I have just bought this little amp, 2024. I had come across your channel a while ago, repairing a much more expensive amp. I was hoping you had looked at this amp and happy to find you have, and a bonus you have done mods on it, to improve on a good basic quote unit. I will be watching the mods in due course. Thank you from a UK person
Thanks for this and all your videos on this little amp. I have been following all your advice so thanks for that. Just wanted to say I have done and are continuing to do some sound test with this amp as is and after using your mods that I have posted on my channel if anyone is interested in the results.
I follow almost all of your videos and would like to thank you again for your great will to help people out with their tube amps. That is super genuine and makes you stand apart and above all the other people I see trying to do the same. I just ordered the parts for my little Reisong A10 and can't wait to start modifying it accordingly to your advice. My best wishes and keep up with this amazing job that you are doing!! Cheers!
Well now. I'm super glad that I watched. Thanks for the info. I've got a couple of Chinese tubes amps and I never even thought of voltage as an issue. I'm going to correct this now and preserve this little amp. (It's most pleasurable to listen to really). Your advice is most welcome. Much thanks for doing this. I look forward to more vids. :)
Hi and thank you for the exceedingly informative video. One quick question, I've literally just purchased a 6p1 in the UK where our standard socket voltage is 230v. The mains input on the 6p1 says 230v. The question being should i ignore this & still purchase a step down transformer ie 230v-110v ?
Hello from Meaford Ontario Canada, My name is Scott and I enjoy your videos so very much , my gosh so much information required hee hee in order to build a great amp like yours , I watched a repair person say that McGohan tube amp m102 is a sleeper gem from the past at ten watts per mono amp as used single in malls for p.a , built like Sherman tanks with top notch components oooooh I want a pr so bad ...and they are cheap cheap cheap I wished I knew your name as so I could ask if you could talk about moding even the McGohan. ...thank you so much for your videos I enjoy them immensely
I’ve owned this amp since 2019 and haven’t had any issues. The unit I purchased had a 5Z4P rectifier tube. I originally upgraded to a Mullard 5Z4G. I recently went back to Amazon to look up a spec I needed and saw that the rectifier tube now delivered is a 5U4GB, so out of curiosity I bough an Electro-Harmonix 5U4GB and have been using that tube since February of this year. While reviewing your video you recommended getting an APC voltage regulator, so I purchased one. My question is, and forgive me if this is obvious, but I’m assuming that I set the voltage regulator to 110v on the back? If so, this leaves the ^ arrow on yellow all the time. I’m assuming this would be normal because the unit is reducing the voltage from 120v to 110v? The instructions for the APC weren’t exactly clear and I may have missed or misunderstood your discussion in your video. Thanks in advance for your comments!
Sorry for the long delay, yeah that arrow being on is normal because you are reducing the voltage. And the rectifier tube is a 5Ц4С which is different from a 5U4G, note the Cyrillic letter Ц looks similar to Latin U but is actually a different tube. It's closer to a 5Z4G.
So any reliability or safety issues using US 120v power, or do I need to step down to 110v? Also I read ECC85 / 6AQ8 are swappable with 6P1 and the Tungsram sound nice, any opinions?
@@SkunkieDesignsElectronics the amp version I'm getting is slightly different than yours, the newer one with a headphone output, and it says it uses upgraded Soviet 6n1neb rather than 6P1 tubes. My research shows these, along with ECC85 are both dual triodes, different than 6P1. Can you confirm? Also it seems if they are selling this in the 120-volt region, then it should work, right? Are you just saying it may get a little hot or maybe prone to a mishap?
The 6P1 is NOT a dual triode, it likely has a 6П1П-eb, note the soviet cyrillic letters. This is not the same as a 6N1 or 6N1P tube. A small signal dual triode won't drive output transformers. That headphone jack unit has always been an option, it's not a "new version". Many China products are sold in 120V regions with 110V power transformers. It doesn't just "get a little hot", it eats tubes as tube amps have no internal voltage regulation. And BTW out of the box, these make very little power and have massive distortion if used at over around 3/4 of a watt.
