Yamaha P2100 score! Pictures!

bikehorn

Transmission Line Junkie
A few hours ago I came home with a Yamaha P2100 power amp I found on craigslist for $100. It has some battle scars from its musician days but I plan to give it a long and comfortable retirement driving my IMF TLS50s. It'll be driven by my NAD 1020 preamp. :music: The ad said the amp had been bridged, so I assumed someone had permanently modified it to operate in BTL mode. I figured if I couldn't unmodify it I'd just replace the amplifier PCBs with an ESP P101 for some lateral MOSFET deliciousness. Just the chassis, power supply and heatsinks were worth much much more than the paltry $100 I was paying. Oh yeah, this thing being a true professional power amp...has got balanced and unbalanced inputs as well as outputs, rack ears, big capacitors(2x 15,000uF Nippon Chemicon), bigger heatsinks and a seriously huge transformer(back of the chassis says 370 VA but the transformer looks bigger than that). I won't be able to test the bass for a while(till I fix the woofers in the TLS50s) but I am expecting thunderous and highly defined bass. :banana:

Some output ratings from the Yamaha Pro site:

85 Watts into 8 ohms with less than 0.05% THD (Total Harmonic Distortion), 20Hz to 20kHz, both channels driven.

140 Watts into 4 ohms with less than 0.05% THD (Total Harmonic Distortion), 20Hz to 20kHz, both channels driven.

Obviously there are more powerful amps out there but this is the biggest piece of iron I've ever owned. It weighs a ton, I would hazard a guess of at least 50 pounds. EDIT: Actually, it only weighs 31 lbs, and I am a weakling.

Happily, when I opened it, I could find no evidence of anyone modifying anything. There was nothing added, nothing appears removed, no signs of soldering and no random wires anywhere. On the Yamaha site the only way of bridging the P2100 appears to be through the use of an external balancing transformer(or other balanced line driver, I guess) so I think maybe the seller, though very knowledgeable about recording gear and techniques, just did not understand bridging. There's a stereo/mono switch on the amplifier's main PCB which when I found it was definitely set to "stereo". Possibly at some point a balanced line driver was being used, but there was no mention of that. Whatever. I measured DC offset on both channels, left was 12 mv and right was 20 mv. Tomorrow I'll test both channels with a crappy speaker to see what happens. At this point though, I believe it to be fully functional and that the seller just was uninformed. :yes:

I neglected to measure the power supply voltage, but some Googling yielded the following from a thread on DIY Audio. There's 2 pairs of output transistors. Oh...and not a single opamp to be found either! All discrete. :thmbsp:

+/- 50 volt rails
370VA consumption from 120vac supply
2SA814/2SC1624 drivers
2SA747/2SC1116A Sanken outputs

Okay okay picture time...yep they are huge(sorry to those with slow connections or low resolution, but I like big pictures), I resized them but was reluctant to knock the picture quality down since I already had lots of digital noise from using a high ISO.

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To get the most out of ESP P101 you'd have to bump up the rail voltages to +/- 70 VDC...:scratch2: Ask me how I'd know..:D 50 volt rails would get you somewhere around 115-125 wpc.
 
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Great amp, I've got four of them here since the mid-80s. Love them.

Manuals are on line, but if you have trouble finding them hit me with a PM.

je
 
To get the most out of ESP P101 you'd have to bump up the rail voltages to +/- 70 VDC...:scratch2: Ask me how I'd know..:D 50 volt rails would get you somewhere around 115-125 wpc.

That's far more than I need....I'm moving up from a 20 wpc Marantz 1040 and that was enough to shake the place up :D

Great amp, I've got four of them here since the mid-80s. Love them.

Manuals are on line, but if you have trouble finding them hit me with a PM.

je

I just found the manual, thanks...and wow, it's extremely thorough, well written and pretty educational too. Extreme engineering went into this amp's design and construction. Needless to say I'm excited about the sound prospects...and pretty re-assured that there couldn't have been physical modifications to bridge it. :scratch2:
 
Another Yamaha Pro Audio convert! If you think the P2100 is good, try some of the bigger brothers like the PC2002M.
 
