Wow....the first REAL nudies pics......I see boobies in the background!!
That's a picture of the guy he hired to help move these things, just taking a momentary rest
Heathkit AA-1800 and AP-1800
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- Start date
That's a picture of the guy he hired to help move these things, just taking a momentary rest
Sithlord2007
New Member
I have three of the AA-1800's. I am considering gutting one for the transformer and building another power supply so each channel has its own dedicated supply. That, and replace all electrolytics and main caps to add more capacitance. Primary purpose will be to create a sub woofer amplifier. One chasis will be for the caps and transformers, the other will be for the amplifier boards and transistors. My father actually did this to an AA-1600. But because he could not get a matching transformer, ended up completely building new supplies for each channel and adding some more transistors (that is putting it lightly! A great deal of work went into it!). Any thoughts?
DavidGoncalv
Active Member
Damn shame to break up an amp like that.
Damage
Super Member
Yea, sell them and buy what you want.
Damon Hill
Active Member
Where's the fun in that?
I've got an AA-1800 with no turn-on/protection board and general fixer-upper. Guess I'll have to duplicate the missing board on a piece of perfboard. Eventually I'll get around to building jumper cables so I can power up the amp and start testing it. I see a couple of blown fuses on the left channel so I guess my work's cut out for me.
My interest in this design is because it's very similar to Marshall Leach's Superamp and I'm curious as to how it'll sound when fixed up. I've used Leach's amplifier design for many years and am very pleased with it.
I've got an AA-1800 with no turn-on/protection board and general fixer-upper. Guess I'll have to duplicate the missing board on a piece of perfboard. Eventually I'll get around to building jumper cables so I can power up the amp and start testing it. I see a couple of blown fuses on the left channel so I guess my work's cut out for me.
My interest in this design is because it's very similar to Marshall Leach's Superamp and I'm curious as to how it'll sound when fixed up. I've used Leach's amplifier design for many years and am very pleased with it.
Ihave an heat ap 1800 its ok preamp idont sell my ,its old school preamp its sounds good ihave it with my mag tubes and do the job ,very smooth with pair of wharfadale . This amp looks have alot of power , they look fantastic and ibelieve its very good vintage power . By any chance isaw your bench . Can you fix an hafler dh 500 both channels working and clear sound but... Above quarter of volume cut off ,turn the switch off and sometimes the sound come back ,working hot . Let me know thanks pw
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solidjackson
Active Member
Ya know, I saw this on the top on the page when I opened this topic.
Heh. One of the weirder search engine ads I've seen... nice looking amp though!
Heh. One of the weirder search engine ads I've seen... nice looking amp though!
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willhowl
Well-Known Member
O/T Alert........
Sorry, I know better........but I had to jump in .....
Heathkit made several products with distortion in the name....Distortion analyzers, meters, and a distortion booster for guitar........so that's the reference ......
Back to the previous ( very interesting....Yay Heathkit!!!!) topic...........willhowl
Sorry, I know better........but I had to jump in .....
Heathkit made several products with distortion in the name....Distortion analyzers, meters, and a distortion booster for guitar........so that's the reference ......
Back to the previous ( very interesting....Yay Heathkit!!!!) topic...........willhowl
Rob41
Don't stop believin'
Very nice!
The Pro-Series gear from Heathkit was (is) some truely amazing equipment.
The AA-1800 was the most powerful and arguably the most refined amp they ever built. In my opinion it's one of the best "Leach double barrel" amps ever made. It's essentially two mono amps only sharing the chassis and the transformer. It's sound is incredibly clean, only amplifying the source equipments sound. As mentioned earlier, due to Federal regulations on kits at the time, they under rated the rms output to 250 watts per channel into an 8 ohm load. In reality, it delivers closer to 350 watts rms per channel with an 8 ohm load! I can't even imagine what kind of headroom this monster amp has. I've got a pair of very efficient speakers rated to handle 400 watts and I've yet to see the clipping indicators light up. The power delivery is just as transparent and effortless at full power as it is at lower listening levels. I cannot comment on the smaller AA-1600 (125wpc rms) as I've never auditioned one, but I can tell you I wouldn't trade the AA-1800 for anything.
