Excellent work. Ok, you're no Mr Carlson or Xraytonyb but you know your electronics and show what can be done on a limited budget at a pure hobby level. I applaud your efforts.
John, it's great to hear that comments do get through and not ignored, I understand that sometimes we can be or seem to be difficult but sometimes we are just trying to get across something that we feel is important. The majority of comments made by me in most electronic video repairs is usually about capacitors! All that I'm trying to do is bring awareness, I can't tell you how many times that I have watched someone working on a repair and see the person go over the capacitors in circuit with an ESR meter and claim that they are all fine even though I can see that the capacitor has leaked out it's electrolyte all over the PCB! And that same person later on still has a problem and can't seem to figure it out, he even say's that he checked the capacitors so it can't be them! I don't know, has RU-vid created a new phenomenon that allows the viewer to see the problem even though they are somewhere else in the world, is this something that someone is going to come out and say that this new phenomenon has been discovered by doctors working on a surgery remotely? Who knows? What I do know though, is that there's only one way at this present time to check capacitors is out of circuit! I wish that I could provide you with a method for this mundane task but I don't. I just don't want this Oh! I checked the ESR and everything is fine to get into the mind of people as this is the only thing that needs to be tested! I'm sure that you have seen Mr Carlson's capacitor tester, it doesn't check for ESR, it checks for DC leakage which is the capacitor failure mode that is responsible for destroying just about every single component that has ever failed in the history of electronics! And yet the message that is being output is that if ESR is fine, then everything is good! I'm just trying to save people a lot of headache trying to fix something, it's not about just about replacing capacitors, it's about knowing what their condition is like. Then you either choose to keep the original capacitor assuming that it is good or put in a new one! That's all! So all that we have is to test for ESR, DC leakage and capacity! Capacity can be a giveaway to condition, it should always measure just under it's rating, if it's too low, it's bad, if it's too high it's also bad. A capacitor that leaks DC takes longer to measure capacity so the tester see's a larger value... Mr Paul Carlson and XRayTonyB's channel are amazing. Their dedication to repair is second to none... Your channel on the other hand offers something different, the thorough testing that you put into amplifiers that are within reach of the masses is a great formula! It's what keeps me coming back each and every single time. So basically something that you are doing is working! Keep up the great work... I like the Ramsa but I can't really say why, it could possibly be something special when working correctly or it could be nothing special? If it's quiet and has decent output, it could be valuable to someone?
@@mrb.5610 Ya I think mine is one step up in power level but pretty similar. I use mine for hi-fi use. It displaced my Threshold Class A amp! I know its subjective but I found it to sound just as detailed and correct but tighter and better bass as well.
OMG authentic vintage JRC 4558 op amps! They're one of the Holy Grails of the guitar world. Worth big bucks. There's only so many of them ever made or left now. They did reissue them. But the reissues are not the same tone as the originals. So you have something on your hands. Whether you know it, or not.
@@envisionelectronics I have a few I found in some vintage gear. I don't strip parts with an iron though. Salvage is *NOT* board rework! So being as the goals are different methods vary too. Personally I use a solder pot myself. In rework the board is the most important component. In salvage the board is worthless and the parts themselves are the only thing of value.
Dunno why some manufacturers cover their circuit boards with goop - I recently repaired a Dell monitor that had a fairly common fault with SMD resistors dying that are covered in a big blob of silicone .... . I mean *WHY* ??? It works just fine without the silicone blob stuck all over the PCB !
hey john .. love your videos .. have learnt quite a bit . i have a question if you dont mind and can answer please . I am trying to replace the tiny speaker in the bluetooth audio airpod ( third party bluetooth ear audio headset ) . What amplifier would you suggest that can drive a 100W speaker ? So take input from the two wires from headset and amplify them and feed to the large speaker. Thank you.
You can drive a 100w speaker with about any amplifier. Speaker sensitivity and other parameters should be more of a concern. It depends on how loud you want it and the frequency response. A lot of the amplifier boards I've reviewed on this channel could work.
shango066 does a good line in street find TV 'resurrections' complete with plenty of free sarcasm thrown in as well. David Tipton is another one I'd recommend - not just the usual 'replace the electrolytics' videos but also some excellent case and mechanical turntable restorations as well.
@@TheTrueVoiceOfReason Shango is who gave me the idea for testing capacitors in circuit by putting audio through them. I just do it at a low level so not to harm or forward bias silicon junctions.
@@JohnAudioTech yep, same here. It's a technique I had never thought of until he showed it, and I was like " that's so simple and direct, why wasn't it ever taught anywhere else? And why didn't I think of that?" It just goes to show that you don't necessarily need $100's - $1000's of equipment to do a good bit of the normal troubleshooting, you can quickly determine/isolate parts/areas just by using a known good cap (à la Shango) and by close inspection as you did here. Does it catch everything, by all means no. But it does get you a good start. That's why I watch so many of "you guys", you never know what bits of really good info will come out during a video.
They may have been cheap back in the day but the passage of time has made some parts in there extremely valuable today. Specifically those authentic vintage JRC 4558 op amps. Which have been reissued they're so sought after. But the originals are still where it's at. Although the reissue has diluted the market. People in the know will pay big for the real thing. The tone of the originals is unmatched.
They probably use the black gunk stuffs as a self killing agent intentionally? So after a fair amount of time the items will fail mechanically as the electronics and design are so good they will run for ages otherwise?
