Tektronix discovered such pcb problems and dealt with them effectively many years ago.
They called it "hook". See p.49 here: https://www.davmar.org/TE/TekConcepts/TekVertAmpCircuits.pdf
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If the woofers were in any other alignment than sealed, I've always been confused by the weird behavior around resonance (as one would expect). If we're looking at orders of magnitude, DA can't play *that* big a difference in the cone behavior versus any sort of resonant structure.
That's neither a pro/con of the DA discussion.
PS Found my old Yamaha T-80 tuner outside in the attic. Not sure it even works anymore. Definitely not as nice as some of the ones being mentioned.
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I do not think this cone movement would be a result of coupling capacitor DA. I am quite sure it is not.
I have also seen speaker cones slowly moving in and out and there were 2 different reasons:
- motorboating
- poorly designed DC servo (step response of the multi stage high pass filter may be very strange)
Hi dadod,
I think that John would refer to that as "mid-fi". But truly, after you hear something better it's difficult to go back. Over time the memory fades I guess.
I have a Nikko NT-100 on my service bench. It's cheap and nasty, and I don't think there is any help for it. It's days are numbered simply because I hear much better tuners on almost a daily basis. These are units that I have aligned and improved, so the comparison isn't at all fair. But it is what it is. That tuner has to go as I sometimes listen to it as I work. I have a line on a Magnum Dynalab FT-101 that might go in there. I'm told it sounds awful, so I guess I'll have to work on it first. The rest of the bench stuff sounds pretty good and it's all been "interfered with" in my way. The amp is a Marantz 1180DC which is close to a 170DC in the amp section. Certainly more than good enough for a bench.
The main reason the tuner is there? So I can find out where really badly misaligned tuners are on the band. Finding the same station is often the only way to get anywhere with some that can't tune the whole range. Happens more than you want to know.
-Chris
... until you hear something that does sound good.
I think that John would refer to that as "mid-fi". But truly, after you hear something better it's difficult to go back. Over time the memory fades I guess.
I have a Nikko NT-100 on my service bench. It's cheap and nasty, and I don't think there is any help for it. It's days are numbered simply because I hear much better tuners on almost a daily basis. These are units that I have aligned and improved, so the comparison isn't at all fair. But it is what it is. That tuner has to go as I sometimes listen to it as I work. I have a line on a Magnum Dynalab FT-101 that might go in there. I'm told it sounds awful, so I guess I'll have to work on it first. The rest of the bench stuff sounds pretty good and it's all been "interfered with" in my way. The amp is a Marantz 1180DC which is close to a 170DC in the amp section. Certainly more than good enough for a bench.
The main reason the tuner is there? So I can find out where really badly misaligned tuners are on the band. Finding the same station is often the only way to get anywhere with some that can't tune the whole range. Happens more than you want to know.
-Chris
Hi Daniel,
You should hook it up again. If it works, have it aligned properly so you can enjoy it. I can't stress how important the antenna is.
I have a BIC Beam Box that was offered to me. I used to sell them in the 70's! It works extremely well for reducing multipath and allowed the receiver upstairs to perform a lot better. Recently I stuck a Magnum Dynalab loaded whip antenna up there and wired it down to the bench. Works fantastically well. I was able to use a cable I prewired into the house, so my long suffering wife doesn't even know it's there. I was told that if she sees anything else in the bedroom she would throw it out. I take her seriously.
-Chris
You should hook it up again. If it works, have it aligned properly so you can enjoy it. I can't stress how important the antenna is.
I have a BIC Beam Box that was offered to me. I used to sell them in the 70's! It works extremely well for reducing multipath and allowed the receiver upstairs to perform a lot better. Recently I stuck a Magnum Dynalab loaded whip antenna up there and wired it down to the bench. Works fantastically well. I was able to use a cable I prewired into the house, so my long suffering wife doesn't even know it's there. I was told that if she sees anything else in the bedroom she would throw it out. I take her seriously.
-Chris
Nothing to do with audio, maybe 24bit integrating A/D's or very high impedance stuff. This stuff got taken out of context and folks ran away with it. People continue to resist quantifying the effects in the exact applications context.
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Yeah, when it's PCB nonlinearities, my first guess is to ultra-low current stuff with all the whiz bang guard rings/etc. in place.
Just make sure whatever you're using isn't too hygroscopic! (Really is there any that are *materially* better for audio? Thick traces for power stuff, sure, but otherwise?)
Just make sure whatever you're using isn't too hygroscopic! (Really is there any that are *materially* better for audio? Thick traces for power stuff, sure, but otherwise?)
+100...and if one can have a directional antenna it assists in both sensitivity and selectivity...unless the two adjacent stations are co-radial. I take money for FM station work, so I invested in an APS 13-element Yagi, 8.5-10dB gain, ~30dB F-B ratio. The Kenwood 600T tuner in wide bandwidth has a capture ratio of less than 1 dB. With an omni antenna it will cleanly lock onto one of two co-channel stations if one is 1 dB or more consistently stronger. With a directional antenna, you can pick out one of many co-channels simply by rotating the antenna.
I could only afford a used Kenwood KT-8300 in college and used it plus a 14-element homemade Yagi plus a ground-mounted nulling dipole to get at stations I wanted many miles away...I wrote an embarrassingly amateurish article about that for a ham radio magazine many years ago, I won't bore you with the details, a reprint is here: FM Broadcast Antennas for Idiots - Pro Audio Engineering
It is the FM broadcast equivalent of DIYAudio...call it DIYRadio!
Cheers!
Howie
That doesn't even make sense unless the substrates are pathologically bad. Which, FR1-FR2 kinda were, to be honest. Fit and finish of a PCB may play a significant role (and always the reminder that the layout is a part of the circuit), but FR4 is already overkill for audio. Which is great because that's one fewer thing to worry about.
IME pcb substrates contribute particular sound character with phenolic paper which has been and still is the budget conscious 'standard' being the worst sounding.
Some of the major Japanese manufacturers used white paper or polyester substrate and these 'sound' different imo.
I agree dielectric constant, dissipation factor etc should be of no consequence at audio frequencies so the cause must be something else.
Dan.
Some of the major Japanese manufacturers used white paper or polyester substrate and these 'sound' different imo.
I agree dielectric constant, dissipation factor etc should be of no consequence at audio frequencies so the cause must be something else.
Dan.
I'd like to get a low band VHF Yagi to pick up the Sneedville PBS channel 2.
Unfortunately, most of the manufacturers of 2-6 low band Yagi have discontinued the 6-10 element versions and the 4 or 5 element versions won't work for me as I'm too far away (probably 45 miles).
I thought about making a 57MHz Yagi from scratch, but decided it isn't worth the effort since there is no assurance it would pick up the station any way.
I have an old Channel master on a four section mast about 25' up but it can't pull in Sneedville.
Being down in a hole does not help much.
Unfortunately, most of the manufacturers of 2-6 low band Yagi have discontinued the 6-10 element versions and the 4 or 5 element versions won't work for me as I'm too far away (probably 45 miles).
I thought about making a 57MHz Yagi from scratch, but decided it isn't worth the effort since there is no assurance it would pick up the station any way.
I have an old Channel master on a four section mast about 25' up but it can't pull in Sneedville.
Being down in a hole does not help much.
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The pcb as a dielectric makes itself known when you have traces above and below and capacitance between traces and ground planes. How the quality of that formed stray C affects the circuit... stability, HF distortion, etc will affect performance compared to different pcb dielectrics.
and, of course the cheap pcb materials absorb moisture easily which complicates the stray C characteristics.
THx-RNMarsh
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