The AP-1800 Preamp is amazing in it's own right. It has a plethora of inputs and sound controls comparing favorably to gear such as the Pioneer Spec components. I actually prefer it to any of the spec gear.
I've had a lot of high end audio equipment over the years and to this day my main system is largely made up of the Heathkit Pro-series gear.
IMO this gear is some of the most under rated of all time.
The high level of performance may be due in part because their engineers were top notch at not only audio equipment but, also at designing ham radio equip., electrical test equip, oscilloscopes, and everything else electronic under the sun.
I try to pick up the Pro-series stuff when I can because quite often people aren't even aware of what they have.
A couple weeks ago I was scoping out Craigslist and came across an ad for a complete set of Pro-series gear with the original rack for $2600. I called the number only to find out it had already sold. Thing is, he only had it listed for less than two hours by the time I called. So now I'm piecing together another Pro-series system for my home office, one component at a time. The search continues.
The Pro-Series gear from Heathkit was (is) some truely amazing equipment.
The AA-1800 was the most powerful and arguably the most refined amp they ever built. In my opinion it's one of the best "Leach double barrel" amps ever made. It's essentially two mono amps only sharing the chassis and the transformer. It's sound is incredibly clean, only amplifying the source equipments sound. As mentioned earlier, due to Federal regulations on kits at the time, they under rated the rms output to 250 watts per channel into an 8 ohm load. In reality, it delivers closer to 350 watts rms per channel with an 8 ohm load! I can't even imagine what kind of headroom this monster amp has. I've got a pair of very efficient speakers rated to handle 400 watts and I've yet to see the clipping indicators light up. The power delivery is just as transparent and effortless at full power as it is at lower listening levels. I cannot comment on the smaller AA-1600 (125wpc rms) as I've never auditioned one, but I can tell you I wouldn't trade the AA-1800 for anything.
The AP-1800 Preamp is amazing in it's own right. It has a plethora of inputs and sound controls comparing favorably to gear such as the Pioneer Spec components. I actually prefer it to any of the spec gear.
I've had a lot of high end audio equipment over the years and to this day my main system is largely made up of the Heathkit Pro-series gear.
IMO this gear is some of the most under rated of all time.
The high level of performance may be due in part because their engineers were top notch at not only audio equipment but, also at designing ham radio equip., electrical test equip, oscilloscopes, and everything else electronic under the sun.
I try to pick up the Pro-series stuff when I can because quite often people aren't even aware of what they have.
A couple weeks ago I was scoping out Craigslist and came across an ad for a complete set of Pro-series gear with the original rack for $2600. I called the number only to find out it had already sold. Thing is, he only had it listed for less than two hours by the time I called. So now I'm piecing together another Pro-series system for my home office, one component at a time. The search continues.
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Which output transistor does the AA-1800 use? I have the AA-1640 that uses the RCA 1B05, 8 outputs per channel. The rails on the 1640 are +/- 91 volts and this will do about 350 watts at clipping. At 110 volt rails on the 1800 I would think it would be capable of over 400w.
Weeb
Active Member
What's the matter with your head?I have black version AA-1600/AP-1800, they sit in the backroom, I've never listened to them.
Bugdozer
New Member
I have a nice system I built back some time ago, AP-1800 Preamp, AD-1703 Octave Equalizer, AD-1706 Active Audio Processor, AD-1702 Variable Electronic Crossover and two AA-1800 Amps. When the Heathkit store in Los Angeles was closing down, I picked up the crossover and second amp for $400. I didn't intend on having the crossover two amps but who could pass on that deal.
Just this past weekend I tore down my first amp, gave it a good cleaning and now I'm waiting on parts for the re-cap. Once the amp is done, I'll do the preamp and then figure what to tackle next. I had forgotten how well designed this equipment is and the parts all seem to be top notch. Having fun!
Just this past weekend I tore down my first amp, gave it a good cleaning and now I'm waiting on parts for the re-cap. Once the amp is done, I'll do the preamp and then figure what to tackle next. I had forgotten how well designed this equipment is and the parts all seem to be top notch. Having fun!
The Leach based circuit came to Heath via an engineer named Dave Kauk who studied under Dr. Leach at Georgia Tech, then went to work for Heath where he designed the AA-1640. After Dave left Heath an engineer named Bruce Trump designed Heath's 2nd generation of the Leach based amp the AA-1800.
