Questions about balanced headphone amp

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Hi,

I am considering to buy a DAC either balanced or unbalanced. I have some unbalanced DIY headphone AMPs but now considering to have a balanced one. My questions are:

1. Is balanced AMP really hard to build? How much harder compared to unbalanced one? What are the difficulties/challenges when building a balanced AMP?

2. Is there any good balanced headphone AMP for DIY? Beta22? SS dynalo? I will prefer the design using discrete components over OPAMP. Any other suggestions?
 
I presume you mean truly balanced (both inputs and both outputs are fully differential).
And not differential input but Gnd referenced output.

> 1. Is balanced AMP really hard to build? How much harder compared to unbalanced one? What are the difficulties/challenges when building a balanced AMP?

Not harder to build than SE amp, when truly balanced.
At least double the cost.
Needs much better matching (quads rather than pairs) when discrete.

2. Is there any good balanced headphone AMP for DIY?

cwtim01 from HK has built the only F5X-HA ever.
I believe it is still his reference.

https://www.diyaudio.com/forums/pass-labs/271926-f5-headamp-12.html#post4789673
Post #562.

See also posts #743~746 describing the difference between SE and balanced.
Posts # 1044~1050 for measurements.


Patrick
 
Hi,

I am considering to buy a DAC either balanced or unbalanced. I have some unbalanced DIY headphone AMPs but now considering to have a balanced one. My questions are:

1. Is balanced AMP really hard to build? How much harder compared to unbalanced one? What are the difficulties/challenges when building a balanced AMP?

2. Is there any good balanced headphone AMP for DIY? Beta22? SS dynalo? I will prefer the design using discrete components over OPAMP. Any other suggestions?

I will tell you this, you can convert balanced output to single ended using a ground loop isolator then combining the grounds. There is actually something to gain from this, even if it is defeating the balanced part.

I can give you links to some isolators that work if you need it.
 
A balanced Beta22 is going to be much harder to build that a SS Dynalo. The Beta 22 is a single channel designed board that would need 4 boards populated, plus a power supply, at over $100 per item (~500US ish) plus whatever casing you want to put it in (and pot, cables, conectors etc). A Balanced B22 is almost always built as a dual chassis design, (PS + Amp), which increases the casing costs. This would easly hit $1K US.

The SS Dynalo is a much more elegant design, because it was designed to be balanced in/out from the beginning. It only needs 2 boards (plus a Power supply), with the up front cost of ~120 for a pair of amp boards, plus $120 for a GRLV Power supply and transformer. Add another $200 for pot, Case, cables, etc, and you are looking at $440, vs $800-$1000 for a Beta22.

Have a look at Bob Katz's impressions of the Pure Bipolar, which is based on the SS Dynalo: Katz's Corner Episode 18: Icelandic Wonder | InnerFidelity

Here's a Thread on Head FI too: Mjolnir Audio Pure BiPolar Amplifier | Headphone Reviews and Discussion - Head-Fi.org
 
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Hi,

I am considering to buy a DAC either balanced or unbalanced. I have some unbalanced DIY headphone AMPs but now considering to have a balanced one. My questions are:

1. Is balanced AMP really hard to build? How much harder compared to unbalanced one? What are the difficulties/challenges when building a balanced AMP?

2. Is there any good balanced headphone AMP for DIY? Beta22? SS dynalo? I will prefer the design using discrete components over OPAMP. Any other suggestions?

If you are new to building and troubleshooting, you might have trouble with the higher parts count of the Beta22 and Gilmore amps.

Why not look at the BAL-BAL design from opc here:

The Wire - All Boards and Kits Explained Here!

Yes, it uses op-amps.
 
A truely balanced circuit should have balanced In and Out in one circuit.
Not two SE amps each driving one phase.
An example in IC is OPA1632.

Beta 22, Dyna_xx also do not belong to that category.
They are opamp-like circuits (with negative feedback) configured to accept differential inputs.
https://sub.allaboutcircuits.com/images/03044.png
https://www.diyaudio.com/forums/hea...borberly-eb602-200-revisited.html#post5741230 (post #11)

They do not have in-circuit cancellation of even harmonics, like e.g. a Blowtorch has.


Cheers,
Patrick
 
If you are new to building and troubleshooting, you might have trouble with the higher parts count of the Beta22 and Gilmore amps.

Why not look at the BAL-BAL design from opc here:

The Wire - All Boards and Kits Explained Here!

Yes, it uses op-amps.

I built the dynalo before. The SS dynalo is similar to dynalo circuit with difference in parts. The problem for SS dynalo is, many BJT are discontinued and need to be replaced by SMD one. Question is, how can I do the matching on SMD??
 
The board designers switched to SMD for the BJTs some time ago, and the latest boards are now fully SMD. I built one of the boards with the SMD BJT's and there does not seem to be a concern with matching. There is a servo that will take care of any issues in that regard.
 
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