Technics SH8025 Equalizer repair part 2

Part 2 to fix this one.
Part 1 troubleshooting here:
• Technics SH8025 Equali...

[@rlwings]

I think EQ is more for dealing with negative room acoustics. If you measure the listening position (and other areas) with good mic and software, EQ can make a world of difference. But until you hear it you'll never know what you're missing.... Love your videos by the way. I like to watch them to relax and also to learn about electronics. Thanks!

[@ESDI80]

I run an EQ on my main system. I have hearing loss in the bass regions so an EQ helps bring up the bass response to where I can here it well. This way I can boost the deep bass and not mud up the mid bass and mid range frequencies. Running flat sounds pretty much like the bass is turned all the way down to me.

[@johnbedell2376]

Equalizers compensate for inadequate room acoustics - not just bad speakers. And speaking of bad speakers - isn’t that more or less an arbitrary statement? Equalizers also tailor the sound to the individuals personal taste. While there may be a proper technique for setting up an EQ, most people - I have found - just adjust it to their liking. At the end of the day, an equalizer is just a glorified bass and treble control that gives listeners more ability to tweak the sound so it sounds good to them.

[@Hagledesperado]

There are two types of EQ users. Those who just want to flavor the sound to their preference, not that there's anything wrong with that. And then there's those who need an EQ because they want to correct something about the room or the speakers. Something that can't easily be corrected through other means, for some reason or other. The latter group is very small, simply because that sort of use case entails knowing what you're doing.

[@raymiehershey5486]

Some people need a eq. After working on a FA 18 jet flight line for 11 years the eq helps fill in some of my hearing problems in the mid to high range. Good video!

[@PeterMilanovski]

I personally love how a graphic equaliser can add color to the sound... I'm just not interested in chasing a flat sound because it just don't sound good to me. Every amplifier and speaker combination that I have owned has sounded different, almost like as if they were putting their own little spin on the sound. Even if you set the tone controls at zero, or if you are fortunate enough to have purchased an amplifier that the designer has mindlessly forgotten to even add tone controls. The pre amplifiers to the power amplifiers and the parts and materials chosen... Every amplifier is adding some form of color to the music.. It's just that some amplifiers offer more choice in how much color you would prefer to have in the music that you like... For everyone else there is graphic equalisers.

[@Truckguy1970]

@7:00 when you were talking about running a cable through the wall that reminded me when one of my friends drilled through his line set to his HVAC unit when he drilled through the wall lol.

[@12voltvids]

I drill through walls daily to install fiber. I open up the wall on the inside so I can see what is there before I drill. I also now put my borescope camera in to see what is in a wall before I drill

[@quasarhi]

Great Job - Nice to see the follow up !

[@zx8401ztv]

Great it's all working :-D That part packing was daft, a small jiffey envelope would have done, it's not a fragile part. No break for food and drink, that is bad, dehydration and blood sugar levels could have created an accident :-(, that customer was being too picky. Find out company policy on health@safety, use the rules against difficult people. It's your health dave, not worth making yourself ill or creating an accident.:-(.

[@finscreenname]

Audiophiles....double face palm. I have a nice system and really nice speakers and have that exact EQ for 35+ years now. It has made my bedroom in moms house sound good and every other house I have lived over the years. There is not a recording made that was not run through a sound board and for that matter there is only a hand full of recordings worth having a high end system for and you better love Lester Johnson and his 2 string bass just because it sounds good. The question no audiophile will answer, you have a sound system in a car, speaker placement is limited at best, seat placement is fixed and you are not putting window treatments over your windshield....what do you do? You want it to sound good you need tone controls and the more the better. PS, Nice work. Glad you saved the classic even if you don't like it.

[@xeroinfinity]

thats great original parts were still available. I like to clip the mids on my EQ just gives everything more dynamic range imo.

[@Fluteboy]

I used one as a teen. I wanted BASS! And a bit of sweetness up top too. But then it was my fault for having non-ported Goodmans speakers. What I never understood were the people who had every slider to the max. If you want loud, why not just use the volume?

[@rawr51919]

First comment. I'd say this is yet another good-quality repair out of you.

