What a nice little quad receiver, I like the layout and the nice blue dial backlight. It looks like it's going to be a nice one to enjoy some Santana in quad off of some Columbia SQ encoded records :)
11:00 - The deal with an 'enameled' pointer, fully mesh the tuning cap, loosen the set-screw(s) on the pulley, move the pointer to '0' via the tuning knob, tighten the set-screw(s) :)
Loved your video, my first amplifier was a Lafayette tube amp in kit form , I also owned Lafayette Criterion speakers and later owned a 4 channel receiver either the same as the one that you repaired or very similar to it . I miss the Lafayette company and their catalog very much as well as Allied Radio and Radio Shack.
Seeing this video sure makes me want to do a restoration on my Panasonic RE-7750. It too is in need of a recap and the controls cleaned. Hopefully someday I will get my hands on a 4 channel record or reel to play on it. I'll be interested to see part 2 and an explanation on the SQ decoder circuit. Thanks for continuing to make videos during this time.
Oh those TO66 unobtainium goodnessness! I have an amplifier that was sold as a kit from an Australian magazine in the early 70's that has TO66 unobtainium goodnessness from Fairchild semiconductor manufacturing in Australia! Someone purchased the kit and did an amazing job at putting it together, I found it at a used Hifi shop in Melbourne and got it to gut it's internals with some high powered class D amps, that was until I plugged it in and had a listen to this 13W rms amp. I didn't know anything about it at the time but I was hooked on it's amazing sound quality, then I started to do some digging and learned that it was designed by the team at Electronics Australia magazine... That's when I found out that the potentiometer on the back was to control the surround channel level. Luckily for me, the amplifier is well documented over a few issues of the magazine which are still available for download on the Silicon Chip magazine website. It's now a treasure that I can't part with. It's a special amplifier with a special connection to audio equipment in Australia! But aren't those TO66 unobtainium goodnessness Just beautiful... So thank you Tony for you time in making this video, with all this time at home, I have literally watched all your videos along with others like Mr Carlson's, Uncle Doug, EEV Blog, Marko Reps, Diodes Gone Wild, Dr Cassette, Great Scot and everyone else that hasn't been mentioned here... Yeah I spend way too much time on RUclips but I regret nothing! You and other might consider yourselves just one person living your life wherever you are, but your life and what you do brings joy to people all over the world, it's true when they say that the world really is a small place..
Lafayette Electronics used Matsushita Electric as their main OEM for almost all their products including their famous CB transceivers . They also used Sanyo and Shin Sibahura as manufactures for the low entry lines of products . I worked for them as a consultant from 1968 until their bankruptcy . At the same time I also worked for RCA as a RF engineer designing antennas systems for AM , FM and VHF and UHF TV stations . At that time RCA was the dominant supplier of broadcasting equipment in the Americas.
@@bigmsound Matsushita sub contracted those manufactures when their productions lines where full and occupied , but Matsushita was always Lafayette Electronics main OEM .
Reminiscent of my Superscope R350, my first resto. It truly is a "baby Marantz". I also have a Marantz 4270, which is why I bought the R350, because I didn't want to butcher the Marantz when I recapped and restored it. I figured I would practice on some less expensive stuff before I tackled my baby. I bought that 4270 back around 1985 BTW for $75 including the Marantz speakers. It has served me all these years, only being restored 3 years or so ago now. And I play it a LOT.
DUDE...... I had those exact SONICS SPEAKERS, they powered my Sanyo 2033 receiver. The Sanyo 2033 was my first foray into so called hi-fi. It was a dorky little 33 watts per channel but I loved it. I brought my little Sanyo with $100 and those exact brand and type of SONIC Speakers using money I made shoveling snow. My second receiver was a Fisher Studio Standard but it was 100 Watts per channel on those same SONIC Speakers. I replaced my SONICS speakers when I was older and brought a SONY 100 watt receiver, it had surround sound. I remember those SONIC speakers fondly indeed!
Some people think winding the bias up will change it into class A, which it does kind of do. They also understand that it will get hot, after all most class A amplifiers do get hot. What they don't understand is the heat sinks just cannot remove that kind of heat. Even the mains transformer is not made for such constant current draw. I'm amazed everything was not damaged.
