This amp has a great reputation...no Wonder it performs so well; it reproduces in nearly every details the circuit developped par James Bongiorno for the SAE amplifiers, the only difference beeing the output stage that works in class H...The SAE amps are older but even better assembled than this Proton...Have a look to the SAE P500 and 2600 models ( the best of the best) to see where this technology comes from...and if you have the chance to listen to a 2500 or a 2600...you'll have a shock.
Bill, what do you know about the D1200's with bridging switch vs. those without? I just picked one of these up and didn't realize so many did not have bridging capabilities. Everything I'm reading online says the later models are missing bridging switches, but mine has a stamp on the bottom saying 5/84, so it appears mine is an early version. I'm getting replacement lamps (LED) and will make a video showing that process (my right side VU meter's lamps are out). My RCA jacks are VERY loose also. I see you mention this. Wow, can't believe they did this! I will replace mine with Tiffany style RCA's in the future.
I've heard of ones that could be bridged, but mine can't. Mine is the only one I've ever seen, other than in photos or videos. I think there was an 1150 dual mono that was basically the same amp but bridgeable. Most of what I know of these amps is from my manual and audio forums and you tube. I will be looking forward to seeing how you replace the jacks, then I will order the parts and fix it. I put it off because I just didn't want to put it back the crappy way it was.
Mine has a place on the board at the back near the RCA's where it says bridging. I read online some people said a switch was internal, others had external switch, and those like mine and yours have no switch (internal or external). Not that big of a deal to me, I was just looking at the manual I downloaded and they show a switch and talk about bridging. I will be making a few videos about mine as well as the NAD 2200 (which is bridgeable). The Proton looks WAY beefier inside though.
From what I have read they removed the bridge switch due to many amplifiers being damaged. I think this was mainly because the power lines were not able to handle such amounts of power. Have never heard of the internal switch for the bridge mode only that the ones without the switch use the same pcb (having all the spaces for the switch and components needed) only without the components. The AA-1150 is dual mono but there was never a bridgeable version of this amplifier.
Great info, but I'm really interested to see my unit has a date stamped on the bottom 1984, making me think I have an "old version" of the D1200 (possibly 1985 version) and which ones were bridgeable and the date(s) they were manufactured.
Made some research and based on the serial number assuming you have a 120v version (although this didnt made any difference from what have seen) if yours is below D12007111 then your amplifier probably is one of the older versions, if it is above D12008051 then it probably doesnt have a bridge switch meaning it is a newer one, between those it is uncertain. Hope this helps a bit! really want to see this amp on the dyno!
Yes, you are correct; those are indeed the output transistors, not part of the power supplies. 2SC3519A (NPN), and their complements, the 2SA1386A (PNP). About $4 each from Digikey.
If I remember correctly, the Proton 1200's main competition that that time, was the NAD 2200PE, which like the Proton, was a commutating amplifier, running mainly off of a "low" power supply, but, switching to a 95v supply rail for transient peaks. Like the Proton, the NAD was a well engineered and constructed power amplifier, but, to cut costs, the output relays were the cheapest relays most electrical technicians had ever seen, and would fail, causing one or both channels to intermittently, drop out. There's not a NAD 2200 out there, that hasn't had the output relays replaced.
Hello great video: I am wondering if you or any other viewers have any info on the Proton AA2120? I recently acquired one and it appears one channel is dead, it looks exactly like the AA1150 which I assume they different power ratings or something. I routinely repair AVRs, Plate amps, amps, etc...and would like to know if anyone can guide me on common issues or where to obtain a service manual. I would appreciate any input anyone could provide, thanks in advance!
The volume of a capacitor is roughly proportional to the energy it can store. The energy stored is 0.5 V^2 C. Notice that voltage is squared. The 15,000 uF capacitors can store three times the energy of the 22,000 uF capacitors.