[@fulwell1]

Blimey, Kingston Road in New Malden is within 15 miles of my home - small world!

[@djshumon]

Hi my Technics ge90 has no signal coming out of it.could you help in what might be the cause,thanks

[@12voltvids]

Could be anything. Check the power supply.

[@djshumon]

@@12voltvids thanks for your reply.

[@johnohara54]

Do you ever use heat sinks? I have some copper alligator clips : do a great job: would hate to order an IC for 10 dollars, 20 dollars shipping from GB, that one IC arrives and you cause a heat-induced short because you did not use heat sinks while soldering. Just like to be sure. Love the videos; try to guess the fault before you get there: only got 27 years . Was the Ic dead short? John O

[@tomdewey9907]

Yup, I agree about the "smoke and mirrors" graphic equalizer need; poor room acoustics/setup and badly designed speakers are/were the base of the problem. My Magneplanar MG-III's always, always sounded superb in my listening room; totally flat amplification; the Adcom GFA-555 power amp is/was a beauty driving those speakers that are so power hungry (325 watts per channel before clipping). Maggie's are still the best if you have the "right" room for them.

[@12voltvids]

But again unless you do a frequency sweep of the listening room you will never know where to set it. Better systems have a microphone you place in the room to tweak it. My old onkyo av receiver has this and I used it when I set up my home theater. In my music room on the other hand I have a pair of large sb7000a speakers. They are a phase linear design with the midrange and tweeters set behind the woofer. This is to compensate for the relative time it takes for the sound to travel from the speaker to the listener. Yes, lower frequencies move slightly slower than the higher frequencies and speaker designers back in the 70s were getting quite clever in the design to attempt to keep everything in phase. These speakers are very efficient. I drive them with only a 40 watt tube amp and they will rattle the windows with no effort. I could probably shake the windows with my 9 watt class a tube amp.

[@tomdewey9907]

Maggies (bi-polar open/no cabinet) are their strength; you just needed plenty of power to drive them. To my ears/experience nothing came close to them from the typical compression "drivers in a box" design.

[@12voltvids]

@@tomdewey9907 the problem with open designs is the air coming off the back of the driver cancels out the signal. Mine are bass reflex ported. Fantastic sound.

[@macgvrs]

One possible use for an equalizer is if you are converting old tapes that maybe don't sound too hot. There are definitely limits to that but it can help improve the sound quality a little. I have had voice recordings that I had a hard time understanding and have used an EQ to at least make clearer and at least I could make out what was being said. It could in no way be said to be good quality but it did help. You can get into trouble with an EQ because you can boost or cut a frequency, or frequencies, for making a recording and then find out it isn't so hot, that it has too much of whatever frequency you boosted or too little of the frequency you cut. You can guess how I know that.

[@12voltvids]

Oh they do have uses for sure. I have just never had one and don't think I need one. My system sounds pretty good to my ears.

[@ramilobernardo9101]

Hi how much is the Panasonic vcr that you sell please.

[@macgvrs]

Ramilo Bernardo Not sure you have the right person. Was this message for 12voltvids?

[@Synthematix]

macgvrs, thats because you are supposed to eq the speakers not the recording.

[@RuneTheFirst]

I remember a gimmicky equalizer from the 80s. It was BSR-branded but this was after they ceased production of changers. I believe Sharper Image was selling it. Anyway, it came with a microphone and built-in white noise generator. I forget how it worked and I wondered if it was any good. Probably not, as it did not inspire any competitors to offer similar. Wonder if any survive...

[@12voltvids]

Many receivers have this feature today and they actually work. The white or pink noise is picked up by the microphone and analyzed. The eq curve is adjusted to make it flat.

[@craggercragger8989]

12voltvids The Audyssey room EQ on my Denon AV amplifier is fantastic - the difference it makes for the subwoofer channel is worth its weight in gold. That being said, for music, the Sony TA-E/N80ES pre and power amps with the Yamaha NS1000M sound fine running "flat".

[@Synthematix]

Craig McLellan Trouble is its not running flat and never can without equalization

[@craggercragger8989]

I'm sure you can work out what I mean.

