Wow these were legends back in the day. I had a 923 and these things rocked. You could beat on these all day every day. They Don't build them like this any more!
Remember: On older amps, the RCA Ground or AMP-Ground has no direct connection to POWER-Ground. That's why the signal was a bit wobbly. There is a resistor between the Grounds to prevent ground loops. The Signal Ground comes from the Headunit. You should ground the oscilloscope to RCA and not to Power-GND.
Indeed, this was done for protection. It was not uncommon for "installers" to hook up power ground to a random screw in the trunk, resulting in the amp taking it's power ground via the RCA cables.
Had this amplifier and the 923 which I purchased back in the early 90's.... They were amazing amplifiers until they got knocked off at a train station car park.... The 1023 cost me $1200AU and the 923 was $750AU which was a lot back then.... The head unit I had and still have is the KRC950.... To my knowledge, the head unit was one of the first for Kenwood in that series to feature a detachable faceplate as an antitheft deterrent and I can safely say that it worked as intended.... Incidentally, that cassette deck, no matter how bad the condition of the cassette tape was, it would play it perfectly even if it has been previously chewed... Something that really struck you when you put the same cassette in your mate's Sony head unit.... One of these days I'm going to make an enclosure with power supply built in so I can use it on a daily basis at home... I still have all my tapes and still buy new old stock and therefore have thousands of them... People don't realise how good compact cassette can actually sound on good quality equipment... Thanks for this video, it has taken me back to the 90's when I thought that I knew everything but in reality I had a lot to learn.... I miss those days!
This video coming at the right time. I was just handed an old amplifier from the 80's that will perform well once fixed. It's failure is likely something similar. It's a pro audio amplifier. Will likely need bias adjusting as you mention. looking forward to that video.
I hvae a new Orion XTR 750.4 that started to have a popping and buzzing sound and would sometimes quit working. I found a large bus bar with that same problem. I added solder to both sides and fixed it. 2 years ago.
Bro. I still have one of these and the 2 smaller vs. also the big pioneer from the same period, i recently fixed an Alpine from mid 90's and a newer Alpine. easy peasy. lol
I haven’t watched the video yet but I am betting it’s a transformer improperly soldered issue. It’s very common since they don’t use any adhesive or glue to hold the transformer.
I have Some old Sony amps here, an XM502X, an XM504X and a Sony XM255EX. The XM504X is actually still in use in our Car, but it's so underpowered for the subwoofer it's driving so I'm replacing it. Got a Sinuslive Sl-A1000D for the sub now. About 1kW at 1 Ohm for only 120€.
I Love the old Sony Xplode Amps. I've got one of the old 500x2 that's 20yrs old never broke. I just got a Taramps HD 3k to replace it on my subs for $180.00 thru Amazon with the 4 yr no hassle warranty. I'm gonna take that Xplode amp and hook it up to some 6x9 woofers or Mids I'm still looking I havent decided yet.
If you mount your amp on the sub enclosure, the vibrations from the bass will vibrate the circuitry of the amp far more than it was rated/designed for. You should NEVER mount your amp to your subwoofer enclosure and if you can, use some rubber feet between the amp and the mounting surface to help absorb some of the vibrations and to protect the amp.
Q i have a 9.5k Deafbonce atom , fullbridge amp, and it has b2tween 100mv and 125mv dc offset. is that an issue i need to worry about? and can that cause my basshead garage watt meter to not read? if so is there a way to fix that?
I have a old ample audio a410x and when i use it i get a beeep in one speaker and a buzz in another beep in left back and buzz in right front. What can it be,i have hooked 2 other 2 channel amps on instead and there is no problems.
I have an old crown dc300 amp with a problem that it throws DC and cooks speakers if it's left on too long. How can I contact you for troubleshooting advice? I will pay you for your time. I also have the original schematic
Come on...these older linear amps are way easier to repair than tracing PWMs on a class D amp! You'll get the hang of it easy! It takes time though...setting the bias to an acceptable level when the amp is hot and other analog phenomena... Been thinking of taking a cheapo fake Alpine (because there are plenty on this region for some awful reason) with a blown output stage but a good power supply section and make myself a hot rod amp and maybe...MAYBE...it can actually put out the 3800 watts it claims to be...or at least half of that
DUDE! you're gonna be a class AB expert in no time, at this rate. killing it on these vids btw.
I admire your enthusiasm and willingness to share all those golden nuggets you keep dropping for us 🙏 a true teacher
Wow these were legends back in the day. I had a 923 and these things rocked. You could beat on these all day every day. They Don't build them like this any more!
These amps were the nuts. If only Kenwood was still the same. Great job.
Remember: On older amps, the RCA Ground or AMP-Ground has no direct connection to POWER-Ground. That's why the signal was a bit wobbly. There is a resistor between the Grounds to prevent ground loops. The Signal Ground comes from the Headunit. You should ground the oscilloscope to RCA and not to Power-GND.
Indeed, this was done for protection. It was not uncommon for "installers" to hook up power ground to a random screw in the trunk, resulting in the amp taking it's power ground via the RCA cables.
Had this amplifier and the 923 which I purchased back in the early 90's.... They were amazing amplifiers until they got knocked off at a train station car park.... The 1023 cost me $1200AU and the 923 was $750AU which was a lot back then.... The head unit I had and still have is the KRC950.... To my knowledge, the head unit was one of the first for Kenwood in that series to feature a detachable faceplate as an antitheft deterrent and I can safely say that it worked as intended.... Incidentally, that cassette deck, no matter how bad the condition of the cassette tape was, it would play it perfectly even if it has been previously chewed... Something that really struck you when you put the same cassette in your mate's Sony head unit....