I'm looking into voltage regulars, but it would already be plugged into my Furman it-ref 20i power conditioner which has a specific output for "power amplifiers - High current ultra low impedance linearly filtered AC power" Would this one alone be acceptable?
Thank uverymuch for your explanation could u please madammake a video on how to repair and test valve tubes I have very old one which have 8 valves the output is 150watts
So I recently had a hum develop in my amp. So I started swapping tubes out, switched the original Rectifier back to the 5AR4 and the power tubes to the original 6P1 tubes. Then I thought, well the hum is kind of higher in frequency. 129hz to be exact (Is what my phone is showing using a spectrum analyzer). This would be a ground loop issue. Question, would the power cable be a possible culprit? Checked inside the case, nothing is out of sorts. Using a multimeter nothing seems to be out of spec. I am getting better sound with the stock 6P1 tubes over the 6P1P tubes. Seems way more spacious and imaging better. Which I thought was kind of weired. Glad to hear you are feeling better. I have 2 young kids in daycare. They are always sick right now. That unfortunately means I am sick all the time too. I have tinitus myself. But it seems music settles it down. Which is what really got me back into audio to begin with.
To diagnose problems like this, first unplug the RCA cables, if it's still there power it up without the driver tubes. That can help isolate where the problem is. And tube rolling is like most audio things, very subjective, depends on your speakers etc.
This amplifier can run 4 or 8 ohm speakers. Depending on how loud you want it, it can pretty much drive anything above 89db. I have hooked numerous speakers to mine. Jenson JHS 1533’s (braced boxes/upgraded crossovers) 94db rating, ATHENA ASB1's, rated 90db and a set of Wharfedale D320’s rated 87db at 4 ohms. The Jensens reach 100db while the wharfedales go to 99db. Critical listening even in a big space is loud enough.
Greetings The overall wattage of a speaker is an overrated spec to judge speaker performance by. The REAL specification you should always be interested in is the speaker sensitivity. The higher the sensitivity, the less output power from the amplifer is required to power the speakers at a given volume. Being the Nobsound 6P1 amp is only 6.8 watts per channel, The higher the sensitivity, the better. Don't purchase any speaker system with less than 91db. The 6.8 wattage bucket is not deep. I selected a beautiful pair of Canadian Fluance Classic Elite Bookshelf speakers. They are rated at 92dB sensitivity. That means they will produce 92dB of volume at 1 watt at 1 meter from the speaker. Pretty efficient with plenty of volume and plenty of wattage left over for my 10x13 foot computer den. Klipsch speakers have even a higher sensitivity. BTW. At Skunkie's suggestion, I immediately ordered an APC voltage regulator. Up to now, my Nobsound was my central heating system for my den. I noticed a definite drop in the overall heat generated by the amplifier. But the APC is bigger than I expected and weighs in at a whopping 10 pounds! Fortunately, it fits nicely behind my computer monitor. Can see it, but the first relay click tells me the unit turned on. The second relay click tells me its it now set for 110v, and I can safely turn on the Nobsound amp.
Does the power supply transformer voltage mismatch is common to all tube amplifiers from china? Or only for those that come with tube rectifier?. I want to know because I have a tube amplifier (ming da) from china which doesn't have tube rectifier and on back lable says 220v, in my country we use 230v, does it have solid state rectifier(regulator) to support range of voltages (like 200 to 240v)do I have to worry about it?
No, tube amplifiers do not use voltage regulation like we normally see in other electronic gear, so if it is designed for 220V and is used on 230-240V, the internal voltages will be higher as a result.
@@SkunkieDesignsElectronics I can find it I know what you're talking about I can find it but they still have it a lot of people use it who buy electronics from Japan
Seeking expert opinions- I have a Fisher KX200 that needs pro attention n recap, not sure of the cost. Question-would I be better off getting one of these Chinese tube amps or spend $$$ and get the Fisher professionally restored? My budget is pretty tight. Sorry for poor Eng n eyesight.
