Does anyone care to ask an amplifier designer a technical question? My door is open.
Keep in mind just because a unit has a XLR input that is no assurance that the input is balanced.A balanced input is no guarantee of better sonics. The devil is in the details. Every audiophile should read Bill Whitlock's AES paper "An Overview of Audio System Grounding and Interfacing" available here https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf |
And, with regard to the great interconnect debate: do you know of any testing done that approaches that of scientific blind testing that shows that any given wire, if made out of a certain material, and wound in a certain way, and shielded in a certain way, will cause electrons to move in one manner as opposed to another that can be explained as doing so and that because of that movement can be explained as yielding sonic performance that is measurably and quantifiably superior, or even just different?One is building a system in which all components sum for the final sound. A cable that sounds fine in one system may not in another. See http://ielogical.com/Audio/CableSnakeOil.php for more information. Be sure to read the PS Audio links. It’s a good primer on audio cable. The great problem in HiFi is that products are touted as ’the solution’ when in reality, only ’an option’ A great deal of what is claimed is absolute nonsense. |
The whole idea of tuning a system with cables seems rather weak to me.The missus once said "Those wires are the only ones where the clarinet sounds like a clarinet." [She had perfect pitch and played the clarinet.] We had decent amp and speakers, so the "wires" were the final tweak. Unless one subscribes to the idea that cables do not alter the sound, surely it makes more sense to replace bad cables than a good amplifier to correct system deficiencies. |
If a system is not broken and has serious deficiencies cables will likely not correct the problem. How can they?I'm not suggesting cables can cure a serious deficiencies. However, since cables interact with the amplifier and the loudspeaker, they can ameliorate slight deficiencies be it amplifier, loudspeaker or environment. Some amplifiers are nearly immune to cables, but loudspeakers are not. |
@cakyol I predict that these capacitors will be in a vicinity with a temperature of about 60 - 65 C most of the time
You may find this link interesting. "Determining end-of-life, ESR, and lifetime calculations for electrolytic capacitors at higher temperatures" https://www.edn.com/design/components-and-packaging/4326347/Determining-end-of-life-ESR-and-lifetime... |
I would like to hear how each of you figured out how much power you needed to buy in watts?Never bought by power. Always purchased by sound. Currently have 100 and 150w SS and 40w tube 84db 1w / 1m. min 3.2Ω, max 16Ω, mean 7Ω Loud level is 90db C weighted slow measured with REW at seating pos 13ft from LS. Don't have low level. Each selection is listened at optimum for type. Sonic wallpaper is MP3 over internet in MONO, MP3 is intolerable in stereo. SS amps not rated @ 4Ω |
The solder joints just fall apart from vibration.Interesting. My Force is still going strong after 15 years. Pre ROHS. Two good questions for sub makers :)Another is "Why provide such useless controls?" Many subs are clearly not designed to be integrated in any meaningful way. Anyone interested in the effort expended, visit http://ielogical.com/Audio/SubTerrBlues.php Most 'non-ap' listeners comment on bass definition rather than quantity. |
We abandoned switchers as they were always audible. So rather than A-B, we had C-D or C-C. We were pretty meticulous in keeping paths as identical and as clean as possible having only the relay contacts as the additional connector. One thing we never did, but probably should have, is have a simulated load for the off item to maintain thermal characteristics more closely. I'd be curious if trained listeners can reliably detect the sound of the switcher. |
minimize artifacts occurring from the interconnect cable between the preamp and amp.Source output 22R, amp inputs 23k5 or 100K. Adding a preamp with attendant switching, circuitry, noise and additional cables is little more than a subtle tone control. It maybe different, but it may not be better. |
@bdp24 - dual controls are not too fiddly if they are 1db or less stepped @apogee14151617 - all components active and passive alter the sound. There is no electrical reason to have a preamp if the source has output level control or the amp has input level control. I use a passive 1db stepped resistor of my own design. It has a sound, but everything does. |
Passives should be at least 10kohm to suit "most" situationsIt depends on the source output impedance what the passive resistance should be. If the output impedance is < 500Ω, a 5k pot is fine. Pots have a different sound than stepped resistor controls. IMO, P&G pots were more musical than Alps when I used passive level controls in the studio. Additionally pots, especially log, track nowhere near as well as stepped resistors. Clio wrote about a phono preamp with passive level control and aux inputs. What a great idea!Whether it is a great idea depends on the topology and to what it is connected. |
