[epaludo]

Quote:

Originally Posted by sacd lover Thats whats weird .... with transformer coupling the amp should have plenty of current drive for low impedence headphones. Do you have the high/ low impedence switch on the back of the amp on the right setting for the K701's?

That's what i was thinking while reading this thread. You might try to change the switch position to see if this issue disappear (IF that's an issue) ...

 

[jamato8]

I was also wondering about that. I wish I was back in the states just to hear this thing. I have been here in China for over a year now and while there are many fine people here I miss being able to do some of the things I can do in the US. Shipping from the states is EXpenisve. Well at least I can read about all of this. I wish someone would post a comprehensive review so I could live vicariously through them. :^)

 

[Michael Avin]

The position of the switch in the back is correct fot the phones I use. However, at the 'all the way on position', the amp is dead quiet with the 701's. So I really no longer care about cranking the volume. With the Senn 600's, and the impedence switch in the correct position, the amp is plenty loud at twelve o'clock. to be continued......

 

[epaludo]

Quote:

Originally Posted by Michael Avin The position of the switch in the back is correct fot the phones I use. However, at the 'all the way on position', the amp is dead quiet with the 701's. So I really no longer care about cranking the volume. With the Senn 600's, and the impedence switch in the correct position, the amp is plenty loud at twelve o'clock. to be continued......

Did tried some Grados with your WooAudio 6 already? Just wondering if your amp switch might not be working and it could be selected for high impedance cans, making a change for low impedance cans impossible. Difficult to happen though, but not impossible ...

 

[jamato8]

The less a normal volume pot in the signal path the better. I set my preamp up so the volume pot was at around 1 to 2 oclock. After I did a bypass, which only keeps one resistor in the signal path it didn't matter any longer.

 

[nichifanlema]

Try listening with other low impedance cans...

I am also using a low impedance 'phone, AT A900LTD (40 ohm) wih my Woo6 (the switch set to low impedance), but I don't have to crank the volume up to 2~3 o'clock....somewhere around 10 o'clock is enough for me.

 

[jamato8]

Quote:

Originally Posted by nichifanlema Try listening with other low impedance cans... I am also using a low impedance 'phone, AT A900LTD (40 ohm) wih my Woo6 (the switch set to low impedance), but I don't have to crank the volume up to 2~3 o'clock....somewhere around 10 o'clock is enough for me.

Ok, so how does it sound??

 

[Michael Avin]

The Woo6 drives both Grado RS-1s and Sennheiser 600's fine. I use the correct switch positions and have a player outputting normal voltage. The AKG701's are just very hard to drive, solid state being all around better for them. PS; the AKG 701's are relatively low impedance cans.

 

[Dept_of_Alchemy]

pics?

 

[jamato8]

You guys are cruel. I am here in China working everyday inside because I have two reports for the UN to get out. The one really fun thing I could do is read how this thing sounds. It this too much to ask? :^) You know, with a few different types of music with details on frequency spectrum and musicality.

 

[Michael Avin]

The sound of the Woo 6 is big round and open. It is softish with no edge or grain at all. I am sending the unit back to Mr. Woo to tweak so that it is a better match for the AKG701's. I will also try Mullards in the 5ar4 position upon return of the amp to me. So far it is up there sound wise with the Mapletree, Channel Island Audio EC-01 and in the sound department. I will keep the forum abreast when it returns. All in all, a lovely piece of audio jewelry for the eyes and the ears. It needs to provide a little more excitement and speed, Hoping the tweeks and the new tubes will provide that.
Happy listening.

 

[jamato8]

Quote:

Originally Posted by Michael Avin The sound of the Woo 6 is big round and open. It is softish with no edge or grain at all. I am sending the unit back to Mr. Woo to tweak so that it is a better match for the AKG701's. I will also try Mullards in the 5ar4 position upon return of the amp to me. So far it is up there sound wise with the Mapletree, Channel Island Audio EC-01 and in the sound department. I will keep the forum abreast when it returns. All in all, a lovely piece of audio jewelry for the eyes and the ears. It needs to provide a little more excitement and speed, Hoping the tweeks and the new tubes will provide that. Happy listening.

A good Mullard GZ34 can help in the bass area and good caps in the power supply can help with speed and articulation. The money really needs to be put into the iron so if the output trans aren't there the amp will not have speed and total transparency but from what you are saying it sounds like the amp is very close to being there. I had the opt's for my preamp custom made. If opt's for a preamp aren't right it will sound slow and muddy by comparison to a good capacitor coupled pre. The same is true for most other opt coupled but with the lower power and current of the headphone amps and preamps it is even more important.

Changing the operating points of the tubes can do some wonders also. Running the power tube section a little hotter with bias or voltage can do some good things or not depending upon the tube. A hotter bias on one tube this size will not change the power noticably but it can change the sound and here even the wattage of the resistor and resistor type can be very important like a good low noise resistor.

 

[Frihed89]

The gain tube matters a lot, despite what Lloyd says. I have the ear + HD something-or-other, fully loaded. I loved the Russian Sovtek. The I tried some "NOS" Raytheons and Sylvanias which i paid a lot for from a private seller. It took the Ear to another level (to my ears): much better soundstaging, better bass, smoother more liquid mids (but still tons of detail), extended open highs. The differences between the two tubes were slight and actually I am going deff.

Stay away from RCA and GE NOS. They did nothing for me, although i was not using tripple micahs.

Good luck

 

[jamato8]

Quote:

Originally Posted by Frihed89 The gain tube matters a lot, despite what Lloyd says. I have the ear + HD something-or-other, fully loaded. I loved the Russian Sovtek. The I tried some "NOS" Raytheons and Sylvanias which i paid a lot for from a private seller. It took the Ear to another level (to my ears): much better soundstaging, better bass, smoother more liquid mids (but still tons of detail), extended open highs. The differences between the two tubes were slight and actually I am going deff. Stay away from RCA and GE NOS. They did nothing for me, although i was not using tripple micahs. Good luck

I do not understand how some can say the tube will not make any difference. A tube is a circuit and each manufacture had their own metalurgy, coating, vaccuum, glass, skill standards. They ALL figure in. Change opamps and find out. Well change tubes, even though they operate in the same specification range this means nothing. I have some Japanese tubes that were not made on the old Mullard tooling. I got them used and thought they may have had it but they are by far the best EL34 I have and I have Amperex from the 50's and some of the best EL34's ever made but the Japanese 34's I have are rare and I have never seen any others. What I am getting at is that tubes are a circuit and they DO make a difference though I will agree that in some circuits it may be less or more depending upon the implementation but in a gain position they will make a noticable contribution or lack thereof to the sound depending upon the quality of the tube.

I have some 1949 12AX7's, the first year of real production and though it isn't my favorite tube these do rock.

 

[jamato8]

double I with they had delete here but that might lead to some odd posts as to someone answering something that is not there. Kind of like talking to ones self, like me right now. Ok John we can go now, ok, . . . whoops.