Nobsound 6P1 Revisited: Fixing the Driver Stage

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Nobsound 6P1 Revisited: Fixing the Driver Stage

Рет қаралды 4,289

Күн бұрын

We are going to revisit this popular made in China vacuum tube amplifier. I want to show in detail how to do some minor changes that transform the sound and performance. I also will show the testing that proves they work.
This third video covers revising the driver section of the amp to resolve the distortion issues cause by the original design of this amp.
The very first video series on this channel was on this amp, and since that time I've learned a lot about not only tube amplifiers, but also about video production and how best to show how to do mods on tube amps. I now have better test equipment and some new ideas on how to possibly get even more performance out of this fun, cheap little amp so stay tuned!

Пікірлер: 38

@WorldView22 2 жыл бұрын

The fact that you have 3.4K subscribers instead of 203.4K is an injustice.

@cau8365 2 жыл бұрын

Another great episode. Looking forward to more 6P1 fun! Thank you.

@alaingingras7224 2 жыл бұрын

I would bet that the ''Chinese manufacturers''are tuning in!

@trashyaudiophile7301 2 жыл бұрын

I can't wait to see if you can bring the power up. Now, I bought a Yaqin MC-84l. And while it has a cleaner top end, it just doesn't have the low end extension this amp has. And to my surprise. Doesn't have more usable watts than this little amplifier has. I am using a simple sound level meter. The Nobsound at 1 meter is pushing a set of Jensen speakers rated 94db at 1 meter to 101db, while the Yaqin pushes to 99db. I also prefer the sound of the Nobsound to the Yaqin.

@trashyaudiophile7301 2 жыл бұрын

I got a chance to really listen again in this video. I am reminded of a company called First Watt. The man who owns the company has stated "The first watt is the most important watt", or something of the effect. As a 1 and a quarter watt amp, I have to disagree with things you say about it not being a good amplifier. As I said in the 1st comment I made. I have a modded set of Jensen JHS-1533's rated 94db. If this amp is pushing the Jensen's to 101db. The amp is capable of pushing 4 watts, or my speakers are a lot more efficient than they were rated. Either or is fantastic. I have a lot of amplifiers, and this one sounds the best since the driver tube mod.

@joeygreenhaw8503 2 жыл бұрын

Just bought this amp. Wished I would have watched your videos beforehand. Sure would love to see you do more modifications on this amp to get more power out of it. For example when you said removing one of the output tubes.

@SkunkieDesignsElectronics Жыл бұрын

I plan to do something more with this amp this fall.

@joeygreenhaw8503 Жыл бұрын

@@SkunkieDesignsElectronics cool. Looking forward to it.

@JohnScheppler 2 жыл бұрын

Great job explaining this simple modification and showing the results. So is the Reisong A10 amplifier better starting point amplifier than the Nobsound P1 amplifier for someone wanting to get started into tube amplifiers?

@SkunkieDesignsElectronics 2 жыл бұрын

I believe so. It doesn't have near the limitations, and you can actually buy it with a 120V transformer that is appropriately sized, with decent quality output transformers.

@dibblethwaite 2 жыл бұрын

I think I'd have changed the cascade to a mu follower or srpp but what you'd done seems to work.

@dibblethwaite 2 жыл бұрын

Cascode I mean

@allenwalters8812 2 жыл бұрын

That's a great coffee cup. looks 70's.

@petegaslondon Жыл бұрын

"Within and Inch of thier lives..." :) Maybe not 'peer reviewed testing', but I DID like the sound of my old AC30 over other EL84 amps, partly as they ran the outputs so darn hot Not so sure about Pre and Driver tubes mind - Modjeski reckoned 'CC88's (6DJ8) shouldnt be pushed much past .6W per triode, for reliability - noise actually went down a bit :) Massive overkill? Your probably right - unless youre going to go into Grid Current territory? 'Course having plenty drive to spare DOES mean youre running nice and low distortion right ? ;)

@2minutes-dharma145 2 жыл бұрын

Good review of the earlier mods. Few months back, I did all the suggested mods and drive my Klipsch RF 82 II , the spl is more than enough for my small room with the vol knob just over 50%. It was interesting to know you are considering redesigning the bias and change the o/p tube from the parallel 6P1 to single tubes for each channel. I always wondered if the two 6P1s could be changed to a single EL34 or 84 , keeping the same power supply and o/p transformer. Should be a simple mod, but not sure of the power and distortion specs. Your thoughts in this matter?

