Re: Wiring for Headphone
Hi Paul,
You cannot tie the speaker grounds (-) together. I mention this in my FAQ section in this page: www.geocities.com/vinnie822
Regards,
Vinnie
mourip said:
Hi Paul,
You cannot tie the speaker grounds (-) together. I mention this in my FAQ section in this page: www.geocities.com/vinnie822
Regards,
Vinnie
Re: Getting rid of the pot & battery supply tip
I also decided to ditch the pots for my 4 channel power amp setup seen here. The low 10k input impedance was a bit low for my source so I added a 4.7k resistor in series. I didn't put any resistors between the input and ground, should I? It doesn't seem to have any negative effect.
I tried using a SLA to see if it produced a "cleaner" sound than my regulated power supply and it didn't. If you blind folded me and told me to to figure out wich power source it was playing from I would'nt be able too.
As far as using a switching supply goes, I havn't tried one yet. I'm going to try hooking one up to the +12v of a PC switching power supply and I'll let you know what I think.
KT said:
I also decided to ditch the pots for my 4 channel power amp setup seen here. The low 10k input impedance was a bit low for my source so I added a 4.7k resistor in series. I didn't put any resistors between the input and ground, should I? It doesn't seem to have any negative effect.
I tried using a SLA to see if it produced a "cleaner" sound than my regulated power supply and it didn't. If you blind folded me and told me to to figure out wich power source it was playing from I would'nt be able too.
As far as using a switching supply goes, I havn't tried one yet. I'm going to try hooking one up to the +12v of a PC switching power supply and I'll let you know what I think.
Re: Re: Wiring for Headphone
Thanks Vinnie. Your Clari-T amp looks like a winner.
Is the separation of grounds an issue with the SI amps in general or is it unique to your own amp due to the diodes you are using on your output? I previously wired up an SI amp to a headphone jack and it player well. The only issue was that it had too much hiss. I ended up sending the amp back thinking that I had a dud 🙂 Perhaps this was the symptom of tying the grounds together? I guess that I could splurge and get some K1000's 🙂
BTW. Would you be willing to give details to us DIYers on adding the diodes on the speaker outputs?
Also can you think of any way I might be able to combine the grounds AND isolate them? Or is this contradictory?
Keep up the good work. Sounds like you are on the right track...
Best,
Paul
Vinnie R. said:
Thanks Vinnie. Your Clari-T amp looks like a winner.
Is the separation of grounds an issue with the SI amps in general or is it unique to your own amp due to the diodes you are using on your output? I previously wired up an SI amp to a headphone jack and it player well. The only issue was that it had too much hiss. I ended up sending the amp back thinking that I had a dud 🙂 Perhaps this was the symptom of tying the grounds together? I guess that I could splurge and get some K1000's 🙂
BTW. Would you be willing to give details to us DIYers on adding the diodes on the speaker outputs?
Also can you think of any way I might be able to combine the grounds AND isolate them? Or is this contradictory?
Keep up the good work. Sounds like you are on the right track...
Best,
Paul
There is no "ground"--the positive and negative outputs float around ground. I'm surprised that tying them together didn't destroy the amp.
Re: Re: Re: Wiring for Headphone
Paul,
Thanks for your kind words.
>>Is the separation of grounds an issue with the SI amps in general or is it unique to your own amp due to the diodes you are using on your output?
It is an issue with Tripath based amps, and has nothing to do with the diodes.
>>I previously wired up an SI amp to a headphone jack and it player well. The only issue was that it had too much hiss. I ended up sending the amp back thinking that I had a dud 🙂 Perhaps this was the symptom of tying the grounds together? I guess that I could splurge and get some K1000's 🙂
If the speakers of the headphones did not have their negative terminals connected together (ie, if you rewired them), you shouldn't have any problem. However, I'm not exactly sure about what output impedance is needed for the headphones.
>>Also can you think of any way I might be able to combine the grounds AND isolate them? Or is this contradictory?
Sounds contradictory, because once you combine them, there is no isolation.
Hope this helps,
Vinnie
Paul,
Thanks for your kind words.
>>Is the separation of grounds an issue with the SI amps in general or is it unique to your own amp due to the diodes you are using on your output?
It is an issue with Tripath based amps, and has nothing to do with the diodes.
