I have a B&O ICEpower 200ASC that I was thinking about using for the output of a guitar amplifier.
I also have a 500VA Hammond toroid power transformer 120/240:120/240... I'd wire it 1:1.
Electric guitar bandwidth is only about 80 to 1200Hz-ish.
The purpose would be to maybe "warm up" the sound a bit.
Am I asking for trouble / bad idea?
I also have a 500VA Hammond toroid power transformer 120/240:120/240... I'd wire it 1:1.
Electric guitar bandwidth is only about 80 to 1200Hz-ish.
The purpose would be to maybe "warm up" the sound a bit.
Am I asking for trouble / bad idea?
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Hi, I am no expert, but it is not possible to add a transformer. Normally the class D amplifier already has an output filter, and 2 transformers, 1 on each polarity. In my opinion not possible except on a class AB. To warm up the sound, I'd rather add a tube preamp in front. Or a tube buffer which has no gain, will depend on the efficiency of the speakers (8, 10 or 12 ", 2x12...etc), the listening level, the microphones of your guitars.
You will have more luck on the forum on Instruments :
https://www.diyaudio.com/forums/instruments-and-amps/
You will have more luck on the forum on Instruments :
https://www.diyaudio.com/forums/instruments-and-amps/
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I've bought - and connected - audio distribution transformers to my class D amplifier output. I happened to get units with full audio bandwidth and as low as 25 Ohms on the primary. They also have 4, 8 and 16 Ohm taps on the secondary.
I drove the 25 Ohm tap with the amp, connected the speaker to the 16. With an 8 Ohm speaker, the amp didnt seem to care one bit. Reversed however (Amp driving the 16, speaker connected to the 25) I could perhaps sense some strain...
Been reading in here how people just pull their class D amps output inductors off completely and say it sounds better - speaker wires connected directly to the amp's output pins. I have not yet reached the point where I'm willing to try this with these transformers. It should work; I'd guess these line matching transformers easily have enough "leakage inductance" to replace the loss of the output inductors.
Assuming for the case where people remove them completely, the speaker wires / speaker VC are doing this function. Some class D amps can operate this way by spec. EMI / RFI being up to the engineer in such a case.
All in the name of the recording studio lore that a transformer can color the sound in a desirable way. If it does, it's something I'm not sure I can even hear.
Go ahead - it's going to work. Let your own ears tell you whether it's worth lugging that 500VA hunk of iron around with your rig.
I drove the 25 Ohm tap with the amp, connected the speaker to the 16. With an 8 Ohm speaker, the amp didnt seem to care one bit. Reversed however (Amp driving the 16, speaker connected to the 25) I could perhaps sense some strain...
Been reading in here how people just pull their class D amps output inductors off completely and say it sounds better - speaker wires connected directly to the amp's output pins. I have not yet reached the point where I'm willing to try this with these transformers. It should work; I'd guess these line matching transformers easily have enough "leakage inductance" to replace the loss of the output inductors.
Assuming for the case where people remove them completely, the speaker wires / speaker VC are doing this function. Some class D amps can operate this way by spec. EMI / RFI being up to the engineer in such a case.
All in the name of the recording studio lore that a transformer can color the sound in a desirable way. If it does, it's something I'm not sure I can even hear.
Go ahead - it's going to work. Let your own ears tell you whether it's worth lugging that 500VA hunk of iron around with your rig.
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But in this case, he would have to remove the 2 existing coils of the Ice before putting on his transformer .... am I wrong ??
The OP is trying to mimic the sound of a traditional tube guitar amp with a Class D amp stage. Adding a 500W output transformer, or any transformer, to the output of a Class D amp and expecting it to saturate and produce the artifacts of an overdriven tube output stage saturating an OT, well, I see a lot of optimistic dreamers here (“Wut $5 Aliexpress chip can haz same sound as $10K Audio Note?”) but this might be the new GOAT.
The short answer is, it won’t. It can’t. Not even close. Class D chip amps behave so completely differently from tube amps you’re better off just buying a DSP modeling amp from Fender/Vox/Blackstar and calling it a day. You’ll get a far closer approximation of a classic tube guitar amp that's loud enough for stage use than you ever will by trying to DIY some assemblage of chip amp boards and whatever you think you can just tack onto them to make them sound and behave like tube guitar amps.
