Inexpensive Tube Amps

Anyone have any experience with the following?  I want to try one just to see how the sound compares to my Yamaha and Denon solid states.  Since the Denon is living on borrowed time I will likely have to replace it this year anyway.  Looking at the Nubsound and noted a Germtune that is identical to the Nubsound but costs a bit more.  Reviews are largely good including those on other forums.
You provide very little information on your situation for one to provide reasonable advice. Regarding the amplifiers under consideration:

These are low watt amplifiers to be mated to speakers with high sensitivity and a benign impedance load. Also fits best in a system playing into a small to medium size room and not playing rock music at high volume. If this is your situation, then give one a try. Be careful with the amp and I assume it can be returned to Amazon after a trial period with little monetary loss.  
Yes,  I won't buy anything that does not come with a money back guarantee.

Based upon reviews I've read, people using amps with as little as 87 db sensitivity into 8 ohms are not having any trouble driving amps like these or the Musical Paradise model.  Trouble in Paradise though since that one is out of stock and may be for a while.  They move fast.

I have a pair of Mirage OM 10 Towers that are 6 ohm and 91 db sensitivity.  Should not pose a problem for any of these.  Also have a pair of Castle Conway 3 Towers that are 8 ohm and at least 88 db sensitivity.  

A guy using the Musical Paradise which puts out 6.5 watts per channel has a pair of Sonus Faber speakers that are a mere 87 db sensitivity and he said they are easily driven beyond a reasonable comfort level for audio with that amp.

Medium size room at the moment 15 by 14.  Will likely be in a smaller room in a couple of years since I doubt I will be staying in my present home.
You get what you pay for. Some Chinese gear can be good, but amps at this price range will be riding the very bottom of the barrel. They will have been cranked out of a factory with very little concern for quality or perhaps even safety.
Save your money and buy a REAL tube amp from Will Vincent (autospec). I have his SE45 amp and it is superb! Need more power? Will can build you a 2A3 or a 6L6/EL34/6550 single-end amp! Beyond these PP is needed for more power: his Dynaco ST70 clones are excellent! 
Read the current thread, First Tube Amp. The OP is auditioning a Yaquin, a highly regarded Chinese built tube amp found on Amazon.
  These seem to be a cut above the mass produced Chinese amps and may be a keeper.

Also, sensitivity of the speaker is not an indication of how well a low power amp will perform. You need to look at the impedance at any given frequency.
YOU need to read the current thread. You are confusing this OP with another. This OP has not purchased any tube amp as of yet, ( including a Yaquin ), just sayin. Best.....
@roberjerman, "Save your money and buy a REAL tube amp from Will Vincent (autospec)"

I think that's a more than excellent way to go.  Will's standard rebuilds are Dynaco ST70 restorations with upgraded parts and aesthetics.  Considering how many of these amps made 40 - 60+ years ago still work well, you can't go wrong.  With modern resistors and capacitors, what too many consider as the lowly ST70 can hang with almost any modern amp, and beat a lot of them.  And as also mentioned, if you want a different flavor or spin on thing, Will does a lot of custom work
I have a pair of Mirage OM 10 Towers that are 6 ohm and 91 db sensitivity.  Should not pose a problem for any of these.  Also have a pair of Castle Conway 3 Towers that are 8 ohm and at least 88 db sensitivity.  
@will62 None of these amps make enough power to drive speakers with efficiency as low as those in the quote. You would want 10X the power at a minimum.  A Dynaco ST-70 is a good suggestion and there are many versions of that amp available.
If YOU are referring to me, I know this is a different OP. Just informing him that I would not trust a cheap Chinese amp in the long run.
You get what you pay for.
I agree with @atmasphere , although I bow to his expertise.
As noted, many of those economical tube amps from Amazon are made in China. Not a bad thing, but I agree with @lowrider57 : 
the Yaquin is a cut above, also the Cayin's are very good. word has it their integrateds are based on the classic McIntosh designs.

You also have the option of a "DIY" tube kit. but Again, I would not buy indiscriminately on Amazon, but go to an audiophile site that sells them, like Bottlerocket or others out there now that are on their 3rd, 4rth, 5th, design iteration and getting better all the time. 