One of these days I'm going to make an enclosure with power supply built in so I can use it on a daily basis at home... I still have all my tapes and still buy new old stock and therefore have thousands of them... People don't realise how good compact cassette can actually sound on good quality equipment...
Thanks for this video, it has taken me back to the 90's when I thought that I knew everything but in reality I had a lot to learn.... I miss those days!
Bro I remember when your videos were only getting 100 likes in weeks even months keep it up your doing great 🤜🤛💪
This video coming at the right time. I was just handed an old amplifier from the 80's that will perform well once fixed. It's failure is likely something similar. It's a pro audio amplifier. Will likely need bias adjusting as you mention. looking forward to that video.
I tinker with a lot of vintage home audio gear and I've encountered this quite a few times. Nice job figuring that out!
I hvae a new Orion XTR 750.4 that started to have a popping and buzzing sound and would sometimes quit working. I found a large bus bar with that same problem. I added solder to both sides and fixed it. 2 years ago.
I've got the same Amp, its a beast and sounds incredible fast! a great example of a high slew-rate desing i would say.
Bro. I still have one of these and the 2 smaller vs. also the big pioneer from the same period, i recently fixed an Alpine from mid 90's and a newer Alpine. easy peasy. lol
Great video Sir keep up the good work I have alot of those old school amplifier working on too nuff respect Sam 👍 🙏
I've an Alpine Pdx 600.1 that I don't know where to start with but I'm gonna learn
I had acouple kenwood 923 running bridged 2 ohm load pulling all the power i could from them sounded really good.
Damn Kenwood amp is a quality built amp!
I have lots of old AMPs, as older as from 1990!!!! And ive repaired a few . These are pioneer gm 1000, 1500, 2200 and so on...
I'm learning so much thank you for teaching us. 👍 What is the life expectancy for an amp. Thank again
@barevids that poor Finder relay! It should be the double pin, single fat contact type rather, type 40.61 👍
I haven’t watched the video yet but I am betting it’s a transformer improperly soldered issue. It’s very common since they don’t use any adhesive or glue to hold the transformer.
Best channel
I have Some old Sony amps here, an XM502X, an XM504X and a Sony XM255EX.
The XM504X is actually still in use in our Car, but it's so underpowered for the subwoofer it's driving so I'm replacing it.
Got a Sinuslive Sl-A1000D for the sub now. About 1kW at 1 Ohm for only 120€.
I Love the old Sony Xplode Amps. I've got one of the old 500x2 that's 20yrs old never broke. I just got a Taramps HD 3k to replace it on my subs for $180.00 thru Amazon with the 4 yr no hassle warranty. I'm gonna take that Xplode amp and hook it up to some 6x9 woofers or Mids I'm still looking I havent decided yet.
The Facebook Messenger notification sounds in this video hafe fooled me!
Great video
Another good video.
What do you mean I shouldn't mount my amp on my sub enclosure?
If you mount your amp on the sub enclosure, the vibrations from the bass will vibrate the circuitry of the amp far more than it was rated/designed for.
You should NEVER mount your amp to your subwoofer enclosure and if you can, use some rubber feet between the amp and the mounting surface to help absorb some of the vibrations and to protect the amp.
@@orangejjay it was a joke...
Q i have a 9.5k Deafbonce atom , fullbridge amp, and it has b2tween 100mv and 125mv dc offset. is that an issue i need to worry about? and can that cause my basshead garage watt meter to not read? if so is there a way to fix that?
Have an older amp making heavy noise/Pop on power on/off even without rca/Signal connected. What could be the Problem?
Just clicked in but looking at the amp (old heat hog) fets probably have loose or cold solder joint, I had several of them have the problem
Another cool repair man. Where can I find your company info? Cheers.
great Guy
I have a old ample audio a410x and when i use it i get a beeep in one speaker and a buzz in another beep in left back and buzz in right front. What can it be,i have hooked 2 other 2 channel amps on instead and there is no problems.
reflow? looks like the joints were really dry from the factory to begin with
I have an old crown dc300 amp with a problem that it throws DC and cooks speakers if it's left on too long. How can I contact you for troubleshooting advice? I will pay you for your time. I also have the original schematic
Hello my friend
DD audio redline 600 15 series - cadence fsx 600 series
1 or 2 ohm How should the connection be
thanks in advance
Also go some old alpine mrv amps 4 channel and 2
Yoooo I had a kenwood kac746 maddd long ago that lil 4ch pushed 4 peavey black widow 18's walled in a Plymouth K car when I was like 17 hahahaha
Omfg hahahahaha
What’s the best way to send you a question?
Go to his Facebook page
I have an autotek mx 5000 I need to have fixed would u be interested in repair them I have 2 if the 5000s and 1 3000.1 all autotek mx. Amplifiers
Come on...these older linear amps are way easier to repair than tracing PWMs on a class D amp! You'll get the hang of it easy! It takes time though...setting the bias to an acceptable level when the amp is hot and other analog phenomena...
Been thinking of taking a cheapo fake Alpine (because there are plenty on this region for some awful reason) with a blown output stage but a good power supply section and make myself a hot rod amp and maybe...MAYBE...it can actually put out the 3800 watts it claims to be...or at least half of that
Yo