I’d like some flexibility with whatever I choose as a source switch/level control in case I decide to use a different power amp.See http://ielogical.com/assets/Audio/PassiveLC1.png here http://ielogical.com/Audio/#LastHurrah. It is possible to use a single resistor value to give perfect passive tracking for any amp impedance. Only caveat is ensure source has low output impedance, say less than 500R and power amp has reasonably high input, say 20k+ |
So my question is, why is it tubes are able to do that? Is it a matter of tubes being lowest in distortion at lower-signal levels (where imaging resides?), and transistors in their curves highest?Back in the 90's when emulating gear in digital, we found that adding even order harmonic distortion brought the image forward and wider, i.e. more tube like. Odd order made the image deeper and more triangular, i.e. more SS like. By careful adjustment of O/E ratios, we could alter the sound stage. We were using 24bit digital and adding distortion at the 16th bit or 0.0015%. Mani phono pre [only for example, not a slur against Schiit]In the upper left corner is a 3 terminal voltage regulator. These devices are notorious for varying between manufacturers and within manufacturers as die changes are implemented or offshored. Additionally, these are active devices with feedback and as such can have horrific impedance and phase characteristics which affect the sound of the circuit powered therefrom. On the same DUT, the regulator can make it sound boxy, shrill, dull, warm, etc. With the same regulator, circuit changes which alter the current draw can cause the same sonic changes. |
If burn in exists in these devices why did we not know about it until recently. I find no references to burn in in the 50s 60s 70s.. when did it start?It's my belief that connectors are the largest culprit. As components became more modular, more connectors. Once I have a system I plan to keep for a while, I remove ALL internal connectors. More than once I've rejuvenated a system by re-plugging ALL connectors, both internal and external. In the studio, we regularly cleaned all connectors, patch cords. Tracking setup required every mic cable be re-plugged 3x to ensure an unoxidized contact. All multitrack cards and console modules were R&R'd. AFAIK, this was SOP in some places going back to the 50's for mics and 70's as consoles and tape decks became more modular. Cable burn-in? Bunkum! |
@pwhinson The Thiel is a low impedance speaker, below 4Ω for most of the range with two steep peaks in the bass. https://www.stereophile.com/content/thiel-cs24-loudspeaker-measurements An amp to drive these speakers should be happy with a 2Ω load. And what speaker wire do you use? |
Sorry to say this is a horrible product.Ouch! Power in Los Angeles could be very problematic. I added a 5300 in about 2003 and it was a significant improvement even though my amp had an internal LC power filter. At the time, I auditioned 2 Panamax, 2 Monster and 1 Furman. The Furman was best, followed by the 5300, then the Monsters and Panamax. Each added it's own coloration. 15 years later in Oregon with different electronics, it still works and I like what it does. Cable and other jacks remain unused. |
@teo_audio Interestingly enough, his entire job rides on doing things that are either unmeasurable or so close to being unmeasurable that it is not worth bothering to try.Not true. It is relatively trivial to measure the diode switching noise*. IF that noise is reflected through the transformer, increased by the transformer** and ameliorated by the power cable, then the results should be eminently measurable. * Discussion on diode transients and measurement thereof here: https://electronics.stackexchange.com/questions/323507/bridge-rectifier-4-diodes-vs-single-chip ** Power transformers step down in operation, so must be step-up on any signal reflected back through them. |
@ramtubes preamp is balanced via electronic buffers. We don’t want to short those.Depends on the circuit design. A lot of pro gear has IC balanced outputs that can short either leg to Gnd and the output acts single ended, driving no current into the shorted leg. However, as Roger said, if you don’t know the output is single ended capable, only use one leg. AND if using balance lines, only connect the screen at the driven end. A shield grounded only at the receiver forms pair of low-pass filters for common-mode noise |
I am getting some ground loop noise from my Classé 5300 amp.I wired studios with 1000's of interconnections. We never used cheater plugs. E V E R !! Solve the problem, don't bandaid it. Sometimes it involved fixing the gear's internal wiring. Are you using balanced or unbalanced inputs? If balanced, remove the screen connection on the amp end. In a balanced system, the screen should be lifted on all the driven ends. Get some shorting plug and start with just the amp connected to the speakers. Add in each component back from the amp. When the hum starts, solve the problem there and continue. |