>>I previously wired up an SI amp to a headphone jack and it player well. The only issue was that it had too much hiss. I ended up sending the amp back thinking that I had a dud 🙂 Perhaps this was the symptom of tying the grounds together? I guess that I could splurge and get some K1000's 🙂
If the speakers of the headphones did not have their negative terminals connected together (ie, if you rewired them), you shouldn't have any problem. However, I'm not exactly sure about what output impedance is needed for the headphones.
>>Also can you think of any way I might be able to combine the grounds AND isolate them? Or is this contradictory?
Sounds contradictory, because once you combine them, there is no isolation.
Hope this helps,
Vinnie
tiroth said:
The TA2024 chip has over current and over temperature protection designed into it, so I'm not surprised that nothing blew up. It's pretty rugged!
Bill has sold most of his amps:
http://www.diyaudio.com/forums/showthread.php?s=&postid=533308#post533308
I am not affiliated with Bill in any way other than buying 2 😉
(and being on DIY Audio!)
http://www.diyaudio.com/forums/showthread.php?s=&postid=533308#post533308
I am not affiliated with Bill in any way other than buying 2 😉
(and being on DIY Audio!)
My version of the SI 5066 upgrade
Here's a link to a detailed build of my SI 5066 upgrade:
http://members.tripod.com/talkgarden/sonic_impact_5066.htm .
It was my first attempt at an audio project. Thanks to all who have contributed to this thread for your advice and inspiration!
Robert
Here's a link to a detailed build of my SI 5066 upgrade:
http://members.tripod.com/talkgarden/sonic_impact_5066.htm .
It was my first attempt at an audio project. Thanks to all who have contributed to this thread for your advice and inspiration!
Robert
Attachments
Robert,
Very nice job on the amp and what an excellent website. That should motivate and instruct those too intimidated into action. Puts my site to shame.
Your first project? Fooled me.
amt
Very nice job on the amp and what an excellent website. That should motivate and instruct those too intimidated into action. Puts my site to shame.
Your first project? Fooled me.
amt
Robert: A great service in walking people through disassembly and reassembly with really excellent photographs. Impressive project.
Maybe I've already asked this, but has anybody thought about using the SI amps to make active speakers? A 2-way speaker could be biamped (one channel per driver) with an appropriate external crossover. What I don't have much sense of is the selection of appropriate drivers and crossover components (the Marchand DIY boards?)
Maybe I've already asked this, but has anybody thought about using the SI amps to make active speakers? A 2-way speaker could be biamped (one channel per driver) with an appropriate external crossover. What I don't have much sense of is the selection of appropriate drivers and crossover components (the Marchand DIY boards?)
Robert,
Awesome website. This is such a big help for those of use modifying the amp. Nice job!
May I offer some input based on my experiences?
Another way to unfasten the board from the melted plastic pins is this:
Instead of melting them with a soldering iron, I used a pair of medium-fine pliers. Since the molten part holding the board on is basically a bit of molten plastic that's flowed to onto the board, essentially "capturing" the board by it's increased diameter, here's what I do:
I take the pliers and and squeeze the molten edges of the pin in toward the center axis of the pin (the pincers of the pliers on opposite sides squeezing towards the center). I go around the circumference of the pin and sqeeze all the plastic toward the center. When I do this, the molten plastic tends to crumble and fall off. When done, the diameter of the plastic pin is now smaller than that of the hole on the board, so now it will come off once the glue is removed.
This is fairly touble-free and, I'd imagine, neater and better smelling than molten plastic?😉
Also, the dial on the pot does come off. Since the dial is recessed into the face of the amp, you'll need to put two small flat edge screwdriver blades under the dial on opposite sides and gently pry it up. When it's off, you'll see that the pot has a "D" shaped shaft and the dial slides right onto it.
The first time I removed the dial this way, I scratched some paint off the face of the amp. Not a big deal if you're moving it to a different box, but if you plan on reusing the SI case, you can slide a sheet of paper or cardstock between where the screwdrivers and the amp face meet (before you pry) to protect the finish.
After the dial has been removed, you'll see that the pot assembly is held onto the amp case with three screws. I think screws that hold this assembly to the case require a #1 Phillips head, the same size you use to remove the two small screws in the battery compartment.