These units live on! I recently decided to restore my AA1800 & its smaller sibling, the AA1600. Replaced all the electrolytics, the power supply caps, upgraded the diode bridge, replaced the high wattage resistors, and full set of new matched output transistors on both units.
Years ago, I had a conversation with the Heath engineering tech from the AA1800 line and he advised lowering the output stage emitter resistors to 0.1 ohms as that was what the design engineer originally wanted but cost, availability and setup adjustment pushed them to the higher value. He also stated that they decided to take an AA1800 he had just built from a kit pulled off the production line and see just what it was capable of doing. As the power supply limits max power to somewhere between 1000W and 1200W, they decided to pull one amp out and give the remaining channel the entire power supply. He said that at 800W with no clipping or failure was where they called it done. Of course, there is no way the amp could do this continously, but this is why it was rated conservatively at 250W with 2.5db dynamic headroom (most measured reviews of the time found at least 3db of headroom.
The reason for my overhaul is the amp pair are going to be used in horizontal biamp setting. I'm splitting the stereo signal into pairs per channel, <350Hz / >350Hz, with the AA1800 getting the lower band with the AA1600 handling the upper. I used xkit's XOVER-2 to handle the active crossover duty. The XOVER-2 active crossovers are centered on 350Hz (B&W provided the appropriate crossover point for biamping the N802s). Other than removing the bridging links on the 802 inputs, no further changes were made to the speakers.
I'm driving the system from the latest Eversolo DMP-A8 Gen2 Master Edition. (My concession to digital)
The final piece of the sonic equation are my B&W Nautilus 802s connected using KnuKonceptz's 8AWG braided cables.
The result.....WOW! I had read about the benefits of biamping these B&W speakers for years, but the planets didn't align until now. The floor of the system is dead silence...blackness. The lower end simply is breathtaking. Bass simply flows like warm honey, rich, rock solid, effortless. The mid/tweeter range exhibits complete control, no solid state harshness period. Absolutely crystal clear clarity. Even at volumes bordering on uncomfortable, neither amp has indicated full output even for an instant.
Granted the B&W N802s are no small contributer to the end result, but without the proper amps feeding them, which the Heath amps clearly meet, the sonic experience would suffer.
Years ago, I had a conversation with the Heath engineering tech from the AA1800 line and he advised lowering the output stage emitter resistors to 0.1 ohms as that was what the design engineer originally wanted but cost, availability and setup adjustment pushed them to the higher value. He also stated that they decided to take an AA1800 he had just built from a kit pulled off the production line and see just what it was capable of doing. As the power supply limits max power to somewhere between 1000W and 1200W, they decided to pull one amp out and give the remaining channel the entire power supply. He said that at 800W with no clipping or failure was where they called it done. Of course, there is no way the amp could do this continously, but this is why it was rated conservatively at 250W with 2.5db dynamic headroom (most measured reviews of the time found at least 3db of headroom.
The reason for my overhaul is the amp pair are going to be used in horizontal biamp setting. I'm splitting the stereo signal into pairs per channel, <350Hz / >350Hz, with the AA1800 getting the lower band with the AA1600 handling the upper. I used xkit's XOVER-2 to handle the active crossover duty. The XOVER-2 active crossovers are centered on 350Hz (B&W provided the appropriate crossover point for biamping the N802s). Other than removing the bridging links on the 802 inputs, no further changes were made to the speakers.
I'm driving the system from the latest Eversolo DMP-A8 Gen2 Master Edition. (My concession to digital)
The final piece of the sonic equation are my B&W Nautilus 802s connected using KnuKonceptz's 8AWG braided cables.
The result.....WOW! I had read about the benefits of biamping these B&W speakers for years, but the planets didn't align until now. The floor of the system is dead silence...blackness. The lower end simply is breathtaking. Bass simply flows like warm honey, rich, rock solid, effortless. The mid/tweeter range exhibits complete control, no solid state harshness period. Absolutely crystal clear clarity. Even at volumes bordering on uncomfortable, neither amp has indicated full output even for an instant.
Granted the B&W N802s are no small contributer to the end result, but without the proper amps feeding them, which the Heath amps clearly meet, the sonic experience would suffer.