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

FlaCharlie said:
While changing tubes will affect the sound to some degree, the best way to get more bass is with some type of tone controls. Yes, it's gotten to be out of fashion but it will make a much bigger difference than rolling tubes willy nilly, which gets really expensive. Different tubes won't change the amp from "bass doesn't seem to be there at all" to good solid bass.

I'd either look for a graphic EQ at your local thrift store or you might want to check out the Schiit Loki if you want something new and stylish.


Out of curiosity, I looked at some reviews of the various EL34s they sell. Almost all of the reviews were written by people who use them in guitar amps, which is pretty much useless for those of us who use them in stereo amps.

Another important thing to remember is that a particular brand of tube will sound very different when used in different amps, with different speakers, as well as all the other variables such as sources used, room acoustics, listening habits and, of course, differences in hearing. So it's best not to put too much faith in tube reviews.
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https://audiokarma.org/forums/index.php?threads/fx-audio-6j1-tube-preamp-a-31-wonder.848535/
 
Valko67 said:
i like very much those Tung Sol's ,i have a preamp tube-03 from Fx audio and changed the stock tubes for the usa electon tubes PN- JAN 5654 W ,i recomand this Pre Amp highly in combination with the A10 , it pump up more Gain to the A10 output and gives the possibility to adjust the treble and Bass and plays with input volume to, i couldn't see my A10 without it, i have disconnected to see differences, and makes a lot to the A10 higher Gain , together with the 12AX7 from the A10 ,they doing very good job,and this FX Tube-03 only costed me only 40euro ,and folowed recommandations ,i have bought also the FX 502S Pro 2.0 End Amp for same money value as tge tube-03 and changed the two stock chips inside for the Audiophile Opamp Authentic Texas Instruments LME 49720 recomended by forum of FX product, and whooow this it also great improvement , it whas already amazing but now its really Top , and no need to soldering , you only have to pull out the stock one and replaced them by thoses , i like it very much to , but can't be compated to the A10 listening experience in accoustic soundings or analogue sounds, ..yes for Shure its very clear sound, yes its very, ehh no , very very powerfull for such small Amplifier, ridiculous small, ridiculously cheap , and ridiculously good, FX have great products ,but you have to folow recommandations of who knows what good is and cheap at same time , companies to tge higher serie like the 802 pro it have nothing to be salivate to the 502 , cotations between the two are flagrantly unexpected in price and in power and the possibilities to change for this great Texas Instruments Audiophile chips that are used in high end and costly Amplifiers , so, i can only recomand this one to, if you need more gain then the A10 for party or such ,i only unplug the input a d the speaker plug output and put them in the Fx , and lets pump up the Jams hahaha , have sweet night Audiophilacs Bro'sss and keep up enjoying and improve it and makes good sounding Music affordable to every wallet
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Where to buy the genuine TI Op Amp chips?
 
BMC said:
View attachment 2129441 View attachment 2129442So it’s been one week since replacing the stock coupling caps with Russian PIO K40y-9 .22uf 400v caps.

The original coupling caps are the orange ones in the pic attached. Soldering was a breeze - even easier than doing speaker crossovers. Took me less than 30 mins total.

The upgrade is quite substantial after the 1 week burn in. Gone is the overly bright tone of the stock caps. Now there is a neutral tone that has a touch of warmth. The plastic sound is gone, and there is now a pure natural sound with more weight on the notes - especially midbass. The dynamics and transients are very much improved. This is very noticeable on complex passages. The soundstage is also deeper and wider.

i got these from Jim McShane, who added the silicon dampers to prevent the metal case from contacting the chassis. Paid 12$ for the pair. This is a very cost effective way to significantly improve this amp.
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Link, please?

thx
 
FlaCharlie said:
I'm actually quite familiar with the mega-thread on the FX and if you read through it you'll find that I've posted to it on numerous occasions.

Though I'm not sure why you're posting a link to it as a response to my earlier post. Perhaps you have the version with tone controls and you're finding them useful?
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I do like to boost the bass occasionally but even flat it adds extra dynamics to me. I have the JAN GE tube version.

bob
 
Waiting for delivery of my Reisong A10 from ebay UK, not called that but the picture matches so think its the same, only difference seems to be its quoted output of 12 watts x 2, tubes etc the same. This is my first tube amp and looking forward to trying it out with my Wharfedale Lintons which have a sensitivity of 90db, hope that will be OK to drive them (holds breath). The Linton's impedance is quoted at 6 ohms nominal and 3.5 ohms minimum. Do you think I should be wiring up to the 4 ohm posts or to the 8 ohm posts? Any advantages disadvantages? And what are the "0" speaker posts for??
 
Easy Action said:
The Linton's impedance is quoted at 6 ohms nominal and 3.5 ohms minimum. Do you think I should be wiring up to the 4 ohm posts or to the 8 ohm posts? Any advantages disadvantages? And what are the "0" speaker posts for??
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You can try both, but I would guess 4 will work better.
0 = negative
 
opnly bafld said:
ou can try both, but I would guess 4 will work better.
0 = negative
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Yes just looked at a review for the Lintons on Stereophile, and they tested them with a tube amp on both 4 and 8 ohm taps, seems both worked but the reviewer preferred the 8 ohm. I can play around as long as I don't do any damage. Might be more volume with 8 ohms? When does 0/negative ever get used?
 