@Iam-mad Жыл бұрын

Actually there is a Nobsound "Mona" EL-34 Version of this amp, wich is quite identical to the 6P1. I have it, and wonder if the mods would work on it too...

@joeygreenhaw8503 2 жыл бұрын

Did you test the 4ohm output to see what it looks like compared to the 8ohm? I appears to be taped off inside the case.

@joemartin6439 2 жыл бұрын

Sweetheart I see you are a wake too many night now. But I sure enjoy your great skill work and tone

@inerlogic Жыл бұрын

Any plans on revisiting this amp? I have the version without the headphone jack in the middle front. Last night i noticed a buzz, maybe a transformer? Volume didn't affect the buzz, and i didn't notice anything while listening to music, it was just in the quiet between songs i heard the buzzing. I completed the mods in this series....... months ago.... Swapped the russian tubes that came with it via china for some NOS tubes from Ukraine after doing the mods.... i shut the amp off, the buzz went away, turned it back on and got a nice light show from the rectifier tube.... oops... i counted to 30, guess it wasn't long enough....

@SkunkieDesignsElectronics Жыл бұрын

I do need to revisit this little guy.

@menachemaltaras5653 11 ай бұрын

Are the values of the mod components the same for the 110V version as the 220V version systems?

@SkunkieDesignsElectronics 11 ай бұрын

Always, the ONLY thing different between countries is the primary winding of the power transformer.

@menachemaltaras5653 11 ай бұрын

Thanks for your response - I did both mods, power capasitor change and added resistor, plus the bias change - and noticed a bit clearer sound quality. did not changed the capacitors in the sound path. Thakns for the clear video and the upgrade

@ToneHobart Жыл бұрын

If I have not made a purchase yet. is there something I can look at around the same price that won't require all the mods... I could do them but since I have not purchased anything yet maybe I can avoid the extra work.

@SkunkieDesignsElectronics Жыл бұрын

I would not buy a Nobsound 6P1. And honestly I have yet to find any of these made in china amps under $1000 that don't need work.

@ToneHobart Жыл бұрын

@@SkunkieDesignsElectronics Thanks... Very helpful. I kind of had the feeling it may go that way, just wanted to make sure.

@bucketlistbeginner 2 жыл бұрын

If you get a chance can you do a show on adding blue tooth.. I’m interested in playing day an iPod without an extra pre amp..

@SkunkieDesignsElectronics 2 жыл бұрын

Interesting idea, I'll look into it!

@claudesandrelli7905 2 жыл бұрын

more parallel tubes will never sound good without separating the electrodes with resistors !!! so for example on each grid 100 ohm and on each cathode 10 ohm ≥2W

@JeepBoiFL Жыл бұрын

So, would I just be better off buying the REISONG A10?

@SkunkieDesignsElectronics Жыл бұрын

If you plan to do my mods to it? Absolutely.

@rkrnddl5 2 жыл бұрын

I have a question please help me. i live in south korea, here we use 220v, so i bought this amp's 220v version from Taobao seller. Q1. can i use same fixed bias mod for my 220V input version nobsound 6p1 amp? Just as like this video(move 1ea of 1m ohm, add 2ea of 1m ohm in series)? For my guessing, it is voltage devider so 1m:2m ratio would be same at 220v i think am i right? And 220v's internal looks same with your video(resistors and wiring things) to me. Q2. Also do i have to mind any other things for modding 220v version of this amp?(worring about difference with your 110v 6p1 mod video) I will wait for your reply and hopping to apply this mod with my 6p1 amp. Many thanks.

@SkunkieDesignsElectronics 2 жыл бұрын

The 220V is ONLY on the primary of the power transformer, all the internal voltages will be the same so yes, same mods.

@rkrnddl5 2 жыл бұрын

@@SkunkieDesignsElectronics thanks for fast reply now i can apply this mod :)

@2minutes-dharma145 2 жыл бұрын

oh, and feedback?

@chriscimino7854 2 жыл бұрын

👍

@ianaintsaying1625 2 жыл бұрын

It seems to me that the logical conclusion is that the Chinese know exactly NOTHING about tube amplifier design.

@Iam-mad Жыл бұрын

I think we should not badmouth but apreciate the work Chinese do, because soldering these together manually is for sure not an easy task for so little money, and I know, they do their best according to their abilities. If You want to see a really fine work of chinese tube amps, go for the "OldChen", they are really good! Pity Skunkie didn´t get one of the OldChens..