But as will all things audio: depends on your budget.
But if I were you, I would look for a used Cayin or Yaquin. You pay less, and if it doesn't work out, you can sell it on the used market for the same price you paid and you dont lose money.
I had a Bada for a while, a Chinese hybrid tube headphone amp, drive the bejesus out of my Sennheiser 600s, hence the hybrid. Dunno if they are still around, maybe.
The lowest I would ever recommend for a tube amplifier would be Yaqin as mentioned above.  Any less and you are seriously gambling your money.  I'd also stay away from older Jolida units as they have issues with the PCB boards - I've been down that road with a SJ302a and it wasn't fun or cheap.  Shuguang also had some decent amps but I'm not sure you'd find any at a 'budget' price.

If you wanted to get a feel for what tubes were and not worry about the hassle, I'd recommend checking out the Dayens Ampino solid state integrated.  Its got that tube sound to it and would be a safe bet to see if you want to jump down that rabbit hole.  When I got this in, my Shuguang 845 monoblocks set to the side for several months while I enjoyed the Ampino.
@lowrider57 , yes I was referring to you. Your statement, then, does not make sense. Sorry, no offense. 
I had a yaqin back in 2005. It caught fire and I came close to losing everything. It was a cheap piece of junk and the amp had sharp edges all over it. Cut my hands on it as well. Bought it brand new off the ebay seller in Hong Kong or perhaps China, its too long ago to remember correctly. That was the last Chinese amp I ever owned. It was a hybrid, solid state outputs and tube input. Power transformer and the entire circuit board was burnt to a crisp and that smell lingered in my house for a long time.  It also took out the crossovers in my Vandersteen 2ce speakers.  Richard Vandersteen insisted I played the speakers too loud, until I told him about the amp catching fire.
I was just about to post my concern about safety....   thanks for sharing that Stereo5
@stereo5 , I'm sorry to hear about the terrible experience you had. Not to undermine your story, but on this forum I've read about a PrimaLuna and at least two Jolida amps catching fire.
  So what's a buyer to do regarding Chinese-built amps? Do we consider these occurrences a low percentage of failure and continue to buy Chinese, or do we stop buying these components completely? I don't have the answer, maybe it's buyer beware.
For what its worth, I haven't had any experience with the hybrid designs but the Yaqin amps I've experienced (probably close to a dozen now) have all been solid for the money.  I'd still have no issue buying an all-tube Yaqin if I had a small budget.  Each piece I've experienced was also manufactured after 2005 so perhaps QC has gone up since then.
I own  a Dared I30 tube intergrated amp 35wpc. I bough it 3 years ago from 
 China. I paid $850 shipping inclued .I love it have used it on a number of different speaker set ups.Dyanco A25s ,JBL 230s,JBL H810s,Sono Fabia Lutos .No problems what so ever .Plenty of power ,beauty piece of equipment .I alsio bought a Yashin tube Pre Amp paided about $250 shipping inclued used it with Carver power amps,Sherwood amp,and Marantz  Amps .Never a problem they are all SS amps.Sounds great.
have you considered Quicksilver? MiniMites or MidMonos used would be in that price range. Ive used quicksilver for years and they are incredibly awesome.
Be careful if considering PrimaLuna. Mine broke down three times in the first 10 months I had it. Never owned such an unreliable piece of hifi gear.
I have 2 friends that own Prima Luna. One has the high powered integrated and the other has 2 dialog mono blocks and a Dialog preamp and BOTH systems have been 100% reliable and they sound incredible. The friend with the mono blocks is using Vienna Acoustics speakers, some big floor standing speakers. The other person is running a pair of Vandersteen 3A signatures. I have listened to these systems with my friends, hours on end and musical, musical, musical they certainly are.

One more thing, if you are planning on getting an amp that is Made In China, you better do it now because there is a Trade War coming.  There are BIG tariffs going into effect for Chinese Made products so the prices are going to go up once the current inventory gets sold.  I am sure some unscruptilous dealers will jack the price up on their current inventory, just to get an extra buck or two so be casreful.
I personally would NEVER buy Chinese.....There are American options and reasonably priced. You buy Chinese and you always worry "will it stop working? will it burn the house down? Is it made out of lead?"
I own mostly McIntosh, made in Binghamton, NY for the last 70 years or so. I do own GE Triton References and Triton 1 speakers, both Made In China, but the company is American owned and I never heard of any of their stuff catching fire. With the Trade War, we will probably be paying more than $100.00+ more for cell phones when the new models come out.
I have a pair of Mid Monos.... they are great amps.   I love them.  I bought a mint pair that was about a year and a half old for $1050, but honestly they are worth their asking price.    Mike Sanders support is top notch, one of the bsst in the biz.
The Quicksilver amps that I have owned have never let me down and sound great. Very affordable as well as made in North America. They have just released an integrated. 
PrimaLuna, their Dialogue Premium HP amplifier is to die for. Absolutely stunning sound and dynamic and built better than amps costing 3 times as much. Truly the best amp my Magnepans have ever played with. Glorious sound.