Chip amps are magical things, they truly are. A $15 TPA3116 board sounds better to my ears than a Dynaco ST70. It’s not even close. But tube guitar amps are a different animal. They sound good when they’re pushed into distortion/overload. We like the artifacts tube guitar amps produce when they’re pushed too hard. Class D amps, not so much. We like Class D amps as long as they stay within their clean range. Beyond that, things get nasty really suddenly and it’s not good nasty, it’s nasty nasty. Unless you’re chasing that nu metal sound where the singer is channeling Cookie Monster, the sound of a distorting Class D amp is not going to make you very happy.
Honestly, just get a cheap Fender or Vox modeling amp. These things are amazing. They sound close enough to ihe old classic amps to fool 99% of anyone in the club, and that 1% who can hear the difference, they can hump a Twin to your next gig. I know this is DIYaudio but getting a chip amp to sound and behave like a 60s Marshall is and will evermore be impossible, even fractionally. God, if only…
The short answer is, it won’t. It can’t. Not even close. Class D chip amps behave so completely differently from tube amps you’re better off just buying a DSP modeling amp from Fender/Vox/Blackstar and calling it a day. You’ll get a far closer approximation of a classic tube guitar amp that's loud enough for stage use than you ever will by trying to DIY some assemblage of chip amp boards and whatever you think you can just tack onto them to make them sound and behave like tube guitar amps.
Chip amps are magical things, they truly are. A $15 TPA3116 board sounds better to my ears than a Dynaco ST70. It’s not even close. But tube guitar amps are a different animal. They sound good when they’re pushed into distortion/overload. We like the artifacts tube guitar amps produce when they’re pushed too hard. Class D amps, not so much. We like Class D amps as long as they stay within their clean range. Beyond that, things get nasty really suddenly and it’s not good nasty, it’s nasty nasty. Unless you’re chasing that nu metal sound where the singer is channeling Cookie Monster, the sound of a distorting Class D amp is not going to make you very happy.
Honestly, just get a cheap Fender or Vox modeling amp. These things are amazing. They sound close enough to ihe old classic amps to fool 99% of anyone in the club, and that 1% who can hear the difference, they can hump a Twin to your next gig. I know this is DIYaudio but getting a chip amp to sound and behave like a 60s Marshall is and will evermore be impossible, even fractionally. God, if only…
stephenl5. Some of the information here is not completely true. The output filter is there to shave off the switching frequency so that won't create radio magnetic waves that will interfere with AM radio etc.. When output chokes are saturated it will induce distortion and therefore class D obviously will sound better without. But its illegal in most countries to spam out radio noise so don't do it. Some class D amps skips the output filter if its directly connecteded to a driver with a few cm of wire. The wire is then to short to act as an antenna. I would just hook up the existing amp and see if you like the effect 🙂. As you said, you'll loose some bandwith but in this case this won't matter. My gueess is that you get less dampening effect of the cone and that could affect the bass. Regarding adding more harmonics it won't sound like a tube amp, but it will change the sound slightly. I would rather put a tube pre in front btw.
In every single instance of a commercially produced digital modeling guitar amp, ALL the tonal and sonic character is handled in the DSP/preamp stage, while the solid-state output stage is treated solely as a clean gain stage of whatever sound the DSP/preamp stage was dialed in for. The classic tube guitar amp sound the OP is looking for is produced by DSP and opamp/diode clipping, not massaging a Class D output stage with EQ or even less effectively, an output transformer.
If the OP’s goal is simply a proof of concept exercise, knock yourself out, it’s your dime. But if he actually wants to get closer to a tube guitar amp sound with a Class D power amp stage, he is strongly advised to forget it and just pick up a cheap Fender/Vox modeling amp. There’s boldly going where no tweak has gone before and then there’s cutting to the chase. Life is too short, especially these days.
If the OP’s goal is simply a proof of concept exercise, knock yourself out, it’s your dime. But if he actually wants to get closer to a tube guitar amp sound with a Class D power amp stage, he is strongly advised to forget it and just pick up a cheap Fender/Vox modeling amp. There’s boldly going where no tweak has gone before and then there’s cutting to the chase. Life is too short, especially these days.
IMHO, OP said "The purpose would be to maybe "warm up" the sound a bit" - not get a full-on tube amp clipping / overdrive sound. It's well known in studio recording - and there's real money being exchanged to back it up - that transformers in the audio signal path "warm up the sound a bit". A bit, being the operative word here.
