The 7225PE was my first amp. Sounded fine to me and had a lot of punch for a 25W amp. Although I didn't ran it hard, it failed twice. Listening to your comments on NAD built quality I understand why. My speakers were 4 ohms so I guess that didn't help. First time it failed it was a blown output. Now sure was failed the 2nd time but when it came back from the shop (NAD certified repair center) I felt it never sounded the same. I sold it shortly afterwards (eventually replaced it by a vintage Pioneer which IMO sounds better and has been more reliable so far). The 7225PE had a "soft clipping" circuit, activated by a switch in the back, It would have been interesting to see the effect - if any - on the scope while driving the amp up to clipping power. Thanks for this good video, I appreciate your channel and workmanship!
Well done Trevor, and fair play for owning up to the solder bridges, it happens. Yeh NAD stuff of this era was built with an expected lifespan, but when you take a look at the other amps that were around for the same price at the time (at least here in the UK) you don't see many of them on repair benches today.
Thank you, bought a Nad home today a 7020. Turning it over to a tech. What looks to be sanyo caps are peeing on the board destroying a number of components. Really like how you demonstrated adjusting the machine.
You aren't too hot on this little NAD, but I have to say that the 7225 and 7020i can handle 2 ohm loads due to their robust power supply. I have used them to run low impedance KEF LS50s to good effect. I tried the same with an 85 wpc Sansui AU-717 and it went into protection! I have been using my NAD 7020i (almost identical to the 7225PE) as a daily driver for going 30 years and it still functions flawlessly.
I would not run this receiver on 2 ohms fersure, I believe the heat sinking is inadequate. I would also be very careful on 4 ohms. The amplifier in this 7225 is not efficient and that coupled with the poor heat sinking is a recipe for overheating and failure. Granted, I do realize we don't all listen to our music full volume but have a look at the watt meter when I had it on the power test. From that you can roughly calculate the amplifier's efficiency and it's well below 50%
Was zoomed in on that Audio Ark sticker, that's old school from their old location on the W side of 124 St, they're on the E side now. That old shop actually looked like an Ark, it was a pretty unique building. Friend of mine knew the proprietor but I was never inside there. Interesting to hear you say that NAD is known for their crap capacitors... I have a 7130 alley find that someone gave up on. I got it going by changing out a bunch of small bypass caps but it quit again so I shelved it. I have lots of caps on hand now so it will get some loving this winter.
28mA seems fair, nowhere near lateral fets demanding 120mA for zero temp co-eff of Vgs vs. drain current. 3rd tier caps saga continues with more recent BEE models, great job getting it done and dusted and thank you for another informative vid - pleasure to follow!
I've had NAD amps all my adult life from 7020i to 375BEE. Yes, the quality is not there and most of them tend to overheat but I wouldn't change them. Another excellent work from Trevor!
@Trevor's Bench At 22:50 when you mention that the two output transistors have no emitter resistors, there are no emitter resistors in a "pure" Class B amplifier, which it looks like that amplification stage is just a Class B amplifier. Hopefully, that's helpful 😉
Maybe it's different in Canada, but the correct pronunciation is by the letters N-A-D, which is how the company pronounces their name. They've made some of the best sounding amps for the money ever, including the 3020 which was a giant killer and the most sold amplifier in history. You're a top notch tech, I'd suggest an anti-static mat on your bench rather than the piece of carpet. They hold solder drips, wire clippings and can generate static shocks. Keep up the good work. Really enjoy your videos.
I do agree that NAD used cheap capacitors. It really bit them in the butt in the 2000s when they started making higher power units that ran very hot and then baked those caps.
NAD has a group of fan boys that like the sound, but as Trev states they were constructed poorly and many are out of commission while a brand like yamaha are still going strong today.
