IMHO caps are the weakest link in a passive crossover, if not all circuits. Definitely room for improvement.Originally Posted by tomt
U must b a rather, popular person.
I only have,
'This page has had 7,721 visits'
'Over there' ...
(Your math skills?)
--------------------------------
As happens,
caps for another endeavor,
and i'll not yet say what,
also pass large current.
These caps also pass 300khz,
often @ 300 -1500 amps,
and upwards, depending on model,
1500+ volts.
So the potential for lower distortion,
may very well be ,
'Built in' ...
Last edited by tomt; July 22nd, 2017 at 06:18 PM. Reason: High fz/low esr
guns kill people,
like spoons made rush limbaugh,
fat ....
IMHO caps are the weakest link in a passive crossover, if not all circuits. Definitely room for improvement.
Your neighbors called. They like your music.
??? A bit too cryptic for me to get your point.......
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
Amen, OG, amen !! I personally feel no one cap, can , or will, do justice to the entire music spectrum.
In any single cap position, ( in my DIY amps, and in my DIY 12 dB Butterworth ALTEC Crossovers, ) I tend to use multiple capacitors, about three minimum, but usually up to seven or eight different capacitors ( all film ), as part of a " bundle" making up the overall " C " value, for each " C " position in the circuit.
This multiple film cap bypassing is FRAUGHT with perils.
Done right, its KILLER to hear. Very few know HOW to best do it. Not all cap brands will meld together. One must determine, from serious listening experiences, what uF values play WHAT parts of the audio spectrum, and LISTEN to the whole " bundle " to make sure it is giving a LINEAR sounding playback one wants, on different types of music, vocal, harpsichord, etc, etc etc.
In amplifiers, ( for use on my own ALTEC speakers ), I only use capacitors where I am forced to use them. That would be in the power supply, and across Rks that are bypassed. In these cases, its almost always about six or seven caps, in a carefully selected bundle, for each " C " position.
Also, regarding caps your comment on " caps being the weakest link ", I would NEVER ( personally ) design and build an amp for my ALTEC speaker, that used a capacitor-couple between two active stages.
That, IMHO, is way too much of a compromise. It is the absolute " worst " possible way to connect two tube stages. A transformer couple would be better, and be mildly acceptable for some, but the best couple of all is direct piece of good wire, Siltech, etc., between two active stages, a direct couple.
The GTO caps, that are the topic of this thread, are used across each " C " position, in my audio amplifiers' B+ filter to the Finals. That is L1/C1/L2/C2 and they are each part of the bundle, one 5 uF GTO in C1, and one 5 uF GTO in C2.
When I disconnect either GTO cap, from either the C1 or the C2 bundle, the ALTEC speakers INSTANTLY get very dull and more ordinary-sounding to me, even though I also have four of these 5 uF GTOs used in my passive ALTEC crossovers, every crossover " C " location, since April 2016.
Interesting, eh !! It is to me !!
Have fun, I do.
Jeff Medwin.....Low Ohms.
Last edited by LowOhms; July 22nd, 2017 at 10:11 PM.
Passive crossovers are by their very nature inherently problematic devices. Phasing being one of the biggest issues.
I just don't see how using multiple components with issues is going to be a final solution.
I still maintain the best solution is eliminating them completely.
Alas, no one has designed a transducer that can cover the entire audio range. The 755A does a credible job of carrying MOST of it.
But even that approach has its own issues, not the least of it pattern control.
A properly executed active system will devastate any system with passives.
Virtually all source material is generated on studio monitors with active crossovers.
Till something better comes along, the best system is still properly executed active crossovers.
As always, opinions vary. But in professional audio those opinions better work. Or in the studio you are relegated to the 95% who make as much collectively as the top 5%.
Last edited by Old Guy; July 23rd, 2017 at 06:22 AM.
Your neighbors called. They like your music.
Hi Old Guy,
I'm just a private audiophile, but I lived in LA, ( 16 years ) where they have some studios. I used to buy tube amps from Alan Sides in the early 1970s, when perhaps he was still in high school. ( Ocean Way Recording Studios ). Been inside Ocean Way, when it was ON Ocean Way in Santa Monica.
You boldly comment :
" A properly executed active system will devastate any system with passives."
.........and I must TOTALLY disagree with you, from my own experience.
Every year I attend RMAF and, when there is time to set it up, ( which doesn't occur each show ) a very simple PASSIVE crossover ALTEC system just EATS any other ALTEC system I personally have heard.
There is only one guy I know of who knows how to do it right, and he UNIQUELY employs multiple bypassing of capacitors in his crossovers, and extensively, because it is needed for full musical expression, ( and he knows HOW to do it ), uniquely in his single ended amps. This fellow gets a " best sounding room " at the show, in certain years, last year 2016, and I believe 2006..... from the better reviewers. ( Stereophile magazine and Six Moons respectively ).
I WILL say this, a great studio can sound wonderful, and if it is biamped, fine !! But what you are hearing is a MASTER TAPE, first generation. Such a good source, and a tape deck, will kill any LP that one may play at a show.
I've been in studios, and now-a-days, I go to these shows to HEAR this one GPA 604 MLTL ( speaker built with GM's input ) system..... every year, last 10 years. I booked my plane fare for Denver, Colorado this past week, for RMAF, October 6-8th.
Of course, if you run SE amps without multiple bypassing ( a SE tube amp IS inherently narrow band, UNLIKE a Push Pull topology ) and you ALSO run passive crossovers without what I call "proper" multiple bypassing, as all but a few do, then ACTIVE BIAMP will be cool to use. But active biamp, IMHO, CAN be beaten, with passive - done well, and with the right amps ( two manufacturers I mentioned ).