What's a good rectifier tubes to upgrade too . I ordered the 4 so it 6p1p ev tubes . I'm looking to gift this amp and want to put new set tubes with it
@@SkunkieDesignsElectronics it's got a lot of hours on it I wanted give all new set of tubes so when I gift it they can go though experience of breaking in the tubes hearing the difference as they own it and listen . If there not a noticable upgrade then I will just order the same tube again
@@paulgood2218 I've never heard the rectifier tube on a SE amp make any difference in the sonics. If you want to have fresh tubes in it, yeah just order the same. I would replace the 6P1 tubes with the soviet version 6P1P-EV or -EB
It's definitely not a pin for pin replacement and even the operating point is different. I actually tried just rewiring the sockets to use them and went back to the 6P1P-EV soviet tubes.
@@SkunkieDesignsElectronics thanks that's what someone else told me and why I wanted to double check. What alternate tubes can I use for the three different types?
fantastic video review. Can you review popular Reisong A10 tube amplifier, too when you can? It seems that youtube favourite Chinese amp and love to hear your thoughts on it. Thank you.
If someone wanted to loan me one to review/test. I'd really like to get my hands on the A50, I know it has the same issue my DIY 300B had, and I'm sure I could make a massive improvement in one of those using $10 worth of parts!
NO HOT SWITCHING of valve rectifiers !!!!!!!!!!!!!!!!!! NEVER DO IT ...... At the era of valve TV sets and radios .....................people knew that...." the twenty minute rule ! "..... and kids were NOT allowed to turn on the radio or TV !
Hmm not sure why you are posting this, I never said you can hot swap tubes and specifically warn about tube amp voltages ruclips.net/video/UeD8j6rt8xQ/видео.html
If you handle the hot rectifier with great care, it seem to be no problem at all. I have hot swapped rectifier tubes 50-100 times last months, and no problem so far. Of course that is not a recommendation from my side, just my experience.
I'm just going to save my money and get a French or Poland made for USA made tube amplifier that I don't have to worry about any of this stuff I mean these These are pretty cool but I have bad luck flying from China Hi-Fi I bought two of the same products one sounded amazing the other one sounded like trash just not worth my time. It's like this brand is pretty popular but I mean how do you know that someone isn't knocking this brand off and making a cheap clone of this that's inferior to the one that she's even reviewing no one knows
I have just bought this little amp, 2024. I had come across your channel a while ago, repairing a much more expensive amp. I was hoping you had looked at this amp and happy to find you have, and a bonus you have done mods on it, to improve on a good basic quote unit. I will be watching the mods in due course.
Thank you from a UK person
Thanks for this and all your videos on this little amp. I have been following all your advice so thanks for that. Just wanted to say I have done and are continuing to do some sound test with this amp as is and after using your mods that I have posted on my channel if anyone is interested in the results.
Great to hear!
I follow almost all of your videos and would like to thank you again for your great will to help people out with their tube amps. That is super genuine and makes you stand apart and above all the other people I see trying to do the same. I just ordered the parts for my little Reisong A10 and can't wait to start modifying it accordingly to your advice. My best wishes and keep up with this amazing job that you are doing!! Cheers!
You are gonna be amazed! I was shocked how much it improved this little amp.
Thanks for this info. I purchased the Line-R 1200 with the 6P1 solely because I found your video. Really appreciate it! And it's a great amp.
Glad it was helpful!
Well now. I'm super glad that I watched. Thanks for the info. I've got a couple of Chinese tubes amps and I never even thought of voltage as an issue. I'm going to correct this now and preserve this little amp. (It's most pleasurable to listen to really). Your advice is most welcome. Much thanks for doing this. I look forward to more vids. :)
Glad I could help!
Thanks, as always, Happy New Year!
Hi and thank you for the exceedingly informative video. One quick question, I've literally just purchased a 6p1 in the UK where our standard socket voltage is 230v. The mains input on the 6p1 says 230v. The question being should i ignore this & still purchase a step down transformer ie 230v-110v ?
