Proton D1200 / AA-1150 / AA-2120 Owners Thread

[Boba MosFET]

I'm a musician who is always looking for recording gear and Reverb is the greediest, most price-inflated marketplace out there. People seriously need to chill and check ebay's "completed/sold" search function to see what people have actually paid for something. To my knowledge no one has ever paid $1149 for a D1200. What do you guys think about this?

Reverb is tailored towards musicians but they have a great hifi presence too. I've bought stuff there that would have cost me 5 times as much on eBay, and never mind Audiogon. There's nothing preventing that guy from lowering his price after he sits on that paid listing for a few months, and eventually he'll be listening to smart offers.

Things change, people change, markets change.

I used to buy and sell on Audiogon. It was geared towards mid-fi about 20 years ago. I found great deals on Hafler gear, and sold some Adcom there. Today they ignore the anodized aluminum gear of my 80s youth and instead sell stuff for people who are looking for that last tenth in their performance, and the prices are high.
You're right about using the completed sales on eBay as a reference, but that is of limited help. It might gauge the market for you as a buyer, but have you ever used it to negotiate with a seller? You might just get a response like "Well go buy it from the other guy then!"
I've gotten excellent gear on eBay but also screwed a few times, and now their listing policies are becoming an incredible hassle so I don't bother selling there anymore. Their search leaves a lot to be desired too. For instance there's no way for me to search for a brand but exclude manuals. So while I might be able to find one Nak or Proton amp, its stuck in two or three pages of listings for owner's manuals, service manuals, repair parts, signs, t-shirts, and that guy who is selling "one repair for a Proton amp" if you pay him and send your amp to him.
The best search function has to be USAM, the worst is Craigs. USAM has a bunch of pulldowns that make the search as exclusive as I want. With Craigs I have to deal with the ads that somehow get around the "exclude duplicates" button, and I also have to keep Boolean negative terms to get rid of the idiots with the key word clouds. You know those guys who have 400 words at the bottom of the ad, and you might see "5.1, 7.1, 9.1, True HD, THX, Blu-ray, 3D" repeat a couple of times in there, proving its been copied and pasted to death?

 

[PabloTincho]

Is the Proton D1200 based on a Nad power amp ?

 

[karljansen]

I've gotten excellent gear on eBay but also screwed a few times, and now their listing policies are becoming an incredible hassle so I don't bother selling there anymore. Their search leaves a lot to be desired too. For instance there's no way for me to search for a brand but exclude manuals. So while I might be able to find one Nak or Proton amp, its stuck in two or three pages of listings for owner's manuals, service manuals, repair parts, signs, t-shirts, and that guy who is selling "one repair for a Proton amp" if you pay him and send your amp to him.

It seems you're missing out on the "advanced" search page at ebay, because it's very easy to screen out all of those things. Here's a search link I created for the keyword "Proton," excluding the word "manual," in the Consumer Electronics category, minimum price $100. I could have also excluded the word "recap" and a couple of other words, which would have eliminated some noise, but check out how much interesting Proton stuff comes up:

https://www.ebay.com/sch/i.html?_nkw=proton&_in_kw=2&_ex_kw=manual&_sacat=293&_udlo=100

There are three D1200s on there (one is for parts), with the most expensive asking $729 Buy It Now, one AA-1150 asking $754 Buy It Now, a couple of the tabletop radios, and 3-4 of the AI-3000 compact systems + other stuff like D540, CD player, car stereos, etc. I'm actually really surprised by what came up.

As far as Reverb goes, I stand by my claim that people on their are insane with their pricing. There seems to be some kind of "upward price spiral" going on and I don't understand what kind of psychology causes it. I think maybe it's sellers looking at what other sellers are asking without checking the price history, and the asking prices just keep building on one another. Then one or two suckers pay the outrageous price, setting a new benchmark. What's sad is those people are usually not the serious musicians who will actually produce music with the gear, they're collectors.