Capacitors of various mfd values can have different voltage ratings. I thought that maybe a capacitor had to be used near it's rated voltage to actually be filled to the capacitance rating. In other words, if it is used in a circuit where the maximum voltage applied to it is only half of it's rating, does it only charge to half rated capacitance, or does it just take more time to charge to full capacitance? And some small physical size caps have higher values in mfd than larger ones. At one time I actually studied this stuff in one of those phonyass correspondence courses. Been so long ago there are things I just don't remember. Maybe I should go dig out my old texts of beginner and intermediate electronics. I like watching Tony D Amore's videos about electronics, but I don't have the math skills like trig to completely follow him.
The capacitor does need to be charged to its full voltage to store the most energy. The voltage rating is simply a rating that the capacitor can withstand before failing. A 100V 100uF and 10V 100uF capacitor charged to five volts will store the same amount of energy. I think you're confusing energy and capacitance. A basic electronics tutorial would probably answer your questions better than I can as a comment here.
Capacitors rated for a higher voltage always need to be bigger because of the necessary distance between the conductors. So the difference in the rated voltage is proportionally more important than the difference in capacity.
Those durations are milliseconds not microseconds! 20µS would be a VERY short burst indeed! I have this amp, it was from 1989. The right channel had every transistor suddenly fail when the output was driven into full clipping AND the output was shorted at the speaker terminal! The protection is fast but not THAT fast. I was able to purchase the parts and the service manual from Proton back in '91 and fix it myself. It still needs its bias adjusted but otherwise is a perfect amp. The lights did burn out and were replaced with LEDs in the early 2000s. There was something about bridging this amp but I believe they may have made a pro model that ran on 240V. It's possible to bridge many amps of this design but tread with caution always! Running both channels in series will put the output at very high voltage as far as audio is concerned and you can get a bad shock.
On my amp the rca input connectors came loose from the board. I wired directly to the board. Later the right input wire shorted and the right meter slammed over to past 800 watts and welded the voice coil of my 8 inch pyle driver. It bunt a trace off the board. I repaired it with a jumper wire. I think it's in the video. This amp would be good driving speakers of 86db sensitivity. Mine are all 98db or more so I've never been able to push the amp to one fourth of it's potential output.
@@vintagestereobuff7005 Yep a loose input on an amp with no gain control definitely can get scary! This is why they need to be powered OFF before pulling RCA cables. Due to the nature of their design, the ground lifts first leaving the now unshielded inner lead going straight the amp's input. It could oscillate either way. A high frequency full output is going to fry tweeters unless they have some type of protection such as a light bulb in series. ;)
I am looking at 2 on ebay,can you tell me if it will throw the bass to my Cerwin Vega AT15's? My Kenwood cuts out when i crank it up. And,can i use the Kenwood as a pre-amp/volume into it? Thanks
Cerwin Vega's are very sensitive and don't really need more than 20 watts. I know, I have an LE12D and a LE15D. Their sensitivity ratings are 98db and 101db @1 watt. Ihave used the D1200 to drive both subs. When I use the D1200 to drive my full range 98db speakers I can only turn it up till the D1200 power meters read 2watts and it's too loud for me. If your Kenwood has pre-outs then you can use it to control the D1200.
The relay in mine is messed up. Has been for years. I put thin wood shim in between relay casing and contact, because back then around 97 I didn't know where to get a replacement. Still don't.
im here bc of Big D ..great video👍👍👍👍
This amp has a great reputation...no Wonder it performs so well; it reproduces in nearly every details the circuit developped par James Bongiorno for the SAE amplifiers, the only difference beeing the output stage that works in class H...The SAE amps are older but even better assembled than this Proton...Have a look to the SAE P500 and 2600 models ( the best of the best) to see where this technology comes from...and if you have the chance to listen to a 2500 or a 2600...you'll have a shock.
The big capacitors are bigger because they need a larger dialectric thickness, so they can withstand a higher voltage. (up to 120VDC in this case)
Yes, the 22000uF are only 63V and the 15000uF are 120V.
