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Xiansheng 708B headphone tube amp - Page 3

post #31 of 413
Thread Starter 
Quote:
Originally Posted by mirumu
Xiang Sheng is a company in China but they seem to have many internet dealers in Hong Kong.

In my experience the tubes have quite a noticeable effect on the sound, especially the 6N3 and the 6N1.
I listened once with the stock set up to be sure it was working, and immediately changed the 6N1 to a Russian 6N1P EB and it seemed to improve the sound - but this was based on just a few minutes experience.

Then I changed the Chinese 6N23 (6DJ8) to the Amperex-Holland 6DJ8 and found an improvement. Over the next few days I tried a variety of 6DJ8 and settled on the RCA stamped made in UK.

I am still waiting on the 6N3P EB tubes from Russia which I suspect will significantly change the sound as did chaging out the two 6DJ8.

Now, just got a message from j214 who advised me the front 6N1 tube is just cosmetic and not part of the signal circuit.

I initially suspected it was just cosmetic but it is powered so I wasn't sure. Changing it had seemed to improve the sound but I only checked this for a few minutes before changing the other tubes.

There are wires running to the circuit but these are likely just heater wires. So I simply pulled the 6N1P tube out and the amp worked without it - proof that this front window tubes is for looks but not function.
post #32 of 413
Just put in a bid on a 708B, and realized I have no idea how one would play with my DT770/80s. Any synergy there, or notable problems?
post #33 of 413
Quote:
Originally Posted by drarthurwells
Now, just got a message from j214 who advised me the front 6N1 tube is just cosmetic and not part of the signal circuit.

I initially suspected it was just cosmetic but it is powered so I wasn't sure. Changing it had seemed to improve the sound but I only checked this for a few minutes before changing the other tubes.

There are wires running to the circuit but these are likely just heater wires. So I simply pulled the 6N1P tube out and the amp worked without it - proof that this front window tubes is for looks but not function.
Haha, I had seen that there were a bunch of yellow/orange LEDs around the outside edge of the window just to give a good looking tube-style glow but it's hilarious that the 6N1 is only there for the same purpose. Glad I didn't spend any money buying quality replacements. On the plus side though, I'm very glad that those wires going to the 6N1 aren't signal wires, it didn't seem a good idea to carry the signal all the way out to the front window along those thin wires.

Nugget, I haven't heard the 708B with the DT770/80s but in my experience, this amp provides a lot of driving power. From this perspective I would be surprised if it had a problem driving 32 ohm headphones like those. I can't otherwise comment on the synergy though.

Edit: My bad, I see the DT770/80 is 80ohms. I still don't think that load would give the 708B any problems, I have driven up to 110ohm headphones from mine without issue.
post #34 of 413

I'm Back

Huh! I just get back and ready to run my 708B..since it was burned and now I'm not afraid any more..i change some the tubes.
-6N3 to 5670 sylvania
-6N1,6N11 to 6922 Gold pins TESLA and amperex...
I just surprise all the sounds it's so wide and big improvement after change these tubes.
Very Happy now no more smoke and my transformer not over heat anymore...
I use it as Pre-Amplifier...
post #35 of 413
Thread Starter 
That's good news.

The stock Chinese tubes are less than ideal.

I am still waiting on the 6N3P EB tubes (old Russian military) to replace the Chinese 6N3
post #36 of 413
Is the 6N1 really just cosmetic? I wouldn't want to spend money on a replacement that's not going to improve the sound
post #37 of 413
Thread Starter 
Quote:
Originally Posted by Robfow
Is the 6N1 really just cosmetic? I wouldn't want to spend money on a replacement that's not going to improve the sound
Yes.

I took mine out.


The 5670 is a sub for the 6N3 but has slightly different values but should improve the sound over the Chinese 6N3.


The 6N11 is the same as the 6DJ8 and this change makes a big difference.
post #38 of 413
Quote:
Originally Posted by drarthurwells
The 5670 is a sub for the 6N3 but has slightly different values but should improve the sound over the Chinese 6N3.


The 6N11 is the same as the 6DJ8 and this change makes a big difference.
From what I have found, the 6N3 tube is the hardest one to find a good replacement for. I tried a General Electric JAN 5670W but it was more noisy than the original 6N3. I then tried a 6N3P-DR which is military grade but different from the 6N3P-EB. This introduced quite a bit of noise and hum so I ended up switching back to the original 6N3 for now.

For the 6N11s, I am currently using a matched pair of TESLA PCC88 tubes. I wasn't that impressed with them initially but they are very transparent and uncolored.
post #39 of 413
Quote:
Originally Posted by drarthurwells
I listened once with the stock set up to be sure it was working, and immediately changed the 6N1 to a Russian 6N1P EB and it seemed to improve the sound - but this was based on just a few minutes experience.

Then I changed the Chinese 6N23 (6DJ8) to the Amperex-Holland 6DJ8 and found an improvement. Over the next few days I tried a variety of 6DJ8 and settled on the RCA stamped made in UK.

I am still waiting on the 6N3P EB tubes from Russia which I suspect will significantly change the sound as did chaging out the two 6DJ8.

