[*Scotty*]

From Blairs simple home setup let's see just how many times his signal may have zigged or zagged. Not counting the digital domain before the DAC's generation of an analogue waveform. It would be nice if the DAC had a separate pin for the voltage used by the part of the DAC that turns the digital into an analogue signal. Many DAC's generate this voltage internally and the noise from digital processing in the DAC contaminates the power to the analogue portion of the DAC.  Let's assume nothing really bad went wrong here and now we are headed to the analogue gain stage and out the back door to the preamp. If an opamp was used here it would be nice if it had a discrete buffer in it's feedback loop so that it didn't have to drive the cables and the preamp directly. It would also be nice if the power supply to the opamp was shunt regulated and the opamp was a good sounding chip with a fast enough slewrate for the job. The DVD player would also sound better if  the opamp was direct coupled without without a bad sounding coupling cap and a hand full useless resistors between you and the music.
It wouldn't hurt if the RCA jacks were pure copper,gold plated with teflon insulation. The interconnect cables regardless of design would sound better with a pure copper/teflon RCA plug.
   We finally got to the preamp, more of the same, RCA jacks,internal wiring,volume pot or signal attenuation design chosen, cascoded active current sources,shunt regulation,local degeneration and global feedback used,size and type of rectifiers used in the power supply,ultra low impedance caps in the power supply,very large oversized power transformer.
And so on. Basically every decision about the components used and the circuit design that was implemented can lead to a zig or a zag in the signal on the way to your ears. The truth can be lost before it ever leaves your CD or DVD player. In the case of very high resolution systems you can lose the race in the internal hookup wire or the cables you use to connect your gear. You have to chose to try to preserve the life present in the original recording at every step of the design process and attempt to minimize the dynamic non-linearity of the circuits and the passive components you use. A successful design will sound more like real life. If your circuit masks the differences between the hookup wire or the jacks you use it needs work. You should also be able to hear the effects of the ubiquitous green solder mask used on circuit boards and those without it. You should be able to hear the size of the reproduced acoustic space shrink as the circuit board is mounted closer to the floor of the chassis. The board needs to be mounted at least an inch away from any chassis surface to minimize the impact of the problem. It's no wonder people pray for synergy between their components when assembling a system given how easily things can go astray in even a simple appearing setup like Blair's.
Scotty

[doug s.]

My favorite amplifier upgrade has become variable negative feedback. This function allows the amplifier to be compatible with an extraordinarily wide array of existing sound systems and tastes. As was stated earlier, synergy is very important within an audio system.

if i could have only one amp, i would keep my mesa baron.  besides having negative feedback settings of 0db, -2db, -4d, & -8db, it can be run full triode at 55wpc, full pentode at 150wpc, or 1/3-2/3 in between at 85wpc & 120wpc respectively.  it is neutral, dynamic, revealing, full bandwidth, has great soundstaging ability, and can drive wirtually any speaker.  its flexibility allows it to perform well w/wirtually any speaker/room combination.  oh, its input impedance can also be set for 60kohms or 110kohms, but you need to desolder a resistor to accomplish this, everything else can be done on the fly, while the amp is playing...

i am presently not using it, as i am running 100db-efficient horns almost full-range, from ~300hz to 20khz, so it's not really needed.  i have a few low power low/zero feedback single-ended amps for this type of speaker.  (actually one of these amps, a custom 4wpc 6v6-based set, does have 0/-2db/-4db feedback settings.)  but, i am sure the baron would do yust fine, even w/the horns, at its full-triode no feedback setting...   

doug s.

[doug s.]

scotty, i can relate to your signal "zig-zag" tale.  i remember when i got on the art di/o dac bandwagon craze.  first, i listened to it stock.  then, i built a pair of canare star-quad ic cables w/resistor attenuators to reduce its pro audio output level from 7v to 2v.  then, i proceeded, in several steps, to slowly upgrade my di/o per info out on the web.  then, i got an isolation transformer for the dac.  then, a second one for the transport.  one of the cd's i used was a hawaiian slack key masters vol ll cd.  i noticed one particular solo guitar cut that seemed to have a subtly noticeable noise floor.  but, every time i did another mod, the noise floor got lower, and more sound of what the musician was doing became apparent.  by the time i was finished w/all the mods, it was clearly evident that the initial "noise" was the sound of the guitarist breathing, and moving in his chair as he played.  it was a fascinating journey!   

doug s.

[Niteshade]

'If your circuit masks the differences between the hookup wire or the jacks you use it needs work."


Audio components need to be made with stability in mind and not be over reactive. As long as the cables, wire, internal components, etc.. are high quality, there should be no measurable signal degredation from them. It would not be good for an audio system tobe over reactive.

I do agree that digital and analog components should be made to allow the purest signal possible to pass without underlying noise or reactive signal attenuation.

[*Scotty*]

If you have encountered an impact on the sound of a circuit as a result of a construction difference between two passive components, carbon film vs metal film resistors for example,
then you have made choice of which one to use based on how the circuit sounds with a particular component in it. The circuit measures the same but sounds different depending on which
resistor you use. If changes in passive components including the jacks used on the inputs and the wire connecting them to input selector switch doesn't impact the resulting sound,as a designer one is faced with a couple of interpretations of the null result. Either passive components like RCA jacks, hookup wire and selector switches have no measurable effect or impact  on the sound of the circuit, or they do and can't be heard with the current circuit design or the system in which it is being evaluated. The Devil is in the details, the more transparent the circuit the more the passive components surrounding it can impact it performance irrespective of measurements.
Scotty

[doug s.]

If you have encountered an impact on the sound of a circuit as a result of a construction difference between two passive components, carbon film vs metal film resistors for example,
then you have made choice of which one to use based on how the circuit sounds with a particular component in it. The circuit measures the same but sounds different depending on which
resistor you use. If changes in passive components including the jacks used on the inputs and the wire connecting them to input selector switch doesn't impact the resulting sound,as a designer one is faced with a couple of interpretations of the null result. Either passive components like RCA jacks, hookup wire and selector switches have no measurable effect or impact  on the sound of the circuit, or they do and can't be heard with the current circuit design or the system in which it is being evaluated. The Devil is in the details, the more transparent the circuit the more the passive components surrounding it can impact it performance irrespective of measurements.
Scotty

your example w/resistors is yust what i discovered when modding my art di/o.  first mod included replacing resistors w/holco metal film resistors.  a definite improvement.  later on, i decided to replace the holco's w/riken ohm carbon film resistors.  a further improvement occurred - more liquid sounding, w/no reduction in transparency...

doug s.