I'm sure they make different voltage units. Every one I have opened up has the mains voltage written on the transformer.
Is output transformer not ever considered a solid state component tho? Thinking of mic preamps I guess
Hello from Meaford Ontario Canada, My name is Scott and I enjoy your videos so very much , my gosh so much information required hee hee in order to build a great amp like yours , I watched a repair person say that McGohan tube amp m102 is a sleeper gem from the past at ten watts per mono amp as used single in malls for p.a , built like Sherman tanks with top notch components oooooh I want a pr so bad ...and they are cheap cheap cheap I wished I knew your name as so I could ask if you could talk about moding even the McGohan. ...thank you so much for your videos I enjoy them immensely
Nice Review. Do you have a circuit diagram?
See my website, there is one published there.
I really enjoy your videos 🙂 thank you
Excellent review, thank you for all the good information. Do you know if the 600 watts version of the APC voltage regulator can work with this amp?
I believe it should be fine but the 1200 is only a few $ more.
I’ve owned this amp since 2019 and haven’t had any issues. The unit I purchased had a 5Z4P rectifier tube. I originally upgraded to a Mullard 5Z4G. I recently went back to Amazon to look up a spec I needed and saw that the rectifier tube now delivered is a 5U4GB, so out of curiosity I bough an Electro-Harmonix 5U4GB and have been using that tube since February of this year. While reviewing your video you recommended getting an APC voltage regulator, so I purchased one. My question is, and forgive me if this is obvious, but I’m assuming that I set the voltage regulator to 110v on the back? If so, this leaves the ^ arrow on yellow all the time. I’m assuming this would be normal because the unit is reducing the voltage from 120v to 110v? The instructions for the APC weren’t exactly clear and I may have missed or misunderstood your discussion in your video. Thanks in advance for your comments!
Sorry for the long delay, yeah that arrow being on is normal because you are reducing the voltage. And the rectifier tube is a 5Ц4С which is different from a 5U4G, note the Cyrillic letter Ц looks similar to Latin U but is actually a different tube. It's closer to a 5Z4G.
So any reliability or safety issues using US 120v power, or do I need to step down to 110v? Also I read ECC85 / 6AQ8 are swappable with 6P1 and the Tungsram sound nice, any opinions?
yes, you need to buck down the voltage to 110. And no the 6AQ8 is a dual triode, the 6P1 is a power pentode, not even similar tubes.
@@SkunkieDesignsElectronics the amp version I'm getting is slightly different than yours, the newer one with a headphone output, and it says it uses upgraded Soviet 6n1neb rather than 6P1 tubes. My research shows these, along with ECC85 are both dual triodes, different than 6P1. Can you confirm? Also it seems if they are selling this in the 120-volt region, then it should work, right? Are you just saying it may get a little hot or maybe prone to a mishap?
The 6P1 is NOT a dual triode, it likely has a 6П1П-eb, note the soviet cyrillic letters. This is not the same as a 6N1 or 6N1P tube. A small signal dual triode won't drive output transformers. That headphone jack unit has always been an option, it's not a "new version".
Many China products are sold in 120V regions with 110V power transformers. It doesn't just "get a little hot", it eats tubes as tube amps have no internal voltage regulation. And BTW out of the box, these make very little power and have massive distortion if used at over around 3/4 of a watt.
I'm looking into voltage regulars, but it would already be plugged into my Furman it-ref 20i power conditioner which has a specific output for "power amplifiers - High current ultra low impedance linearly filtered AC power" Would this one alone be acceptable?
Is it 110V output? If not, no. That's not going to do anything.
Enjoyed the review. Are there any inexpensive tube amps that you like out of the box without significant modifications?
Honestly, not really.