These screws hold the pot's black cylindrical mounting ring to the case. The pot, itself, secured to this black ring with a standard flat hex nut and washer.
The pot's mounting assembly includes a black cylindrical mounting ring, the pot, the pot's circuit board, and the wires and connectors that attatch the pot's board to the main board.
The pot I replaced the stock one with, an Alpha, sits much lower than the stock pot, so I had to cut a portion off of the black mounting ring to give the board proper clearance.
Also, since the Alpha pot uses a knurled knob insead of a "D" shaft, I was unable to reuse the dial. Instead, I use a small screwdriver to turn the slotted shaft in order to adjust the volume. Doesn't look so nice, but it works.
I basically changed this pot out to experiment without doing a full rebox. I imagine that most people taking the amp apart will move everything into a new case, so probably won't mess around too much with the pot mounting on the SI case.
Great website, Robert!
Best,
KT
Awesome website. This is such a big help for those of use modifying the amp. Nice job!
May I offer some input based on my experiences?
Another way to unfasten the board from the melted plastic pins is this:
Instead of melting them with a soldering iron, I used a pair of medium-fine pliers. Since the molten part holding the board on is basically a bit of molten plastic that's flowed to onto the board, essentially "capturing" the board by it's increased diameter, here's what I do:
I take the pliers and and squeeze the molten edges of the pin in toward the center axis of the pin (the pincers of the pliers on opposite sides squeezing towards the center). I go around the circumference of the pin and sqeeze all the plastic toward the center. When I do this, the molten plastic tends to crumble and fall off. When done, the diameter of the plastic pin is now smaller than that of the hole on the board, so now it will come off once the glue is removed.
This is fairly touble-free and, I'd imagine, neater and better smelling than molten plastic?😉
Also, the dial on the pot does come off. Since the dial is recessed into the face of the amp, you'll need to put two small flat edge screwdriver blades under the dial on opposite sides and gently pry it up. When it's off, you'll see that the pot has a "D" shaped shaft and the dial slides right onto it.
The first time I removed the dial this way, I scratched some paint off the face of the amp. Not a big deal if you're moving it to a different box, but if you plan on reusing the SI case, you can slide a sheet of paper or cardstock between where the screwdrivers and the amp face meet (before you pry) to protect the finish.
After the dial has been removed, you'll see that the pot assembly is held onto the amp case with three screws. I think screws that hold this assembly to the case require a #1 Phillips head, the same size you use to remove the two small screws in the battery compartment.
These screws hold the pot's black cylindrical mounting ring to the case. The pot, itself, secured to this black ring with a standard flat hex nut and washer.
The pot's mounting assembly includes a black cylindrical mounting ring, the pot, the pot's circuit board, and the wires and connectors that attatch the pot's board to the main board.
The pot I replaced the stock one with, an Alpha, sits much lower than the stock pot, so I had to cut a portion off of the black mounting ring to give the board proper clearance.
Also, since the Alpha pot uses a knurled knob insead of a "D" shaft, I was unable to reuse the dial. Instead, I use a small screwdriver to turn the slotted shaft in order to adjust the volume. Doesn't look so nice, but it works.
I basically changed this pot out to experiment without doing a full rebox. I imagine that most people taking the amp apart will move everything into a new case, so probably won't mess around too much with the pot mounting on the SI case.
Great website, Robert!
Best,
KT
To use these amps for headphones with a common ground, couldn't you simply use the hot connector of each channel? I realize it would cut the voltage swing in half, but wouldn't there still be plenty for low-Z headphones? Or would leaving the colds disconnected trip a protection mode?
I asked this question on AudioCircle, but haven't received an answer. After reading this entire thread I think this is a better place to ask:
OK so I finished re-working my Sonic Impact and was ready for a test run last night. Hooked up the speakers, input, and battery.........no left channel!
I double checked my connections, both input and output, still nothing.
Mods: I rewired the mini-plug input to accept dual RCAs, changed the speaker output wires to 18ga and bumped the power input leads that used to go from the 8 AAs to 18ga wired directly from my 12v SLA. That is pretty much the only mods I did so far. The stock pot is still there. No caps or inductors have been replaced yet. No complicated surface soldering.