In the process of downsizing, I just sold my pair of Quicksilvers.  Lovely sound, the kind which all but a handful of Chinese product cannot approach.  Apart from the need for avoiding brittle (JJ) 5AR4 rectifiers, never a hiccup.  The dead simple (Dynaco) circuit, and the use of readily available parts provide both sonic and long term ownership benefits.  Apart from a transformer failure, an owner who understands tube amps (or any technician) will be able to keep it on the road indefinitely.

DEFINITELY recommended
The OP's listed options implies a budget of <$300 but those particular models are not suitable for the target speakers. If you insist on that budget, you're better off looking for a hybrid model with 25-35wpc power and return it if you don't like it. The main problem with those moderately cheap priced amplifiers is their quality is hit or miss, crackling tubes, scratchy volume control, etc. They may actually sound decent if you happen to get a "good" one...
had a primaluna for 7 years. great sound, have a Vista Audio I84. great amp 10 watts.  700.00 used
I guess I didn’t make myself very clear in my initial post. No point in responding to most individual posts since they have gone off in a completely different direction than my desire to obtain information on the amps mentioned.

Some of these posts I find rather condescending. I have heard tube amps and that is the reason I am interested in buying one. I did own a Qinpu A3 hybrid which I liked very much despite its mere 8.5 wpc. Sadly it broke when I relocated a year ago and they are no longer made. BTW. That little amp easily drove both pairs of speaker I mentioned in the OP. Volume knob at 9 AM was more than loud enough for me. Thus, I am confident that one of the tube amps mentioned in that post should be able to handle either pair of tower speakers.

I liken the advice I am getting from most of you as somewhat insulting. If I HAD the money I WOULD look at more expensive gear. I have numerous projects that I have to address for the next year, and all require money. Some minor house repairs, buying a new audio processor, a new transmitter for my flea powered Part 15 AM radio station, a new computer, a new CD player, a new computer printer and more. I DO NOT have much money to spend on anything since I have so many things to replace at once. And the fact that the prices of some or most of these items could rise before the end of the year makes it imperative that I start buying now to save money. I have to take what I can get. I liken this advice to the following. I ask someone where to find a reasonably priced Chinese restaurant that has good food and instead I get steered towards a Seafood place that costs ten times as much money as I can afford for dinner. That doesn’t work. This also reminds me of a quick story from many years ago at my friend’s place. Someone that had trouble with his comprehension of a request. My friend and his wife had a friend over for wine and cheese. About 1 AM they were ready to hit the hay and when they ran out of wine and cheese they asked the friend to leave. At that point in time the friend’s only response was "do you have any more cheese?" He was totally oblivious to their wishes. And no, it was not me. But this is precisely how most of you are behaving on this subject.

Buying used, again is NOT an option. NOT an option. I have already purchased a Denon amp used that needed work a few months after I bought it. And it still apparently has some issues. Same for a Yamaha Receiver I bought last year. Still works but needs some work since a couple of inputs don’t work. Not worth it when you factor in the cost to repair such old units. I don’t want to spend hundreds on a tube amp of any type if it is used only to find it starts having problems which won’t be under warranty. I can’t afford that problem again.

From where I sit many of you don’t understand free market capitalism. There is a reason those amps from China are so cheap. Cheaper labor. Less government regulation for business. Those same amps if they were made in the USA would likely cost several times more money and many of you would then rave about how great it is that someone can build a tube amp of this nature for perhaps $600. But because it is a lot cheaper you dismiss them as crap.

I’ve read a fair amount of reviews on a variety of these Nobsound, Gemtune and Douk tube amps. Most people are not only happy with them but said they are the best amps they’ve owned or sound better than Solid State amps costing several times more. And a couple more people have said that they’ve had tube amps that cost thousands and these little Chinese made amps give you almost as good sound without the high price. That speaks volumes that they have good engineering and design and hopefully are well built. Yes, some have been defective but buying new allows me to return the unit if I don’t like it or it is defective. I don’t have that option with used gear unless I buy it on Ebay and get lucky and find someone that offers a Money Back Guarantee. But again the cost to do that is prohibitive at this time.