Thank uverymuch for your explanation could u please madammake a video on how to repair and test valve tubes I have very old one which have 8 valves the output is 150watts
I've done many training video :) Here are a few
ruclips.net/p/PLtEhh3UpOsiDdHABS0q5byT2gAQ5z31Hk
So I recently had a hum develop in my amp. So I started swapping tubes out, switched the original Rectifier back to the 5AR4 and the power tubes to the original 6P1 tubes. Then I thought, well the hum is kind of higher in frequency. 129hz to be exact (Is what my phone is showing using a spectrum analyzer). This would be a ground loop issue.
Question, would the power cable be a possible culprit? Checked inside the case, nothing is out of sorts. Using a multimeter nothing seems to be out of spec.
I am getting better sound with the stock 6P1 tubes over the 6P1P tubes. Seems way more spacious and imaging better. Which I thought was kind of weired.
Glad to hear you are feeling better. I have 2 young kids in daycare. They are always sick right now. That unfortunately means I am sick all the time too. I have tinitus myself. But it seems music settles it down. Which is what really got me back into audio to begin with.
To diagnose problems like this, first unplug the RCA cables, if it's still there power it up without the driver tubes. That can help isolate where the problem is. And tube rolling is like most audio things, very subjective, depends on your speakers etc.
@@SkunkieDesignsElectronics I have unplugged all sources, still there. I will try unplugging the driver tubes
So the hum ended up being an outlet in my house. Had a broken plug. Should have checked it with the Yaqin.
@@trashyaudiophile7301 Thanks for the follow-up!
Good morning, a question, this amp doesn't have much power output .... would it work with 100 watt speakers?
The important spec to look at is the sensitivity, usually stated as db per watt. You need 91db per watt or better. Preferably 95+
This amplifier can run 4 or 8 ohm speakers. Depending on how loud you want it, it can pretty much drive anything above 89db.
I have hooked numerous speakers to mine. Jenson JHS 1533’s (braced boxes/upgraded crossovers) 94db rating, ATHENA ASB1's, rated 90db and a set of Wharfedale D320’s rated 87db at 4 ohms. The Jensens reach 100db while the wharfedales go to 99db. Critical listening even in a big space is loud enough.
Greetings The overall wattage of a speaker is an overrated spec to judge speaker performance by. The REAL specification you should always be interested in is the speaker sensitivity. The higher the sensitivity, the less output power from the amplifer is required to power the speakers at a given volume.
Being the Nobsound 6P1 amp is only 6.8 watts per channel, The higher the sensitivity, the better. Don't purchase any speaker system with less than 91db. The 6.8 wattage bucket is not deep.
I selected a beautiful pair of Canadian Fluance Classic Elite Bookshelf speakers. They are rated at 92dB sensitivity. That means they will produce 92dB of volume at 1 watt at 1 meter from the speaker. Pretty efficient with plenty of volume and plenty of wattage left over for my 10x13 foot computer den. Klipsch speakers have even a higher sensitivity.
BTW. At Skunkie's suggestion, I immediately ordered an APC voltage regulator. Up to now, my Nobsound was my central heating system for my den. I noticed a definite drop in the overall heat generated by the amplifier. But the APC is bigger than I expected and weighs in at a whopping 10 pounds! Fortunately, it fits nicely behind my computer monitor. Can see it, but the first relay click tells me the unit turned on. The second relay click tells me its it now set for 110v, and I can safely turn on the Nobsound amp.
Does the power supply transformer voltage mismatch is common to all tube amplifiers from china? Or only for those that come with tube rectifier?.
I want to know because I have a tube amplifier (ming da) from
china which doesn't have tube rectifier and on back lable says 220v, in my country we use 230v, does it have solid state rectifier(regulator) to support range of voltages (like 200 to 240v)do I have to worry about it?
No, tube amplifiers do not use voltage regulation like we normally see in other electronic gear, so if it is designed for 220V and is used on 230-240V, the internal voltages will be higher as a result.
@@SkunkieDesignsElectronics thanks
You are awesome. I enjoy the vids
There's one on Amazon that takes 115 and puts it down to 110 and it's rated it's designed for amplifiers people use it even on non tube amplifiers.
Link?