It's not just the caps, it's the whole package. Made in Taiwan was not a good move for NAD. The PCB board quality and soldering is problematic. The plastic knobs and faceplate are not what you'd expect from a high end manufacturer
Small world as I recently picked up the exact same unit for cheap with one channel gone in it. The seller said one channel didn't work and I found out why when I got it home. I pulled the cover off and both output transistors on the one channel were missing. Looking closer, Q's 408, 410, 412, and 414 had been removed and replaced loosely in their respective positions on the board. They all tested bad as did another transistor and several resistors and caps on the same channel. Someone over at AK said the way these were designed, if an output shorted, it would take out lots of other components along with it and I bet that's what happened here. Since I never tried to power it up, I think I'll order just enough parts to try and get it working again before diving into it. Thanks for posting this video as now I can see the solder bridge mentioned in the manual. Have you noticed any discrepancies between the service manual specs and what is actually installed on the board? I'm not near the unit at the moment but I do remember different ratings of some items when they were removed for testing than what was called for in the manual. Its just when I go to order replacements, I better stick to what was in the unit instead of going by the manual.
Trev and Turntable Guy on Friday.....nice. Trev when are you doing the 1249? I bought a Hakko pump and it changed my life. Should have bought one sooner. It really is great.
Nice to hear the Hakko is working good for you. These pumps really do make life easier The 1249 is on the bench right now. Hopefully I can get it finished before Friday's deadline otherwise there will be no vid next week
NAD 7225PE was an excellent receiver, I had one in the begining of the nineties and the sound was really amazing for the price I paid ! Good job otherwise. My speakers were Tannoy Oxford...
This confirms once again the lack of quality control from NAD, besides the use of crappy components....Maybe the best thing to when one bought a NAD was to rebuild it after the purchase . by the way I almost never saw those bad soldering on 'early vintage ( 1970's ) ....even many or most of those old ELNA's still measured within spec . Soldering was done manual before wave soldering. Cooling was still with bigger radiators and so on .... I never bought a NAD .........I think I never will even when I liked the little 3020 ..........but after seeing the inside I said NO. Thanks for your passionated quality work Trevor ...makes dinking my first coffee in the morning more tasty .
Actually found some info on audio karma about adding emitter resistors to these units. Particularly after the original outputs have been replaced. Seemed to be any issue with a few of the smaller 20-25wpc NADs of this era.
Do you know what was the reasoning behind adding emitter resistors? If the amp was designed to work without them and it's working fine, what benefit did this provide? I'm curious
@@TrevorsBench my understanding is that the original design relied on the high internal resistance of the output transistors. But modern replacements do not share that feature and as such benefit from adding emitter resistors. I have one unit that had this done by a previous repair person who cut traces and added 0.33 3W resistors in on the bottom of the PCB.
I took my NAD 7400 receiver for repair and the guy is having a hard time finding the correct transistors/capacitors to complete the work. Can anyone suggest a good place to get those parts?
NAD generally contracted out manufacturing to Tatung or Sangean in Taiwan, in the days when non-Japanese far-Eastern contract manufacture was sub-standard. Although to be fair low-cost UK based assembly probably wouldn't have been all that much better! The tape decks and CD players tended to just be tarted up versions of CKD kits from Sanyo and made in Taiwan. I was never sold on them tbh despite the British design, at the price the mainstream Japanese stuff was usually a lot better build.
You can buy the meter on Aliexpress or Ebay. The rest is home made, The box, cable and outlet were repurposed for this meter. It's very cheap and simple to build
Uninspired look? Yep. They even said it themselves - they spend very little on frills and looks and put the money into quality circuitry for the best possible sound at every price point. I just restored a 7020e (the non-PE version) and love it. The problem was the third party manufacturing and parts.
I've been listening to this 7225 for almost two weeks now and it does sound good for a low power receiver. It's been working flawlessly and running cool. I can't imagine it sounded too good before with the bias set to almost 0
@@rjonzun5828 Call me crazy but I'd say capacitors among other things that age over 30 years and still work are at least decent tier. These amps though have nothing in terms of self-protection so they are quite easily blown, however failures mostly happen because of owners' mistakes.
