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IVY III - output impedance and driving capability
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Russ and Brian,
With the IVY II on the Buffalo 32S it was possible to change the output impedance by cutting traces. I used this "feature" to use two sets of XLR outputs for headphones and amp, respectively. Will the IVY III have a similar option or will it be one output "good for everything"?
Nic
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Yes. It has 22.1R output resistors that you can either install or jumper.
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What would be the max vrms put out if it's shorted? Does the new IVY have this option on the balanced outs as well? I'm going to be using this setup to drive headphone as well. Thanks, -Ken Brian Donegan wrote:Yes. It has 22.1R output resistors that you can either install or jumper. Edited by user Tuesday, February 16, 2010 2:08:52 PM(UTC)
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Both the SE and balanced output are ~2VRMS at 0db input. It drives headphones very well. :) Edited by user Tuesday, February 16, 2010 3:43:08 PM(UTC)
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So SE and balanced outputs are the same VRMS?
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Correct. :) But it is very easy to tailor both to your particular taste. :) Edited by user Tuesday, February 16, 2010 9:47:01 PM(UTC)
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Ok.
For my own understanding - even though the IVY III is not, it's usually the case that balanced outputs are double the vrms as se on the same source right?
So when people talk about building a balanced amp point out that the gain is effectively doubled that would only be the case where the balanced output of the source is doubled?
As in if I were building a balanced amp being fed by the IVY IiI the gain would be the same being fed se as it would balanced? I hope that's all clear, thanks.
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The SE output is the single ended differential sum of the two balanced output. The SE output is based on the balanced signal not the other way around. You would not want the balanced outputs to be too hot, nor the SE too cold. :) 2VRMS is standard and both outputs are set to this. :) The advantage to balanced outputs is not the signal level, but the noise cancellation and balanced load. It is quite simple to adjust the gain of either output should you desire. Cheers! Russ Edited by user Thursday, February 25, 2010 8:35:33 PM(UTC)
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Forgive my ignorance, but what kind of headphones can the Ivy III drive? Could it drive the Sennheiser HD600s for example - I think they're 300 ohms? Edit: I have read the manual in which you say they drive 'phones down to 16 ohms - is there no maximum?. Presumably using the balanced outputs would be better? If using the Ivy III to sometimes use as a preamp and sometimes as a headphone amp, I assume it's best not to jumper the output resistors? PS The HD600 manual apparently advises an amp capable of 200mW at 300 ohms. Edited by user Friday, April 16, 2010 9:39:42 AM(UTC)
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Higher impedance loads are generally easier to drive than lower impedance loads.
I drive my HD650s all the time.
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Brian Donegan wrote:Higher impedance loads are generally easier to drive than lower impedance loads.
I drive my HD650s all the time. Interesting. Most of what I read on forums seems to indicate that HD650s require a high level of amplification to get the most out of them. I'm more willing to accept your advice however. Thanks for that. Have you converted them to take a balanced input? I have some Grado SR80s (can't afford the good Sennheisers at the moment) that I was thinking of making balanced since I had already re-cabled them with a separate starquad cable going to each driver. Would it be worth doing?
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Quote: Would it be worth doing? In my opinion, yes.
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I'll give it a go. I suppose I could always install a switch to bypass the output resistors when using 'phones.
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With 150ma drive capability and 2VRMs output I think you will find it will drive just about any headphone extremely well.
I have used 600ohm headphones down to 16ohm IEMs.
There is honestly nothing to compare to driving your cans straight from the DAC. It is simply awesome.
Cheers!
Russ
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Russ White wrote:With 150ma drive capability and 2VRMs output I think you will find it will drive just about any headphone extremely well.
I have used 600ohm headphones down to 16ohm IEMs.
There is honestly nothing to compare to driving your cans straight from the DAC. It is simply awesome.
Cheers!
Russ The thing is, I have nothing to compare those numbers to but if you say they're good then they must be good. I have tried my Grados driven from the SE outputs and they did sound great. Thanks guys.
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Hello,
according the manual of IV-3 you can choose the values of R13 & R16 to adapt the tension level of your output, 2 examples are given : 180 Ohms for 2V and 356 Ohms for 4V, I would like to give the possibility to adjust theses levels by a potentiometer by placing for each level a couple of resistors, so what would be these values to have levels between 1V and 4V with step of 0,5V?
Sorry for my bad english and thanks for your help.
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This is not a very good or safe idea. Placing a pot in the feedback loop will be very noisy, hard to match (channel to channel and rail to rail), and failure can potentially cause damage (though this is less likely).
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Thanks for your advice Brian, but I thought about a selector (not truly a pot) to select the output voltage (just 3 or 4 possible values) before powering on the IVY, for instance 1V -> ampli 1, 2V -> preampli, 3V -> ampli 2, 4V -> headphone ... maybe a geek feature?!
The essential is your products sound wonderful!!
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That is more possible, but the other thing to consider is keeping the feedback paths as short as possible. It's always something :)
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jbbidet wrote:Thanks for your advice Brian, but I thought about a selector (not truly a pot) to select the output voltage (just 3 or 4 possible values) before powering on the IVY, for instance 1V -> ampli 1, 2V -> preampli, 3V -> ampli 2, 4V -> headphone ... maybe a geek feature?!
The essential is your products sound wonderful!! I have done something like this with my Buffalo 32S. It works pretty well and I cannot hear any detrimental effect of the longer feedback path. Even if I have used a very good switch there is quite some popping going on when you change gain. If you implement it I suggest you to turn of the DAC when you operate the switch. With a high-quality switch, resistors and wiring it is a pretty costly mod and I don't think I will implement it on my Buffalo II in the works, also because the actual difference in sound level is surprisingly modest....... Nic
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