|
Post by jimwilliams on Jun 19, 2014 10:01:21 GMT -6
Opto's create their own distortion problems from how they are interfaced. If used in front of a bipolar amplifier, bias current shifts can cause errors and DC shifts. De-couple it with a cap and you add a resistive thermal noise source. Use a non-inverting jfet opamp and you have another form of THD from a modulating input impedance. Opto's may be clean by themselves but they also open up another bag of problems when you use them, including matching and a gain range that is variable to each device.
Some VCA designs are rather dirty, look at older dbx fet based 202 cans for those examples. Modern dbx VCA's are improved, the that corp 2180 series can do .007%, a bit better than the .02% from earlier 2150 integrated VCA designs found in 160X comps. The 4300 series VCA's include detectors and the VCA, some versions throw in a mediocre opamp to save design effort/parts. The Foot uses one of those VCA's, they measure about .01% THD. It was designed as a low cost part, I've used them in MI bass amp designs.
The Aphex VCA is a little different, it's a differential VCA design that cancels a lot of THD compared to single ended designs like the that 2180 VCA's. Those do .002%, best in class. So far I've not heard of anyone that can hear that error.
|
|
|
Post by jimwilliams on Jun 18, 2014 9:37:21 GMT -6
Aphex 651's not only measure .002% THD, the slew rate is decent. They shine with extreme compression too. This is because of the high frequency expander, it maskes the compression effect and restores the lost high frequency details you always loose with higher amounts of compression.
They also have the widest adjustment range and up to 50/1 ratios.
A guy at the Record Plant said it best:
"It's like there's a little man inside running a fader up and down who's smarter and faster than we are".
|
|
|
Post by jimwilliams on Jun 18, 2014 9:10:39 GMT -6
The bridge is part of it, I use the old style folded edge bridges, those are cold rolled hard steel. Saddles can be rolled smooth steel or knurled, I prefer smooth as string bending can cause the string angle to rub and loose sustain. A also have one with brass saddles, a far less twangy tone. New models now use a flat bridge plate and six Strat vintage style saddles.
The steel plate used to mount the bridge pickup spreads the magnetic field out underneath the pickup. It does little to effect the tone as the strings are located on the other side of that field. What it does do is create the nagging squealing under higher gain. That is the plate actually moving at that frequency. Dipping it in wax helps but removing it solves the problems of microphonics if you use the latex/lockwasher technique. The neck pickup cover can also be a location for mechanical feedback, all of my pickups are wax dipped, the ones with the metal cover are dipped assembled to create a solid piece that can't vibrate. I also use latex hose to mount it, no springs are those are also magnetic and will vibrate/squeal at higher gains. Early Hendrix recordings and live shows had him play 1965 era Strats that also used latex hose to mount the pickups. Later CBS Strats switched to steel springs, you can hear Hendrix struggle to control the squealing of those guitars.
The secret of the Telecaster bridge pickup spank is the geometry of the coil. It is a larger bobbin than a Strat pickup and that focuses a narrower magnetic field under the strings than you get with a Strat or Jazzmaster pickup. That is due to the windings, it's a rather narrow stack with cotton string used to fill out the bobbin after winding. If you look at a Jazzmaster pickup, it's a flatter bobbin with the windings spread out further away from the magnet poles. That grabs a wider aperature of the string's field making for a fatter tone.
The magic of the Telecaster is found in the player's hands. With that ability to create a wide pallet of string tones from the player, it's as individual a sound as the player wishes to develope. Compared to Gibson humbuckers that double the fundamental frequency, those tend to make the player sound more anonomous and alike unless the player developes a unique way of attacking the strings.
|
|
|
Post by jimwilliams on Jun 18, 2014 9:09:57 GMT -6
The bridge is part of it, I use the old style folded edge bridges, those are cold rolled hard steel. Saddles can be rolled smooth steel or knurled, I prefer smooth as string bending can cause the string angle to rub and loose sustain. A also have one with brass saddles, a far less twangy tone. New models now use a flat bridge plate and six Strat vintage style saddles.
The steel plate used to mount the bridge pickup spreads the magnetic field out underneath the pickup. It does little to effect the tone as the strings are located on the other side of that field. What it does do is create the nagging squealing under higher gain. That is the plate actually moving at that frequency. Dipping it in wax helps but removing it solves the problems of microphonics if you use the latex/lockwasher technique. The neck pickup cover can also be a location for mechanical feedback, all of my pickups are wax dipped, the ones with the metal cover are dipped assembled to create a solid piece that can't vibrate. I also use latex hose to mount it, no springs are those are also magnetic and will vibrate/squeal at higher gains. Early Hendrix recordings and live shows had him play 1965 era Strats that also used latex hose to mount the pickups. Later CBS Strats switched to steel springs, you can hear Hendrix struggle to control the squealing of those guitars.
