[danlayman]

I'm considering adding a Behringer digital eq / dac to my system.  Its analogue output is specified as +12 db.  Will this overload a Bryston BP-25 (Manufactured 2000)?  I will be using balanced connections?

[Sebastiaan de Vries]

Dear danlayman,

No It works fine with the BP-25. I have a DEQ2469 myself. You can switch the gain factor analogue on the backside.

Original the opamps in the In and output stage of the DEQ-2496 sucks, the same for the capacitors in the signal pad. It is better to upgrade to a Bryston DA board. Feed the ultracurve digital from a cd transport, and feed the digital output of the ultracurve to the digital input of the dac board. In this way you only use the DSP powerk of the ultracurve.

If you still wish to use the Ultracurve analogue, check our site. My company update the Ultracurves with decent in and output stages as a beter powersupply. http://www.soundevolution.nl Sorry it is al in dutch

With kind regards,
Bas

[danlayman]

Thanks for the reply.

I'm aware  that the analog section of the Behringer is not the greatest.  I've heard mixed reviews on how well the piece works as a D/A -some say its very transparent, others say its mediocre.  I'm going to give it a try and see what I think of it.  My current CD player is nearly 10 years old (CAL Audio CL-10), so the newer DAC's may make up for the weaker analogue section for me.  If not, I will purchase a stand-alone DAC or upgrade my BP-25.  Actually, though, I'm not 100% sure  that my vintage BP-25 can take the DAC upgrade.

[James Tanner]

Yes the vintage BP25 can take the DAC upgrade.

james

[danlayman]

Hi James -

Do you agree that  the BP-25 be OK with the +12 db output level from the Behringer?  

What would be the approximate cost of the DAC upgrade to my BP25 if I were to decide to go that route?   The Behringer only has balanced or optical digital outs, no coax, so I'd need to look for some sort of adapter cable.

[James Tanner]

Hi,

No problem with the plus 12.
The upgrade is $1000 US.

james

[danlayman]

Thank you, sir.  Quick response, as usual!

[Sebastiaan de Vries]

Dear danlayman,

The ultracurve itself has a great DSP power. It are only the in and output stages that suck and sound horrible. In the way as I described Transport > ultracurve > Bryston dac the ultracurve have no negtaive effects anymore (also not in jitter because the bryston dac use asychrone reclocking).

And yes then there is the subject "room correction". I know James don't like it, but one day I gonna convince him aswel

Make sure you use the ultracurve in "dual mono" mode. So you have to messure left and right.

I know most demonstration's with room correction sound bad. And that's all beacause most people don't know how to use them.

Let me show you my sistuation. I have a fullrange loudspeaker system. Capable of producing 20Hz. I'm a bass player myself and I want at home the same impact and feeling as live. Now I have a really big problem. My room have a big peak at 60 Hz. almost 14db!.

The first problem is that this frequency excist in almost every record and every instrument. So it is always there. The biggest problem for me is, that you never noticed the real subfrequent tones. Let's say a low B of a bassguitar. That is a frequency of 31Hz. I know so wel how this tone feel and sounds. My loudspeakers can produce that. But in my room I only hear the second harmonic of 62Hz. Because this is my room resonance. You don't feel and don't hear the low 31Hz. It is total masked bij the second harmonic of 62Hz. Horrible! After the ultracurve remove al the peaks, my lowend is so so tight equal, and so deep. For the first time it was possible to hear a low A of 27,5Hz. from a steynway! And that al with removing frequency bands.

How flat you're loudspeakers are, how good theyr phase response is. YOu never gonna hear a 31Hz. if you have a huge peak at 62Hz. The only solution is either basstraps our a total acoustical treatment or room correction.

If you use the ultracurve to make the frequency response totally flat. It gonna sounds horrible. In total you gonnan loose +/- 15db. of gain in the bass from 20 to 100Hz. this beacuse every room have a big bassboost. So use the auto eq to make everthing flat. But later ad a bassboost filter in the PEQ that boost the lowend between 30 and 150 Hz. 6db. You don't gonna stress the sysem, because you add a thing that's removed before. So you have back you're bass, but now without peaks. The bass become tight and so pinpointed. Just like bass has to be! LAter this week I will show you messurent's.



With kind regards,
Bas

[danlayman]

bas -

Yes ideally I would like to use the Behringer just for room correction, and ultimately I probably will do that.  Upgrading my BP-25 or purchasing a stand-alone DAC will likely be in the future, but is not feasible right now.

One thing I don't like about upgrading the Bryston is that it would have only a coax in, whcih the Behringer does not have as an output connection.  What are you doing for that problem?

My main goal is to smooth out upper bass response in my room.  I've been working wit h speaker positioning for quite a while in my new house and believe I have it optimized but I still have a broad 3-4 db hump in the 100-200 octave, which adds some unwanted thickness to voices.  It may be partially due to my speakers too, Dynaudio Contour 1.3SE, although it wasn't apparent in my previous environment.   Other than that, my bass is reasonably, but not completely flat.  The Contour's tweeter is shelved down just a bit, which I may try to bring back up a db or so in the top octave.  

I debated about this purchase because I very much like my CAL CL-10 player and hate to take its sonics out of the equation.  I wish I could feed the corrected digital signal back to it, but I can't.

I would like to read more about your mods, but I can't read Dutch I'm afraid.  I know there are several people doing this.  Perhaps it might be an alternative to a DAC upgrade.

[Sebastiaan de Vries]

One thing I don't like about upgrading the Bryston is that it would have only a coax in, whcih the Behringer does not have as an output connection.  What are you doing for that problem?

Dear danlayman,

As far for the AES/EBU xlr output on the Ultracurve, you can use this with the S/PDIF rca input on the BP-25 dac board. You have to solder a bridge between pin 1 and 3 of the xlr connector. You solder the live signal (tip of the rca on the other side) on pin 2. then solder the ground (ring on the rca) to pin 1 of the xlr. That works perfect.

The difference between s/pdif and aes/ebu is the first bit, the voltage and the impedance. The AES/EBU input of the ultracurve work with the lower s/pdif voltage. the first bit only carry a copy bit. An work fine with s/pdif. Nothing to worry about. The only drawback is (inabsolute sense) the impedance mismatch between the s/pdif (75Ohm) and the AES/EBU (110ohm). Without correction it still work fine without problem's. But with respect to get the lowest jitter possible jou have to make a impedance correction with a couple of resistors or a pulse transformer.

Not really necessary, but if you wantto go so far just give me a mail and I will help you . Don't let this hold you to upgrade to a dac board . I work the same way like you, and go from RCA S/PDIF to XLR AES/EBU. I'm also to lazy to make a impeance matcher It work fine.

With kind regards,
Bas

[dubkarma]

I'd like to know the maximum input voltage (RMS) that the BP-25 can accept via its balanced inputs before overload.

That's because. . .

I've recently started using a Universal Audio 2192 ADC/DAC with the BP-25 and I suspect its analogue output is overloading the balanced input on the preamp.

The outputs on the DAC can be trimmed; the question is by how much. I believe maximum output with the factory settings is spec'd at 22 dBu which is apparently 9.75 Vrms.

Knowing the overload input voltage of the BP-25 would give me a target for recalibrating the output voltage of the DAC.

Thanks!