Bill, what do you know about the D1200's with bridging switch vs. those without? I just picked one of these up and didn't realize so many did not have bridging capabilities. Everything I'm reading online says the later models are missing bridging switches, but mine has a stamp on the bottom saying 5/84, so it appears mine is an early version. I'm getting replacement lamps (LED) and will make a video showing that process (my right side VU meter's lamps are out). My RCA jacks are VERY loose also. I see you mention this. Wow, can't believe they did this! I will replace mine with Tiffany style RCA's in the future.
I've heard of ones that could be bridged, but mine can't. Mine is the only one I've ever seen, other than in photos or videos. I think there was an 1150 dual mono that was basically the same amp but bridgeable. Most of what I know of these amps is from my manual and audio forums and you tube. I will be looking forward to seeing how you replace the jacks, then I will order the parts and fix it. I put it off because I just didn't want to put it back the crappy way it was.
Mine has a place on the board at the back near the RCA's where it says bridging. I read online some people said a switch was internal, others had external switch, and those like mine and yours have no switch (internal or external). Not that big of a deal to me, I was just looking at the manual I downloaded and they show a switch and talk about bridging. I will be making a few videos about mine as well as the NAD 2200 (which is bridgeable). The Proton looks WAY beefier inside though.
From what I have read they removed the bridge switch due to many amplifiers being damaged. I think this was mainly because the power lines were not able to handle such amounts of power. Have never heard of the internal switch for the bridge mode only that the ones without the switch use the same pcb (having all the spaces for the switch and components needed) only without the components. The AA-1150 is dual mono but there was never a bridgeable version of this amplifier.
Great info, but I'm really interested to see my unit has a date stamped on the bottom 1984, making me think I have an "old version" of the D1200 (possibly 1985 version) and which ones were bridgeable and the date(s) they were manufactured.
Made some research and based on the serial number assuming you have a 120v version (although this didnt made any difference from what have seen) if yours is below D12007111 then your amplifier probably is one of the older versions, if it is above D12008051 then it probably doesnt have a bridge switch meaning it is a newer one, between those it is uncertain. Hope this helps a bit! really want to see this amp on the dyno!
Yes, you are correct; those are indeed the output transistors, not part of the power supplies. 2SC3519A (NPN), and their complements, the 2SA1386A (PNP). About $4 each from Digikey.
If I remember correctly, the Proton 1200's main competition that that time, was the NAD 2200PE, which like the Proton, was a commutating amplifier, running mainly off of a "low" power supply, but, switching to a 95v supply rail for transient peaks. Like the Proton, the NAD was a well engineered and constructed power amplifier, but, to cut costs, the output relays were the cheapest relays most electrical technicians had ever seen, and would fail, causing one or both channels to intermittently, drop out. There's not a NAD 2200 out there, that hasn't had the output relays replaced.
I had one of these from new and had the same exact problem with the input connector. This amp had lots of power but sound quality wasn't very good.
Hello great video: I am wondering if you or any other viewers have any info on the Proton AA2120? I recently acquired one and it appears one channel is dead, it looks exactly like the AA1150 which I assume they different power ratings or something. I routinely repair AVRs, Plate amps, amps, etc...and would like to know if anyone can guide me on common issues or where to obtain a service manual. I would appreciate any input anyone could provide, thanks in advance!
The volume of a capacitor is roughly proportional to the energy it can store. The energy stored is 0.5 V^2 C. Notice that voltage is squared. The 15,000 uF capacitors can store three times the energy of the 22,000 uF capacitors.
Capacitors of various mfd values can have different voltage ratings. I thought that maybe a capacitor had to be used near it's rated voltage to actually be filled to the capacitance rating. In other words, if it is used in a circuit where the maximum voltage applied to it is only half of it's rating, does it only charge to half rated capacitance, or does it just take more time to charge to full capacitance? And some small physical size caps have higher values in mfd than larger ones. At one time I actually studied this stuff in one of those phonyass correspondence courses. Been so long ago there are things I just don't remember. Maybe I should go dig out my old texts of beginner and intermediate electronics. I like watching Tony D Amore's videos about electronics, but I don't have the math skills like trig to completely follow him.
