picked up an ST-S444ES sold as an ST-S555ES; boo.
after adjusted price i decided to keep it. it was out of adjustment, so tinkered it back to showing correct frequency when tuned. then proceeded to tinker with all adjustments for learning
did it to ear / dmm measure where applicable and seemed to be more sensitive and sound MUCH better than all other tuners I have. Yay.
Just picked up a ST-S555ES and is an actual ST-S555ES; yay.
however it
doesn't sound nearly as good, comparatively muted higher end. nothing noticeably different low end. Seems it has more distortion too.
auto seek doesnt work, just keeps seeking.
The output relay disengages at times for "no reason"
using my learnings first go, easily fixed auto seek via muting adjustment if i recall correctly (maybe it was VCO adjustment?).
somewhat sorted the output relay disengaging at odd times. still will do it but maybe a few times a day and turns back on before my brain even registered it clicked lol
so tried to adjust the secondary and did this mostly because not using proper tools
Am wondering about replacing the slug or perhaps the whole thing (adjustable inductor?) with this one that is in a Teac TX-100 / entry level tuner.
Is that possible?
after adjusted price i decided to keep it. it was out of adjustment, so tinkered it back to showing correct frequency when tuned. then proceeded to tinker with all adjustments for learning
did it to ear / dmm measure where applicable and seemed to be more sensitive and sound MUCH better than all other tuners I have. Yay.
Just picked up a ST-S555ES and is an actual ST-S555ES; yay.
however it
doesn't sound nearly as good, comparatively muted higher end. nothing noticeably different low end. Seems it has more distortion too.
auto seek doesnt work, just keeps seeking.
The output relay disengages at times for "no reason"
using my learnings first go, easily fixed auto seek via muting adjustment if i recall correctly (maybe it was VCO adjustment?).
somewhat sorted the output relay disengaging at odd times. still will do it but maybe a few times a day and turns back on before my brain even registered it clicked lol
so tried to adjust the secondary and did this mostly because not using proper tools
Am wondering about replacing the slug or perhaps the whole thing (adjustable inductor?) with this one that is in a Teac TX-100 / entry level tuner.
Is that possible?
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Use a small jewellers type screw driver, carefully break away at the rest of the slug without damaging the coil former and it will come out in small pieces.
Then find a similar size ferrite tuning slug and use a plastic or ceramic tuning tool (Like this one) to screw back in carefully and slowly.
To adjust the receiver RF tuner properly you are going to need a specialised FM RF signal generator otherwise you'll end up making things worse.
Then find a similar size ferrite tuning slug and use a plastic or ceramic tuning tool (Like this one) to screw back in carefully and slowly.
To adjust the receiver RF tuner properly you are going to need a specialised FM RF signal generator otherwise you'll end up making things worse.
I would actually recommend using something more like a matchstick if it will grip or if not then get a splinter of wood that will fit and shave it down. A metal screwdriver that only contacts in a small area will crack these dust cores.
Also remember to use a non ferrous trimmer when actually adjusting.
Also remember to use a non ferrous trimmer when actually adjusting.
Plastic always for these, too brittle for hard tools (modern ceramic is tougher than steel, note). Iron dust cores are very weak, IF transformers are usually iron-dust, not ferrite (has higher Q I think).
thank you all for the advice;
so is not recommended to just swap the entire "unit" meaning the two "adjustable inductors" (sorry am not sure if that is what these are)
for determining if the cracked sony one is iron dust am presuming I can just check if it's ferromagnetic? (am presuming the ferrite is not)
so is not recommended to just swap the entire "unit" meaning the two "adjustable inductors" (sorry am not sure if that is what these are)
for determining if the cracked sony one is iron dust am presuming I can just check if it's ferromagnetic? (am presuming the ferrite is not)
They are RF transformers. Only use the proper tools for adjustments.
Velleman Universal 6 PIECE TV/Ham Radio Alignment Trimmer Tool Set W/ Extender | eBay
Velleman Universal 6 PIECE TV/Ham Radio Alignment Trimmer Tool Set W/ Extender | eBay
IF transformers, normally, though there are other uses.
Ferrites are ferrimagnetic, which is the same as ferromagnetic for most intents and purposes(*). Iron dust looks different to ferrite. Its made of extremely fine dust in a resin matrix, can be rather crumbly, ferrite is an extremely hard solid (harder than steel).
Bringing a permanent magnet near some types of ferrite will permanently change their RF behaviour - don't do that!
(*) ferrimagnetic means there are more than one type of atom in the crystal, such that the different types align opposite, but don't cancel out since they have different strengths (partial cancellation). Ferromagnetic has one type of magnetic atom that all align one way (no cancellation). Antiferromagnetic (for instance chromium metal) has one type of magnetic atoms or layers that alternate magnetic direction, thus completely cancelling out (its hard to tell an antiferromagnetic material from a non-magnetic material in fact, but antiferromagnetic layers can affect nearby ferromagnets).
I saw there's an op amp current source (Howland current pump) with a 600R load resistor to the
tuner ground, but then the remote RCA adapter has another 600R resistor to the preamp ground,
with a coupling capacitor. I don't get that, the tuner still seems to output a voltage signal,
a current source into the internal 600R, and the Rout is 600R. Half the output current goes to the preamp.
Why would the internal load resistor be the same as the remote resistor instead of larger,
so most of the signal current would go to the preamp? Half of the current seems to be wasted.
tuner ground, but then the remote RCA adapter has another 600R resistor to the preamp ground,
with a coupling capacitor. I don't get that, the tuner still seems to output a voltage signal,
a current source into the internal 600R, and the Rout is 600R. Half the output current goes to the preamp.
Why would the internal load resistor be the same as the remote resistor instead of larger,
so most of the signal current would go to the preamp? Half of the current seems to be wasted.
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Am with you on that for sure! the 444 I have sounds very good / best i've heard.
I wanted the a/b antenna option and a few more presets is a nice bonus.
was disappointed it was in need of maintenance / not aligned.
and disappointed I had used a metal tool on it which is wrong for a number of reasons; not least of which is may have spoiled the primary since the metal bit i used is somewhat magnetic and now know thanks to Mark's awesome explanation about ferro / ferri magnetic
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they're particularly good circuits: Direct Comparator series I think all have very high signal / noise
for the 555 usable sensitivity is 0.8uv
can't speak for the 555 since mine is in disrepair.
am not sure about better than other GOOD tuners; I think there are MANY well regarded tuners out there.
for the 444, yes. I guess local can still be within the realm of too strong a broadcast and weak broadcast. I live a few KM from a pop music tower and about 20 from local college low power transmitter.
the 444 handles the close by pop station with no issue, and is able to grab a decent signal from the college.
is just as susceptible to adjacent HD radio stations as other tuners. what used to be one of the better stations now sounds pretty bad.
am not sure about better than other GOOD tuners; I think there are MANY well regarded tuners out there.
for the 444, yes. I guess local can still be within the realm of too strong a broadcast and weak broadcast. I live a few KM from a pop music tower and about 20 from local college low power transmitter.
the 444 handles the close by pop station with no issue, and is able to grab a decent signal from the college.
is just as susceptible to adjacent HD radio stations as other tuners. what used to be one of the better stations now sounds pretty bad.
555ES has two antenna inputs, one with switchable attenuator for very strong signals
I use external antenna into unattenuated input and just a piece of wire in another
One other feature I like about this tuner is that you can select for each station separately if you want wide/narrow, or stereo/mono or hi-blend or muting, or which antenna input, it gets memorized with the station frequency. For another station, you can memorize totally different settings. Most tuners memorize just a frequency.