[@Synthematix]

Craig McLellan Yea i know what you mean fella, you meant untouched

[@1pilotsteve]

An ESD strap has a 1 Mohm resister which connects to the ground for proper static discharge. Simply placing your hand on the chassis may not discharge the EST properly. That is what I was thought in school...Just saying...

[@12voltvids]

An esd strap has a 1m ohm resistor to protect you from electrocution should you contact an energized circuit. Low enough to discharge static build up high enough to not allow a dangerous current should contact with energized circuit. In this case the unit is unplugged. No risk of shock.

[@1pilotsteve]

@@12voltvids you could probably arc weld with that ic in your hand and it wouldn't fail...lol. probably 741 op amps or Darlington transistors...pretty hearty.I.worken.on lots of CMOS multiplexer cards that would blow up if you put your hands on anything near by. Also..the term we were thought was P/N junction " wounding" from ESD...not hurt it enough to kill it right away but.shorten it's I enjoy the channel very much. I am 61 and I used to fix everything back in the day.. Now it's Chinese and Costco throw away... Great job..

[@12voltvids]

@@1pilotsteve Esd can damage cmos chips quite easily. That is why the ground strap is used because static is formed on your clothes, depending on the fabric every time you move. Keeping your hand on something metal that is grounded or at least large enough to absorb any build up will protect those devices. As you said not all devices are going to be damaged but some may have their life shortened.

[@amtpdb1]

Question: You are so good figuring out things with out a schematic. I just do small fixes, but my 3d printer popped last night and the backlight went out on the lcd screen. I was told that it might be the lcd driver for the backlight as I still can see the screen with a flashlight. How do you figure out which chip is for the backlight? I looked up all the chips but none say lcd driver or anything to do with a backlight not lighting. Thanks for any help.

[@williamsquires3070]

amtpdb1 - the backlight should just be a small LED or grain-of-rice bulb; getting to it is probably the trickiest part of the operation, assuming the backlight was the only thing to fail. One lead should go to ground (if the IC is sourcing current), or to Vcc (if the IC pin is sinking current.) the other lead should be in series with a dropping resistor that goes to the IC pin. Worst case; just wire the series combination across the +5v rail and ground, and change the (value of the) dropping resistor and it’ll always be on when power is applied. Be sure to lift the IC pin that was driving it, or the magic smoke could be let out! Rled = (Vcc - Vled)/(Iled), where Vcc is your positive supply rail, Vled is the forward voltage drop of the LED, and Iled is typically 10-20 mA (.01-.02 A). Calculate Rled and choose the next higher standard 5% tolerance value. Simpler way; see if the thing already has a “power on” LED; if it does - and it’s bright enough - see if you can physically move it so it’s in the location of the backlight in there now, and splice in new wires to run it over there! HTH!

[@12voltvids]

Usually it is not the driver. Usually it is one of the LEDs. They do fail and are failing in quite high numbers. They are driven in series. If one goes out they all go out. Measure the voltage. If it is high then it is an led problem not a driver problem.

[@amtpdb1]

William Squires Thanks for the information.

[@amtpdb1]

12voltvids Thanks, great videos.

[@glenngoodale1709]

Nice video

[@riakawai9339]

12voltvids how much did you sell the Panasonic vcr

[@ramilobernardo9101]

Which is the last one that you repair

[@mcintoshkid]

mate your absolutely right,,with a good stereo system and great speakers u don't need an equa

[@BP-bx6si]

Equalizers are just another way to get some more money out of you. I just had fiber installed at my house today. Unlike your customer I was actually helpful to the installer. Cut the hole in the shiplap with a reciprocating saw and cleaned up the mess while he did all the wire pulling. One of the better contractors that t e l u s has. I showed him your Channel.

[@BP-bx6si]

Yes I know you're not a contractor Dave. My neighbor a few doors over always asks for you by name when he contacts the phone company for service. He says you have fixed his problems caused by a previous contractor every time, and on top of that , are interesting to talk to.

