[skhan007]

Besides the phase splitter, are there noteworthy differences between WA22 Gen 1 and Gen 2?

 

[muckyfingers]

The 1/4” output is flush with the faceplate rather than recessed and mounted with a nut, later Gen 1 models and Gen 2 models share this feature.

Gen 2 models added the preamp outputs in the back.

Woo also switched to a smooth alps volume pot rather than the more expensive stepped attenuator volume pot found on older units.

Newer and "better" transformers.

 

[Badas]

The 1/4” output is flush with the faceplate rather than recessed and mounted with a nut. They added the preamp outputs in the back, which are the same as the front Dual XLR outputs, but routed to the back as well. Woo also switched to a smooth alps volume pot rather than the more expensive stepped attenuator volume pot found on older units. Other than those changes and the phase splitter, Woo says they’re the same.

So mine must be a hybrid between Gen 1 and 2 then? Purchased 2014.
Mine has 1/4 output flush mounted, stepped attenuator volume pot, but no XLR preamp output on the back.

 

[muckyfingers]

So mine must be a hybrid between Gen 1 and 2 then? Purchased 2014.
Mine has 1/4 output flush mounted, stepped attenuator volume pot, but no XLR preamp output on the back.

There were a couple of inbetween models, like Gen 1.5, if you will. They have the flush 1/4” output, none had the preamp in the back, but some did have holes with plugs where the preamp would be located in Gen 2 models.

 

[CAJames]

Maybe we’re both right and they changed the way the 1/4” output is wired once the phase splitter was introduced.

Here’s the thing I don’t understand. The 1/4” plug has 3 connections: left, right and ground. How did you wire that in parallel to a balanced signal that has 4 phases: L+, L-, R+ and R-? This isn’t a rhetorical question, it sounds like you have tested this.

 

[muckyfingers]

On 1st Gen WA22’s, as that’s what I have and have seen other photos of, L- and R- at the headphone output, not at the balanced input, are wired to Ground. Which is why I, and others, say it is the same signal for all 3 outputs.

 

[muckyfingers]

Here’s the thing I don’t understand. The 1/4” plug has 3 connections: left, right and ground. How did you wire that in parallel to a balanced signal that has 4 phases: L+, L-, R+ and R-? This isn’t a rhetorical question, it sounds like you have tested this.

Think of it like this, when using your headphone XLR cable with the WA22, the WA22 is internally wired just like this adapter

 

[muckyfingers]

Here’s a great quote from another thread, that summarizes much of the confusion around the WA22 and the “balanced” questioned.

i.e. The WA22 is “balanced, differential” on the inputs, but only “balanced” on the headphone outputs.

The Woo Audio WA22 is a fully balanced amp with both balanced inputs and balanced outputs. The confusion regarding the WA22 stems from the confusion people have between the terms "balanced" and "differential".

For the purposes of this discussion:

A balanced circuit only means that you have two signal conductors, each with the same impedance to circuit ground.

A balanced, differential circuit means you have two balanced conductors, each with the same signal except on one conductor the signal is inverted (180 degrees out of phase).

Each channel of the WA22 has two signal inputs, + (in-phase signal) and - (inverted-phase signal) , (balanced and requiring a differential signal pair) and a ground. Each of the signal inputs feeds a separate drive circuit to either side of the transformer primary.

This creates a balanced, differential drive circuit that works by applying an amplified version of the original audio signal (+) to one side of the transformer primary while simultaneously applying an amplified inverted version of the original audio signal (-) to the other side of the transformer primary. Driving both sides of the transformer primary with a differential circuit doubles the slew rate (rise time) of the amplifier, and reduces noise induced from the external balanced cable run through the internal circuit. Actively controlling both sides of the transformer primary should also reduce distortion (grounds do float) but some may argue that it is negated by having dual drive circuits - each contributing distortion components.

While the WA22 will work fine with a single-ended input (rca), half of the drive circuit stays dormant at 0 Volts (or floats around a little) and the true audio performance of the WA22 remains underutilized.

The outputs of the WA22 transformers are balanced - all conductors (output signals and ground) have the same impedance to circuit ground. When I bought my WA22, I asked Jack Woo about the issue and he advised that while the XLR and 1/4" outputs share a common ground, the output ground is not connected to circuit ground - hence the output conductors are balanced.

There is definitely an advantage (audio performance) to using a balanced differential circuit to drive the transformer primary but it is unclear what advantages one would gain with a differential output from the transformer.

What comes out of the WA22 transformers is one left-channel signal, one right-channel signal, and a common ground. You can connect to the output via 1/4" TRS, dual 3-pin XLR, or single 4-pin XLR. It is unclear what advantage a balanced HP cable would make as the XLR outputs are electrically the same as the 1/4" TRS.

