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True Bass/Output transformers

Castle Knight 2 Speakers


Well-Known Member
Jan 28, 2008

The following was posted on the hktubeaudio group.


Hi all.

Tamura has the best deep bass, but if you want upper bass you should choose something else like Tango or Hashimoto.

With bass, one absolutely must distinguish between true deep bass versus mid/upper bass. Confusing these two separate types of bass is the source of most confusion about bass.

When most audiophiles talk about good bass they are generally talking about mid/upper bass, not true deep bass. They want to hear good bass guitar and good drums. The mid/upper bass region will involve the kick (around 80Hz I think) and slam (around 100-120Hz) regions. It is for this very reason that people can use bookshelf speakers that roll off quickly below 60Hz in a brick room and think they have good bass.

As far as true deep bass goes, this is 20-40Hz, perhaps stretching to 50Hz. The only common instrument that goes down here is the deep left hand of a grand piano. There are other instruments such as organ with true deep bass, but they are far less commonly listened to than piano. What true deep bass is critical for is room ambience. To really create the sense of that live recorded environment you must do 20-40Hz.

To show you how confused people have become about good bass, consider whether vacuum tubes or solid state are better for bass. The propaganda has been that solid state is better, but that is not really true. In the older days, the older Asian audiophiles who played turntable and tubes would tell the young uns that tubes had better bass just listen to it. The young uns would say, Look at the scope. But the young uns were wrong in assuming that the scope told you everything about what you were hearing and nothing else mattered. Solid state with its negative feedback has:
(a) much more limited bandwidth in both treble and deep bass than a great modern tube setup (dont confuse the bad old bandwidth restricted tube setups for these; and it is the increasing stripping of harmonics in the 12-25 kHz range that creates the solid state bandwidth issue even if the fundamentals could go to ultra-high frequencies if they were recorded, which they are not);
(b) less harmonics / dynamics because of the negative feedback (this becomes especially critical in the bass region because a slight time error to harmonic structure will be hard for the human brain to repair here long explanation for another day);
(c) what some people think of as good electric bass guitar and drums is not how it sounds in real life; they are used to the clean sound stripped of harmonics, but this is artificial.

So if a vacuum tube system truly does 20-60Hz it will give you a musically accurate 20-60Hz, whereas solid state struggles greatly to do so.

Where solid state has its advantage is in controlling speaker drivers. But remember these critical points.
1. Although solid state power amps can control the driver for the fundamental notes they suck at the harmonics.
2. Power amps are only one component. What about your entire front end? The solid state here is not controlling any drivers but just compromising your sound quality.
3. It is very possible to build a great subwoofer using vacuum tube amplification. We have done so. Most people cannot be bothered trying.

Now, back to OPTs. The most important aspect for true deep bass response is the amount of core. This is why I selected a Spark-made huge C-core for my subwoofer amp lots of iron and subwoofer use makes it fall below the lower mid error in the Spark factory sound. The Tamura transformers generally have the most core (whether iron, permalloy, or amorphous core) of all the available Japanese transformers. For true deep bass, Tamura is best and has the best room ambience.

However, if you are looking for upper bass, Tamura really suffers a lowering of resolution in that region. So those looking for mid/upper bass are not going to be so happy. The most important point about using Tamura is to never pair it with another transformer with weakness in upper bass. For example, never pair a Tamura choke with a Partridge OPT in the same loop. If you do not inflict a double fatality then you will be fine.

Otherwise, if what you want is great mid/upper bass and you will compromise on not having that great true deep bass, choose Hashimoto (which is overall AAAAA level with some loss of resolution in the high treble) or Tango (which is AAAAA in the mid/upper bass only but loses resolution significantly elsewhere, especially in the entire treble).

By the way, chokes have exactly the same factory sound as OPTs, and in the Japanese chokes I own Tamura (both amorphous and iron), Hashimoto and Noguchi. I specifically chose not to waste money paying many times more for the Japanese OPT when I could get the same effect for much, much less from a choke. For OPTs I use those of the Shanghainese sifu for the front and side channels (these have the best midrange of any contemporary transformer, better than a Kondo Japan; only the vintage Tesa Paris is better for midrange), Partridge for centre channel, Spark C-core custom for subwoofer, and Spark for rears.

On a related topic, I fully agree with Tim de Paravincini that solid state (all solid state components especially the front end) need an output transformer to sound good.



Staff member
Oct 18, 2009
There are a few points which I can relate to especially the stripping of harmonics thingy which is clearly perceivable.