[TheShaman]

Hey all,

Santa brought me a pair of AKG 702s and I really need your help to choose some decent amplification.
No, my laptop's output is not up to the task (to put it mildly)..

The requirements:

1. I'd like to build both a ss and a tube amp.
2. I'm mostly listening through speakers so I want something good (which will hopefully keep me happy for a long time) but not very expensive.
3. The ss amp should sound like ss (aka neutral and detailed with good control over my headphones) and the tube amp should be a as flexible as possible so that I can adapt to my mood (from neutral to "tubey") by tube rolling, tampering with feedback etc... For that reason alone I'm prepared to spend more on the tube unit.
4. There should be at least a PCB for these. A kit would be even better.
5. The tube amp must be able to run on 6H30Ps. By "run" I don't mean "be able to power on with these tubes" but also have decent performance.
6. It'd be nice to have the tube amp work as pre-amp as well, but I don't care enough to settle for a lesser amp just to have this option.

So, I've made a shortlist containing two amps of each type and I hope this'll also give you guys a better idea of what I'm looking for (in terms of complexity, price, performance etc.)..

As far as the solid state amp is concerned, my shortlist includes:

1. CK2III
2. PIMETA V2

I'm leaning towards the CK2III mostly because you have everything everything on one board which I like but, on the other hand (and based on what I've read) it seems the PIMETA v2 has a potential for better sound and there is generally more room for customization..

Moving on to the tube amp, the two options I'm considering are:

1. EHHA
2. SOHA II

I did my research and I was all set for the EHHA but I was put off when I recently read a comment by Alex Cavalli himself that EHHA is considered obsolete and EHHA II is in the works.. He was mostly referring to the availability of 6GM8, which wouldn't be an issue in my case since I'm planning on using the 6H30P right from the start, but still...

From what I understand the EHHA is more expensive and complicated than the SOHA II but it also offers better sound quality.
I had also considered the Bijou but I recall reading that such an amp is not the best choice for my low impedance AKGs and, even if it were, the EHHA must be even better..

Btw, at some point I'll get down to building an All-In-One Aikido preamp for a friend (6CG7/6H30P combo) so I'll try to test it in headphone amp duties as well.
I haven't come across any sort of comparison between such an Aikido and the other amps discussed here more often but if it turns out very good I might just go for that instead of building an amp that I've never heard (and might or may not be better).

Phew! That's all..

Any input/info (objective or subjective) that'll help me choose between those amps (or even make it harder by suggesting something not on my shortlist), would be appreciated!

 

[jezz]

I would suggest the CK2III and the SOHA II. I have 2 reasons for you.

• The CK2III and SOHA II can both be made for similar prices
• They both have onboard power-supplies and are designed with similar performance goals in mind. Their build complexity matches this.

You list the Pimeta and the EHHA, however those are on different "extremes" of the difficulty, price, and performance spectrum. It is much easier to compare a β22 to the EHHA and likewise a mini3 to a Pimeta. If you want to amps that are somewhat "matched" in their design intentions, the CK2III and SOHA II are the way to go.

That said, if you want to go for the EHHA's level of performance, if you build a σ22 in a modular way (i.e. it can be plugged/unplugged from amps), the EHHA and β22 both run on the same supply voltages and so thte same σ22 could be used for both. The EHHA does have its heater supply, but a fair portion of the two amps would be common.

Incidentally, my understanding was that the EHHA I wasn't going to be made obsolete by the EHHA II; the EHHA II is designed from the start to be a speaker amplifier. To continue the comparisons to AMB Labs, a β24 type of creature.

Short version: CK2III & SOHA II or β22 and EHHA are my votes.

 

[TheShaman]

Thanks for the input jezz.

Quote:

Originally Posted by jezz /img/forum/go_quote.gif You list the Pimeta and the EHHA, however those are on different "extremes" of the difficulty, price, and performance spectrum.

Difficulty is not an issue and I thought V2 of the PIMETA could be made to sound pretty good (on par with CK2III if not better?) that's why it's there. Please, correct me if I'm wrong.

You're also right about the cost but I don't mind spending a little more on the tube amp if that's what it takes to get flexibility and performance that I want.
You see, I'm basically a ss guy and I assume I won't be let down by a CK2III-class amp while, on the other hand, I'm afraid I might be disappointed by my tube amp and that's why I'm aiming a bit higher for that one.
Hope it makes sense.

Quote:

Originally Posted by jezz /img/forum/go_quote.gif That said, if you want to go for the EHHA's level of performance, if you build a σ22 in a modular way (i.e. it can be plugged/unplugged from amps), the EHHA and β22 both run on the same supply voltages and so thte same σ22 could be used for both. The EHHA does have its heater supply, but a fair portion of the two amps would be common.

Hmm.. I never thought about combining EHHA and β22 in one chassis.
I mean I'm sure I did see a head-fi'er post pics of such a setup before, but I never really projected this solution on my case. Thanks for that!

Using a single σ22 would probably bring the cost down a bit.
I might not be able to afford both of these amps right away but I can always build one of them first and add the other later.

I'll have to think about that.
CK2II and SOHA II are probably more than enough for my (zero) experience with quality headphones and the limited time I've spent with them, but, knowing me, at some point down the road I'll start thinking about EHHA and β22. If I go for those right away I'll probably save money in the long term (and there is not much to upgrade to, anyway).

