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Any 805A based amp owners?

Nixxuz

Nixxuz

Super Member
Looking to pick up a new amp since I sold one of mine. I've narrowed it down to a pair of 300B monoblocks or a SE 805A capless based design. There's very little price difference, and I know the 300B is regarded pretty highly as a decent tube. But I saw the 805A, and was fairly intrigued, as it claims 25wpc, which makes it more flexible that the 8wpc of the 300B.
I'm aware that components, topology, etc. are just as important in determining which of these amps to buy, but I can't seem to find too many people who have run an 805 based amp, so I'm just trying to get some opinions from those familiar with the sound.
 
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It really boils down to the effeciency of your speakers.
7 Watts is a 300B amps Limit, 22-25 for the 805, 814's 822 somewhere around the same
Lethal Voltages for the big power tubes
 
Nixxuz said:
Looking to pick up a new amp since I sold one of mine. I've narrowed it down to a pair of 300B monoblocks or a SE 805A capless based design. There's very little price difference, and I know the 300B is regarded pretty highly as a decent tube. But I saw the 805A, and was fairly intrigued, as it claims 25wpc, which makes it more flexible that the 8wpc of the 300B.
I'm aware that components, topology, etc. are just as important in determining which of these amps to buy, but I can't seem to find too many people who have run an 805 based amp, so I'm just trying to get some opinions from those familiar with the sound.
Click to expand...

I have not owned one but I've always heard good things about the Cary 805. I built 845 amps myself years ago and it's a very good sound, very robust and powerful. Hopefully some Cary owners will chime in.
 
And here is your chance to talk me out of it lol. But, in all honesty, I think I am committed. Either of these options would be upgraded before ever even being powered on. Coupling caps would be replaced for sure. The 300B would eventually get power and pre tubes replaced. But the monoblocks use a PCB design, while the 805A uses P2P wiring. The 5881A tubes in the 805 would be replaced with KT77's. I know these are both budget Chinese amps, but I've had pretty good luck so far. Of course, I understand that there are some who wouldn't give either of these amps a 2nd glance, mostly due to their origins.
https://hifi-exquis.com/en/tube-amp...805-lamp-amp.html?search_query=805A&results=2
https://hifi-exquis.com/en/300b-2a3...eo-2-pieces.html?search_query=300B&results=55
 
I have a Yaqin 300B SE stereo amp and mingda 300B and 845 SE monoblock amps. Each of the amps sounds very good. I attribute this to their output transformers.

The transformers on these amps are much larger than on the ones you selected. The mingda mono blocks each weigh 50 lbs or more and each of the output transformers weigh 17 lbs. The Yaqin amp weighs more than 50 lbs.

Look at the weight of the amps. I think the weak component in the amps you selected will be the transformers.

Steve
 
steve... said:
I have a Yaqin 300B SE stereo amp and mingda 300B and 845 SE monoblock amps. Each of the amps sounds very good. I attribute this to their output transformers.

The transformers on these amps are much larger than on the ones you selected. The mingda mono blocks each weigh 50 lbs or more and each of the output transformers weigh 17 lbs. The Yaqin amp weighs more than 50 lbs.

Look at the weight of the amps. I think the weak component in the amps you selected will be the transformers.

Steve
Click to expand...

I was going to say that the output transformers in particular look awfully small for that output tube and power rating.
 
I dunno. I would generally agree, but my little Elekit 8200R kind of makes me wonder exactly how heavy transformers have to be. It's only 14lbs. and it sounds pretty good. I know bigger iron is better for sustaining output, but whatever I buy is only going to be driving a pair of 99dB efficient wideband drivers. I'm not going to be taxing the amp/s overtly with a great deal of driver extension.
This is going to be part of a tri-amped setup.
One amp for the 99dB wideband drivers.
One amp for a pair of new Heil AMT1's.
A Class D for the LF drivers.
So I don't really need a lot of watts. The 805A I was considering more for "big tube" aesthetics I guess.
 
I doubt that hey have real Alps Volume pots. Ever price a Real one?
Make sure you get schematic's
When Ed Duda was Alive he had nothing good to say about the Chi Com stuff, other than they Look Nice.
Couldnt even tell the Value of the Resisters, Not following Known industry standards.
 
Nixxuz said:
I dunno. I would generally agree, but my little Elekit 8200R kind of makes me wonder exactly how heavy transformers have to be. It's only 14lbs. and it sounds pretty good. I know bigger iron is better for sustaining output, but whatever I buy is only going to be driving a pair of 99dB efficient wideband drivers. I'm not going to be taxing the amp/s overtly with a great deal of driver extension.
This is going to be part of a tri-amped setup.
One amp for the 99dB wideband drivers.
One amp for a pair of new Heil AMT1's.
A Class D for the LF drivers.
So I don't really need a lot of watts. The 805A I was considering more for "big tube" aesthetics I guess.
Click to expand...

The Elekit is an 8wpc amp. This is supposedly 25wpc with a high-current, high-impedance output tube. That means a very hefty output transformer to get any kind of bandwidth. It might be fine, but as someone else pointed out, if you compare it with, say, the Line Magnetic 805 amp, you can see the difference in the iron. As I mentioned, I've built 845 SE amps, and the output transformer is everything. I'm just saying that for $700, don't get your hopes too high.
 
zackthedog said:
The Elekit is an 8wpc amp. This is supposedly 25wpc with a high-current, high-impedance output tube. That means a very hefty output transformer to get any kind of bandwidth. It might be fine, but as someone else pointed out, if you compare it with, say, the Line Magnetic 805 amp, you can see the difference in the iron. As I mentioned, I've built 845 SE amps, and the output transformer is everything. I'm just saying that for $700, don't get your hopes too high.
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Well, I can appreciate your view. I think I'm still going to try it. Mostly because, for all the misgivings people seem to have when it comes to Chinese tube gear, I haven't yet found someone who has purchased an item and found it to be just plain terrible. It almost always ends up being better than they expect, at least from the people I've encountered. Yaqin, Oldchen/Laochen, Reisong. All of them have been most usually regarded as pretty good, and possibly very good with a few tweaks. So I suppose I'm willing to take a chance on this one. If it ends up as a hot pile of garbage, well, lesson learned.