Well done, it's a hell of a lot better :-D Touchy presets, they have way too much range and too rough in operation. People pay for quality, i don't think Nad tryed hard enough. Over priced.
I bought one of these 7225PE new back in the day, but wasn't that impressed with the sound of it. One channel failed after a few months. Got it fixed under warranty, but it never was any great amplifier. Maybe by replacing all caps with better quality once, and also replacing those cheap 2N3055 for real audio transistors would help.
You don't buy NAD for pretty. Go somewhere else for that. Sold allot of hifi in my day, and NAD was the bargain that everyone loved for the sound. Not the looks. Only thing was the quality control was horrible. They would get the deserved mantra, Not Another Defect. There were choice ones that really hit it out of the park. The Silver Series, the Master Series, they really get it done. The Classic series and Monitor series was iffy on quality. But if you got a good one, they were awesome. The 2600, 7600, 2400, 7400, and the C370 and 270 were pretty good. NAD isn't the only one for garbage caps. Many companies are about costs. I sold Rotel its keen competitor, and its parts were a bit better than NAD. NAD is that brand that was great on the bargain. But now they are stupid expensive, and value equation through the years just evaporated. Many makes way better than NAD now.
The 7225PE was my first amp. Sounded fine to me and had a lot of punch for a 25W amp. Although I didn't ran it hard, it failed twice. Listening to your comments on NAD built quality I understand why. My speakers were 4 ohms so I guess that didn't help.
First time it failed it was a blown output. Now sure was failed the 2nd time but when it came back from the shop (NAD certified repair center) I felt it never sounded the same. I sold it shortly afterwards (eventually replaced it by a vintage Pioneer which IMO sounds better and has been more reliable so far).
The 7225PE had a "soft clipping" circuit, activated by a switch in the back, It would have been interesting to see the effect - if any - on the scope while driving the amp up to clipping power.
Thanks for this good video, I appreciate your channel and workmanship!
Well done Trevor, and fair play for owning up to the solder bridges, it happens. Yeh NAD stuff of this era was built with an expected lifespan, but when you take a look at the other amps that were around for the same price at the time (at least here in the UK) you don't see many of them on repair benches today.
I appreciated hearing my home town band at the outro. Good work Trevor.
Thank you, bought a Nad home today a 7020. Turning it over to a tech. What looks to be sanyo caps are peeing on the board destroying a number of components. Really like how you demonstrated adjusting the machine.
You aren't too hot on this little NAD, but I have to say that the 7225 and 7020i can handle 2 ohm loads due to their robust power supply. I have used them to run low impedance KEF LS50s to good effect. I tried the same with an 85 wpc Sansui AU-717 and it went into protection! I have been using my NAD 7020i (almost identical to the 7225PE) as a daily driver for going 30 years and it still functions flawlessly.
My 7020e drives a couple 4-ohm KEF C55 speakers with no sweat. And most importantly, it sounds great.
I would not run this receiver on 2 ohms fersure, I believe the heat sinking is inadequate.
I would also be very careful on 4 ohms.
The amplifier in this 7225 is not efficient and that coupled with the poor heat sinking is a recipe for overheating and failure.
Granted, I do realize we don't all listen to our music full volume but have a look at the watt meter when I had it on the power test.
From that you can roughly calculate the amplifier's efficiency and it's well below 50%
Was zoomed in on that Audio Ark sticker, that's old school from their old location on the W side of 124 St, they're on the E side now. That old shop actually looked like an Ark, it was a pretty unique building. Friend of mine knew the proprietor but I was never inside there.
Interesting to hear you say that NAD is known for their crap capacitors... I have a 7130 alley find that someone gave up on. I got it going by changing out a bunch of small bypass caps but it quit again so I shelved it. I have lots of caps on hand now so it will get some loving this winter.
And the Dead Kennedys is a nice touch!