We also seem to be hitting peak nostalgia for people of a certain age who can now afford to buy things they lusted after in the 80s but were too young and broke to afford. An example is Nakamichi tape decks and analog synthesizers like the Juno-106. Forget that blank cassettes have to be ordered from this one USA company that still makes them, and other than that are no longer even made. I bought two Juno's, one for $525 and another much more recently for $800. I paid $200-$300 each on top of that to have the voice chips replaced. The average asking price for these on Reverb today is currently around $2500, for one of the most mass-produced analog synths of the 80s. They're great, but they are not rare at all.

It's at the point where I feel pressure to buy things I've always wanted but don't really "need," because if I don't buy it now it will eventually be priced out of my reach. It's the same with housing: every day that you don't buy a house is the last day it will ever be that cheap again, until some kind of massive housing crash, but then you'll also lose your job and can forget about buying a house. It seems like there's no way to win other than to get lucky. Maybe the past 3 years have just made me super pessimistic.

 

[karljansen]

Is the Proton D1200 based on a Nad power amp ?

This heavily researched article below explains the history of Proton and their relationship to NAD. They were built in the same factory but have completely different circuits. Both incorporated "dynamic power" circuitry that NAD called "Power Envelope," and Proton called "Dynamic Power on Demand." I own a NAD 2400 with PE and always thought it sounded great. I believe the speaker relays have finally started to go bad and I'll hear scratching noises out of one channel sometimes, so I put it in storage until I have the funds to have it looked at.

PROTON Audio, NAD and Dynaco are Cousins. Inventor of Dynamic Power on Demand Amplifiers.

Have collected: Stereo equipment, records & CDs, film & digital cameras, diecast & slot cars, and much more. But as I age, I have been selling many.

therobbcollections.blogspot.com

Here's an AK thread and post by Raynald that discusses the NAD and Proton dynamic power feature, and how some people tried to push it beyond its capabilities and blew out a lot of speakers, but also goes into what was good about it:

NAD 2xxx "Power Envelope" Amp Cautionary Tale or just a Whitewash?

Hi All, I came across this article the other day looking for info about fixing my NAD 1300: http://newsgroups.derkeiler.com/Archive/Rec/rec.audio.tech/2008-04/msg00111.html It is not about the NAD 1300 but a long diatribe against the "Power Envelope" NAD amps of the 2xxx series like the...

audiokarma.org

 

[etrain68]

Hi my experience with the d1200 is that it's a neutral but detailed amplifier with full control of the bass notes specially at reference levels with my klipsch rp-8000f,with the Onix a-2150 with my klipsch the midrange and highs are more forward and less control of the bass notes,the parasound a 23+ is a little bit less neutral than the proton d1200 but still very detailed and enjoyable to listen too.
First second and third choice are.
#1-Proton d1200
#2-Parasound a 23+
#3-Onix A-2150
This is all dependent on what speakers are you using.

 

[etrain68]

Found it! It's the Onix A2150. I'm guessing it's a rebranded AA-2120. There's one for sale on ebay right now: https://www.ebay.com/itm/225469032321
View attachment 2833212View attachment 2833213 View attachment 2833214 View attachment 2833215View attachment 2833226

More with the internals. If this is accurate, then it's very different from the D1200. Wonder if that's what the AA-2120 looks like:

View attachment 2833233 View attachment 2833232

The onix with the fans on the top is my amplifier I posted in offer up a while ago I still have it and working like a dream I posted pictures down below

 

[PabloTincho]

Here are some reviews for Proton amp and preamps

 

[karljansen]

Interesting that the Stereo Review article refers to the front glass as a "piece of plastic." Strange that they weren't able to tell that it's glass. The other reviewer seems to pan the AA-1150 as totally inadequate for powering his big and expensive speakers. I wonder if that's true, or if it's another reviewer who feels they need to throw some shade in order to seem "unbiased."

Here's a scan of the manual for the AA-1150 from the AK database: http://akdatabase.org/AKview/albums/userpics/10007/Proton AA-1150 Owners Manual.pdf

What's interesting is that the manual states that the AA-1150 is "dual-mono." I don't see any mention of "dual-mono" in the D1200 manual. Now I'm confused, because I was under the impression that both the D1200 and AA-1150 are not dual-mono, and that one power supply handles normal power and the second is for the extra power required by the DPD circuit. Are they both dual-mono, just the AA-1150, or neither?

