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Old

Onkyo SE200-PCI sound card windows 10 driver issues / disable immezio 3D effects

Posted 8th October 2015 at 07:35 AM by rjm (RJM Audio Blog)
Updated 23rd November 2015 at 11:30 PM by rjm

Apologies for the Google-friendly title, I'm hoping people experiencing the same problem will find their way here.

Onkyo download page: http://www.jp.onkyo.com/support/pcau...d/se200pci.htm

Current version is 5.60C, last update was 2012 to be compatible with Windows 8. Driver package 5.60C installs without issues on Windows 10 64 bit. The AudioDeck utility installs as well.

However, all is not well:

On installation, Immezio 3D effects are enabled. This locks the sample rate at 48 kHz. 44, 96, and 192 kHz cannot be selected. Deselecting the Immezio 3D effects prompts a reboot, but the Immezio 3D effects remain enabled after rebooting. The card is stuck at 48 kHz. 3D effects (which enables the DSP processing such as Qsounds, EAX, A3D) cannot be shut off.

I see three possible workarounds:

1. Find a command line switch, or edit the installation batch file to disable Immezio 3D on installation...
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Old

Orb JADE-1 headphone amplifier and DAC : review

Posted 2nd October 2015 at 05:07 AM by rjm (RJM Audio Blog)
Updated 9th November 2015 at 01:44 AM by rjm

This is a headphone amplifier with digital inputs, not a DAC with a headphone jack. Though technically given equal board space, the headphone amp, with hot-running single-ended class-A output stage, is surely the centerpiece of the design. (The Asahi Kasei DAC, with MUSES01 for the I-V, is no slouch mind you.)

First impressions. It is large, solid, and very nicely made, but - after seeing the inside - rather simple, spartan even. From the DAC output to the headphone jack is just two op amps and two transistors, the op amps being shared between channels. A third op amp most likely just buffers the analog line output. Apart from the headliner MUSES01 op amp none of the parts are especially expensive, though many were clearly carefully chosen for sound quality - the 2SC5196 for example. The TE7022 USB receiver is a disappointment, as is, to be honest, the single set of power rails and the use of dual op amps shared between channels.

On a positive note, the front...
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Old

Choosing a USB DAC

Posted 26th September 2015 at 11:49 AM by rjm (RJM Audio Blog)
Updated 9th October 2015 at 04:24 AM by rjm

My Onkyo soundcard drivers stopped working when I upgraded to Windows 10. Onkyo says they have no plans to release a patch, so I'm left with no high quality audio solution for my computer. Since I already have a good headphone amplifier, what I'm mainly looking for is a high quality line level analog output.

One options is another soundcard, the ASUS Xonar STX being the obvious choice. I dunno, it doesn't grab me.
I was thinking with going with an external box this time, connected via USB. As this opens up about a zillion options, I'm going to limit things to,
  1. Respected audio brands with a solid reputation for digital audio.
  2. Small enough to be placed on top of my computer case.
  3. $500-ish, used or new.
My short list includes the following: Denon DA-300usb, TEAC UD-301, and Onkyo DA-1000. Teac also makes the 301's big brother, the UD-501. This is a much nicer unit, very substantial. A bit large. Rounding out the field is the LUXMAN DA-100 . These can be found deeply...
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Old

Audio Op Amps

Posted 26th June 2015 at 02:59 AM by rjm (RJM Audio Blog)
Updated 1st October 2015 at 07:04 AM by rjm

I'm often asked "which op amp sounds better".

The reply is usually a scowl and muttered "does it look like I care!?" Which is something of a lie... I do care about getting op amps to sound good. It's the phrasing of the question I dislike.

Op amps do not come in "good, better, best" flavors. All it is - and this is pretty obvious I would have thought but apparently not - all this is about is matching an op amp to the job it's going to do; the circuit it's going to be sitting in.

The op amp you'd choose to use as a DAC IV converter is different from the one you'd choose to back a 100k volume potentiometer in a preamp is different from the one you'd choose for an MC phono preamp input stage...

Why do you think there are like a thousands of different op amps to choose from in the first place? It's because there are thousands of combinations of op amp characteristics and properties ... not because companies...
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Old

Jenson JE-990 discrete op amp

Posted 8th June 2015 at 07:45 AM by rjm (RJM Audio Blog)
Updated 9th June 2015 at 12:09 AM by rjm

LTSpice copy (protection diodes removed) of the original JE-990 circuit. Even with BC327/337 subbed in for all the original transistors the simulation works without further modification.