Now, just got a message from j214 who advised me the front 6N1 tube is just cosmetic and not part of the signal circuit.

I initially suspected it was just cosmetic but it is powered so I wasn't sure. Changing it had seemed to improve the sound but I only checked this for a few minutes before changing the other tubes.

There are wires running to the circuit but these are likely just heater wires. So I simply pulled the 6N1P tube out and the amp worked without it - proof that this front window tubes is for looks but not function.

Hi,I would say if 6N1 is purely there for cosmetic purposes,by changing it how would u notice the difference in sounds quality???

I noticed that the connections comes from the power supply section only and nothing goes out from that tube.
post #40 of 413
Quote:
Originally Posted by mirumu
From what I have found, the 6N3 tube is the hardest one to find a good replacement for. I tried a General Electric JAN 5670W but it was more noisy than the original 6N3. I then tried a 6N3P-DR which is military grade but different from the 6N3P-EB. This introduced quite a bit of noise and hum so I ended up switching back to the original 6N3 for now.

For the 6N11s, I am currently using a matched pair of TESLA PCC88 tubes. I wasn't that impressed with them initially but they are very transparent and uncolored.

HI,I do agree with u that 6n3 is the hardest. I replaced mine with Western Electric 2c51 and it has increased the noise quite alot i would say.The noise is quite noticeable at 11clock onwards already. However,the 2c51 do bring out alot of details in my songs and I love it.

Since I normally listen at volume lower than 10 oclock,so i'm ok with this big gain tube, hehee....
post #41 of 413
Quote:
Originally Posted by edwinywh
Hi,I would say if 6N1 is purely there for cosmetic purposes,by changing it how would u notice the difference in sounds quality???
From my reading drarthurwells was saying that he initially thought there was a difference in the sound but that he had only listened for a few minutes and that really it was having no effect.

Quote:
Originally Posted by edwinywh
HI,I do agree with u that 6n3 is the hardest. I replaced mine with Western Electric 2c51 and it has increased the noise quite alot i would say.The noise is quite noticeable at 11clock onwards already. However,the 2c51 do bring out alot of details in my songs and I love it.

Since I normally listen at volume lower than 10 oclock,so i'm ok with this big gain tube, hehee....
That does sound like my initial impression of the GE 5670W. I felt that it might have been a bit more detailed too but I found the noise was bothering me a bit too much so I took it out quite quickly. I'd like to put it in again some time and spend more time listening with some headphones that don't expose the noise as much as my Shure E500s.

I'd quite like to track down a Sylvania 5670 or some other Russian 6N3P variants to try in that socket as well.

I know what you mean about the gain, I think I'm normally listening at less than 9 o'clock.
post #42 of 413
Quote:
Originally Posted by mirumu
From my reading drarthurwells was saying that he initially thought there was a difference in the sound but that he had only listened for a few minutes and that really it was having no effect.


That does sound like my initial impression of the GE 5670W. I felt that it might have been a bit more detailed too but I found the noise was bothering me a bit too much so I took it out quite quickly. I'd like to put it in again some time and spend more time listening with some headphones that don't expose the noise as much as my Shure E500s.

I'd quite like to track down a Sylvania 5670 or some other Russian 6N3P variants to try in that socket as well.

I know what you mean about the gain, I think I'm normally listening at less than 9 o'clock.

Hi!
Thanks for clarifying with wat drarthurwells was saying. =) I might have interpret it wrongly.

Yah,do try the amp with diff headphones.U might enjoy it??

I'm currently driving a pair of Grado's SR80.I feel that the bass is quite weak or rather,not as punchy and loud like i wan it to be. Any tips to enhance the bass?

Cheers,
Edwin.
post #43 of 413
Thread Starter 
Quote:
Originally Posted by edwinywh
Hi!
Thanks for clarifying with wat drarthurwells was saying. =) I might have interpret it wrongly.

Yah,do try the amp with diff headphones.U might enjoy it??

I'm currently driving a pair of Grado's SR80.I feel that the bass is quite weak or rather,not as punchy and loud like i wan it to be. Any tips to enhance the bass?

Cheers,
Edwin.
The bass is weaker, and dynamic impact is less, with the 708B compared to my Bada PH12 (which cost twice as much as the 708B).

At its price level the 708B is excellent though.
post #44 of 413
Quote:
Originally Posted by drarthurwells
The bass is weaker, and dynamic impact is less, with the 708B compared to my Bada PH12 (which cost twice as much as the 708B).

At its price level the 708B is excellent though.

Hi, I take it that you are referring to stock Bada PH12?

Because for the XS 708b usually it has gone through some tubes rolling and/or power cords replacement.
post #45 of 413
Quote:
Originally Posted by edwinywh
Hi!I'm currently driving a pair of Grado's SR80.I feel that the bass is quite weak or rather,not as punchy and loud like i wan it to be. Any tips to enhance the bass?
That's much my experience with the Grado SR80s and the XS 708B as well. I haven't noticed this with other headphones. I find EQ is the only way to make this combination sound right to me although I find cutting better than boosting otherwise the distortion becomes a problem.
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