@@SkunkieDesignsElectronics ?
@@SkunkieDesignsElectronics I can find it I know what you're talking about I can find it but they still have it a lot of people use it who buy electronics from Japan
Seeking expert opinions- I have a Fisher KX200 that needs pro attention n recap, not sure of the cost. Question-would I be better off getting one of these Chinese tube amps or spend $$$ and get the Fisher professionally restored? My budget is pretty tight. Sorry for poor Eng n eyesight.
Get the Fisher repaired
@@SkunkieDesignsElectronics 👍thanks
What's a good rectifier tubes to upgrade too . I ordered the 4 so it 6p1p ev tubes . I'm looking to gift this amp and want to put new set tubes with it
No reason to replace it, the 5Ц4С is a good tube and has the right voltage drop for this amp.
@@SkunkieDesignsElectronics it's got a lot of hours on it I wanted give all new set of tubes so when I gift it they can go though experience of breaking in the tubes hearing the difference as they own it and listen . If there not a noticable upgrade then I will just order the same tube again
@@paulgood2218 I've never heard the rectifier tube on a SE amp make any difference in the sonics. If you want to have fresh tubes in it, yeah just order the same. I would replace the 6P1 tubes with the soviet version 6P1P-EV or -EB
@@SkunkieDesignsElectronics thank you so much for your response , I just ordered the ev tubes this afternoon .
Here's the Skunkie Design playlist (8 videos) about this amp: ruclips.net/p/PLtEhh3UpOsiDHpQLd8v08cEPgaGrExAnq
I think the 6AQ5 tubes will work inplace of the 6P1 tubes?
It's definitely not a pin for pin replacement and even the operating point is different. I actually tried just rewiring the sockets to use them and went back to the 6P1P-EV soviet tubes.
@@SkunkieDesignsElectronics thanks that's what someone else told me and why I wanted to double check. What alternate tubes can I use for the three different types?
@@SkunkieDesignsElectronics to bad you couldn't use like a EL84 or something
The Chinese 6p1 were noisy and had hums. The Russian 6p1 was good and not far behind 6aq5.
fantastic video review. Can you review popular Reisong A10 tube amplifier, too when you can? It seems that youtube favourite Chinese amp and love to hear your thoughts on it. Thank you.
If someone wanted to loan me one to review/test. I'd really like to get my hands on the A50, I know it has the same issue my DIY 300B had, and I'm sure I could make a massive improvement in one of those using $10 worth of parts!
I like this amp.
Put a 50 ohm 5 watt resistor in the AC line and you'll get 110 volts into it.
Has anyone tried this?
Thanks for these videos. They’re great learning tools in common language. 👍🏻
Glad you like them!
🙋❤️👍
Klipsch is not accurate on their sensitivity rating just know. It’s way high and dishonest. Great info / videos !
It's a few db lower than rated.
NO HOT SWITCHING of valve rectifiers !!!!!!!!!!!!!!!!!! NEVER DO IT ......
At the era of valve TV sets and radios .....................people knew that...." the twenty minute rule ! "..... and kids were NOT allowed to turn on the radio or TV !
Hmm not sure why you are posting this, I never said you can hot swap tubes and specifically warn about tube amp voltages ruclips.net/video/UeD8j6rt8xQ/видео.html
If you handle the hot rectifier with great care, it seem to be no problem at all. I have hot swapped rectifier tubes 50-100 times last months, and no problem so far. Of course that is not a recommendation from my side, just my experience.
I'm just going to save my money and get a French or Poland made for USA made tube amplifier that I don't have to worry about any of this stuff I mean these These are pretty cool but I have bad luck flying from China Hi-Fi I bought two of the same products one sounded amazing the other one sounded like trash just not worth my time. It's like this brand is pretty popular but I mean how do you know that someone isn't knocking this brand off and making a cheap clone of this that's inferior to the one that she's even reviewing no one knows
このメーカーは偽物を売っていたことがあるので少し不安です。
That doesn't surprise me at all.