and in they went, the right way round! Now THIS was more like it! Now we are cooking on gas. These are two full sized 627 opamps and they obviously love 18V; space, openness, clarity, PRAT in spades and very tactile in the mids and highs, these are very very good at this voltage. Music has an eloquent flow that is undeniably entrancing, dynamic yet never pushy, allowing the best from the little valves that don't sound "little" at all - the best I've heard so far anyway.
Bearing in mind that all this is with the stock resistors and poly box caps on the first board. I'm working on the case for the 'upgrade' board at the moment. Along with metal film resistors, this board has 0.1uF Black Gates in place of the box caps - only the four in the signal path - and I used already well run-in BGs pirated from another project, I didn't fancy waiting hundreds of hours for new versions of the little suckers to run in
I fancy leaving the 627BPs on board even when running the amp as a preamp. The new 'preamp/headphone amp case will have two inputs switchable from the front.
So far, this little amp is making the output from the dock port of an iPod Classic sound amazingly good, only the real transparency and deepest bass dynamics are missing from the picture and that's something the FrankenZero can easily take care of.
Will post pics when the new case is finished, or at least practically useable. S-man
Surprisingly, I felt that I preferred the sound of the AD825s with 9V, regardless of any gains in the bottom end, they just sounded a little harder in the mids and I was a little less engrossed in the overall sound.
So I thought to try the OPA627s again and immediately cooked the little board! DOH, I had it in around the wrong way, after so many ins and outs, I made a booboo. Sigh. Well, I knew I had another one or two and I spotted a new pair of full sized OPA627BPs on a Black Dog board and in they went, the right way round! Now THIS was more like it! Now we are cooking on gas. These are two full sized 627 opamps and they obviously love 18V; space, openness, clarity, PRAT in spades and very tactile in the mids and highs, these are very very good at this voltage. Music has an eloquent flow that is undeniably entrancing, dynamic yet never pushy, allowing the best from the little valves that don't sound "little" at all - the best I've heard so far anyway.
Bearing in mind that all this is with the stock resistors and poly box caps on the first board. I'm working on the case for the 'upgrade' board at the moment. Along with metal film resistors, this board has 0.1uF Black Gates in place of the box caps - only the four in the signal path - and I used already well run-in BGs pirated from another project, I didn't fancy waiting hundreds of hours for new versions of the little suckers to run in
I fancy leaving the 627BPs on board even when running the amp as a preamp. The new 'preamp/headphone amp case will have two inputs switchable from the front.
So far, this little amp is making the output from the dock port of an iPod Classic sound amazingly good, only the real transparency and deepest bass dynamics are missing from the picture and that's something the FrankenZero can easily take care of.
Will post pics when the new case is finished, or at least practically useable. S-man
studeb
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Sensay,
Are you changing the supply V for the opamps? With the L4949 there, wont it stay at 5V?
Quote:
Are you changing the supply V for the opamps? With the L4949 there, wont it stay at 5V?
Quote:
| Originally Posted by sennsay /img/forum/go_quote.gif Okay, play time
Bearing in mind that all this is with the stock resistors and poly box caps on the first board. |
netsky3
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Thanks sennsay, i've found a power supply at 15V, tomorrow i'll try it with the amp to understand if i have problem of current
Now is in burn-in waiting for the new opamp
Now is in burn-in waiting for the new opamp
sennsay
1000+ Head-Fier
Quote:
You are absolutely correct, studeb, where I think it makes the biggest difference is to the plate/anode voltage, the tubes just seem to perform better and are imparting a cleaner signal to the opamp/s. Only minutes ago I have discovered that I might get a better channel balance by having the two 180 kohm anode resistors as closely matched as possible. Just a few ohms difference there, makes a bigger difference in actual plate voltage and therefore you need to rebalance the voltage with the vol pots or variable resistors, whichever you have. I was surprised at the difference in voltage at the anode of the tubes (pin 1-the one marked in red) and how much was needed at the pots to bring them even. Well, that's my theory anyway, how much difference it really makes if the tubes aren't matched might well throw that theory out the window, in practicality.
So, in the spirit of equality and, ahem .. slightly fussy matching
, I removed the 'inaccurately matched' carbon resistors and replaced them with two precisely matched metal film resistors instead.
Thus far, the Black Dog board with the two OPA627BP opamps has become the new reference and the addiction level of sitting with a set of Denon AH-D1000 cans on has taken another big notch forward!