Sometimes the mounting screws and transistor case get oxidized. Make sure the resistance between the screws and transistor case is as close to zero as possible. To maximize the output and reduce the heat and clipping on the output transistors at higher output.
My first amp was a "Laff-At-It" (that's what my late brother and I used to refer to them!), from the 60's, complete with GERMANIUM transistors and a *negative* DC supply! It was given to me by a hobbyist that was giving some of his stuff away. I Heathkit TV Alignment Generator (featuring the "Incre-ductor'), and a Heathkit VTVM - both 50's models. I couldn't find one on the Google Machine, but it *did * exist :)
Seems to me someone attempted to replace the dial pointer light and messed up its tracking along the guide. And to boot the pointer doesn't light. Two strikes!
I would argue that the moment you recap an old piece of audio gear it's no longer what it was when new. The differences alone in ESR on modern caps can make a difference. Now will a recap make it sound better then it does at this point in time, yes most likely. Once recapped it won't sound exactly like it did when brand new IMO. Good vid, glad your voice isn't annoying like another similar RUclipsr.
I realize your post is a year old, but I just overhauled a SX-780 and came across another dead SX-780 (since repaired) and just did a side-by-side. The first has had what I'd guess most would consider extensive mods... the STK packs have been replaced w/discrete components, the TA 7136s replaced with modern parts (out of necessity, not shotgunning parts), and it's fully re-capped. The 2nd 780 is (basically) stock, no recap, no mods aside from replacing a dead STK module w/the (only) working one I pulled from the first SX780. While I cannot know what any SX780 sounded like new, the modified SX780 sounds clearer than the stock 780 does at this point... so if the choice is to leave it alone or recap, and sound quality is the goal, I'd suggest recapping over originality, and any receiver, (thoughtfully) modified or simply restored, sounds better than a dead receiver, which is the direction all of these are headed w/o service.
@@db3ll Considering how old some of the caps are, I would recap it as well. It will probably sound better then it did when it was new, however it probably won't sound the same as it once did when new. Sooo many factors in play here. In the end, if your happy with the results then you have a win.
o.m.g!! i had a pair of those very same speakers sonics i bought at a thrift store many years ago they must had sound great with that 7.5 watts/chanl.reciver .
The burning question is... who was the OEM supplier Lafayette used for this era receiver? I have followed Radio Shack's receiver line for decades (I used to work there when in college) and they switched from time to time just to keep us guessing. Lafayette did the same, and their receivers were always well built.
My current Stereo is a Yamaha CA-610 that I restored and some Soundcraft Spirit Absolute 2 with new tweeters. And a Maya 44 pci sound card as DAC. I eager to get into DSPs and building a Class D Bi-Amp system
Sweet setup! If you want to get into DSP and Class D, take a look around Parts Express. They have quite a bit to choose from, although their stock might be a bit low at the moment due to the current global situation.
I was thinking about using an ADAU1701 based dsp board but before that I be gifted a calibrated measurement Mic from a friend who's Synthesizer I repair from time to time
I always wondered who built Lafayette's Amplifiers in Japan; this series of 4 channel Receivers in particular. Hoping someone here can answer that question ? Lafayette, back then was headquartered in Long Island, NY. And their Business Model was very similar to Radio Shack, catering to the "DIY" crowd.
Tony, great video but I was puzzled that you didn't reattach the thermistors onto the heatsink prior to setting the bias. The thermistors are a critical part of the amplifier biasing circuit, reducing Vbe with increasing temperature to prevent thermal runaway and it seems like you caught things just in time before any damage was done. It didn't hum cold, so wondering if the biasing had really been tweaked or the current increase was due to the thermistors not seeing the actual heatsink temperature?
It would have been better if I did the thermistors first, but I dnd't want to wait for the thermal adhesive to dry. In addition, the instructions explicitly say to make the bias adjust with the amp/heatsink at room temperature. The stabistors won't have any effect until the heatsink begins to warm up above room temp. There was extreme excessive current on the outputs at room temp. Over 400mA when there should have been less than 40. It was absolutely power-tweaked. The hum was due to the excessive current at the power supply. Thanks for the comment!
replace the gears made from resin to something made from brass, could someone have been messing around with bias on the Class A output stage. Class A stages will always run hot like the FINAL amplifier, actually I was warned off from buying a FINAL amplifier and bought a TECHNICS SUA900 MKII which worked well but developed a hum problem as I suspect that the bamboo based electrolytics have dried out so I don't use it anymore so I bought a SONY soundbar and subwoofer and haven't looked back, just wondering would it have been a better idea to maybe go with 2N3055 power transistors which can take a higher current.