Quote:

Originally Posted by jezz /img/forum/go_quote.gif Incidentally, my understanding was that the EHHA I wasn't going to be made obsolete by the EHHA II; the EHHA II is designed from the start to be a speaker amplifier. To continue the comparisons to AMB Labs, a β24 type of creature.

Yes, that's exactly what I thought as well, until I read this post.

Hope Alex can clarify that for us.

 

[mugdecoffee]

I used a Bijou and k701s for at least 6 months and I thought it was a great match. The soundstage and sense of space was fantastic. I did find the bass a little lacking though that may be a fault in the k701s more than the amp. I don't think their lowish impedance really matters much with the Bijou's adjustable negative feedback. I'd keep it on your list.

If you want to tune your tube amp, the CTH may be the way to go. It can use an absurd array of tubes with no adjustments. It also only requires 1 tube for stereo so tube rolling is cheaper than most other tube amps.

 

[dpmiller]

x2 for the Bijou or CTH with k702s; I also use k501s with both amps. Not much experience with other headphones, but I like what I hear with these.

B22 in the works...

 

[jezz]

Quote:

Originally Posted by TheShaman /img/forum/go_quote.gif Hmm.. I never thought about combining EHHA and β22 in one chassis. I mean I'm sure I did see a head-fi'er post pics of such a setup before, but I never really projected this solution on my case. Thanks for that!

Just to clarify, I don't mean in the same chassis. I mean having the β22, the EHHA, and the σ22 in three different chassis'. Then having a common umbilical between the σ22 and the β22 and the EHHA (so you could run σ22 + β22 or σ22 + EHHA).

From what I've seen, you can sell your existing DIY amps to fund new amps in the FS forums and not take a loss on them. That said, it's less soldering in the long run if you go straight for the "big guns." I don't think it'll save you much money though.

I'm pretty sure both the CK2III and the SOHA II are available as kits from Glass Jar Audio if you ask Jeff. Then again, so are the EHHA, β22, σ22, and the Bijou. The EHHA is slightly less kit-friendly as you would still need to assemble a heater supply, and I can't comment on the Bijou. If money is no object or you're going for this in the long term, I'd suggest the EHHA and β22 route.

 

[TheShaman]

Thanks for your input everyone. Much appreciated.

Quote:

Originally Posted by mugdecoffee /img/forum/go_quote.gif If you want to tune your tube amp, the CTH may be the way to go. It can use an absurd array of tubes with no adjustments. It also only requires 1 tube for stereo so tube rolling is cheaper than most other tube amps.

Quote:

Originally Posted by dpmiller /img/forum/go_quote.gif x2 for the Bijou or CTH with k702s; I also use k501s with both amps. Not much experience with other headphones, but I like what I hear with these.

Thanks guys.
Isn't the CTH a bit on the lowish end compared to the other amps discussed here?
From the comments I've read it must be something like CTH < SOHA II < EHHA.
The Bijou would probably be in the same league as SOHA II.

Again correct me if any of the above is wrong because I'm trying to assemble the puzzle with any pieces I can find in forum - I haven't had a chance to listen to any of these amps.

Quote:

Originally Posted by jezz /img/forum/go_quote.gif Just to clarify, I don't mean in the same chassis. I mean having the β22, the EHHA, and the σ22 in three different chassis'. Then having a common umbilical between the σ22 and the β22 and the EHHA (so you could run σ22 + β22 or σ22 + EHHA).

Oh, OK. That's an even better idea then..!
I misunderstood because your post reminded me of that other build I was telling you.
I'm pretty sure that build had everything in one case (and the goal was to try and have the sigma plugged in onto both simultaneously) but I think your solution is neater.

Quote:

Originally Posted by jezz /img/forum/go_quote.gif The EHHA is slightly less kit-friendly as you would still need to assemble a heater supply, and I can't comment on the Bijou. If money is no object or you're going for this in the long term, I'd suggest the EHHA and β22 route.

A heater supply won't be a problem. In fact I consider it a plus for the EHHA because the 6H30P needs a heavy-duty heater supply to work properly and I'm afraid the other amps we're discussing (esp. those with built-in power supplies) won't be able to run it properly.

As I was saying, I had pretty much decided on the EHHA (although it troubled me that not many people have built it here, which goes for the Aikido as well) because it seems to offer many of the things I'm looking for (reportedly high-endish sound, flexibility in terms of tubes, feedback etc.) but it was the recent comment of Alex Cavalli that made me reconsider.
If he wasn't referring to the EHPA (aka speaker amp version of the EHHA) and there is indeed a new EHHA II headphone amp coming our way, it'd probably be wise to wait, at least on the tube amp front.

 

[TheShaman]

On the solid state front, some other amps that are not discussed a lot, I think, are Zen-like amps and generally of the pure, simple, single-ended, Nelson Pass school of thought stuff. Any input on those?
Death Of Zen is a good example or some Szekeres variations with gain.

 

[johnwmclean]

jezz, that’s exactly what I’m building atm. A dual σ22 for duties between a balanced EHHA and balanced β22.

 

[TheShaman]

Balanced would actually suit me better since I have a Buffalo 32S as well, but such a setup would definitely be out of budget!
Still, let us know how the two amps compare.

 

[TheShaman]

How would you guys say an EHHA compares to an Aikido (6H30P on the EHHA, 6CG7+6H30P on the Aikido) for both preamp/headamp duties?

 

[TheShaman]

Not much info (nor experience) on the high voltage Aikido, I see.

Is it because the rest of the designs discussed here (mostly Cavalli, AMB and Tangent stuff) are considered superior or is it just harder to build (higher voltages etc.) ?