How the 'upgrade' board will sound is something I await with near-abated breath, I am utterly intrigued. S-man
| Originally Posted by studeb /img/forum/go_quote.gif Sensay, Are you changing the supply V for the opamps? With the L4949 there, wont it stay at 5V? |
You are absolutely correct, studeb, where I think it makes the biggest difference is to the plate/anode voltage, the tubes just seem to perform better and are imparting a cleaner signal to the opamp/s. Only minutes ago I have discovered that I might get a better channel balance by having the two 180 kohm anode resistors as closely matched as possible. Just a few ohms difference there, makes a bigger difference in actual plate voltage and therefore you need to rebalance the voltage with the vol pots or variable resistors, whichever you have. I was surprised at the difference in voltage at the anode of the tubes (pin 1-the one marked in red) and how much was needed at the pots to bring them even. Well, that's my theory anyway, how much difference it really makes if the tubes aren't matched might well throw that theory out the window, in practicality.
So, in the spirit of equality and, ahem .. slightly fussy matching
Thus far, the Black Dog board with the two OPA627BP opamps has become the new reference and the addiction level of sitting with a set of Denon AH-D1000 cans on has taken another big notch forward!
How the 'upgrade' board will sound is something I await with near-abated breath, I am utterly intrigued. S-man
netsky3
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Today I have used my amp with a CDP as source and after a long burn in with a psu at 15V the sound is a little better but i don't like the bass, the drums on Echoes sounds with less punch, soft and behind the others instruments than without the amp and usinge the cans on the CDP
Sennsay do you can compare this Song with and without the amp?
Maybe with 18V can be a little better?
Sennsay do you can compare this Song with and without the amp?
Maybe with 18V can be a little better?
netsky3
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Great differences with my portable CDP sony, the sound is better with the line out (why??
) and with this PSU at 15V there's a little hum, maybe for the bad quality of the current so i have "filtered" the current with 2 caps (1470 uF total
.gif)
) is good thing?
With the burn in the sound better anyway.
Sennsay, do you listen tool right? I've noticed that:
CDP with line out -> amp -> headphones and Vicarious on playing the amp goes on clipping and distortion even with the trimport setted on 10 o'clock.
Is a problem or you too have this "problem" ??
Thanks
With the burn in the sound better anyway.
Sennsay, do you listen tool right? I've noticed that:
CDP with line out -> amp -> headphones and Vicarious on playing the amp goes on clipping and distortion even with the trimport setted on 10 o'clock.
Is a problem or you too have this "problem" ??
Thanks
sennsay
1000+ Head-Fier
Quote:
A couple of points here, the tube amp actually has a soundstage, although I'm not familiar with Echos, it may actually be recorded with the drum kit behind the other instruments, many are. I have found the same thing between this amp and the Corda 2Move, the bass is good on both yet presented differently, being a little deeper in the stage with the tube amp compared to the Corda, which is a touch deeper and more immediate - I love 'em both, depends on the music.
It's unlikely an 18V supply will be 'better' than a 15V supply, not a lot of voltage difference compared to a shift from 9V to 18V.
Hey, netsky3, it just may be that this little amp really doesn't suit your listening preferences or the cans you are using, no shame there, it happens to all of us sometime.
You may be experiencing some hum by using what, a mains powered supply? I have noticed that if I connect my first amp, which has no case, to a CDP or even the DAC, then I too get some hum, which reduces significantly when I touch the earth terminals on the inputs. Mine is absolutely silent when coming from the iPods. The Mk II amp has a case, though it is not yet lined with any form of shielding.
Which output opamp are you using now?
| Originally Posted by netsky3 /img/forum/go_quote.gif Today I have used my amp with a CDP as source and after a long burn in with a psu at 15V the sound is a little better but i don't like the bass, the drums on Echoes sounds with less punch, soft and behind the others instruments than without the amp and usinge the cans on the CDP Sennsay do you can compare this Song with and without the amp?
Maybe with 18V can be a little better? |
A couple of points here, the tube amp actually has a soundstage, although I'm not familiar with Echos, it may actually be recorded with the drum kit behind the other instruments, many are. I have found the same thing between this amp and the Corda 2Move, the bass is good on both yet presented differently, being a little deeper in the stage with the tube amp compared to the Corda, which is a touch deeper and more immediate - I love 'em both, depends on the music.
It's unlikely an 18V supply will be 'better' than a 15V supply, not a lot of voltage difference compared to a shift from 9V to 18V.
Hey, netsky3, it just may be that this little amp really doesn't suit your listening preferences or the cans you are using, no shame there, it happens to all of us sometime.
You may be experiencing some hum by using what, a mains powered supply? I have noticed that if I connect my first amp, which has no case, to a CDP or even the DAC, then I too get some hum, which reduces significantly when I touch the earth terminals on the inputs. Mine is absolutely silent when coming from the iPods. The Mk II amp has a case, though it is not yet lined with any form of shielding.
Which output opamp are you using now?
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