So unless someone comes up with an explanation why a transformer works that way at a line level signal, but not at a speaker level signal, I'd say OP's quest has merit. Perhaps he can hear the difference and it's a pleasing effect.
Regarding engineering the circuitry of such, I've guessed that the "leakage inductance" of such a transformer would swamp the value of those little output inductors, so they may be dispensed with. No reason to do so if they're already in place - just sayin'.
By keeping lead lengths short, you can reduce EMI if they're removed. The experiment will work either way and I for one would be interested if any perceptible "warmth" increase is noted.
So unless someone comes up with an explanation why a transformer works that way at a line level signal, but not at a speaker level signal, I'd say OP's quest has merit. Perhaps he can hear the difference and it's a pleasing effect.
Regarding engineering the circuitry of such, I've guessed that the "leakage inductance" of such a transformer would swamp the value of those little output inductors, so they may be dispensed with. No reason to do so if they're already in place - just sayin'.
By keeping lead lengths short, you can reduce EMI if they're removed. The experiment will work either way and I for one would be interested if any perceptible "warmth" increase is noted.
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The OP probably wisely checked out six posts ago but for pedant's sake I'll add two more cents and then I'm done.
Whether the original request was for merely some subtle "warmth" to the sound, or what I took to mean a more comprehensive tube guitar amp sounding rig where the IcePower amp board served as the output stage, I stand by my guidance that merely adding a transformer to the signal chain, either before the power stage or after, is not going to do anything except make the chassis heavier. You could always bypass all this internet stranger speculation and just call IcePower themselves to ask them about hanging a Hammond PT on their amp's output as an OT, if you've always wondered what Danish laughter sounds like.
If it's just a bit of "warmth" the OP wants, just double your guitar cable and let the added capacitance take care of rolling off the HF. Or add a small shunt cap on the amp's input from signal to ground will roll off the top end -- just adjust the value to taste. Start with a .047uf cap and go from there. Much lighter and cheaper than a transformer in the signal path, which is going to be really, really hard to hear at all unless it's quite terrible, which Hammonds aren't, even when you try using PTs as OTs, which you shouldn't. But don't take my word for it, call up Hammond and ask them, and then you can hear what Canadian laughter sounds like.
If the OP wants to turn his IcePower amp board into a tube guitar amp soundalike, and he doesn't want to go the route of a dedicated modeling amp, then I advise treating the amp board as a clean PA head with a full-range PA speaker and feeding the IcePower the line-level signal from something like a POD. No one's going to laugh at that setup, not even in English.
Whether the original request was for merely some subtle "warmth" to the sound, or what I took to mean a more comprehensive tube guitar amp sounding rig where the IcePower amp board served as the output stage, I stand by my guidance that merely adding a transformer to the signal chain, either before the power stage or after, is not going to do anything except make the chassis heavier. You could always bypass all this internet stranger speculation and just call IcePower themselves to ask them about hanging a Hammond PT on their amp's output as an OT, if you've always wondered what Danish laughter sounds like.
If it's just a bit of "warmth" the OP wants, just double your guitar cable and let the added capacitance take care of rolling off the HF. Or add a small shunt cap on the amp's input from signal to ground will roll off the top end -- just adjust the value to taste. Start with a .047uf cap and go from there. Much lighter and cheaper than a transformer in the signal path, which is going to be really, really hard to hear at all unless it's quite terrible, which Hammonds aren't, even when you try using PTs as OTs, which you shouldn't. But don't take my word for it, call up Hammond and ask them, and then you can hear what Canadian laughter sounds like.
If the OP wants to turn his IcePower amp board into a tube guitar amp soundalike, and he doesn't want to go the route of a dedicated modeling amp, then I advise treating the amp board as a clean PA head with a full-range PA speaker and feeding the IcePower the line-level signal from something like a POD. No one's going to laugh at that setup, not even in English.
Overdriving a transformer and saturating it will cause its input impedance to fall to approximately zero, hopefully causing the amp's protection features to cut in and drop the signal completely (the only other alternative with class D is exploding the MOSFETs).
Doesn't sound workable concept to me. And a power transformer doesn't have the bandwidth for audio, you'll might even cook the core through the large eddy-current losses if kHz power is put into it.
Doesn't sound workable concept to me. And a power transformer doesn't have the bandwidth for audio, you'll might even cook the core through the large eddy-current losses if kHz power is put into it.