Someone in this thread says: "BTW, if the D-1200 is a scaled-up version of the AA-1150, it may not be true dual-mono. The two power supplies in the AA-1150 look different, and I found out that one of them is for the DPD, the other for normal operation. I don't know if the D-1200 follows the same rule, but the DPD must get power from somewhere..."

 

[PabloTincho]

According to the review, the D-1200 is not dual mono, it has a power reserve like the Nec A-10 integrated amplifier, in addition the AP-1000 the review mentioned about being dual mono but that is not correct for that preamp, probably what they meant , 2 power supply, one for the line stage and the other one for the phono section

 

[karljansen]

According to the review, the D-1200 is not dual mono, it has a power reserve like the Nec A-10 integrated amplifier, in addition the AP-1000 the review mentioned about being dual mono but that is not correct for that preamp, probably what they mean, 2 power supply, one for the line stage and the other one for the phono section

I noticed that about the AP-1000 and "dual mono!" Check out the PDF file with the AA-1150 manual in the introduction. It states that the AA-1150 is dual-mono. Is it possible that even the manual is wrong?

 

[PabloTincho]

Well to be honest that British review was very bland, mostly his opinion and not very informative

 

[HPMguy]

Dual mono would imply a separate rectifier and filter caps for each channel at least, and probably a separate transformer, although I guess separate windings for each channel would be more or less equivalent.

My Kenwood 1100 has a triple set of main filter caps, and the high voltage switch circuit has a delay for dropping it, I would assume to avoid switching noise and voltage spikes. I suspect I'll never see it work, rarely have more than 0.5W on the meters.

I suspect what kills these amps is serious overdriving them into low resistance loads (six speakers for instance) or reactive loads at very high volumes. I cannot imagine ever using much of that power unless I was providing the sound for a large outdoor event full of deaf people, for my own purposes I suspect I'll hardly ever see the meter LEDs light up past the bottom one.

 

[karljansen]

From the inside it really looks like it's dual-mono, even if it's not. That's why there's some confusion about this issue.

Dual mono would imply a separate rectifier and filter caps for each channel at least, and probably a separate transformer, although I guess separate windings for each channel would be more or less equivalent.

My Kenwood 1100 has a triple set of main filter caps, and the high voltage switch circuit has a delay for dropping it, I would assume to avoid switching noise and voltage spikes. I suspect I'll never see it work, rarely have more than 0.5W on the meters.

I suspect what kills these amps is serious overdriving them into low resistance loads (six speakers for instance) or reactive loads at very high volumes. I cannot imagine ever using much of that power unless I was providing the sound for a large outdoor event full of deaf people, for my own purposes I suspect I'll hardly ever see the meter LEDs light up past the bottom one.

 

[sregor]

Service manual for AA-1150 shows two transformers, both same part number and both with separate low and high voltage secondaries, so it agrees with "dual mono"

 

[PabloTincho]

What about the preamp AP-1000 ?
What do you make of the design?

 

[karljansen]

Service manual for AA-1150 shows two transformers, both same part number and both with separate low and high voltage secondaries, so it agrees with "dual mono"
View attachment 2921901

Let us know what you think about the D1200 (that's the unit in my internals photo above). Is it dual-mono, or is it one side for regular power and the other for the dynamic power?

 

[sregor]

D1200 is two transformer wired as a single center tapped setup.

 

[karljansen]

D1200 is two transformer wired as a single center tapped setup.

So in other words, not dual-mono, right?

 

[sregor]

So in other words, not dual-mono, right?

Right. (should have put it in the post....)

 

[PabloTincho]

Well got lucky today and was able to pick up a D1200 for $100 and many audio pieces that I did not want , and also got the matching preamp AP-1000 for $120, the amp has serious power

What I am going to do with a; Denon Professional 500C CD, AudioSourrce Model Pre One, Bose speakers 301 ?