On Impulse I ordered a Boyuu Reisong A10 EL34, class A. Any experience? Add your opinion on it.

[BMC]

Verified--it's a weiner winner! The 5AR4 came a day early, and the amp fired up with no problems.

I bought this amp with no tubes, which was an option from the seller I used. I have to say the amp was packed like a fortress, arrived in flawless condition, and it worked on the first try.

For tubes, I decided on the ElectroHarmonix 6CA7, Voshkod Rocket 6N2P, and the Tung-Sol 5AR4. It is sounding fairly good right now, even though the amp and tubes haven't broken in yet. Dead quiet too! Its main use will be on my desktop feeding a pair of KEF LS50s and a small powered sub beneath the desk. Once it breaks in, I may give it a try in my big system.

The KEF LS50 shows a nominal impedance of 8Ω with a minimum of 3.2Ω. I'm guessing I should keep these on the 8Ω taps.

Nice - Glad you got it going! The 4 ohm taps seem cleaner with more weight to the mirdrange and better woofer control. 8 ohm gets louder, but thinner sounding in the mids, mid bass a little thinner too. Bigger soundstage on the 8 ohm. This is on the Klipsch bookshelves, which dip below 8 in the lower frequencies.

How are the KEF’s mating with it?

 

[Old Guy8]

Verified--it's a weiner winner! The 5AR4 came a day early, and the amp fired up with no problems.

I bought this amp with no tubes, which was an option from the seller I used. I have to say the amp was packed like a fortress, arrived in flawless condition, and it worked on the first try.

For tubes, I decided on the ElectroHarmonix 6CA7, Voshkod Rocket 6N2P, and the Tung-Sol 5AR4. It is sounding fairly good right now, even though the amp and tubes haven't broken in yet. Dead quiet too! Its main use will be on my desktop feeding a pair of KEF LS50s and a small powered sub beneath the desk. Once it breaks in, I may give it a try in my big system.

The KEF LS50 shows a nominal impedance of 8Ω with a minimum of 3.2Ω. I'm guessing I should keep these on the 8Ω taps.

Great you got it going, no issues.
Do you think there's enough umph for you ls50s?

 

[Tubeglowpio]

Are you commenting on my posting the schematic and saying that I should have just kept it to myself?

If so, the whole point of forums like this is to share helpful information. For instance . . .

The schematic shows that it does operate in UL mode as you can see that the screen of the output tube (Pin 4) is tied to an ultralinear tap on the output transformer through a 100 ohm resistor. You can also see that, in stock form, there is no switch that allows you to run it in either triode mode or pentode mode. So if you wanted triode or pentode you would need to modify the amp.

While I don't own one of these amps I am curious about different designs. If you own one it's always a good idea to have a schematic.

As one would expect, there is nothing really innovative about the circuit. It's pretty much the same as the other Chinese SE EL34 amps out there. The main differences I noticed are the use of a different input tube and the fact that they are using a hybrid PS.

Apparently they got a good deal on PTs that don't have a center tap so they created an artificial center tap using diodes in order to use a tube rectifier. I've done this myself with a couple of amps I built from scratch. It works just fine, although I'd use quieter diodes than the 1N4007s.

That schematic is an easy find so no one should get upset anyways, I wonder a good match for the output transformer or an upgrade even.

 

[Wildcat]

How are the KEF’s mating with it?

Do you think there's enough umph for you ls50s?

Plenty for the LS50s, since they are only a few feet from me and I don't listen loud at the desk. If these were filling the entire room, though, the power would be lacking. So far I get the impression this is a very clean sounding amp, and I have to say that even at close range the soundstage is really nice.

 

[BMC]

So I was able to find a pair of some big Klipschs - the RF-35. They are 98db efficiency with 2 8” woofers each in 40” high cabinets.

Unbelievable how well these work with the A10! As loud as I could ever want in my medium to large room. The dynamics are there big time. The soundstage is wide and deep. Imaging is huge. The warmth of the amp gets the perfect tone with the RF-35’s. With my sub, I can live with this setup for a while (the bass is pretty nice even without)

Needless to say, the R-51m bookshelves are being returned. I hate to see them go, but they were really a gateway drug. The RF-35’s cost me a mere $50 more than the bookshelves cost.

 

[rudolfo]

Are you commenting on my posting the schematic and saying that I should have just kept it to myself?

If so, the whole point of forums like this is to share helpful information. For instance . . .