Hi. I have a question. I love vintage hifi from 80’s-90’s. I buy many old equipment and I noticed that they sound much less clearer (much less treble) than what they were sounding when they were new. What’s getting old in them? Is it the old capacitors acting as filter? What’s the reason they sound much less clearer? THX
In most cases, it is due to the electrolytic capacitors. As they age, the electrolyte dries out or leaks out, which changes the performance/value of the capacitor and affects the sound. Caps can become leaky (both chemically and electrically) or open, and in some cases can even short out. This is why it is a common practice for people to replace the electrolytic capacitors - a practice known as "re-capping". Failing transistors can also affect the sound, as they can cause weak signals as well as crackling and popping noises. In extreme cases, they can even damage other parts of the amp by shorting out. Thanks for the comment!
Hey Tony I have a 4 channel unit similar to this with a Gladding name on it. Still see's weekly usage. I may get into the back and do some mods as you showed. What's the thermal paste you used?
Never been a fan of needless and possibly damaging tweaking. My school of thought has always been whether CB or audio if you want more power just get a bigger amp. Although if everything is properly set up and tuned correctly, you may find you don't need more power.
Not entirely, they were already in trouble trying to compete with Radio shack. The situation with the 23 channel CB's was kind of the last nail in the coffin. Had the company been doing much better to begin with, they might have been able to absorb the loss.
i had a 1980s lr 9090 receiver 90wattsch awww man left channel out put was blown when i got it early sanken amp output chip finding one next to impossible?? if i had xrays t. knowledge and stereo skills i could have fixed it !!!!
I would suggest that you watch my video entitled "Frequently Asked Questions - XrayTonyB". I explained that it may take a while to respond to all the e-mails. I only do this as a hobby. I own a full time business in the medical imaging repair industry that takes up a lot of my time. In addition to that business, I have a family and many other obligations. I receive, on average, 40+ e-mails a week, most of which I try to answer. It usually takes two or three weeks for me to answer an e-mail, but sometimes I can get to them sooner. I do this at no charge to try to help others learn. If you need an answer that quickly, I would suggest that you visit the AudioKarma or DIYAudio websites and post your question there. You could also reach out to someone who does this for a living. Be patient and I'll get to your e-mail as time permits. Others who sent their question before you have been patiently waiting as well and I want to make sure I give them the same attention that I will give you. I'm only one person, please try to remember that.
Tony you make watching solder melt interesting! 👏🏻👏🏻👏🏻
Thoroughly enjoyed seen a rare now-a-days receiver like this. Another great video Tony. Thanks for showing it! Can't wait until the finish.
What a nice little quad receiver, I like the layout and the nice blue dial backlight. It looks like it's going to be a nice one to enjoy some Santana in quad off of some Columbia SQ encoded records :)
Havent seen A Quasi-Complementary Amplifier in quite a while. Great Video Tony
Great video Tony, thank you, I’m a fan of 70’s Lafayette gear. If I remember correctly most of the stereo gear was made by Kenwood-Trio. Stay safe
11:00 - The deal with an 'enameled' pointer, fully mesh the tuning cap, loosen the set-screw(s) on the pulley, move the pointer to '0' via the tuning knob, tighten the set-screw(s) :)
Loved your video, my first amplifier was a Lafayette tube amp in kit form , I also owned Lafayette Criterion speakers and later owned a 4 channel receiver either the same as the one that you repaired or very similar to it . I miss the Lafayette company and their catalog very much as well as Allied Radio and Radio Shack.
Seeing this video sure makes me want to do a restoration on my Panasonic RE-7750. It too is in need of a recap and the controls cleaned. Hopefully someday I will get my hands on a 4 channel record or reel to play on it. I'll be interested to see part 2 and an explanation on the SQ decoder circuit. Thanks for continuing to make videos during this time.
