DIY progress report

Jump to Latest
#901
I couldn't resist. Over the weekend I put a TAD 1201 in the
Kleinhorn with TAD 4001 / Emlar Horns on the top and El Pipe-O
on the bottom. In case you happen to own any of these, I'll put
up a quickie article soon.

Did I mention I live in California?
 

Attachments

  • slippers.jpg
    slippers.jpg
    62.7 KB · Views: 1,398
#905
jacco vermeulen said:
Mind if i ask where the strength of the F1 lies compared to the Al.30 ?
Click to expand...

El Pipe-O doesn't like a current source - the bass is muddy and
resonant without a decent damping factor.

Driving the Lowthers and Fostex types, the current source
has some advantages in delivering more bottom and top and
it has a more live sounding character. These drivers are over-
damped, being very light with big magnets, so it's no surprise.

With the current source it's very easy to tailor the Q on the
bottom end (resistor in parallel) and the baffle step correction if
needed (RC network in parallel).

Some drivers, like the 8 inch Lowthers have a character on the
top octave of a peak and a dip, and you can fix that up a bit with
an LRC circuit in parallel.

Of course you can do this with active equalization, but somehow
I've not achieved as good a sound that way, although the curves
are much flatter yet. I've speculated on the cause, and one of
these days we'll need to investigate whether it's crappy op amp
circuitry, high Q filter sound, or the speaker's interaction with
the passive networks. I really don't know at this time.

😎
 
#907
I don't know, but my guess is that it's a reasonable approach.
Susy only works well in low feedback systems, and its strength
is its performance in low feedback. Given the phase shift that
you will be enjoying on your filtered output, very low feedback is
probably how you will want to go.

😎
 
#908
😎 concept is 😎 concept, can be exported anywhere. From PassLabs to ClassD, have tobe very 😎 one to be able to do that.

Mr.Pass, a little question about classD, do you mind? I also thinks alot about phase shift that LC filter caused. Which do you agree more for classD, feedback is taken before LC or after LC filter?
 
#911
Dear Mr. Pass,


I am just wondering what happened with transconductance Zen, or V8 if I can name it?

Perhaps the modifications from ordinary Zen into transconductance are so simple, and it is "understandable" that most folks here will be able to do it...I tried it, but it was not so successful...

So I decided to wait for another article
😀

I am sure you have more important things to do, but after F1 articles and current source crossover ones, wouldn't it be nice to have one about Transconductance Zen?

I believe it shouldn't jeopardize F1 in any way...

Or, maybe there isn't enough interest for this?

Only assuming...:xeye:


Best Regards,

Vix
 
#916
it depends what you call 2 stages

I sometimes read here that in an amp, a follower doen't count as a stagr per se, neither does a cascode transistor (you can see the emitter follower as a voltage follower, and a common base (cascode) as a current follower)

so, an amp with a diff pair/vas/follower output stage has only 2 stages?
 
#918
Bricolo, I would say the input diff is one, the vas the second, and the current gain the third one. I wonder how would look a zen current source, and have some schemes in my spice software.

But I'm expecting another rabbit from that hat.
 
#919
Raka said:
Let me ask you something... are you going to make it in two stages?
Click to expand...

One stage.

Bricolo said:
it depends what you call 2 stages

I sometimes read here that in an amp, a follower doen't count as a stagr per se, neither does a cascode transistor (you can see the emitter follower as a voltage follower, and a common base (cascode) as a current follower)

so, an amp with a diff pair/vas/follower output stage has only 2 stages?
Click to expand...

I count a follower as a stage, so in your example this would
be 3 stages, 4 if the output followers are darlingtons.

I don't call bias current sources or cascode devices gain stages.
The question to ask is: what gain do they contribute? If the
gain is negligible or non-existent, then they are not gain stages.

You can have common-emitter (or common source) devices used
as level shifters and have them look like a VAS, but they can be
set up so that they don't contribute gain, in which case I suppose
you can leave them out of the gain stage count.

I think of this as a practical definition, much like the discussion
of whether you can have a no-feedback amplifier.

😎
 
#920
I count a follower as a stage, so in your example this would be 3 stages, 4 if the output followers are darlingtons.
Click to expand...
I remember in A75 project Mr.Pass considers putting a driver stage or not for the final stage. The decission is not to put it.

How about this to count stages. From input signal to output terminal, how many base/gate that the signal must pass, then it is a number of stages. If the signal is passing thru emitor/collector/source/drain, it doesn't count as a stage, because the signal doesn't enter to base/gate.
 
You must log in or register to reply here.
Top Bottom