One interesting note, when I only fed the amp the left channel input, I got a very weak signal coming from the right speaker, still nothing from the left. This could just be crosstalk or bleedover I guess. When fed into the right channel the volume from the right speaker is normal. I get absolutely nothing from the left speaker, ever. The amp worked fine before I "made it better".
Does anyone who has modded one of these things have any helpful suggestions....besided buying a new one? At least I'm breaking into DIY and modding on a cheap $30 jobby.
What would you recommend checking first assuming I might have burned something out with soldering iron heat? Most of the soldering took place on near all the right channel circuitry (from what I can tell), yet the left channel is the problem.....
Thanks.
Todd
OK so I finished re-working my Sonic Impact and was ready for a test run last night. Hooked up the speakers, input, and battery.........no left channel!
I double checked my connections, both input and output, still nothing. Mods: I rewired the mini-plug input to accept dual RCAs, changed the speaker output wires to 18ga and bumped the power input leads that used to go from the 8 AAs to 18ga wired directly from my 12v SLA. That is pretty much the only mods I did so far. The stock pot is still there. No caps or inductors have been replaced yet. No complicated surface soldering.
One interesting note, when I only fed the amp the left channel input, I got a very weak signal coming from the right speaker, still nothing from the left. This could just be crosstalk or bleedover I guess. When fed into the right channel the volume from the right speaker is normal. I get absolutely nothing from the left speaker, ever. The amp worked fine before I "made it better".
Does anyone who has modded one of these things have any helpful suggestions....besided buying a new one? At least I'm breaking into DIY and modding on a cheap $30 jobby.
What would you recommend checking first assuming I might have burned something out with soldering iron heat? Most of the soldering took place on near all the right channel circuitry (from what I can tell), yet the left channel is the problem.....
Thanks.
Todd
Member
Joined 2002
A follow up to my previous post....
I rewired everything with some 20ga solid core for the power and cat5e solid core, one twisted pair per run. Plugged it and hoped for the best.
SOUNDS GREAT! So apparently somewhere I had managed to short my left channel when I had it wired previously. I tested with a multimeter for a short and didn't find one before. But anyway it works now.
So now on to mods....I notice somewhat of a trend in replacing the pot with an alpha or carbon pot. What about the one cap on the board? Any consensus on upgrading that thing?
Modding is so much more fun when it actually works! 😀
Todd
I rewired everything with some 20ga solid core for the power and cat5e solid core, one twisted pair per run. Plugged it and hoped for the best.
SOUNDS GREAT! So apparently somewhere I had managed to short my left channel when I had it wired previously. I tested with a multimeter for a short and didn't find one before. But anyway it works now.
So now on to mods....I notice somewhat of a trend in replacing the pot with an alpha or carbon pot. What about the one cap on the board? Any consensus on upgrading that thing?
Modding is so much more fun when it actually works! 😀
Todd
Bill F. said:
I think to use this as a headphone amp you'd want to rewire the headphones so that they didn't have a common ground. This same is required for the hi-end HeadWize amp.
dave
I'll bet rewiring the 'phones to make them work will be worth it!
Well, I'm late to this party, but finally get my amp.
First, its TINY. Everyone has such good cameras that they were able to take good closeup pics and it looked bigger. It is mighty cute!
Second, I hooked it to my office speakers-small made in China Celestions- and it sounded so good, I couldn't stand it and ran into the living room and hooked it to my Basszillas. Fantastic mid and highs-really great! But they didn't get my 15 inch bass drivers really going. The Brian GT gainclones I was using were great on bass. I am going to use the gain clone on the bass and the Sonic on the mids and highs, using the existing passive crossovers. I'll bet it will be fantastic.
Well, I'm late to this party, but finally get my amp.
First, its TINY. Everyone has such good cameras that they were able to take good closeup pics and it looked bigger. It is mighty cute!
Second, I hooked it to my office speakers-small made in China Celestions- and it sounded so good, I couldn't stand it and ran into the living room and hooked it to my Basszillas. Fantastic mid and highs-really great! But they didn't get my 15 inch bass drivers really going. The Brian GT gainclones I was using were great on bass. I am going to use the gain clone on the bass and the Sonic on the mids and highs, using the existing passive crossovers. I'll bet it will be fantastic.
- Status
- Not open for further replies.