This is no slight against the WA22. It is a very elegant design. As I mentioned, it is unclear what audio advantage would be gained with a differential output. The WA22 is an ultra high-performance audio amplifier with balanced differential inputs, class A differential amplifier circuits, and balanced single-ended outputs.

https://www.head-fi.org/threads/woo-wa22-balanced-vs-unbalanced-input.634551/page-2

 

[skhan007]

Here’s a great quote from another thread, that summarizes much of the confusion around the WA22 and the “balanced” questioned.

i.e. The WA22 is “balanced, differential” on the inputs, but only “balanced” on the headphone outputs.



https://www.head-fi.org/threads/woo-wa22-balanced-vs-unbalanced-input.634551/page-2

This is great information, thank you for posting!

I'm on the lookout to buy a WA22 and given some of the above posts, the Gen 1 doesn't sound like a bad option all. I don't think I'll ever need/use preamp outs, the phase splitter sounds like a "nice to have" but I don't think its absence would lessen my experience. I believe the volume pot change would be a non-issue. That all being said, maybe a Gen 1 at a somewhat lower price point could be entertained?

 

[muckyfingers]

This is great information, thank you for posting!

I'm on the lookout to buy a WA22 and given some of the above posts, the Gen 1 doesn't sound like a bad option all. I don't think I'll ever need/use preamp outs, the phase splitter sounds like a "nice to have" but I don't think its absence would lessen my experience. I believe the volume pot change would be a non-issue. That all being said, maybe a Gen 1 at a somewhat lower price point could be entertained?

Yes, the Gen 2 has a couple of nice to have options over the Gen 1. The volume pot on the Gen 1 is the better/ more expensive version. The preamp on the back of the Gen 2 is convenient, but you could also use adapters on a Gen 1 and use any of the headphone outputs as the preamp.

Finally, if using a balanced DAC, you aren’t missing any performance. If you do wind up needing or wanting to use the RCA inputs on a Gen 1, then sending it in for the phase splitter upgrade is an option.

 

[mab1376]

Besides the phase splitter, are there noteworthy differences between WA22 Gen 1 and Gen 2?

The other main new feature was XLR pre-amp outputs.

Does anyone have any internal pics comparing Gen1 to Gen2?

I have a Gen2 from March 2022, and curious about how they compare internally.

 

[9bphillips]

I am listening to my wa22 and getting static electrical interference from my phone. I know this is normal but is there a way to minimize it? I have noticed when my phone touches my cable I get interference. Would a sleeved cable help with this? It is really only audible when no music is playing and it isn't really that bad but since I sit close to my wa22 and I like scrolling through headfi or faces sometimes while listening I would like to cut down on the static interference. I will be getting a new cable for my Atrium and VC soon and will probably be getting it sleeved and longer than my cable i have now so I can sit further from the Amp. I am hoping getting it sleeved would help but if not is there anything else I could do to minimize it?

 

[muckyfingers]

I am listening to my wa22 and getting static electrical interference from my phone. I know this is normal but is there a way to minimize it? I have noticed when my phone touches my cable I get interference. Would a sleeved cable help with this? It is really only audible when no music is playing and it isn't really that bad but since I sit close to my wa22 and I like scrolling through headfi or faces sometimes while listening I would like to cut down on the static interference. I will be getting a new cable for my Atrium and VC soon and will probably be getting it sleeved and longer than my cable i have now so I can sit further from the Amp. I am hoping getting it sleeved would help but if not is there anything else I could do to minimize it?

A sleeved cable wouldn’t help, unless the sleeve is some specialized RF reducing/blocking type of material. Using better internally shielded cables would help.

Physical distance is the proven solution. If you do find another solution, please do post about it.

 

[u2u2]

If you have a 1st Generation WA22, the balanced input will give you louder outputs across all headphone connectors, the XLR out to the headphone will still be the same volume as the 1/4", again because they are wired in parallel. The RCA input will only use half the amplifier circuit, thus only giving you half the volume, even if using the XLR output.

On 2nd Generation models, Woo began using phase splitters on the RCA inputs, to give you the same volume as the Balanced input. You can still send in your 1st Generation unit for this upgrade, for about $350.

If you open up your unit, you can see that all the headphone connectors are wired together, they are the same signal. You can also double check this with a multimeter, there is nothing different from the XLR outputs and the 1/4" output, other than the connector itself.

Phase splitter has been in use for many years. Most likely 2014 or earlier. This is a many times recurring theme from the older WA22 threads. I had a big interest in finding solid answers on the splitter and headphones outputs before buying my 2015 build WA22. Perhaps there is more to the storey on the 2nd gens. Can you expand on it?

 

[muckyfingers]

Until I get a Gen 2 in my hands, I can't be 100% sure. I currently own a 1st Gen, without the phase splitter upgrade. The information I shared above comes from my experience opening up my unit, Gen 2 info is second hand, mostly from this community, and things Woo have said regarding this topic.

edit: I've made corrections to my previous posts, mainly that the phase splitter was introduced prior to the Gen 2 model release.