WooAudio WA5 and Akg K1000's are in the house - Upgraded PSU is in 6/2 - Page 8

Did you check the fuse? A blown fuse is not all that uncommon because sometimes at turn on you can hit a peak current flow, which can blow the fuse.

Normally all commercially available components of this type will have a fuse. It is required even for insurance purposes. Are you sure there isn't one at the back by the IEC power cord inlet?

Do you have spare rectifier tubes? If one has gone bad that can also be the problem. Have you ever noticed any arcing of the rectifier tubes on turn on? I have blown a fuse on the 6, well on many amps, and most of the time it seems the fuse is stressed after time, if it gets hit by a high current flow a few times, and then finally blows. With replacement all is well. My Cary Six Pacs blew fuses every couple of months, just their nature.

I wouldn't but what I have done is use the ceramic fuse vs the glass case fuse. They are supposed to be filled with sand so you get less vibrations on the filament although this is not the reason they are designed this way but for audio I find it a plus. I have used them and like them. I purchased mine at a good hardware store. No way would I buy a super expensive fuse to just blow. Clean the ends real good with alcohol for good contact. I have tied the contact enhancers and while they work good at first they tend to dry out and then actually make the contact worse.

Yep, well at least you did it the right way. Sorry for the power supply problem. Well at least you will only need to send the power supply section back. Did you pop the bottom of the supply and check the circuit?

Just for the heck of it I wonder what the continuity of the transformer is like? I have seen the primary short to the secondary, which causes a major problem.

Sophia Princess 274B/n mesh plate on WA5 - first impressions

Well, I finally found time to do the switch. Before the 274B I have a pair of Philips Metal Base GZ34 on the WA5. The sound is clean and fast, bass is tight, well mannered, and overall tonality is neutral.

The other tubes compliment I am using are Sophia Princess 300B Carbon Plates (25 hours from new) and a pair of Tung Sol 6SN7 GTB. These remained unchanged after I dropped in the 274B, which are mesh plate, Princess series from Sophia, and was bought new.

What I can say is the 274B has a very different character from the GZ34 metal base. It is far from subtle. First there is more bass - both in terms of quantity and depth. Second, the overall sound is richer, or I should say, denser across spectrum. Some people may call it "sweet" but not syrupy. Third, the far end treble is not as detailed as the GZ34 and tends to roll off earlier. Overall, it is a very different presentation from the Metal Base GZ34.

I listened to the 274B through a GS-1000, recabled in APS v3. This is the first time the GS-1000 sound "right". The recabling has helped to control the bloomy bass of the GS-1000 better, but with the 274B, it is just a tad too much for me for some tracks that comes with plenty of bass. Mind you, it is not bloated, but the GS-1000 does has a fat bottom end and even with the recabling it is still there, though it is still well mannered. Then the mid range with 274B is what makes the GS1000 a better can.

I then switched to a Grado HP-1, also recabled in APS v3. Now this is what the HP-1 should sound ! The bass is well balanced - deep, in a good quantity, textured and enjoyable. the 274B gives the HP-1 that touch of warmth which make the HP-1 sounds very organic and engaging, but nothing is loss in terms of resolution.

I am now listening, with the same tube setup, with the K1000 ( sorrry, again recabled by APS v3) and using my favorite reference CD ('This is K2 HD Sound") and I would say the 274B is made for listening with the K1000. Everything is better - the bass is well supplemented, and the mid-range is scarily good. Very engaging, natural soundstage and overall it is a joy to listen to .

This is my impression for the first 10 hours. I do think the GS-1000 would sound better overall with the GZ34 metal base, but the mid range with the 274B has make the GS-1000 almost a different pair of cans.

I do hope over time the bass will tighten a bit more but we will see. But the Sophia Princess 274B is a worthwhile investment for tube rolling on the WA5.

Next week, I will drop in a matched pair of Bad Boys to see how the combination sounds.

Until then, have a good weekend.

F. Lo

Some pics of the 274B





F. Lo