[jbua5150]

Good stuff.

I also run Shunyata Research NR power cords. As where you run Isotek & Audioquest power conditioners, I kept with Shunyata and run a Hydra Delta D6. It's amazing how good the Shunyata NR line are at significantly lowering the noise floor. Add in the Hydra Delta D6 and it's shocking how black the background can get.

For the WA6-SE gen 1, the best 6DE7's I've found are the five star Toshiba's that Woo Audio sells. These are NOS tightly matched pairs from the 1970's. Very good. A harder pair to find but still available if you look long enough are the Tung-Sol 6DE7's. A very full bodied sound that doesn't sacrifice detail. I recommend both.

I've tried almost all of the top 20-25 rectifiers in the Dubstep girl's 5U4G thread. For the WA6-SE gen 1, to my ears the Osram/GEC/MWT/ U52 from the 1950's is about the best. A excellent budget friendly option that is still available if you are patient and look hard enough is the Marconi Canada 5U4G. This was made by Radiotron Valve Company in the 1950's and 1960's in Montreal Canada. Very sweet sound with a polite presence. Of course the Cossor 53KU is another fantastic example but these tend to be pricey. I didn't like the Western Electric 422A. I thought the high end was disjointed and smeared. It lacked the seamlessness of the U52 and the 53KU. Of course I can't forget about the classic and outstanding metal base GZ34. In the WA6-SE gen 1 I found this rectifier to add a faster speed to the warm signature that this amp has. Woo Audio amps are known to have a warm and slow presentation. Some suggest that the Woo Audio house sound comes from the way they wind their transformers. Indeed, I think with the exception of the new Woo Audio Luna amp, I've heard everything in the line-up and Woo definitely has a specific soinc signature. The metal base GZ34 almost brings a soild-state speed into play. It cuts though the mud and adds a different and welcomed tonality.

Either way, congrats on the WA6-SE gen 1. You've got yourself an amazing amp. Have fun with it. Plenty of rolling options for both the driver tubes and of course many options for rectifiers.

I have a pair of those Toshiba 6DE7, and fully agree with your statement. Definitely my favorite 6DE7.

 

[fzman]

Don't know if I am insane, lucky, or both. I n my travels today, I browsed a small antique shop in which there was a small bowl of loose tubes (no boxes) (completely untested) along with a small quantity of relays that fit some tube-like sockets, and were pretty beefy. I browsed thru the tubes and found a GE 5U4GB, that looked like it was in decent shape - no bent pins, locator pin not cracked or brlen, glass completely intact, etc. $7 later, I popped out my Sophia 274B, pictured recently in this thread. Volume all the way down, leaning AWAY from the WA6-SE,, i turned the power knob and crossed my fingers.

Works fine, and has been playing for 10 minutes or so already. and I am pretty confident that it is more dynamic and has better low-end slam than the Sophia. Cymbals are very crisp, but I think string bass may favor the wooden body rather than the string - piano, likewise gives the body slightly more emphasis than the hammer sriking the strings.... (OR I'm imagining the whole thing- yet having no expectations, hard to attribute confirmation bias to this).

So, dodged a wasting $7 bullet, and a giant 'blow-up-my-amp' bullet. Also ordered an ALO Studio Six last bnight (used), so I am am outta control already. Not only pretty far down the rabbit-hole, but, apparently, picking out carpetting and drapes for it - (tubes are probably more like scones, but the idea holds ture).

Happy happy

 

[IvanE92]

Picked up a used WA6 today for $400. Love how well they pair with my OG Focals (using Peace EQ) on the low gain setting. Simply fantastic. Going to need to listen to this setup for a while before I tweak any further. That, and look at upgrading my JDS Atom DAC.

 

[RobertSM]

Don't know if I am insane, lucky, or both. I n my travels today, I browsed a small antique shop in which there was a small bowl of loose tubes (no boxes) (completely untested) along with a small quantity of relays that fit some tube-like sockets, and were pretty beefy. I browsed thru the tubes and found a GE 5U4GB, that looked like it was in decent shape - no bent pins, locator pin not cracked or brlen, glass completely intact, etc. $7 later, I popped out my Sophia 274B, pictured recently in this thread. Volume all the way down, leaning AWAY from the WA6-SE,, i turned the power knob and crossed my fingers.