That's far more than I need....I'm moving up from a 20 wpc Marantz 1040 and that was enough to shake the place up :D

BTW They sound awesome...101's that is. I built mine to the Max... 800VA transformers, 40A/600V rectifiers, over 50,000uf per rail.. running the 4 mosfets per channel with 70vdc rails.Sweet..
 
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good for you! i've got the smaller p2050 and i find it a clean performer, built like a battle-tank.
 
Okay gents, I soldered up some quick'n dirty RCA to 1/4" cables and tested the amp for any faults. I couldn't find any, and sound was making it through to the test speaker, so I went ahead and connected the TLS50s.

Even with the subprime condition of my woofers, all I can say is holy crap!!! This amp sounds incredible! It is so quiet that even with the channel gains all the way up and the volume control on my preamp at maximum, there was absolutely ZERO hiss or background buzz from my speakers with no signal present. I mean none. I had to check if the amp was actually on even with my ear next to the tweeter.

Once I actually applied signal I realised I'd have to back the gain down to about halfway to retain the volume control's range. Anyway, the sound is jaw-dropping. I've never experienced this kind of authority from a piece of gear I've owned. Low level details are exploding from the speakers. So many of them that I don't know what to do with them all. It's sensory overload...madness!!!! It seems like lyrics in familiar songs are a lot easier to understand. The bass definition is nothing short of shocking as well. All this is from listening to mp3s...I haven't got my turntable set up so I can't give the Yamaha a full test. Obviously though, I am using only 1/100th of its reserve of power, dynamics and control.

Natural Sound, indeed...but don't take that to mean "boring and sterile". Far from it, the sound is very alive. I think this amp is going to the grave with me. Wow.
 
Okay gents, I soldered up some quick'n dirty RCA to 1/4" cables and tested the amp for any faults. I couldn't find any, and sound was making it through to the test speaker, so I went ahead and connected the TLS50s.

Even with the subprime condition of my woofers, all I can say is holy crap!!! This amp sounds incredible! It is so quiet that even with the channel gains all the way up and the volume control on my preamp at maximum, there was absolutely ZERO hiss or background buzz from my speakers with no signal present. I mean none. I had to check if the amp was actually on even with my ear next to the tweeter.

Once I actually applied signal I realised I'd have to back the gain down to about halfway to retain the volume control's range. Anyway, the sound is jaw-dropping. I've never experienced this kind of authority from a piece of gear I've owned. Low level details are exploding from the speakers. So many of them that I don't know what to do with them all. It's sensory overload...madness!!!! It seems like lyrics in familiar songs are a lot easier to understand. The bass definition is nothing short of shocking as well. All this is from listening to mp3s...I haven't got my turntable set up so I can't give the Yamaha a full test. Obviously though, I am using only 1/100th of its reserve of power, dynamics and control.

Natural Sound, indeed...but don't take that to mean "boring and sterile". Far from it, the sound is very alive. I think this amp is going to the grave with me. Wow.

When I first heard the PC2002M, that's exactly how I felt. The manual provides test results to back up the amp's performance and what I am hearing. I have many great amps in the house and have heard many more "super" amps. The PC2002M is at or near the top of the heap.
 
When I first heard the PC2002M, that's exactly how I felt. The manual provides test results to back up the amp's performance and what I am hearing. I have many great amps in the house and have heard many more "super" amps. The PC2002M is at or near the top of the heap.

Yours has those awesome looking meters too :drool:
 
Battle scars!!

Pro series Yamaha's, I really enjoy my P2201. Good going on your score! You will be able to clean yours up like i had to due to battle scars from road use, my p2201 came out of a studio, may sound lame but use a magic marker if paint work is not an option to clean up the scuffs especially on the rack handles. Not much you can do for the face plate due to over tightening, mines the same, damm gorillas.:thmbsp:
 
When I first heard the PC2002M, that's exactly how I felt. The manual provides test results to back up the amp's performance and what I am hearing. I have many great amps in the house and have heard many more "super" amps. The PC2002M is at or near the top of the heap.