Oh those TO66 unobtainium goodnessness! I have an amplifier that was sold as a kit from an Australian magazine in the early 70's that has TO66 unobtainium goodnessness from Fairchild semiconductor manufacturing in Australia! Someone purchased the kit and did an amazing job at putting it together, I found it at a used Hifi shop in Melbourne and got it to gut it's internals with some high powered class D amps, that was until I plugged it in and had a listen to this 13W rms amp. I didn't know anything about it at the time but I was hooked on it's amazing sound quality, then I started to do some digging and learned that it was designed by the team at Electronics Australia magazine... That's when I found out that the potentiometer on the back was to control the surround channel level. Luckily for me, the amplifier is well documented over a few issues of the magazine which are still available for download on the Silicon Chip magazine website. It's now a treasure that I can't part with. It's a special amplifier with a special connection to audio equipment in Australia! But aren't those TO66 unobtainium goodnessness Just beautiful... So thank you Tony for you time in making this video, with all this time at home, I have literally watched all your videos along with others like Mr Carlson's, Uncle Doug, EEV Blog, Marko Reps, Diodes Gone Wild, Dr Cassette, Great Scot and everyone else that hasn't been mentioned here... Yeah I spend way too much time on RUclips but I regret nothing! You and other might consider yourselves just one person living your life wherever you are, but your life and what you do brings joy to people all over the world, it's true when they say that the world really is a small place..
Lafayette Electronics used Matsushita Electric as their main OEM for almost all their products including their famous CB transceivers . They also used Sanyo and Shin Sibahura as manufactures for the low entry lines of products . I worked for them as a consultant from 1968 until their bankruptcy . At the same time I also worked for RCA as a RF engineer designing antennas systems for AM , FM and VHF and UHF TV stations . At that time RCA was the dominant supplier of broadcasting equipment in the Americas.
Many of Lafayette's CB's and stereo equipment were OEM'd by Cybernet and Trio (kenwood). This receiver looks like it was OEM'd by Cybernet of Japan.
@@bigmsound Matsushita sub contracted those manufactures when their productions lines where full and occupied , but Matsushita was always Lafayette Electronics main OEM .
Reminiscent of my Superscope R350, my first resto. It truly is a "baby Marantz". I also have a Marantz 4270, which is why I bought the R350, because I didn't want to butcher the Marantz when I recapped and restored it. I figured I would practice on some less expensive stuff before I tackled my baby. I bought that 4270 back around 1985 BTW for $75 including the Marantz speakers. It has served me all these years, only being restored 3 years or so ago now. And I play it a LOT.
DUDE...... I had those exact SONICS SPEAKERS, they powered my Sanyo 2033 receiver. The Sanyo 2033 was my first foray into so called hi-fi. It was a dorky little 33 watts per channel but I loved it. I brought my little Sanyo with $100 and those exact brand and type of SONIC Speakers using money I made shoveling snow. My second receiver was a Fisher Studio Standard but it was 100 Watts per channel on those same SONIC Speakers. I replaced my SONICS speakers when I was older and brought a SONY 100 watt receiver, it had surround sound. I remember those SONIC speakers fondly indeed!
Oh how I get excited when I see a new video from you! Thank you sir.
Some people think winding the bias up will change it into class A, which it does kind of do. They also understand that it will get hot, after all most class A amplifiers do get hot. What they don't understand is the heat sinks just cannot remove that kind of heat. Even the mains transformer is not made for such constant current draw. I'm amazed everything was not damaged.
I'm sure I will enjoy this one Thanks Tony for being who you are
Fixing dial-cord issues. You're a *better* man than I !
Sometimes the mounting screws and transistor case get oxidized. Make sure the resistance between the screws and transistor case is as close to zero as possible. To maximize the output and reduce the heat and clipping on the output transistors at higher output.
My first amp was a "Laff-At-It" (that's what my late brother and I used to refer to them!), from the 60's, complete with GERMANIUM transistors and a *negative* DC supply! It was given to me by a hobbyist that was giving some of his stuff away. I Heathkit TV Alignment Generator (featuring the "Incre-ductor'), and a Heathkit VTVM - both 50's models.