[@Synthematix]

"Equalizers are just another way to get some more money out of you." - Well What a dipshit comment that was, eq's are needed because all speakers have a different frequency curve and you use the eq to flatten the sound of them, people shouldnt comment on here unless they know what theyre talking about. Theres no such thing as a flat speaker and never will be, bass and treble controls along with loudness buttons are all equalizer controls. you need to get the frequency plot for your speakers and adjust the eq accordingly. 20 band eq per channel is the minimum i would use. you equalize the speaker not the music.

[@12voltvids]

@@Synthematix Right but good speaker design will generate a relatively flat response in a proper listening environment. Typically big large speakers are much better than the new modern ones. Eq can improve the sound of inefficient speakers for sure. I have just never had a need for it. My system sounds excellent as it is. On some speaker systems equalization is mandatory. Try listening to some bose 901 without the eq unit and see how bad that sounds.

[@Synthematix]

12voltvids Oh i know how bad bose sound without a DSP, and no wonder! their speakers always have nothing but midbass drivers and bose never use tweeters, this combination alone is why i hate them! but concerning eq's, nearly every piece of modern music has been eq'd, (but this is an entirely different thing) years ago speakers used to have their frequency plots printed on the cabinet and then you used the eq to flatten any spikes and boost any drops on the chart, more bands the better this is why i love computers. my speakers are harsh at 150hz so i use the eq to drop the 150hz band down by 5db. once your speakers have been equalised properly they will sound even better, all this said some people dont like flat sound and prefer bass heavy speakers, thats absolutely fine, everyone is entitled to listen to music how they please, i personally use a subwoofer for bass and let the midbass do the job it was designed for. using a good eq ive never ever needed to use crossovers in my speakers (yamaha floorstanders), they are direct coupled. only component inside mine is a 2UF capacitor for the tweeter thats it. this is where custom eq presets come in to play, this can take hours to do properly but damn its worth it. And you 12volt vids have the luxury of some very good quality scopes/testers, its a real fun thing to do and the end result is mind blowing. crossovers are not accurate enough to eq a speaker properly but a good eq is, on my wharfedales the difference in sound is night and day i tell ya. i simply fitted rocker switches at the back of each cabinet to bypass the crossover. you can then do an a-b test you wont believe the difference, most x overs strangle the midbass drivers. if you use ann eq with a crossover you are "double eq'ing" and thats a bad idea, which is why eqs got the bad reputation of causing distortion. however, Very Very expensive speakers have crossovers the size of housebricks, these are tuned to each driver, not mass produced. but speakers this high end cost in the region of £1,500 each

[@12voltvids]

@@Synthematix Right but by adding extra eq you are undoing the work of the recording engineer. I have had amps with EQ in them. My home theater all does. I leave it all off. It is personal preference but being a musician from my younger years I know what an acoustic instrument is supposed to sound like and my vacuum tube amp into a pair or sb7000a speakers is as close to that sound as I have heard.

[@jeremygold6487]

Can I send you my Memphis car amp for repair? Won't switch out of protect mode.

[@12voltvids]

I never did any work on car audio.

[@ElectoneGuy]

Freedom 55. Looking forward to getting out of the corporate world...

[@12voltvids]

These days it is freedom 65 if you are lucky. I could actually pull the pin now if I wanted, but i want to pump up my pension for a few more years. Also there could be a buyout. A bunch of guys i know just took a package. Different departments. So I hang I there to see what it in the future.

[@jefferyb304]

It aggravates me when systems have nothing but preset EQ's. A lot of times in the past, if the system just had bass and treble controls, I'd have them wide open.

[@Synthematix]

Factory preset eqs are useless unless you are using a system with its correct speakers (all in 1 system)

[@jefferyb304]

The last all in one I had was new from the early 2000's It was blah. I hooked up a DVD player to it. It quickly became my prefered way to play CDs. The same DVD player is how I play CDs with my Sansui 551. It has a readout like a CD player has.

[@Fluteboy]

jefferyb304 Whoever thinks up those presets must be a masochist. They are a true oddity.

[@renatoscutube]

What's with your voice??

[@12voltvids]

?

[@renatoscutube]

12voltvids Your voice sounds a bit muffled. Do you have a cold or something like that?

[@12voltvids]

@@renatoscutube Nope not that I am aware. Was dog tired after a brutal all day job.