The secret of the Telecaster bridge pickup spank is the geometry of the coil. It is a larger bobbin than a Strat pickup and that focuses a narrower magnetic field under the strings than you get with a Strat or Jazzmaster pickup. That is due to the windings, it's a rather narrow stack with cotton string used to fill out the bobbin after winding. If you look at a Jazzmaster pickup, it's a flatter bobbin with the windings spread out further away from the magnet poles. That grabs a wider aperature of the string's field making for a fatter tone.
The magic of the Telecaster is found in the player's hands. With that ability to create a wide pallet of string tones from the player, it's as individual a sound as the player wishes to develope. Compared to Gibson humbuckers that double the fundamental frequency, those tend to make the player sound more anonomous and alike unless the player developes a unique way of attacking the strings.
|
|
|
Post by jimwilliams on Jun 17, 2014 10:44:26 GMT -6
I have 6 or 7 Telecasters here. One is a custom 12 string I built back in 1979 with a birdseye maple body and a Fender Shennadoah 12 string neck from the late 1960's. That has custom wound pickups done back in 1979 by a little known fellow in Santa Barbara called Seymour Duncan. Those are wound to 2k ohms each with a resonant frequency of 32k hz. It has active treble/bass EQ built in.
The rest are 6 stringers, hollow, solid, mohagany, maple, ash and alder and my Let It Be solid rosewood. Each are set up with a preamp/boost circuit fitted with a hum nulling circuit. A dummy coil is fitted under the strings and a trim pot nulls out the hum to -80 db. This way I get classic Tele tones and no noise. The pickups are all stock windings. One tele is a Jim Adkins's hollow/Les Paul special design with P-90 pickups.
Since I love Hendrix style levels and feedback, I modified the mechanics to handle those SPL's. The bridge pickup's steel plate is gone, replaced by lock washers and latex rubber hose for the springs. The bridge is secured with silicone glue to prevent howling at high volumes. The innards are all lined with adhesive copper foil tape and grounded. The string ground is replaced with a .022uf cap to prevent lethal shocks.
There is no buzz nor hum when your hands are removed from the strings. The preamps will drive very long cables without losses and will even drive a set of headphones. They all look stock on the outside.
|
|
|
Post by jimwilliams on Jun 13, 2014 9:19:41 GMT -6
Vaporware for simulated audio?
I'll just dream instead. It's cheaper and has instant delivery.
|
|
|
Post by jimwilliams on Jun 11, 2014 9:55:59 GMT -6
I'm sure there are some guys here with some stories...I remember hearing guys getting LA2A's out of the trash in the early 80's... Funny you mention that. A couple of years ago a friend in LA was walking downtown when he passed a trash dumpster. He noticed something shiney on top. Yes, it was a pair of UREI LA-3A's. They had a sticker on them, Los Angeles City. He brought them down and now he has a nice pair of fixed up LA-3's.
|
|
|
Post by jimwilliams on Jun 11, 2014 9:48:53 GMT -6
Now you know what the coach makers went through when automobiles came out. Or what the sword makers went through when muskets took over.
In order to sell a product it must have value and a market. Music no longer has either. Music is free, or close to it. Those that produce it can't expect to be rewarded for a product most don't want to buy.
When I was a kid I had a ball and bat, a record player and a guitar. Today's kids have the world on their smart phones. That's a whole lot of competition for attention. Music has been reduced to a background filler while engaged in other activities. Just try and sit a 17 year old down to "listen" to a piece of music. They can't.
It is fun to play, but that's about it. Music is a great avocation but a poor man's vocation.
Funny, my mom warned me about a career in music back in the mid 1960's.
Guess she was right.
|
|
|
Post by jimwilliams on Jun 8, 2014 11:27:02 GMT -6
Turn down the guitar to zero. Noise gone? It's the guitar.
|
|
|
Post by jimwilliams on Jun 8, 2014 11:20:56 GMT -6
As to dither and jitter, these are effects that occur from the LR clock (word clock) of the converters. When the files are manipulated in the software the LR clock is not used to time the data. It is applied by the DAC during playback or the ADC during encoding.
What I hear from editing software is a detruction of the fidelity of the original track. When you stack up those tracks I hear that screeching top end that seems to be more extreme when mass compression is added on top. That is the sound of today's DAW productions, a top end that is not natural nor in porportion. It's the "kelly clarkson" type of sound I hear not only in modern pop productions but also in jingles on TV and movie trailers, the "Pro Tools" sound.
No matter how engaging the music may be, if I hear that sound I turn it off, it's not enjoyable. Even my cats will run out of the room if that stuff is being played here.