Personally, Old Guy, I don't have the funds to buy the total amp and MLTL speaker system I hear each year at RMAF, so I seek DIY solutions. I DIY my Passive VOTT crossover, and I have been DIY building DHT amps since 1982, starting with Bob Fulton as a mentor, a long time.
Old Guy, I can see, that you try to post the truth, from your direct experience. I post counter to you, NOT to be argumentative at all, but respectfully, to share with others up here, what I have personally experienced listening, and what is " my " audio truth.
No need for us two to be at each other's throats, and degrade with words, a person we do not know or fully understand !! Its demeaning to the degrader, and to the degraded,..... both lose. Lets, " us two ", find a nicer way, and leave room for tolerance and better understanding.
Also, always realize, I am just a private party, I will make errors, and I am not presently in the audio business ...but
LOL, I am older than you Old Guy, and UNlike many readers up here, I have listened to 604s in my home since December 1944, when my Mom, Rose, was nursing me !! If we put our minds to it, we can get along with each other.
On high efficiency speakers, ( from what "I" can tell, IMHO. YMMV ), when using ONLY the latest and most UP-TO-DATE version of this one tube manufacturer's SE 2A3 amp, it has never been beaten by any other tube amp. Since 1989. The Manufacturer himself does tell me privately, he thinks the S.F. Bay areas boys' very latest Spectral DMA-200S will sound, or perhaps does sound " just like his tube amp ". He'd like to have one .
That is all for now. Lets keep the flaming minimal, and the tone nice and easy please !!!! I told TODD "I" would, several months ago, and I am proceeding .
Thanks, everyone.
Low Ohms.....Jeff Medwin
Last edited by LowOhms; July 23rd, 2017 at 09:24 AM.
Agreed on we don't need to be at each others throats, provided you respect other opinions as much as your own. Let's face it, there has been a shortage of that. Or let me rephrase that, at least a perceived shortage. Both of us could perhaps make better choices in wording.
I'm painfully honest and more than a bit blunt. People who like it sugar coated often don't like me.
If I might suggest , you see a very limited slice of the audio world at RMAF. There is a very large world outside of it.
Honestly, the best crossovers I have heard are the Dolby Lake stuff, and they are active. But yow are they pricey.
For instance:
Dolby Lake DLP 4 x 12 processor Dolby Lake
My methods and GM's are similar I believe, in that we both like to be precise. Greg, feel free to contradict me if I am off base.
I just like things to be called what they really are, and I prefer my information straight with as few superlatives as possible. After all we are communicating, not selling.
RMH
Last edited by Old Guy; July 23rd, 2017 at 10:45 AM.
Your neighbors called. They like your music.
OK maybe I have better things to do with my money but in an effort to keep and open mind I purchased 4 of these GTO caps from that guy in the Netherlands and used them in my passive crossover. I used 2 pair in series to give me 2.5uf (required is 2.2uf but close enough) for a 6th order crossover to an 8 ohm pair of MR902's (without the internal cap) that I use to fill a little of the top end over 311-90/288G's with levels matched using an autoformer. At first they seem like they sounded good but after a bit of listening they became fatiguing. I went back to my PIO Deulunds and all is well. My system may not be the greatest but when A/B without changing anything the GTO cap isn't anything special and are lower on the spectrum than Russian Hybrid PIO's. That's my experience, others may find they work fine but for me they were a science experiment that failed.
What you say, I certainly believe.
But I don't know how much one can tell using the cap as a final cap in a SIXTH order crossover. Think of all the complex parts preceeding it, and the losses involved BEFORE the driven signal ever gets to the cap !!
In contrast, my use was simple, as the bypass C in a 12 dB Butterworth, one in each " C " sections.
The difference, when the GTO ( and its bypasses) is the ONLY C ( albeit in a bundle ) in the simpler circuit, to that driver .....was fantastic to my ear.
Also, I use them in my SET amp, across C1 and C2 to the Finals stage, AND in the ALTEC crossover. When a GTO is not in the amp, the entire ALTEC system, to my ear, returns to blah..........................normal, like most everyone elses'.
One nice thing, the four caps you tried cost about ten dollars each, shipped, versus a single 2.2 uF Dueland Cast PIO-Cu at 100 VDC , which I just looked up, and is offered here in the USA discounted at $443 each.
Well, thanks for giving it a try. Consider bypassing the Cs in your output stage, amplifier next, since you have the GTOs on hand. Have fun listening to that, I do !!
Jeff
Last edited by LowOhms; August 9th, 2017 at 12:57 PM.
I must admit, my fingers and my mind weren't in sync as I meant to type 1st order but my fingers typed 6th order and I still missed it while proof reading. Don't ask how I did it as the 1 and 6 are far apart on the keyboard - guess I'll cop to old age. Apologies to all.
Yes the Duelunds are much more costly and as a result I run the risk of having a Placebo effect on my hearing having spent that much money (I got real good deal from a friend that was hung with them from a project that went south but it was still the most I've ever spent on a pair of caps) but as I said the GTO's did not measure up to the Russian K75's which can be had for about the same money as the GTO's. I must admit that I did not use them in my amps as they are solid state and they are direct coupled to the output and don't go through a cap. I could use them to bypass the 4 - 18,000uf power supply caps but I'm not sure if that will be worth the effort ... maybe one day.
I don't mean to offend or start a back and forth but just report what I found/heard. Again, this was my experience, with my system and my old ears processing the info through a mind that isn't as sharp as it once was. Again sorry for the typo.
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