Apologies for the lengthy post but I really believe this is necessary to get through my message to a few people that don’t get it. think I will start a new thread on this with a different subject line. That may improve my chances of getting the information I desire.
I understand what you're saying, and I guess audiophiles should be forgiven if they try to up the budget; it's just our nature, and they're trying to steer you to something better. I agree with you that some of these inexpensive ones that you have found probably sound very good, but as one poster cautioned, be careful to read available reviews to see that there haven't been any safety concerns, like catching fire. I read one such review on stereomojo I think, about an inexpensive Chinese that caught fire early on.
Anyway, Best of Luck. 
Quicksilvers  never require work on them. They will work the same in 400 years. Worth saving up for.
Thanks.  I am fortunate that I can even consider buying a new amp this year what with all the other projects that I have to spend money on.  Yes, I can save for something and that may happen if I determine I would be better off spending more.  But I have more reading to do.  The vast majority of reviews of these affordable imported amps are positive and that says a lot.  I think I read the review about one catching fire.  That was years ago and I would think the manufacturer made some changes in the design to insure that does not happen again.  A few times would be enough to deter anyone from buying once the word got around.

Never heard of Quicksilver except for the courier company out of Minnesota.  LOL  Will at least research this amp and go from there.
see this many times in the forums  where the OP will ask for opinions on a certain piece of equipment that they are thinking of getting......and when members suggest that you the OP look at something better, the OP then bring up other issues that stop the OP from getting something better.      a lot of times , if you buy something "better" then you dont feel the need to upgrade a few months down the road and you get get off the audio merry go round for a bit.        

regarding buying used......the equipment that you bought used and had issues with, it wasnt bought you have no feedback.    if you were to buy a used piece of gear here and you had an issue with it, that seller would do everything they can to make things right with they dont want the negative feedback.

I get that not everybody has extra money to just buy what they want....and if you are interested in any of these amps , then why not just get one and try it out yourself vs starting a thread on it ?      if you get it and dont like it, then send it back ( if you can ).          
Quicksilver is a company out of California that's long been known for making Mono Power Amps, hence the poster referring to a pair of them.  They've also released their first integrated amp recently, which retails for around $2K.

Like you I have been researching integrated amps on a budget.   I decided this would be my time to try Tubes after having been Solid State my whole life going all the way back to when I built a Hafler DH200 from a kit, and progressing over the years through brands like Aragon, Krell, Arcam, and YBA.  I'd dispersed my system several years ago when the realities of work and family left little time for listening to music.   I'm now getting back into the hobby but doing so on a budget.

I've just ordered a Yaqin, which is on it's way now, from one of the sellers you linked to.  I considered waiting to save up for a Quicksilver, or a used Conrad Johnson, but you know what - I can listen now and save at the same time for a future upgrade.  I have many vinyl friends of old sitting in sleeves waiting to make my acquaintance again.   Like you, I've never heard what I ordered and spent some time considering the fact it's from China.   The many positive reviews of those who've tried them, some of whom clearly know of what they speak, convinced me.  Good luck!

addyson815.  I thought the point behind forums such as this was to exchange ideas and gain information?  Precisely why I posted.  Boards like this would not exist if everyone just went out and tried a component without asking other people for some information or advice.

sbuckley.  Thanks for the info.  Good points.
OP, the three components you had listed, it looks like the first and the third one are the same amplifier just rebranded. If it were me, I'd go with the one of those two since they seem to have less moving parts to go wrong. By the way, I also bought a Yaqin A3 on a whim a year or so ago and it lives in my office driving a pair of small bookshelf speakers. It sounds OK for the $130 that I paid for it but it is not a proper representative of what a tube amplifier can and should sound like. And yes its 8.5wpc can drive medium efficiency speakers - I tried it with my Vandersteen 2Ci for giggles and music came out but it is nowhere near the sound quality that comes out of those speakers when fed properly.    
Will i too sense your frustration as Roxy54 described. Things do have a tendency to go off the rails a bit when inquiring on a budget Chinese product at such a reasonable price. I would only add these points in assessing whether or not to consider these products. Do you know a technician that can go over the amp prior to firing it up? Can you afford to send it back, presumably on your dime if it doesn't work out? What is the absolute limit of your budget, can you afford the risk if something bad happens beyond the amp? 