The schematic shows that it does operate in UL mode as you can see that the screen of the output tube (Pin 4) is tied to an ultralinear tap on the output transformer through a 100 ohm resistor. You can also see that, in stock form, there is no switch that allows you to run it in either triode mode or pentode mode. So if you wanted triode or pentode you would need to modify the amp.

While I don't own one of these amps I am curious about different designs. If you own one it's always a good idea to have a schematic.

As one would expect, there is nothing really innovative about the circuit. It's pretty much the same as the other Chinese SE EL34 amps out there. The main differences I noticed are the use of a different input tube and the fact that they are using a hybrid PS.

Apparently they got a good deal on PTs that don't have a center tap so they created an artificial center tap using diodes in order to use a tube rectifier. I've done this myself with a couple of amps I built from scratch. It works just fine, although I'd use quieter diodes than the 1N4007s.

I don't own one of these amps but I was a bit curious when I saw the configuration. 1 EL34 per channel. I'm able to mod a lot of "guitar amps" and in that world the 2-EL84 has a bit more leverage when it comes to tonality and depth. However on a hifi, this would be an interesting amp to work on. Just curious how much this can drive a 98db 10 inch 75-80 watts speaker.... Very nice looking little amp.

 

[Wildcat]

Just curious how much this can drive a 98db 10 inch 75-80 watts speaker.... Very nice looking little amp.

98dB/watt sensitivity? You could drive one watt into the speaker and get 98dB of output. That's way louder than I would listen, and low-powered tube amps are known to work well with high-efficiency speakers (especially horns). Typically your average (RMS) power is a lot lower when listening, and you'd exceed one watt during peaks. It's no powerhouse but for me it works well in a smaller system where I usually have it at moderate levels, probably nowhere near one watt. And my LS50s are about average efficiency.

 

[rudolfo]

sounds good. I was gonna ask anyone that owned this and perfectly match to your speaker if you eve dialed your amp above halfway and what is your opinion or results.
Thanks,

 

[BMC]

rudolfo,

I have 98db Klipsch with 2 8” woofers. I can go past halfway and then some. I sit about 8’ back, and it does not compress the image on most tracks.

On the more complex, dynamic tracks, it will compress a bit. These are with the stock power tubes. I’ll see how it does when my XF2 pair shows up.

 

[rudolfo]

rudolfo,

I have 98db Klipsch with 2 8” woofers. I can go past halfway and then some. I sit about 8’ back, and it does not compress the image on most tracks.

On the more complex, dynamic tracks, it will compress a bit. These are with the stock power tubes. I’ll see how it does when my XF2 pair shows up.

Sounds good and I get the picture. Very informative and thank you for sharing. That's actually the way how I listen too. But yes I do understand that this is not really a big amp. I'm just trying to see what kind of upgrade I need to add on the amp "in the future" if I decide to go that route. But more likely I'm going to stay with EL34 amp. I have auditioned a 2A3 and 300B amp not too long ago. Real great amps but, but its not for me.
I have to be honest to my choice of equipment and sound and I'm afraid I will have to stick with EL34 or KT88 depending on how the circuit is built. This setup is actually going into my living room. We hardly even use that area for I spend most of my time in my music/work room.
Congratulations on you XF2. Those are real nice sounding tubes. I was actually talking to someone in another site about getting some backup output tubes for I'm only using the stock ones. Its still sound good for I haven't really put much hours in it. going back I was looking at the gold lion kt77 reissue on how it sound to the PL amps.
I began looking at my stock tubes and I found a quad of XF2 but these are my backup tubes for the marshall amp and I don't wanna use it on hifi. Just for kicks and giggles I installed it that morning. I cant really describe it in words beside that was the optimum sound that I got from my amp. in the beginning the highs and the mids are already present but I notice the bass was a bit tamer than the stock tubes. After a few hours of running it, the bass just went to life and a lot more than what I had before in all 3 frequencies..
Its just amazing. But Ill be honest with you, the next day, I took it off and put back my stockies. Because I know that Ill be looking for that sound from now on and I don't think I can afford price tag.
Enjoy your new amp and your upcoming tubes...

 

[FlaCharlie]

I don't own one of these amps but I was a bit curious when I saw the configuration. 1 EL34 per channel. I'm able to mod a lot of "guitar amps" and in that world the 2-EL84 has a bit more leverage when it comes to tonality and depth. However on a hifi, this would be an interesting amp to work on. Just curious how much this can drive a 98db 10 inch 75-80 watts speaker.... Very nice looking little amp.

Looks like Wildcat answered your question. Yes, with one watt in you'll get 98db and you get an additional 3db each time you double the wattage. So 2 watts would be 101db, 4 watts 104db, etc. Same as with any amp.