C1 seems to be critical for stability. C2 and C3 damp overshoot seen on the simulated square wave response, hinted at by the high frequency rise in frequency response shown in the screen grab below.

My impression is that this circuit is of the heavily optimized, no-stone-left-untouched variety.

Sourced from m.nats page and The John Hardy Company.
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Old

AT-HA5000

Posted 21st May 2015 at 01:32 PM by rjm (RJM Audio Blog)
Updated 27th May 2015 at 01:54 AM by rjm

This post, about a push-pull MOSFET output stage for a headphone amp, got me thinking again about the Audio Technica AT-HA5000, which is something of a benchmark in its class. The "basic" signal circuit (not a complete schematic, it's clearly missing some ancillary details) is attached below. Probably out of MJ originally.

I think with any circuit like this, the differences are less about the MOSFETs and the operating points and more about the front end and what tricks you do with the power supply. That, and how you make sure it doesn't go up in a puff of vaporized silicon taking your headphones with it.

The Audio Technica schematic has nice old-school Zener regulators, a discrete JFET front end, a long tailed pair + current mirror for voltage gain and "proper" BJT Vbe multiplier and driver stage. Q7 is presumably in thermal contact with Q10,11 providing overtemp protection, and the output has a protection relay (not shown in detail) for...
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Old

Szekeres 2015

Posted 20th May 2015 at 06:00 AM by rjm (RJM Audio Blog)
Updated 18th June 2015 at 11:26 PM by rjm (added schematic of original version)

The circuit was originally hosted on Headwize, but the site seems to have gone offline.

It was a single stage resistively-loaded MOSFET follower, a unity gain current buffer used to drive headphones.

Some updated versions provided below. As noted in the comments the "Reverso" version with the CCS on the V+ and a p-channel mosfet has better PSRR performance, especially with voltage divider network R6,R7,C4 on the collector of Q2.

So good in fact that I switched around the n-channel version to use a negative voltage rail to obtain the same result!
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Old

JLH-2005 headphone amplifier

Posted 18th May 2015 at 08:15 AM by rjm (RJM Audio Blog)
Updated 27th May 2015 at 01:52 AM by rjm

I was perusing this thread earlier today. Which led me to what I think is the original source, at least as a modern, relatively clean headphone amp version of the original original (by way of ESP).

Some comments from our own Nelson Pass are seemingly relevant.

AC coupled, and simplified to a single supply voltage, the circuit can be run at +5 V operation (USB, etc) with fairly decent performance.

The circuit is optimized for 16 ohm headphones.
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Old

A headphone amplifier gain calculator

Posted 2nd May 2015 at 05:30 AM by rjm (RJM Audio Blog)
Updated 2nd May 2015 at 05:33 AM by rjm

You input the headphone sensitivity and impedance, and it spits out what I think is the ideal amplifier gain.

Even if you disagree (personal preference, difference input levels, etc.), the difference will be consistent regardless of headphone as long as the specified parameters are correct.

The gain value setting is tailored to normal line level input and listening fairly loud with the volume control at 9~10 o'clock. The output series resistance is assumed to be zero ohms.

Adjust as desired, and note that 3~6 dB either way will still be a usable. If your amp has a large output series resistance the gain Av should be scaled up as,

(Routput + headphone Z)/(headphone Z)
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Old

Doin' a "Gilmore" : a discrete transistor headphone amplifier

Posted 10th March 2015 at 12:17 AM by rjm (RJM Audio Blog)
Updated 13th March 2015 at 10:42 PM by rjm

Recently I spent some time updating the diamond buffer of Sapphire headphone amp circuit. Later I stumbled on Kevin Gilmore's headphone amp circuit. Well, I'd read it before, but it had slipped my mind.

On seeing the Gilmore circuit again the thought process re. a Sapphire+Gilmore went something as follows,

"Toss out op amp, convert the Gilmore dual-LTP front end to bipolar, bolt the Sapphire3 buffer stage to the back, and substitute in the Sapphire3 current sources. Wrap in a mild feedback loop."

The result is shown attached. The Vbe multiplier is still a simple resistor (R33) ... that may need to be refined to add thermal throttling. The offset servo is not shown, but the action is shown as Vadj. Alternatively a trim pot would be placed between R30 and R32 to provide a small measure of offset adjustment. Most of the open loop gain is controlled by R14,R15 ... it seems to me that some work could still be done in that area. Despite going...
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