I couldn't find one on the Google Machine, but it *did * exist :)
Good job on that amp. At idle the thing was consuming over 1A at 50v!!! no wonder it got hot. Surprised it didn't pop a transistor.
Cool, thanks for the entertaining video. Nice way to pass the time when we are in isolation.
Thanks Tony. Need these videos righr now. 👍
Seems to me someone attempted to replace the dial pointer light and messed up its tracking along the guide. And to boot the pointer doesn't light. Two strikes!
Great, as usual... I look forward to continuing...
Neat receiver. Stay safe when you're on the job.
Another way to set the DC balance is to run it up to clipping and adjust for symmetrical clipping.
I would argue that the moment you recap an old piece of audio gear it's no longer what it was when new. The differences alone in ESR on modern caps can make a difference. Now will a recap make it sound better then it does at this point in time, yes most likely. Once recapped it won't sound exactly like it did when brand new IMO. Good vid, glad your voice isn't annoying like another similar RUclipsr.
I realize your post is a year old, but I just overhauled a SX-780 and came across another dead SX-780 (since repaired) and just did a side-by-side. The first has had what I'd guess most would consider extensive mods... the STK packs have been replaced w/discrete components, the TA 7136s replaced with modern parts (out of necessity, not shotgunning parts), and it's fully re-capped. The 2nd 780 is (basically) stock, no recap, no mods aside from replacing a dead STK module w/the (only) working one I pulled from the first SX780. While I cannot know what any SX780 sounded like new, the modified SX780 sounds clearer than the stock 780 does at this point... so if the choice is to leave it alone or recap, and sound quality is the goal, I'd suggest recapping over originality, and any receiver, (thoughtfully) modified or simply restored, sounds better than a dead receiver, which is the direction all of these are headed w/o service.
@@db3ll Considering how old some of the caps are, I would recap it as well. It will probably sound better then it did when it was new, however it probably won't sound the same as it once did when new. Sooo many factors in play here. In the end, if your happy with the results then you have a win.
I’m curious if those bias adjustment pots ended back on their factory tick marks. Great video! Thanks. :)
You didn't talk about the FM dect output.. This is very unusual as most didn't have this. The good ole days SCA fm receivers
I'm curious to know how close to the "factory ticks" those pots were after you adjusted the idle current.
o.m.g!! i had a pair of those very same speakers sonics i bought at a thrift store many years ago they must had sound great with that 7.5 watts/chanl.reciver .
The burning question is... who was the OEM supplier Lafayette used for this era receiver? I have followed Radio Shack's receiver line for decades (I used to work there when in college) and they switched from time to time just to keep us guessing. Lafayette did the same, and their receivers were always well built.
My current Stereo is a Yamaha CA-610 that I restored and some Soundcraft Spirit Absolute 2 with new tweeters. And a Maya 44 pci sound card as DAC.
I eager to get into DSPs and building a Class D Bi-Amp system
Sweet setup!
If you want to get into DSP and Class D, take a look around Parts Express. They have quite a bit to choose from, although their stock might be a bit low at the moment due to the current global situation.
I was thinking about using an ADAU1701 based dsp board but before that I be gifted a calibrated measurement Mic from a friend who's Synthesizer I repair from time to time
Very good...lovely videos...awesome!
Simply excellent! Thanks
I remember Lafayette CB radios .. Hmmm, never saw any Lafayette stereos ...
I always wondered who built Lafayette's Amplifiers in Japan; this series of 4 channel Receivers in particular. Hoping someone here can answer that question ? Lafayette, back then was headquartered in Long Island, NY. And their Business Model was very similar to Radio Shack, catering to the "DIY" crowd.
Yes sir, I worked at the Lafayette in Flushing Queens, NY... BUY ONE SPEAKER AND GET THE OTHER FOR ONE DOLLAR. Those were the days
Tony, great video but I was puzzled that you didn't reattach the thermistors onto the heatsink prior to setting the bias.
The thermistors are a critical part of the amplifier biasing circuit, reducing Vbe with increasing temperature to prevent thermal runaway and it seems like you caught things just in time before any damage was done.
It didn't hum cold, so wondering if the biasing had really been tweaked or the current increase was due to the thermistors not seeing the actual heatsink temperature?