Works fine, and has been playing for 10 minutes or so already. and I am pretty confident that it is more dynamic and has better low-end slam than the Sophia. Cymbals are very crisp, but I think string bass may favor the wooden body rather than the string - piano, likewise gives the body slightly more emphasis than the hammer sriking the strings.... (OR I'm imagining the whole thing- yet having no expectations, hard to attribute confirmation bias to this).

So, dodged a wasting $7 bullet, and a giant 'blow-up-my-amp' bullet. Also ordered an ALO Studio Six last bnight (used), so I am am outta control already. Not only pretty far down the rabbit-hole, but, apparently, picking out carpetting and drapes for it - (tubes are probably more like scones, but the idea holds ture).

Happy happy

Excellent find on the GE 5U4G.

Congratulations of the ALO Studio Six! Feel free to jump into the Studio Six thread or send a PM if you need help with tube rolling options. I've spent alot of time and effort and have come up with some really brilliant combinations that run the gambit of sonic signatures. I've also become pretty good friends with the designer of the Studio Six. He's definitely helped guide me and my decisions to squeak out every last bit of proformance possible.

Woo Audio WA6-SE & ALO Studio Six, an excellent and complimentary pair of amplifiers. Good times ahead for you, for sure!

 

[fzman]

Excellent find on the GE 5U4G.

Congratulations of the ALO Studio Six! Feel free to jump into the Studio Six thread or send a PM if you need help with tube rolling options. I've spent alot of time and effort and have come up with some really brilliant combinations that run the gambit of sonic signatures. I've also become pretty good friends with the designer of the Studio Six. He's definitely helped guide me and my decisions to squeak out every last bit of proformance possible.

Woo Audio WA6-SE & ALO Studio Six, an excellent and complimentary pair of amplifiers. Good times ahead for you, for sure!

Thanks for your kindness and generosity and your wisdom. It's been years since I had tube gear and I think I;ve been subconsciously avoiding it to protect myself from rampant tube-rolling and constant new-toy syndrome. I've also learned from my DIY and op-amp rolling days that the more you mess with stuff, the more likely you will mess it up or break it.
I'm also old enough to understand that reading about stuff online is not a substitute for actually hearing stuff for yourself. Having a reference and a target also helps, plus being confident enough to answer the 'why question' with 'because it makes me happy' is a complete answer, so long as I am being honest with myself. That said, having someone point you in the right direction, is a wonderful thing to have access to. Thanks!

It's also nce that the Woo is a reasonable size and weight (even if two chassis) for tweeking purposes. It's almost a one-hander (again, per chassis) unlike a lot of gear which takes both hands, maybe bending at the knees, or even the big-dogs where you spring for beer and pizza (or tofu and Kombucha for you Cali folks) for the byddy(s) you hve to get to help you lift the thing.

The fun has begun!

 

[jonathan c]

• I do love the 2nd Generation WA6SE. There are times () when I wish that I could try 12AT7s or 12SN7s via adapters in the 13DE7 sockets. However, this cannot be done in the SE version.
• Oh, well; the 13DE7 (13FD7) category has good candidates. My favourite is the ‘yellow print’ Sylvania 13DE7: clear, dimensional, dynamic. The smaller field of choice has its benefit : I can focus on the choice of rectifier tube, currently the Brimar CV1863 KB/FE….

 

[fzman]

Scored a matched pair of 1960s NOS, RCA 6DE7's on eBay, that just arrived today. They have about an hour or so on them so far, and they are an interesting contrast with the Raytheon 6EW7s that the 6-SE arrvied with. Having quite recwently re-entered the tube world, and having only heard this amp with the above-mentioend dual triodes, i cannot say what aspects are Raythen vs RCA, vs DE vs EW for them. the RCA 6DE7s sound more resolving than the EW7s. They come across as more balanced, in the sense that no specific performance parameter jumps out at you. The ^DE7s seem to give slight priority to the strings rather than the body of the instrument, better control of the bass, and more LF extension. Is is a bit more shimmery/sparkly/delifcate, while the ^EW7s have a bit more of that palpable, velvety liquidity and sweetness. These are subtle differences, not in-your-face differences. I like both.