I have found a cure for it: Stay off the DAW's. Stick with a dedicated recorder and an analog mix/outboard setup. Then music sounds like it used to, engaging, easy to listen to, no fatigue.
Funny how we have all this modern technology and computing power, yet recorded music has never sounded so bad. There is a reason many worship the records of days past, not for just the music, but for the sounds.
|
|
|
DI's
Jun 8, 2014 11:01:08 GMT -6
Post by jimwilliams on Jun 8, 2014 11:01:08 GMT -6
I have a pair of LA-4's going out next week. Those are modified with very large power supply caps, very fast and super quiet AD opamps, all the coupling caps are removed, it's a direct coupled signal path. Bandwidth is raised on the top end and a few resistors and output stage gain is lowered.
The weakness is the opto cells, they have a very slow release rate.
|
|
|
Post by jimwilliams on Jun 7, 2014 11:27:59 GMT -6
A 50 db pad is rather severe. You would need the mic pre to take +50 db of gain to reach unity, with 50 db of noise added.
Most mic pads use a smaller series resistor, about 4.7k. Then pick the shunt resistor to taste to achieve the attenuation desired. Use a pot and it's variable. Tap in on the other side of the transformer and you skip the iron colors and up to 20 more db of gain you won't need.
|
|
|
Post by jimwilliams on Jun 7, 2014 11:21:42 GMT -6
Looks like a decent simulator. Might be a good training tool like a flight simulator.
|
|
|
Post by jimwilliams on Jun 5, 2014 12:18:05 GMT -6
Standard hi fi RCA connectors are about 24 ohms. It is beneficial to use the proper temination impedance. Canare F-10 connectors are not very expensive and are worth using.
Toslink is also ok, if you use quality fiber optic connectors. I use pure glass fiber optic cables here and they sound better than the plastic versions.
Yes, some will balk at the cost of a Kimber pure silver coax S/PDIF cable. None balk at the sonics though. If you are a home guy, pay your bills first. If you are a pro, it's another tool in the box. When someone spends $$$ on a certain mic pre, box or processor, it's usually determined to be valuable. A cable that improves the sound of your entire production for under $300 seems to be a very good value to me since it will not wear out and will last for many projects. YMMV.
|
|
|
Post by jimwilliams on Jun 5, 2014 9:41:02 GMT -6
I also got a bill from TNT. Not for this but for returning a Soundcraft 6000 master module to Ireland. It was sent back to me by the owner after an opamp fried. I never got a TNT bill from the first time I returned it, I never heard of this company. Now they want $44 for duties on a shipment that originated in Ireland and returned to Ireland.
It was also carefully marked as 'returned from repair' so I suspect foul company operations. Why the recipient was not billed is also strange as I don't live in Ireland.
$900 is also a bit steep for a Nevey kit, I'd rather just rework a Gap or similar and pocket the difference, but that's because I'm cheap.
|
|
|
Post by jimwilliams on Jun 5, 2014 9:25:39 GMT -6
Check the construction and design. Sealed cab's are best for me and my guitars. I don't like 5/8's plywood construction like Marshall, too boxy and they tend to rattle.
I have 3/4" plywood cabs and MDF cabs. The MDF is the most solid sounding, but also the heaviest.
Most of the speakers are Eminence, Red Coats, Legends, etc. I love their stuff next to those Chi-com 'brit' speakers. They take the power, don't suffer from power compression and they sound better to me. They are also more efficient, offering more volume per watt.
|
|
|
Post by jimwilliams on Jun 5, 2014 9:19:45 GMT -6
Does that DAC have the National LME opamps or did you pop for the Analog Devices ADA 4898-1 opamps? Mine was the first done with the AD chips per my request. They are offered as an upgrade I would recommend.
Also, the S/PDIF cable will have a large effect on the results. Canare and Mogami make 75 ohm S/PDIF cable. Terminate those with Canare F-10 RCA connectors, those are also made at 75 ohm impedance. Avoid 'hi-fi' RCA cables, too slow, too much stray capacitance and the wrong impedance.