Easy Action said:
Yes just looked at a review for the Lintons on Stereophile, and they tested them with a tube amp on both 4 and 8 ohm taps, seems both worked but the reviewer preferred the 8 ohm. I can play around as long as I don't do any damage. Might be more volume with 8 ohms? When does 0/negative ever get used?
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Amp will have same or less power.
0 = negative, 4 and 8 = positive; 0 is always used along with either 8 or 4.
 
steelgtr said:
Thanks, Charlie

This version?:

https://www.digikey.com/en/products/detail/texas-instruments/LME49720NA-NOPB/1647708
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Since I don't own an FX I can't tell you the exact version. It's always best to buy parts like this from a major supplier like Digi-Key because counterfeits are common. Ask about the specific parts in the FX thread, some of them would know.

As I recall, some of the opamps they've been swapping can just be plugged in and others need to be soldered to an adaptor of some kind first. Doing so probably requires a microscope.

The first version of the FX had no opamps. I believe they may be part of the tone control circuit yet, apparently, they aren't actually needed since I've seen posts by people who say they simply removed them and they prefer the sound without them.

I know the FX is quite popular - especially with people who are new to tubes. But, IMO it seems a bit crazy how far people go, and how much people spend, on tube rolling, cap replacement, op-amp rolling, etc. when the biggest problem with the implementation of the FX is that it operates the tubes at very low voltages. And none of the mods have any effect on that.

My interest in the FX was piqued a while back, when I was breadboarding a preamp using a variety of tubes and the same simple (anode follower) circuit. I got curious and one FX owner was kind enough to measure the voltages so I could duplicate it on my breadboard. I tried the FX tube at stock voltages and then at more "normal" voltages suggested by the tube data sheet.

If you take the tube's triode plate curves (the FX uses a pentode wired as a triode) and draw a load line based on the stock operating point it's truly horrible. Yet, it sounds better than the curves would lead you to believe.

Not surprisingly though, it sounded significantly better at normal voltages. I posted a couple of schematics of my "normal operating point" versions in the FX thread.

I never seriously considered using the FX tube because I knew it had much more gain than I needed. Most modern systems don't really need any gain at all, since power amps can normally be driven to full power by the output of a CD player or DAC alone. Some "tube flavor" is nice, though, and an active stage can often improve dynamics compared to a "passive preamp", aka a volume control.

The Reisong A10 is an integrated amp with its own preamp section already built in. But it's possible that its input section may have some issues. Inexpensive Chinese tube amps often seem to employ questionable design choices - see the recent thread and videos about modding a Nobsound 6P1 amp.

https://www.audiokarma.org/forums/index.php?threads/nobsound-6p1-amp-flaws-mods.939092/

So it's not too surprising that you prefer the sound of the A10 with the FX and since you have the version that has tone controls that should make it even more useful.

While many owners like the sound of the FX, the gain is probably the biggest problem. There are a lot of comments about how touchy the volume control is - the useful range is quite limited. So it's difficult to make minor level adjustments, it's often either too quiet or too loud. But, since the Reisong has its own volume control, you can just turn it down to the point where the control on the FX has more useful range.

I breadboarded several different tube types using the same circuit. The emphasis was more on the "tube flavor" aspect but I still wanted to have a bit of gain available if necessary.

Here's a link to what I built: https://www.audiokarma.org/forums/index.php?threads/1626-preamp-build.931276/
 
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My A10 arrived, from UK warehouse but in original Chinese box, well packaged, double boxed. Build quality surprisingly good. It's a little heavyweight!. Small manual included all in Chinese! Moment of truth, would it be powerful enough to drive my Wharfedale Lintons rated at 90db (6 ohms). Yes it does! Turned up to around 12.00 (half way) its plenty loud enough (this with 8ohm taps). Jury still out on the all important sound quality, at the moment it sounds good but very tubey and thin, hopefully as others have mentioned it will fill out and improve with burn in time and possibly tube upgrades. If so there may be no going back to solid state.
 
Easy Action said:
My A10 arrived, from UK warehouse but in original Chinese box, well packaged, double boxed. Build quality surprisingly good. It's a little heavyweight!. Small manual included all in Chinese! Moment of truth, would it be powerful enough to drive my Wharfedale Lintons rated at 90db (6 ohms). Yes it does!
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The only real issue most of these made in China amps have is their power transformers have the primary wound for 110V. Running them in the US skews all the voltages inside, especially the heaters, 10% up, which can make them eat tubes. There are solutions, but if this is ignored, it likely will cause problems in the future.

 
StepheK said:
The only real issue most of these made in China amps have is their power transformers have the primary wound for 110V. Running them in the US skews all the voltages inside, especially the heaters, 10% up, which can make them eat tubes. There are solutions, but if this is ignored, it likely will cause problems in the future.
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Yes I've read that, I'm in the UK which has 230 volts mains and the box it came in was marked 230 volts so I hope it will match up, but I don't know?
 
Easy Action said:
Yes I've read that, I'm in the UK which has 230 volts mains and the box it came in was marked 230 volts so I hope it will match up, but I don't know?
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I think they "Mark the box" and put in ads that it works on whatever voltage is in the country they sell it in. My guess is it has a 110/220V transformer (My Nobsound 6P1 does) so at 230V it's ~4-5% over. Ideally you would check the heater voltage and make sure it's not wildly out of spec. You could remove one of the driver tubes and check the heater voltage there.

Here is a datasheet showing the max range is 5.7V to 6.9V. I get concerned if I see over 6.7V.

el34 sheet.png
 
StepheK said:
I think they "Mark the box" and put in ads that it works on whatever voltage is in the country they sell it in. My guess is it has a 110/220V transformer (My Nobsound 6P1 does) so at 230V it's ~4-5% over. Ideally you would check the heater voltage and make sure it's not wildly out of spec. You could remove one of the driver tubes and check the heater voltage there.
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Thanks for the info and data sheet which I've saved. I'm not technically competent to be checking it but fortunately there's a local engineer that is very good, so I'll just have to see how it goes and if I have problems I'll pass it on to him.
 
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