It would have been better if I did the thermistors first, but I dnd't want to wait for the thermal adhesive to dry. In addition, the instructions explicitly say to make the bias adjust with the amp/heatsink at room temperature. The stabistors won't have any effect until the heatsink begins to warm up above room temp. There was extreme excessive current on the outputs at room temp. Over 400mA when there should have been less than 40. It was absolutely power-tweaked. The hum was due to the excessive current at the power supply. Thanks for the comment!
29:10 - Uh-oh! I see some 'UFO' transistors :)
replace the gears made from resin to something made from brass, could someone have been messing around with bias on the Class A output stage. Class A stages will always run hot like the FINAL amplifier, actually I was warned off from buying a FINAL amplifier and bought a TECHNICS SUA900 MKII which worked well but developed a hum problem as I suspect that the bamboo based electrolytics have dried out so I don't use it anymore so I bought a SONY soundbar and subwoofer and haven't looked back, just wondering would it have been a better idea to maybe go with 2N3055 power transistors which can take a higher current.
Hi. I have a question. I love vintage hifi from 80’s-90’s. I buy many old equipment and I noticed that they sound much less clearer (much less treble) than what they were sounding when they were new. What’s getting old in them? Is it the old capacitors acting as filter? What’s the reason they sound much less clearer? THX
In most cases, it is due to the electrolytic capacitors. As they age, the electrolyte dries out or leaks out, which changes the performance/value of the capacitor and affects the sound. Caps can become leaky (both chemically and electrically) or open, and in some cases can even short out. This is why it is a common practice for people to replace the electrolytic capacitors - a practice known as "re-capping". Failing transistors can also affect the sound, as they can cause weak signals as well as crackling and popping noises. In extreme cases, they can even damage other parts of the amp by shorting out. Thanks for the comment!
Hey Tony I have a 4 channel unit similar to this with a Gladding name on it. Still see's weekly usage. I may get into the back and do some mods as you showed. What's the thermal paste you used?
Never been a fan of needless and possibly damaging tweaking. My school of thought has always been whether CB or audio if you want more power just get a bigger amp. Although if everything is properly set up and tuned correctly, you may find you don't need more power.
lots of caps to change and test.
What do today's receiver tuner sections look like compared to these old ones? Do you have any pictures of modern ones?
I did some videos on synthesized tuners when I did the Realistic STA-2200, Carver MXR-2000 and Pioneer F-28 anong others. Check those videos out.
Is it true that Lafayette's downfall was getting stuck with unwanted 26 channel CB's when the 40 channel sets came out?
Not entirely, they were already in trouble trying to compete with Radio shack. The situation with the 23 channel CB's was kind of the last nail in the coffin. Had the company been doing much better to begin with, they might have been able to absorb the loss.
i had a 1980s lr 9090 receiver 90wattsch awww man left channel out put was blown when i got it early sanken amp output chip finding one next to impossible?? if i had xrays t. knowledge and stereo skills i could have fixed it !!!!
do you have an SQ generator?
Tighten down those screws, they say.
Fixing the bias .. hum dinger ...
33:20 - Try re-booting it :)
First, good job dude
I’ve sent you emails and you never do respond back so I don’t even know why you even leave your email account up
I would suggest that you watch my video entitled "Frequently Asked Questions - XrayTonyB". I explained that it may take a while to respond to all the e-mails. I only do this as a hobby. I own a full time business in the medical imaging repair industry that takes up a lot of my time. In addition to that business, I have a family and many other obligations. I receive, on average, 40+ e-mails a week, most of which I try to answer. It usually takes two or three weeks for me to answer an e-mail, but sometimes I can get to them sooner. I do this at no charge to try to help others learn. If you need an answer that quickly, I would suggest that you visit the AudioKarma or DIYAudio websites and post your question there. You could also reach out to someone who does this for a living. Be patient and I'll get to your e-mail as time permits. Others who sent their question before you have been patiently waiting as well and I want to make sure I give them the same attention that I will give you. I'm only one person, please try to remember that.
@@xraytonyb - that reply was FAR too polite.
@@johncoops6897 Agreed....
We need more flu epidemic, and stay at home orders to keep you at home making videos for us. 😂
Thoughtful evaluations.