28mA seems fair, nowhere near lateral fets demanding 120mA for zero temp co-eff of Vgs vs. drain current. 3rd tier caps saga continues with more recent BEE models, great job getting it done and dusted and thank you for another informative vid - pleasure to follow!
I've had NAD amps all my adult life from 7020i to 375BEE. Yes, the quality is not there and most of them tend to overheat but I wouldn't change them. Another excellent work from Trevor!
Thanks Alexis
@@TrevorsBench are you in the Edmonton area sir? I very much enjoy your videos and wonder if you’d be open to repair some of my equipment?
Bryan
The point of the design of NAD products is simplicity. IMO, they have a great design.
@Trevor's Bench At 22:50 when you mention that the two output transistors have no emitter resistors, there are no emitter resistors in a "pure" Class B amplifier, which it looks like that amplification stage is just a Class B amplifier. Hopefully, that's helpful 😉
Maybe it's different in Canada, but the correct pronunciation is by the letters N-A-D, which is how the company pronounces their name. They've made some of the best sounding amps for the money ever, including the 3020 which was a giant killer and the most sold amplifier in history.
You're a top notch tech, I'd suggest an anti-static mat on your bench rather than the piece of carpet. They hold solder drips, wire clippings and can generate static shocks. Keep up the good work. Really enjoy your videos.
I do agree that NAD used cheap capacitors. It really bit them in the butt in the 2000s when they started making higher power units that ran very hot and then baked those caps.
NAD has a group of fan boys that like the sound, but as Trev states they were constructed poorly and many are out of commission while a brand like yamaha are still going strong today.
Trevor actually had a very interesting video about repairing two C350 amps with this specific issue.
It's not just the caps, it's the whole package. Made in Taiwan was not a good move for NAD. The PCB board quality and soldering is problematic. The plastic knobs and faceplate are not what you'd expect from a high end manufacturer
NAD is one of the sweetheart companies in the high-end community. Interesting to see the lack of quality here.
Small world as I recently picked up the exact same unit for cheap with one channel gone in it. The seller said one channel didn't work and I found out why when I got it home. I pulled the cover off and both output transistors on the one channel were missing. Looking closer, Q's 408, 410, 412, and 414 had been removed and replaced loosely in their respective positions on the board. They all tested bad as did another transistor and several resistors and caps on the same channel. Someone over at AK said the way these were designed, if an output shorted, it would take out lots of other components along with it and I bet that's what happened here. Since I never tried to power it up, I think I'll order just enough parts to try and get it working again before diving into it. Thanks for posting this video as now I can see the solder bridge mentioned in the manual. Have you noticed any discrepancies between the service manual specs and what is actually installed on the board? I'm not near the unit at the moment but I do remember different ratings of some items when they were removed for testing than what was called for in the manual. Its just when I go to order replacements, I better stick to what was in the unit instead of going by the manual.
Trev and Turntable Guy on Friday.....nice. Trev when are you doing the 1249? I bought a Hakko pump and it changed my life. Should have bought one sooner. It really is great.
Nice to hear the Hakko is working good for you. These pumps really do make life easier
The 1249 is on the bench right now. Hopefully I can get it finished before Friday's deadline otherwise there will be no vid next week
NAD 7225PE was an excellent receiver, I had one in the begining of the nineties and the sound was really amazing for the price I paid ! Good job otherwise. My speakers were Tannoy Oxford...
This confirms once again the lack of quality control from NAD, besides the use of crappy components....Maybe the best thing to when one bought a NAD was to rebuild it after the purchase .
by the way I almost never saw those bad soldering on 'early vintage ( 1970's ) ....even many or most of those old ELNA's still measured within spec .
Soldering was done manual before wave soldering.
Cooling was still with bigger radiators and so on ....
I never bought a NAD .........I think I never will even when I liked the little 3020 ..........but after seeing the inside I said NO.
Thanks for your passionated quality work Trevor ...makes dinking my first coffee in the morning more tasty .