Please elaborate. I don't how the shorted lead drives no current? A cross-coupled opamp circuit wherein shorting one of the leads to 0V removes its drive. It was very common in the 70's & 80's. Later Analog Devices created monolithic driver with similar functionality and much better performance due to tighter on chip resistors and thermal tracking than discrete parts. Sorry I don't have examples or numbers. I would think the screen should be connected at both ends and the negative leg to the RCA body.I was speaking of Balanced like XLR. Single end Dual wires inside a screen should have the screen connected to the body at the driving end only and the -ve lead connected at both ends. |
In regard to Bi-Wiring speakers from the amplifier, does this separate route of connection in general improve the sound of the speakers or is it just one of those HiFi mythsAs in all things HiFi, the devil is in the details. For a technical look at Bi-Wiring, please see http://ielogical.com/Audio/CableSnakeOil.php/#BiWire Please note that these are Spice models and not actual system measurements. |
My understanding of the technical reason is it reduces the negative affects of the crossover by (almost) directly connecting the amplifier to the drivers.Bi-Wiring has no effect on the crossover. In an electronic circuit, when current flows through a resistance, voltage is developed. In a Mono-Wire system the tweeter connection is modulated by the woofer current. By providing a direct path to the low impedance amplifier output, the tweeter is not modulated by the woofer circuit current. On some program material, it is quite evident, not so much on others. YMMV. The best crossover is no crossover. When are we going to stop piddling around with tiny effects when we can bi amp and do something that really makes a difference.As mentioned earlier, the devil is in the details. Some speaker crossovers are more complex in their action than a symmetric electronic one. My dbx223 sits in the cupboard because the dual 4th order did not sound as well as the 4th/2nd passive on the mains or the electronic 3rd / passive 1st for the sub. Digital may have promise, but at this stage, new hardware elicits no interest. |
I too would like a link to this kit, I can't find it anywhere diyAudio Store has Pass's LX-Mini kit https://diyaudiostore.com/products/analog-crossover-network It's not as flexible as the B4, but can be customized for user desired Fc and order |
Why shouldn't decent tone controls, and maybe even loudness controls come back in fashion?Fashion is the operative word. In the recording studio, we had EQ of several flavors: Peak, Shelf, Parametric, Sub-Octave graphic. Various equalizers by Neve, API, Massenberg, UREI, etc. plus console module EQ by Trident, MCI, Neve, API, etc. plus mic 'EQ' for Neumann, AKG, Sony, Shure, etc. plus mic pre EQ from all the aforementioned and more. Each has its own characteristics and colorations to create the palette desired. The problem with a 'generic' tone control on a HiFi is that 99% of the time, its not in the required frequency range and it's pure serendipity if the chosen frequencies align with source, recording, loudspeaker and room defects. At our local venue, we have a small 32 channel mixer. EQ is digital and extremely flexible, incorporating most of the functionality of a whole rack of outboard EQ. It does not color tonality in the same manner as individual analog devices, which all add colorations along with level and phase changes. Sometimes a good thing, sometimes not. I for one would love to have a couple channels built into my CD player that I could control with my phone. I could then save settings in CDP and it would recall them for each disk. A nice feature would be to save templates, e.g. "Sh.tty Columbia Remaster" for easy recall as generic corrections. A reasonable DAC with such flexibility might open my wallet in a heartbeat! |
The talk I saw about the DIY kit version of the First watt B4 was maybe six months ago, on a Nelson Pass-related DIY Forum site."However, there is progress. The DIY versions of the SL crossover and a version of B4 should be in the store in a month or so, starting with just the pcb + Jfets kit, to be followed by more complete w/ parts versions." Nelson Pass in diyAudio Pass Labs 2018-02-13 : https://www.diyaudio.com/forums/pass-labs/165756-pass-labs-b4-crossover-questions-post5340382.html |
How can some do with so little power and others "think" they need all those watts? Truth is nobody measures and the majority guessing are way off.Some of us both measure and calculate ;-) My 36w PL5 calculates to 93db¹ @ 3.75m with 86db/V²/m speakers. Add in a couple of db crest factor, and I'm outta gas @ 95db peak. Confirmed with scope and RTA. To reach 105db, I'd need 323w for unclipped peaks. 150wpc SS only gets me to ~100db peak because SS clips less gracefully. A 9 watter requires a listening distance of about 1.9m or 92db/V/m loudspeakers. ¹ = room effects ignored ² = 2.83V |