The capacitor does need to be charged to its full voltage to store the most energy. The voltage rating is simply a rating that the capacitor can withstand before failing. A 100V 100uF and 10V 100uF capacitor charged to five volts will store the same amount of energy. I think you're confusing energy and capacitance. A basic electronics tutorial would probably answer your questions better than I can as a comment here.
and there are 2 of the 15ks each side (high v rail) compared to the single 22ks. or did i miss something?
Capacitors rated for a higher voltage always need to be bigger because of the necessary distance between the conductors. So the difference in the rated voltage is proportionally more important than the difference in capacity.
I was just calibrating the quiescent current and vaporized 3 transistors when the clip slipped. Well rip D1200.
Just made a video showing VU meter lamp replacement - ua-cam.com/video/zbT9zxEx7WE/v-deo.html
BigDWiz And he just got another subscriber because of you. Not sure how I missed this channel. Good stuff.
Right channel has statics when audio is playing. No other issue. Any idea what could it be? thank you
What type of amplifier is this? I'm taking a guess on a class AB since the output transistors are complementary. PNP and NPN in a push-pull config?
Yes, it's class A/B complementary symmetry push-pull.
Those durations are milliseconds not microseconds! 20µS would be a VERY short burst indeed! I have this amp, it was from 1989. The right channel had every transistor suddenly fail when the output was driven into full clipping AND the output was shorted at the speaker terminal! The protection is fast but not THAT fast. I was able to purchase the parts and the service manual from Proton back in '91 and fix it myself. It still needs its bias adjusted but otherwise is a perfect amp. The lights did burn out and were replaced with LEDs in the early 2000s.
There was something about bridging this amp but I believe they may have made a pro model that ran on 240V. It's possible to bridge many amps of this design but tread with caution always! Running both channels in series will put the output at very high voltage as far as audio is concerned and you can get a bad shock.
On my amp the rca input connectors came loose from the board. I wired directly to the board. Later the right input wire shorted and the right meter slammed over to past 800 watts and welded the voice coil of my 8 inch pyle driver. It bunt a trace off the board. I repaired it with a jumper wire. I think it's in the video. This amp would be good driving speakers of 86db sensitivity. Mine are all 98db or more so I've never been able to push the amp to one fourth of it's potential output.
@@vintagestereobuff7005 Yes they are loose even on a new amp. Not a good design! I'd prefer balanced inputs with proper Neutrik XLRs. ;)
@@vintagestereobuff7005 Yep a loose input on an amp with no gain control definitely can get scary! This is why they need to be powered OFF before pulling RCA cables. Due to the nature of their design, the ground lifts first leaving the now unshielded inner lead going straight the amp's input. It could oscillate either way. A high frequency full output is going to fry tweeters unless they have some type of protection such as a light bulb in series. ;)
Those transistors on the bottom are all output devices.
I am looking at 2 on ebay,can you tell me if it will throw the bass to my Cerwin Vega AT15's? My Kenwood cuts out when i crank it up. And,can i use the Kenwood as a pre-amp/volume into it? Thanks
Cerwin Vega's are very sensitive and don't really need more than 20 watts. I know, I have an LE12D and a LE15D. Their sensitivity ratings are 98db and 101db @1 watt. Ihave used the D1200 to drive both subs. When I use the D1200 to drive my full range 98db speakers I can only turn it up till the D1200 power meters read 2watts and it's too loud for me. If your Kenwood has pre-outs then you can use it to control the D1200.
I have one of those and it doesnt go out of protection mode. Any thoughts about that?
Shorted output transistors
Do you have one to sell or trade
Bill , do you repair a Proton pre-amp 1100 - somewhere a cold soldering, fires up only once in a while
The relay in mine is messed up. Has been for years. I put thin wood shim in between relay casing and contact, because back then around 97 I didn't know where to get a replacement. Still don't.
Can you repair mine. I would pay you to repair it
I don't work on anything I don't own. Besides, shipping and dealing with proper packing would be a pain in the ass. Sorry.