The point is that there are going to be compromises beyond labor and lack of regulatory requirements in China. I would try one if i could afford it failing without too much expectation that it could be returned back to China. Sure they may replace broken parts but good luck returning and expecting a full refund. If it were me and i were in your situation i would seriously consider a used tube design from an established manufacturer at the limit of what you are willing to pay. At least you will be able to resell with little if any monetary loss. One can read the on line reviews and conclude all is wonderful in paradise but at THOSE prices paradise may be too much of a bargin or in your case risk. You have received several excellent recommendations on some mainstream  manufacturers and you seem very thoughtful in processing. Good luck! 
tubegroover.  Most likely I will buy from Amazon.  Or perhaps the Paradise model which is also a North American based company.

Again, those prices would be considerably higher if the products were manufactured here.  Since the companies in China are still around and selling these, knowing how the free market system works, they likely are making better products now than a decade ago.  If they sent out a lot of junk, they would go out of business.  
kalali. Thanks. Yeah, I am leaning towards what you suggested. The tubes are excellent from what I’ve read and they are easy to roll if necessary.

My A3 did drive my OM 10’s very well. They are 6 ohm and 91 db sensitivity. The Castle Conway 3’s were OK with that amp but I now have them paired with my old Yamaha A500 amp and there they shall stay. I bet the OM 10’s will be great with one of these little tube amps.

Wish I could biwire though.  The OM 10's really shine when bewired.  But will likely be more than happy with the sound of the tubes with them.

keep riding the merry go round........

Oh well, just trying to offer an experienced and hopefully helpful viewpoint but your cute response makes me second guess. I know very well how the free market works as well Will. Again, good luck, it seems your query was looking for affirmation of something that you already decided, not other alternative options that may be more viable to someone on a shoestring budget. 
What I think most of you fail to grasp is that I have a limited budget for this.  If I had wanted to hear about alternatives then I would have asked specifically for advice or information about other brands or models.  I already did preliminary research and determined that these inexpensive imports offer most of what I am looking for at a fraction of the price.

I don't need people telling me to spend either several hundred or perhaps thousands on something like audio gear.  I already have to spend THOUSANDS of dollars on other electronic gear, home repairs etc.  Audio while important, takes a back seat to the other things as this stage.  

From where I sit the reading comprehension of some of you is below average.  Steering me into a direction where I have to spend money I don't have budgeted, I would like to avoid is not helpful at all. 
Tubegroover. My initial query was straight and to the point. I wanted to know about the three amps that I linked to. I don’t see any other request for additional information about any other amps.

Over the years I've found this board to have some knowledgeable and helpful people.  But when it comes to these little tube amps it is obvious I am dealing with people that are fairly prejudiced and also have not had experience with this gear and to compensate for that lack of experience, steer you off in another direction.  

" From where I sit the reading comprehension of some of you is below average"

that will surely win you over some new friends with a comment like that.

"   I already did preliminary research and determined that these inexpensive imports offer most of what I am looking for at a fraction of the price. "

then if that is the case, buy one and stop arguing with everybody......

you started a thread, asked for opinions, members suggested to get something that would be a better value, and you get all pissy and start insulting people.            

buy something that you can build a system around and not have the urge to upgrade 2-3 months down the road....even if it takes you 6 months or longer to save up, it will be worth it in the long run.    then you can get off the merry go round for a bit.
addyson.  You are delusional.  I wanted feedback from people that had experience with the units mentioned.  Here is the OP:

Anyone have any experience with the following?  I want to try one just to see how the sound compares to my Yamaha and Denon solid states.  Since the Denon is living on borrowed time I will likely have to replace it this year anyway.  Looking at the Nubsound and noted a Germtune that is identical to the Nubsound but costs a bit more.  Reviews are largely good including those on other forums.

Nowhere do I mention that I need feedback on any other pieces of gear right now.  I am in fact finding mode and I have my own method of conducting research.  What you and some others have just achieved by your continued pressure to look at other gear that I don't have under consideration right now, is to steer me either towards one of the aforementioned amps in the links or in some other direction.  

Pissy?  Not really.  But I am ticked off at the responses I am getting since they are not what I asked.  I want to hear from people that have experience with the three amps mentioned right now.  That's all.
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Will62 I feel your frustration and see this happen all the time on threads. It might seem as if members on here simply cannot help themselves when commenting on your thread with no first hand experience of the amps you had asked about, and perhaps you wish they would keep their alternative recommendations to themselves. 

Having said all of that, I have seen many times when this happens where the op took a different direction based on what the members on here recommended and the outcome turned out to be very positive for the poster.

Im just saying, I don’t believe there is any malicious intent going on here and it could very well be that very few if any members on here will have any experience with your choices.

Best of luck on your search.