I've ordered, and hope to get soon, the following:

!!!!) (Recommended Single) 5Z4G Brimar UK black plates NOS 1950's (57/40 and 58/40) (recommended for Audio Note) × 1

(!!!!) (Best Pair) 6EW7 Hitachi Japan branded Westinghouse BIG BOTTLE NOS 1970-1972 (4.3/4.4ma and 60/61ma) × 1

(!!!) (Best Pair) 6DE7 Sylvania black plates NOS 1960's - 1970 (5.1/31ma and 5.2/33ma) (Woo Audio) × 1

this will give me two pair each, of the 6DE7 (Sylvania and RCA) and 6EW7s, (Raytheon and Hitachi/Westinghouse. Also give me a 5Z4G to compare to my 5U4G.....

That's it for now (famous last words). It'll be enough of an arsenal to make the relevant compairons, and have enough data points to have a decent overview of what this amp can do, and how tube-rolling changes the sound....

 

[BryceS]

Gents,

I have 12 month old second generation WA6 fitted with a 1960’s Phillips GZ34 rectifier and 1970’s RCA 13DE7 driver tubes. It is my first and only tube amp. It sounds excellent paired with a Schiit Modi Multibit DAC connected with short ddhifi cables.

I mainly listen with it using HD600s with a nice braided GUCraftsman cable but also use DT1770s, Mr Speakers Aeon Flow Open and Dan Clark Audio Aeon Noire. The WA6 does surprisingly well with the Aeons, especially the Noire which seem to do better on the WA6 courtesy of the better tuning compared to the older Flow Opens, the bass is cleaner and the lack of current versus a typical solid state amp doesn’t seem to effect the bass very much at all with the Noire.

Now with that out of the way, my question !

The WA6 makes a soft hum through the headphones that is just barely audible with HD600 in a dead quiet room and completely inaudible with the less sensitive Aeons. With IEM, not that I really care but as a frame of reference, it is quite noisy and the hum can be heard on quiet passages of music. The hum sounds like transformer noise to me.

When warm the tubes are dead quiet, they have probably over 100 hours use on them. I’ve tried several sets and they make no difference to the hum. After around only 30 seconds of warm up winding the volume pot right up with no music playing doesn’t alter the volume of the hum at all even with IEM when testing. I’ve had it in two houses 650km (400 miles) apart and it is no different, I’ve put an iFi DC blocker on the power socket and an iFi AC purifier on the outlet, I’ve switched other electrical equipment off, I’ve unplugged everything from the WA6 except the power cord and headphones (and tubes obviously) and absolutely nothing makes the hum any better or any worse.

It really isn’t bad with full size headphones and, as indicated above, with my preferred HD600 it is only just audible with no music playing in very quiet conditions but I’m a bit ……retentive and it is one of those things that is annoying once you know it’s there despite that in normal use it can’t be heard.

Is the (presumably transformer) hum typical with the WA6 ? Am I concerning myself about nothing ? Am I hoping for to much for a relatively entry level tube amp to be pitch black quiet ?

 

[ColSaulTigh]

Gents,

I have 12 month old second generation WA6 fitted with a 1960’s Phillips GZ34 rectifier and 1970’s RCA 13DE7 driver tubes. It is my first and only tube amp. It sounds excellent paired with a Schiit Modi Multibit DAC connected with short ddhifi cables.

I mainly listen with it using HD600s with a nice braided GUCraftsman cable but also use DT1770s, Mr Speakers Aeon Flow Open and Dan Clark Audio Aeon Noire. The WA6 does surprisingly well with the Aeons, especially the Noire which seem to do better on the WA6 courtesy of the better tuning compared to the older Flow Opens, the bass is cleaner and the lack of current versus a typical solid state amp doesn’t seem to effect the bass very much at all with the Noire.

Now with that out of the way, my question !

The WA6 makes a soft hum through the headphones that is just barely audible with HD600 in a dead quiet room and completely inaudible with the less sensitive Aeons. With IEM, not that I really care but as a frame of reference, it is quite noisy and the hum can be heard on quiet passages of music. The hum sounds like transformer noise to me.