Actually found some info on audio karma about adding emitter resistors to these units. Particularly after the original outputs have been replaced. Seemed to be any issue with a few of the smaller 20-25wpc NADs of this era.
Do you know what was the reasoning behind adding emitter resistors?
If the amp was designed to work without them and it's working fine, what benefit did this provide? I'm curious
@@TrevorsBench my understanding is that the original design relied on the high internal resistance of the output transistors. But modern replacements do not share that feature and as such benefit from adding emitter resistors. I have one unit that had this done by a previous repair person who cut traces and added 0.33 3W resistors in on the bottom of the PCB.
I took my NAD 7400 receiver for repair and the guy is having a hard time finding the correct transistors/capacitors to complete the work. Can anyone suggest a good place to get those parts?
NAD generally contracted out manufacturing to Tatung or Sangean in Taiwan, in the days when non-Japanese far-Eastern contract manufacture was sub-standard. Although to be fair low-cost UK based assembly probably wouldn't have been all that much better!
The tape decks and CD players tended to just be tarted up versions of CKD kits from Sanyo and made in Taiwan. I was never sold on them tbh despite the British design, at the price the mainstream Japanese stuff was usually a lot better build.
I only have harman/kardon.
Strange but with your uploads I give a thumb up even before watching ...............
Thanks Frank for your continued support
Nice job Trevor ! I have a question for you, where did you find the mains digital power meter indicator that whe see at 18:00 ?
You can buy the meter on Aliexpress or Ebay. The rest is home made, The box, cable and outlet were repurposed for this meter.
It's very cheap and simple to build
@@TrevorsBench ok thank you !
Am I seeing that right? 50kHz tuning steps on FM?
Yes
Uninspired look? Yep. They even said it themselves - they spend very little on frills and looks and put the money into quality circuitry for the best possible sound at every price point. I just restored a 7020e (the non-PE version) and love it. The problem was the third party manufacturing and parts.
I've been listening to this 7225 for almost two weeks now and it does sound good for a low power receiver. It's been working flawlessly and running cool.
I can't imagine it sounded too good before with the bias set to almost 0
I knew that NAD skipped the frills and focused on the circuitry but I've been hearing they used cheap components as well??
@@rjonzun5828 Call me crazy but I'd say capacitors among other things that age over 30 years and still work are at least decent tier. These amps though have nothing in terms of self-protection so they are quite easily blown, however failures mostly happen because of owners' mistakes.
@@TapesNstuffS The Taiwanese built NADs were ok, but the mainland China built stuff had horrible capacitors.
Well done, it's a hell of a lot better :-D
Touchy presets, they have way too much range and too rough in operation.
People pay for quality, i don't think Nad tryed hard enough.
Over priced.
I bought one of these 7225PE new back in the day, but wasn't that impressed with the sound of it.
One channel failed after a few months. Got it fixed under warranty, but it never was any great amplifier.
Maybe by replacing all caps with better quality once, and also replacing those cheap 2N3055 for real audio transistors would help.
Not sure why yours failed but if I had to guess I would say it was likely a bad solder joint that opened up
@@TrevorsBench Hi. They replaced the output transistors and a few other components. Thats all I remember.
You don't buy NAD for pretty. Go somewhere else for that. Sold allot of hifi in my day, and NAD was the bargain that everyone loved for the sound. Not the looks. Only thing was the quality control was horrible. They would get the deserved mantra, Not Another Defect. There were choice ones that really hit it out of the park. The Silver Series, the Master Series, they really get it done. The Classic series and Monitor series was iffy on quality. But if you got a good one, they were awesome. The 2600, 7600, 2400, 7400, and the C370 and 270 were pretty good. NAD isn't the only one for garbage caps. Many companies are about costs. I sold Rotel its keen competitor, and its parts were a bit better than NAD. NAD is that brand that was great on the bargain. But now they are stupid expensive, and value equation through the years just evaporated. Many makes way better than NAD now.
👍👍😎✌️🤟