There are several variations of these low cost Chinese SE EL34 amps. Sometimes the same amp is sold under different brand names. From what I've read, you should take their power claims with a grain of salt but since you have efficient speakers you'll probably be OK.

In the guitar world there are numerous SE (single-ended) amps. The most well known would be a Fender Champ which uses a single 6V6. Some of the Princetons used a single 6L6 and there are numerous others that use essentially the same circuits with minor parts variations. I'm not aware of any SE guitar amps that use an EL34 but I'm sure there must be some.

If you have experience modding / working on guitar amps you should also consider an amp pulled from vintage console stereo. Lots of threads on here about them, especially Magnavox. You can often find old consoles locally for under $50.

 

[Old Guy8]

sounds good. I was gonna ask anyone that owned this and perfectly match to your speaker if you eve dialed your amp above halfway and what is your opinion or results.
Thanks,

With ADS L470, 92db spl speakers, at 5 ft. in 11 x 13 room. 12 oclock volume gives 70 dbs. Sounds fine to me. Yes with these efficiency speakers, a limit what 6 wpc can do.

 

[BMC]

Sounds good and I get the picture. Very informative and thank you for sharing. That's actually the way how I listen too. But yes I do understand that this is not really a big amp. I'm just trying to see what kind of upgrade I need to add on the amp "in the future" if I decide to go that route. But more likely I'm going to stay with EL34 amp. I have auditioned a 2A3 and 300B amp not too long ago. Real great amps but, but its not for me.
I have to be honest to my choice of equipment and sound and I'm afraid I will have to stick with EL34 or KT88 depending on how the circuit is built. This setup is actually going into my living room. We hardly even use that area for I spend most of my time in my music/work room.
Congratulations on you XF2. Those are real nice sounding tubes. I was actually talking to someone in another site about getting some backup output tubes for I'm only using the stock ones. Its still sound good for I haven't really put much hours in it. going back I was looking at the gold lion kt77 reissue on how it sound to the PL amps.
I began looking at my stock tubes and I found a quad of XF2 but these are my backup tubes for the marshall amp and I don't wanna use it on hifi. Just for kicks and giggles I installed it that morning. I cant really describe it in words beside that was the optimum sound that I got from my amp. in the beginning the highs and the mids are already present but I notice the bass was a bit tamer than the stock tubes. After a few hours of running it, the bass just went to life and a lot more than what I had before in all 3 frequencies..
Its just amazing. But Ill be honest with you, the next day, I took it off and put back my stockies. Because I know that Ill be looking for that sound from now on and I don't think I can afford price tag.
Enjoy your new amp and your upcoming tubes...

Thanks for the comments on the XF2’s. I can’t wait to compare with the stocks. This amp makes it a lot easier and cheaper to upgrade when you only need a pair.

i have just rolled in a pair of mullard cv4024 12AT7 (with tube socket adapters). Sounds warmer, more detailed and deeper bass. Also more sparkle to the highs. Prior tubes were Voshkod Rockets, which are nice and neutral.

 

[rudolfo]

Thanks for the comments on the XF2’s. I can’t wait to compare with the stocks. This amp makes it a lot easier and cheaper to upgrade when you only need a pair.

i have just rolled in a pair of mullard cv4024 12AT7 (with tube socket adapters). Sounds warmer, more detailed and deeper bass. Also more sparkle to the highs. Prior tubes were Voshkod Rockets, which are nice and neutral.

Yes that makes practical sense. its only has 2 output tubes so with a 12ax7 family. That's actually a good thing you're able to observe the difference on the sound of the 12at7.
On my amp roll the main drivers too. I notice that some of the12ax7 especially if the plates are small than the usual, they gain to distort more faster than a wide or longer plate. They do on some of the 5751. One of my favorite tubes are the Raytheon black plates. whenever I install 2 of those on my amp it sounds like I just put a super tweeter on top my tower speakers. crystal clear with a lot of tonal dimensions. the old rca grey plates are warm and has a lot of syrupy mids. very nice too. I'm pretty sure theres a lot more americans, british and germans.
These radios are very good investments and you can actually do your personal things while listening to the stereo. Makes you so much in a better place than being out especially at these times...

 

[rudolfo]

Looks like Wildcat answered your question. Yes, with one watt in you'll get 98db and you get an additional 3db each time you double the wattage. So 2 watts would be 101db, 4 watts 104db, etc. Same as with any amp.

There are several variations of these low cost Chinese SE EL34 amps. Sometimes the same amp is sold under different brand names. From what I've read, you should take their power claims with a grain of salt but since you have efficient speakers you'll probably be OK.