When warm the tubes are dead quiet, they have probably over 100 hours use on them. I’ve tried several sets and they make no difference to the hum. After around only 30 seconds of warm up winding the volume pot right up with no music playing doesn’t alter the volume of the hum at all even with IEM when testing. I’ve had it in two houses 650km (400 miles) apart and it is no different, I’ve put an iFi DC blocker on the power socket and an iFi AC purifier on the outlet, I’ve switched other electrical equipment off, I’ve unplugged everything from the WA6 except the power cord and headphones (and tubes obviously) and absolutely nothing makes the hum any better or any worse.

It really isn’t bad with full size headphones and, as indicated above, with my preferred HD600 it is only just audible with no music playing in very quiet conditions but I’m a bit ……retentive and it is one of those things that is annoying once you know it’s there despite that in normal use it can’t be heard.

Is the (presumably transformer) hum typical with the WA6 ? Am I concerning myself about nothing ? Am I hoping for to much for a relatively entry level tube amp to be pitch black quiet ?

Can you hear a PHYSICAL hum from the transformer area of the amp itself? Does the sound happen with other tubes inserted? Does the hum change "frequency" or "intensity" if you physically touch the amp? On my WA6-SE's, I found certain driver tubes will generate more "hum" than others. I also found that, of all things, an Emotiva CMX-2 cured ALL hum, giving me inky black background unless I crank the amp all the way to max (definitely NOT recommended).

Also, upgrade from a basic power cable to anything of quality (I use the $50 ones off Amazon)..

 

[BryceS]

Can you hear a PHYSICAL hum from the transformer area of the amp itself? Does the sound happen with other tubes inserted? Does the hum change "frequency" or "intensity" if you physically touch the amp? On my WA6-SE's, I found certain driver tubes will generate more "hum" than others. I also found that, of all things, an Emotiva CMX-2 cured ALL hum, giving me inky black background unless I crank the amp all the way to max (definitely NOT recommended).

Also, upgrade from a basic power cable to anything of quality (I use the $50 ones off Amazon)..

Yes there is also a slight hum from the amp itself.

Other tubes make no difference and touching the amp makes no difference.

Literally nothing I have tried makes any difference at all, only flipping the impedance selector does anything but that is slight. I assumed that is because it changes the transformer windings that are in use.

An “audiophile” power cord is the one thing I haven’t tried, it seemed an unlikely fix when other power related things make literally no difference.

I had resisted other power related items for the same reason, the iFi ones I have at the moment do nothing so it seemed unlikely it was related to the power supply rather than the transformer itself.

I’ll look into cables and the Emotiva unit.

 

[ColSaulTigh]

It could quite possibly be the transformer itself, especially if you can hear a physical hum.

Have you tried a "Humdinger" (or device of it's kind? I know a couple of people have used them with much success.

 

[fzman]

DC offset on the ac power line, and/or a badly distorted sine wave coming 'from the wall' can make transformers physically vibrate-especially toproids. This is made worse if they are not vibration-mounted, or have loose mounting bolts. Power conditioners/filters, per se, do not fix this problem.

That said, the lowest impedence, cleanest power delivery possible makes a big difference in how well your audio gear performs. If rectiofier tubes make a difference, stands to reason that power cords may also help, if you chose the right ones.

 

[ColSaulTigh]

DC offset on the ac power line, and/or a badly distorted sine wave coming 'from the wall' can make transformers physically vibrate-especially toproids. This is made worse if they are not vibration-mounted, or have loose mounting bolts. Power conditioners/filters, per se, do not fix this problem.

That said, the lowest impedence, cleanest power delivery possible makes a big difference in how well your audio gear performs. If rectiofier tubes make a difference, stands to reason that power cords may also help, if you chose the right ones.

Yep, that's where I was going with my questions.

 

[senseitedj]

My favorite rectifier in the WA6-SE.

That is my favourite too, I have the GEC version .

Quick question - how many hours have you had on this tube? just an estimate. Wondering how long these tubes last...

 

[RobertSM]

That is my favourite too, I have the GEC version .

Quick question - how many hours have you had on this tube? just an estimate. Wondering how long these tubes last...

So I'm sort of guessing I have maybe 1,600-1,700 hours on my Osram labeled U52.

It still has tons of silvering from the getter flash and sounds great. My suggestion is to enjoy it. Rectifiers especially can have long long lives.