The best S/PDIF cable I've used is the Kimber pure silver coax. Yes, it is expensive, but nothing else is as revealing.
|
|
|
Post by jimwilliams on Jun 4, 2014 8:40:56 GMT -6
That's my experience. Anytime data is manipulated, it changes, for the worse. Straight record/play files avoid that change that I call "digititus". Do that and all gain/frequency manipulation is done in the analog domain those changes are avoided, but it causes most DAW AE's to flip out not knowing how to do those things in the analog domain.
|
|
|
Post by jimwilliams on Jun 3, 2014 10:29:32 GMT -6
I used to blow those things up back in the 1960's. I guess I'm getting older. I loved the tube amp built into the guitar case, an electrical nightmare, but convienient.
|
|
|
Post by jimwilliams on Jun 3, 2014 10:23:49 GMT -6
A friend of mine who does absolutely killer work tells me the GAP is a great device. That wasn't me but it's still true. I got mine for free. I replaced the 184 BC transistors (BC parts tend to sound spitty IME) with Toshiba 2SC3329BL's. I used Wima FKP-2 caps for the smaller values and transformer networks. The el caps are Panasonic FR, enlarged and bypassed with poly film caps. The power supply section was rebuilt with FR large caps. The 072 meter opamp was decoupled from the main audio rails to eliminate interference. The 2N3055 is an ON Semi device and the output transformer is a Jensen. This is Neve on steroids as it's less noise, better top end details, greater low end depth and smooth, smooth, smooth. I put about $150 in parts into it, most of that was the Jensen.
|
|
|
Post by jimwilliams on Jun 3, 2014 10:15:15 GMT -6
First, avoid nasal mics like the U-87. Then shove a couple of ear plugs into the nostrils or use a clothes pin on the nose.
If that doesn't work, use a "Breath-rite" nasal strip on the noise, opening it up may lessen the honk.
|
|
|
Post by jimwilliams on Jun 3, 2014 9:57:44 GMT -6
Either you hear the differences or you don't. If you don't, use zip cable and save the $. The AES also had a detailed speaker cable review/test about 20 years ago in the Journal. They used everything from zip cord to 10 awg auto battery cable. Yes, the battery cable tested and sounded poorly.
The winner? It was a 32 section data wire, not too different than Ray Kimber's multi-strand 8TC. It's interesting reading if you want to look it up.
My "ears" were opened when I visited Ray's facility in Ogden, Utah. He has a rather large industrial building, full of winding gear, the lab and other areas. I brought my favorite mic cable, the Belden 9182 LAN network cable along with a pair of modifed AKG 414 mics and a High Speed mic preamp. The belden 9182 is a low noise, 150 ohm impedance, teflon wrapped 22 awg shielded cable with a 70% propagation delay and a gigahertz bandwidth. Stray capacitance is a very low 8 pf/foot. It was designed to carry heavy, fast data loads across from building to building, they also make a plenum version. Paramount Pictures also wired their entire foley building with it after I brought down a couple 100' runs to try out. You can hear that from 1996 on in all of their releases.
The Belden sounded very good and then Ray had an employee quickly make up a 20' run of AGSS 19 awg pure stranded silver 3 brand into a mic cable. We plugged than in after listening to the Belden. Ray looks at me and asks, "pretty quiet wire, ehh?".
Yes it is. There is all that noise we are always used to hearing drop off. It was weird. A 3 braid, UN-shielded cable that is dead quiet? We wrapped it around large power transformers in the Krell power amps and still no hum pickup. Every other cable still has that background noise but this stuff is so quiet you think there's a noise gate someplace, but you still hear every detail, in fact, you hear details other cables absorb. At about $100 per foot, it ought to be great and it is. With silver at $19 per ounce, it's also a good investment.
|
|
|
Post by jimwilliams on Jun 2, 2014 9:34:22 GMT -6
Bolt on neck, usable for stage smashing. If you light it on fire, the poly finish will take off into a fireball.
I'll stick with my desert burst "custom 'sweat' shop" Epi.
|
|
|
Post by jimwilliams on Jun 2, 2014 9:29:10 GMT -6
Any decent player knows feel and tension is most important. Just the weather messes up my neck tension. If too dry, the necks all move away from the strings. Too humid, the strings rattle.
Imagine the slop created by alternative tunings? Retune, adjust neck, set intonation, rinse and repeat.
I'd rather just grab another guitar set up that way.
|
|
|
Post by jimwilliams on Jun 2, 2014 9:23:06 GMT -6
I've used Kimber 8TC for speaker cables since the 1990's. I found nothing close for the price. It's a 16 wire teflon coated pure copper design. Yes, it's a PITA to strip, combine and solder. I use 8 sections twisted around the other 8 and solder them together with 4% silver solder. Those are fitted into gold plated heavy duty banana plugs to fit the Adcom GFA power amp and JBL speakers.
Ray Kimber knows wire and has the Agilent and HP network analyzers to test it with. I know of no other high end cable makers with a lab like his. His pure silver/teflon wire is even more impressive, as is the price. I also use the silver wire in my mics between the capsule and jfet, the fader wiring in my console and a few runs of his 19 AWG pure silver AGSS 3 braid for mic cables and the output of my console to the PCM4222 ADC.
Once heard and used, it's pretty hard to go back to copper.
|
|