In the guitar world there are numerous SE (single-ended) amps. The most well known would be a Fender Champ which uses a single 6V6. Some of the Princetons used a single 6L6 and there are numerous others that use essentially the same circuits with minor parts variations. I'm not aware of any SE guitar amps that use an EL34 but I'm sure there must be some.

If you have experience modding / working on guitar amps you should also consider an amp pulled from vintage console stereo. Lots of threads on here about them, especially Magnavox. You can often find old consoles locally for under $50.

Yes I think this speaker should be a good start. I was initially going looking at a 300b for a 2nd amp and that's how I met Mr. Casey from Zu audio. So I ordered these speakers while in the making I was able to audition several 300B and 2A3 amp. They are very nice amp thou I can in a conclusion that I will just stay with the non exotic tubes like EL34 based on preference and long term enjoyment.
Going to the guitar, majority of the single-ended are the old tweed/champ models Princeton basically brown and silver faces..
I worked a lot of the old marshall amps which is basically a blatant copy of the 59 bassman circuit with an added mid and slight modification of tone stack and rectifier....
About 7 years ago, I bought a Chinese amp yaqin mc-100b. Its a good sounding amp and still do for I still have it now as only a backup. I use to run that amp like theres no tomorrow. I think I went to almost 19 power tubes rolling so that's about 32,000 hrs. of continuous pleasure of use. I like the sound of that amp and but I have to maintain it a lot and its not really as easy as other amps with its spaghetti wirings in the way and not too much space to put extras and serious modifications besides adding a large sets capacitors, heat sinked resistors. a cooling fan on top of the cage. motorized remote volume control. startup timer.......
With the job and the house, I told myself, I'm gonna get another amp. not just with a factory warranty, but an extended warrantee local to nationwide so if anything I can just send to them and I can just concentrate on my other stuffs. So I bought the primluna.
.... Now I am missing the headaches... I was looking at the reisong circuit. Very inciting. and its up and running,,,,,
I was also looking at a several chinese amps today including the Willsenton R8 KT88/EL34 . the inside of that amp is just breath taking. they even used the Japanese super quiet input relays and much better capacitors with above average wrings, remote and then some....
But who knows right, only time will tell. Atleast with the reisong its more simplified and easy to fix as like what @BMC said. I think Ill just go with it. Thanks,,,,,,
You probably bought one already...

 

[rudolfo]

.... I just saw the shipping guy last friday and seems like he didn't have good day. He threw a box in my garden. "There's your da,,,n reisong.. I just quit yesterday."

 

[Pseudoty]

New user 1st post noob so take it easy on me, oh and I read the entire thread. My A10 arrived yesterday and I was very impressed with the packaging. I got it all setup and working without issue. I am using this amp for two purposes both using my B&W CM9 S2s 89db sensitivity. I am playing Tidal MQA files from my MacBook to my Meridian Explorer “DAC” into the A10 with no issues. Sound is great with volume at 10 o’clock in my medium sized room sitting 12 feet away I am getting 75db. Bass is decent but not powerful and the lower frequencies are not felt. If there is anything I could do to enhance the bass that would be good.
The issue I am having is with the second purpose, my TT the Audio Technica LP60 which has a pre-amp is giving me almost no volume. I put on side 1 of “The Wall” and was waiting for the intro and nothing. I have the A10 turned up to 2 o’clock, didn’t want to push it any higher, and can barely hear it but there is sound so all of the connections are correct. I have tried swapping the inputs on the back of the A10 but no change, tried both settings on the TT (Line and Phono), tried Different speakers Martin Logan Motion 40 which are 4 ohms 92db sensitivity and had to put my ear to the speaker to hear anything.
So any tips on what I can do other than buying a new TT?
ETA: This setup TT and B&Ws sound fine playing through my Yamaha A860 photo input.

 

[BMC]

Glad you like the amp! Did you make sure the AT turntable has the switch on the “line” position?

 

[Katalyst]

.... I just saw the shipping guy last friday and seems like he didn't have good day. He threw a box in my garden. "There's your da,,,n reisong.. I just quit yesterday."

Did the amplifier survive the landing?

 

[Pseudoty]

Glad you like the amp! Did you make sure the AT turntable has the switch on the “line” position?

Thanks for the reply and yes I tried both settings on the back of the TT which did make a difference but nothing you could hear well enough to listen to. I tried the DAC hooked up to both inputs and no issues. I tired just playing the macbook audio to take the DAC out of the equations and no issues with volume only with the TT all other things being equal.