And I got a schematic for it, hand drawn on a piece of notebook paper no less;
xinxin-805_diagram.jpg
 
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The transformer size is less important if this is going to be the mid or high frequency driver.

What do you plan to drive with the amp?

I setup an ESS AMT1A for bi-amping. I crossover at 1khz with an 18 DB per octave crossover. I use a Mingda EL34 push pull for the base and the Yaqin 300B SE for the Heil tweeters.

The 300B AMT combination is awesome.

I tried Golden Tube Audio SE-40, classD, Denon and McIntosh solid state amps for the bass but I was never happy with the combination. The solid state amps were fatiguing and the SE-40 didn't control the bass very well at higher volumes. When I got the EL34 push pull amp and put it in the system it was the right combination for me.

Steve
 
steve... said:
The transformer size is less important if this is going to be the mid or high frequency driver.

What do you plan to drive with the amp?

I setup an ESS AMT1A for bi-amping. I crossover at 1khz with an 18 DB per octave crossover. I use a Mingda EL34 push pull for the base and the Yaqin 300B SE for the Heil tweeters.

The 300B AMT combination is awesome.

I tried Golden Tube Audio SE-40, classD, Denon and McIntosh solid state amps for the bass but I was never happy with the combination. The solid state amps were fatiguing and the SE-40 didn't control the bass very well at higher volumes. When I got the EL34 push pull amp and put it in the system it was the right combination for me.

Steve
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Almost the same as what I plan on doing.
I currently have the Elekit 8200R running my mids/highs.
Drivers are Lii Audio Fast10S and a titanium dome tweeter, both of which are about 98dB efficient.
I like the sound of ribbons/planars/AMT type tweeters, so I bought a pair of the new production Heil AMT1's. I was using a Yaqin MC-13S to power the Heils, and the Elekit to power the Lii drivers. I had put up the Yaqin for sale on CL before I decided to use it for just the tweeters. I had honestly forgotten that I had it listed until last week when a fellow called about it. I decided to sell it based on wanting a 300B based amp, and would then put the Elekit on tweeter duty, and whatever new amp I got would power the Lii Audio drivers.
While looking at 300B amps, I chanced upon the 805A I linked in this thread. I was intrigued by the "big tubes" and thought I'd look further into the idea.
I can see how it might be a bit confusing/not a great idea to some. But I have a pretty non-traditional system, as it seems you do, so I think it's going to work out for my purposes.
I did already order it, in any case, so I guess I'll see how it turns out in a couple weeks here.
 
The Heil AMTs have a flat impedance curve and work very well with SE amps. I tried various push pull amps over the years but always came back to using an SE amp with them.

For various reasons (diaphragms and housing) at high levels the distortion goes up significantly as you as you go below 1khz. Many people prefer them above 3khz. I listen at low volumes (< 85 DB SPL) and prefer the 1khz crossover.

I do plan to try a midrange with a crossover from ~500 to 2500 hz and the AMT above that. I am interested in the results you get.

Have you compared the AMTs with your SE amp against your push pull amp?

How do you plan to crossover between the 3 amps?

Steve
 
My Heils are crossed over at roughly 9khz, as the Lii Audio drivers are quite good up to probably 14khz. I don't seem to suffer any perceptible problems from comb filtering, so it doesn't concern me. The Lii drivers run full range. The Heils are crossed over with a simple 2nd order filter consisting ostensibly, of a cap and an inductor. I did not compare the Heils before I sold my P/P amp, and both my amps, when I receive the 805A, will be SE. Both SE amps will run full signal to the Heils and, and the Lii drivers, and the Crown XLS has a programmable -24dB filter I set to 125hz.
 
zackthedog said:
I was going to say that the output transformers in particular look awfully small for that output tube and power rating.
Click to expand...

Yep. Look here, for an idea of how big of an output transformer it takes to REALLY get 16 watts before clipping, single-ended, with decent bass power output:

https://www.audiokarma.org/forums/i...nture-into-the-world-of-se-amp-design.923539/

index.php


And, even that was only capable of 10 watts at 20Hz...

I don't see any possible way those 805 amps can make any appreciable power below 100Hz, with transformers that small. Mind you, they may be great for the high-end of a bi-amped system- but asking them to make bass? I don't see how it can happen, unless there's some really exotic core materials in those output transformers. And there's a limit even to what the most exotic materials could do, given that small size.

Regards,
Gordon.
 
Well, it finally showed up. Kicker though; They forgot to send the 2nd shipment with the 805A tubes! Situation was clarified and the tubes are on their way, but, in the meantime, I found an NA based seller that has Shuguang 805A tubes in stock, with fairly cheap overnight delivery. So they should be here tomorrow. Since I have time, I figured it wouldn't be a bad idea to open her up and get a good look, and some pics, of her guts. Plus an exterior shot.
IMG_0705.JPG
IMG_0704.JPG
I'll update as soon as I can get it up and running with stock impressions.
 
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