Hello all,

I received my Buffalo + IVY in december and soldered everything together during Christmas holiday. I connect it to my computer with Toslink, but since it was for me the first time it took me a long, long time to get this going. Anyway two days ago I had sound for the first time. The first thing I noticed in about one second was that the left channel played much louder than the right. I roughly estimate the difference form listening at different positions to about 10 dB. Any possible explanations? This difference was stable during two evenings of listening two hours.

Further I notice that with every new song the first fraction of a second is missing. When a song starts abrubtly this is quite nasty. I have not seen my two problems in other messages on this forum and up to now I did not notice any other dropouts.

A final question: does this stuff have a break-in time? In other words: does the sound change/improve the first hours/days/weeks when in use? The reason for this question is that from first hearing I do not really share the enthousiasm of other persons on this forum. I do perceive a clear improvement in the bass: it is definitely deeper and more detailed than from my previous DAC. But the mids, highs and sound stage are maybe marginally better. This is to some extend influenced by the imbalance, but maybe my old DAC with USB was already quite good (www.twindac.com). Additional questions to this: Did anyone of you ever compare Toslink vs USB on the same DAC? Is there a big difference between Toslink drivers and/or fibers? I am running my first test with a cheap plastic fiber.


Kind regards,
Eddie

@Eddie: I can only answer your second question about break-in. On the Buffalo there is some break-in but I suspect it is more due to the ears adjusting to the sound. In reality the change is ever so slight and it does not take much time to settle down, as (IMO) there is no cap in the signal path at all. I came from a e-mu1212M's analog board but modded heavily, and the change is fairly pronounced and dramatic from there. I don't know that the soundstage or imaging was much improved myself, but the tonality was more 'correct', accurate and honest but without being sterile or harsh. There would be room for improvement for sure, with a better I/V but for now I'm totally satisfied.

As for your case, you can't judge a piece of equipment if the levels are off in the two channels. Imbalance is one of the prime reasons for poor soundstage and overall listening experience.

HI Eddie,

On the Buffalo, there is an IC4. It is next to the DIP switches. Is it installed?

Hi Eddie, the reason I asked is because your symptoms sound like a DAC that is not being configured correctly via I2C. Is it possible the PIC is in backward?

What power supplies are you using? Can you attach a picture?

You attach a picture by clicking on the attach button (upper right of the message) after you have submitted your reply.

Edited by user Friday, February 27, 2009 5:09:23 PM(UTC)  | Reason: Not specified

Did you attach a picture? If it's too big, you can email to us at Questions@twistedpearaudio.com

[EDIT]: see the pic now. Please send a higher resolution copy via email.

Edited by user Saturday, February 28, 2009 1:11:56 PM(UTC)  | Reason: Not specified

Hello Russ,

1. Lots of other occupations last week, but the checks I performed on the connections were already done with a DMM.
2. I connected the Toslink module to D1 and found a significant improvement in sound quality! My problems with the unbalance and the intros did not disappear.

Yesterday evening I did a check with a test-CD that has a mono 1-kHz signal recorded at 0 dB. For a reference I measured the outputs of a cheap CD-player. It gave 1.69 Volt-AC and ~1 mV-DC on both channels.

When I measured the Buffalo I saw rather strange readings both AC and DC but the left and right channel were always identical.

On the IVY I measured with the 0 dB sine wave: 1.85 V-AC at the left channel and 0.469 at the right channel. The DC is -8 mV on both channels. The difference is a factor 4, that makes 12 dB difference, not far from the 10 dB that I estimated by ear. The left channel is indeed the loudest when playing music.

If I switch off the sine wave I measure a V-DC of -1.01 at the left and -0.257 at the right. These DC values change with time. The AC-values in this case are 7 mV on both channels.

I have heard that it should be possible to connect the Buffalo directly to an amplifier. I would like to test this, but how should I do that with single ended inputs? How can I measure the outputs of the Buffalo to check its performance?


Kind regards,
Eddie

Hello Russ,

I am sorry but this is too short for me.

1. On Internet I found several ways of going from balanced to unbalanced:
-connect pin 1 and 3
-with resistors
-with a transformer
-with opamps (like in the IVY),
but never with capacitors. I attach a figure that I made up myself, is that what you mean? What value do I need? Something like 1 uF?

2. So I should disconnect the IVY in order to measure the outputs of the Buffalo? (I think I now understand why my DMM dropped to zero shortly after connection: the IVY-input is in a feedback loop). Can I leave the outputs of the Buffalo open or is it better to have a load resistance, e.g. 10 kOhm?


Kind regards,
Eddie

Hello Russ,

This afternoon I did what you suggested. First I measured the outputs of the Buffalo with the 1 kHz, 0 dB sine wave. Both channels gave 1.68 V so that was promising. Then I listened to three CD's but already after the first few seconds I noticed that the channels are now balanced and the sound is better than with the IVY: more detail, more natural. I now must come back to my first post: the Buffalo is a lot better than my old Twindac!

One nasty problem, however, remains: at the beginning of a song the lock-led is out for a moment and the first fraction of the song is missing. Sometimes I hear a click when the lock-led switches on again. If the song starts abrubtly then the first word a the text is severely distorted. I guess that this is not the normal way for the Buffalo to start. Unfortunately I have no other options than the Toslink to get the signal to the DAC. Any suggestions how to solve this issue?


Kind regards,
Eddie

Hello Russ,


Thanks for the information.

Will I get rid of these clicks if I use USB? My previous DAC had USB and never gave clicks at the start of a song.

Another solution could be to force the computer to send SPDIF data inbetween tracks. Unfortunately I have no idea how that should be done. Could you give me any clues on this?


Kind regards,
Eddie