Here are the results from the PC5002M, which uses the same transistors as the PC2002M and possibly your P2100 as well. A little hard to see, but pretty solid if you ask me ;):

SCAN0007.JPG


SCAN0008.JPG
 
Okay gents, I soldered up some quick'n dirty RCA to 1/4" cables and tested the amp for any faults. I couldn't find any, and sound was making it through to the test speaker, so I went ahead and connected the TLS50s.

Even with the subprime condition of my woofers, all I can say is holy crap!!! This amp sounds incredible! It is so quiet that even with the channel gains all the way up and the volume control on my preamp at maximum, there was absolutely ZERO hiss or background buzz from my speakers with no signal present. I mean none. I had to check if the amp was actually on even with my ear next to the tweeter.

Once I actually applied signal I realised I'd have to back the gain down to about halfway to retain the volume control's range. Anyway, the sound is jaw-dropping. I've never experienced this kind of authority from a piece of gear I've owned. Low level details are exploding from the speakers. So many of them that I don't know what to do with them all. It's sensory overload...madness!!!! It seems like lyrics in familiar songs are a lot easier to understand. The bass definition is nothing short of shocking as well. All this is from listening to mp3s...I haven't got my turntable set up so I can't give the Yamaha a full test. Obviously though, I am using only 1/100th of its reserve of power, dynamics and control.

Natural Sound, indeed...but don't take that to mean "boring and sterile". Far from it, the sound is very alive. I think this amp is going to the grave with me. Wow.

Yep, that's about it. They just quietly go about their jobs...you get spoiled really quickly. These are the only amps that have stayed with me for 20+ years...lots of other "good" to "very, very good" amps have come & gone.

Enjoy.

je
 
Here are the results from the PC5002M, which uses the same transistors as the PC2002M and possibly your P2100 as well. A little hard to see, but pretty solid if you ask me ;):

SCAN0007.JPG


SCAN0008.JPG

Thanks for the scans. The square wave performance will tell you the most about how accurate an amp is and the PC5002M has near perfect reproduction. Of note are the vertical attack and decay in the 20 hz trace. I've seen 20 Hz results from other well respected amps that are shockingly bad and look like sine waves. The flat tops indicate the PC5002M does not lose energy (not surprising) so no information is lost. The 20kHz trace shows minimal rounding, nearly all amps I've seen have some rounding but the duration of the plateau is noteworthy. The PC5002M's results are easily the best I have seen. Many "Holy Grail" amps and receivers (which shall go unnamed) do not come close. When doing comparos, the differences are easily heard and trust me, once you have heard superior performance, you do not go back.
 
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Thanks for the scans. The square wave performance will tell you the most about how accurate an amp is and the PC5002M has near perfect reproduction. Of note are the vertical attack and decay in the 20 hz trace. I've seen 20 Hz results from other well respected amps that are shockingly bad and look like sine waves. The flat tops indicate the PC5002M does not lose energy (not surprising) so no information is lost. The 20kHz trace shows minimal rounding, nearly all amps I've seen have some rounding but the duration of the plateau is noteworthy. The PC5002M's results are easily the best I have seen. Many "Holy Grail" amps and receivers (which shall go unnamed) do not come close. When doing comparos, the differences are easily heard and trust me, once you have heard superior performance, you do not go back.

That is some pretty interesting information. I think my receiver and integrated days are over.

The only thing I could think of that I'd want to do is to recap the power supply. It sounds incredible as it is, but 25+ years of pro sound use has probably left its mark on those PS cans. 30,000 uF cans in the same physical dimensions can be found now and I wonder what they'd do to the bass grip. Also there are bypass caps on the rectifier bridge, but not on the reservoir caps themselves...as well as no bleeder resistors. I think down the road these would be "nice to haves". Anyone tried?
 
That is some pretty interesting information. I think my receiver and integrated days are over.

The only thing I could think of that I'd want to do is to recap the power supply. It sounds incredible as it is, but 25+ years of pro sound use has probably left its mark on those PS cans. 30,000 uF cans in the same physical dimensions can be found now and I wonder what they'd do to the bass grip. Also there are bypass caps on the rectifier bridge, but not on the reservoir caps themselves...as well as no bleeder resistors. I think down the road these would be "nice to haves". Anyone tried?

The cans in the PC2002M are 22,000 uF 100V x 2.
 
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