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Old 22nd July 2004, 06:26 PM   #21
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I beg your pardon Guido?

Making an electronic circuit that behaves like a choke is not that difficult, isnít it?

Cheers
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Old 22nd July 2004, 08:13 PM   #22
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Quote:
Originally posted by Pjotr
I beg your pardon Guido?

Making an electronic circuit that behaves like a choke is not that difficult, isnít it?

Cheers
Feel free to build your own guys. This is DIY.

To be honest I am disapointed by the reactions of some among you.

I launch a new product, share and explain about the background and the way it works, and then acused of robbing people because of the prices of the products.

De beste stuurlui staan aan wal
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Old 22nd July 2004, 08:24 PM   #23
Previously: Kuei Yang Wang
 
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Guido,

Just a few words. I like your approach and work/research and it confirms some things I have been thinking about. As a result I have been thinking about a somewhat differnet realisation myself and posted here. That has nothing to do with commercial products for sale but is a discussion of the topics.

As you well know I have decided to use your products in my commercial modification packages. When I comment I do not mean to suggest your products are not good, on the contrary, those I have encountered are.

Sayonara
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Old 22nd July 2004, 09:23 PM   #24
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Quote:
Originally posted by Guido Tent

Feel free to build your own guys. This is DIY.

To be honest I am disapointed by the reactions of some among you.
<Off-topic>

Well Guido,

That is not our point, at least not mine. You are answering questions that come up with an undertone that makes it going that way.

Better to be kind and patient and elaborate things to those asking if you want to market something. We donít blame your product, but may we put up some questions please and have a healthy discussion?

Cheers
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Old 23rd July 2004, 12:31 AM   #25
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Hello Guido, good to see your new product. I'm guessing that the current source has a very high impedance at audio frequencies, and the voltage regulator has some sort of long-time-constant DC servo circuit - which makes the whole thing emulate a low-DCR large-value inductor.

Back when I first built the Amity in 1997, I was appalled just how bad a 3-pin DC regulator sounded on the paired VV32B's. It was nice having less than 10 microvolts of noise appear at the speaker terminals - I've measured noisier preamps - but the sound quality was opaque, closed-in, undynamic, and just plain unlistenable. Switching to AC - a matter of moving a few wires - made all the difference, resulting in a very lively, sparkly sound, completely different. Noise level was OK, about 3mV of 60 and 120 Hz, and no buzz at all.

It wasn't until Christian informed me of the ETF.03 comparison between different types of heating that I considered DC heating at all - it sounds like the current-sourced and paired-choke heaters came out well, which is good news for folks that might want DC - and that could be me as well.

One thought - did you consider paired current sources, so both sides of the filament see a high impedance? Or maybe you already built that and found no difference sonically. Curious what you found ...
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Old 23rd July 2004, 08:05 AM   #26
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Quote:
Originally posted by Kuei Yang Wang
Guido,

Just a few words. I like your approach and work/research and it confirms some things I have been thinking about. As a result I have been thinking about a somewhat differnet realisation myself and posted here. That has nothing to do with commercial products for sale but is a discussion of the topics.

As you well know I have decided to use your products in my commercial modification packages. When I comment I do not mean to suggest your products are not good, on the contrary, those I have encountered are.

Sayonara
Hi Sayonara

I haven't had bad feelings with your reaction, actually your the one who needed the least information before understanding the principle and turning it around into some DIY version.

best regards
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Old 23rd July 2004, 08:40 AM   #27
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Quote:
Originally posted by Pjotr


<Off-topic>

Well Guido,

That is not our point, at least not mine. You are answering questions that come up with an undertone that makes it going that way.

Better to be kind and patient and elaborate things to those asking if you want to market something. We donít blame your product, but may we put up some questions please and have a healthy discussion?

Cheers
Hi Pjotr

If the perception on my reaction is as such, I would like to say that it is not intended. I can be quite short in responding, time is limitted for me.

cheers
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Old 23rd July 2004, 08:45 AM   #28
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Quote:
Originally posted by Lynn Olson
Hello Guido, good to see your new product. I'm guessing that the current source has a very high impedance at audio frequencies, and the voltage regulator has some sort of long-time-constant DC servo circuit - which makes the whole thing emulate a low-DCR large-value inductor.

Back when I first built the Amity in 1997, I was appalled just how bad a 3-pin DC regulator sounded on the paired VV32B's. It was nice having less than 10 microvolts of noise appear at the speaker terminals - I've measured noisier preamps - but the sound quality was opaque, closed-in, undynamic, and just plain unlistenable. Switching to AC - a matter of moving a few wires - made all the difference, resulting in a very lively, sparkly sound, completely different. Noise level was OK, about 3mV of 60 and 120 Hz, and no buzz at all.

It wasn't until Christian informed me of the ETF.03 comparison between different types of heating that I considered DC heating at all - it sounds like the current-sourced and paired-choke heaters came out well, which is good news for folks that might want DC - and that could be me as well.

One thought - did you consider paired current sources, so both sides of the filament see a high impedance? Or maybe you already built that and found no difference sonically. Curious what you found ...
Hi Lynn,

Good to meet you here.

Your guess is right.

I prefer AC voltage over DC, but I do not like intermod increasing by 20dB, due to that AC (for SE that is, I have not measured on PP, but be warned, no hum does NOT mean no intermod)

Yes, ETF03 was fun, not at least because of the heater shootout but we learned a lot

The major advantage of DC heating is that you get rid of the humbucking pot - OUT of the signal.

The main advantage of current heating is that we don not throw away information.

If both sides of the filament see high impedances, how would we arange the cathode to close with the anode current ?

See you in December

cheers
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Old 23rd July 2004, 01:56 PM   #29
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Quote:
Originally posted by Guido Tent



Hi Bas,

A voltage source has a low impedance, compare with car battery, it maintains the output voltage, "regardless" of the load

A current source has a high output impedance, it maintains the output current, regardsless of the load.

My design has a high output impedance, hence does not short the differential audio current generated in the DHT

cheers
Hmmm, good idea Guido, I knew you were cooking up
some goodies over there but would never have picked
a DHT heater voltage reffed current source, smart thinking!

OK, here's a question, WRT differential audio current generated
in the heater, is it better to reference one end of the heater,
or would a theoretical centre point be better, sort of pseudo
balanced?

Good luck, I'm sure the implemetation is first class.

Terry
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Old 23rd July 2004, 04:36 PM   #30
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Quote:
Originally posted by Terry Demol


Hmmm, good idea Guido, I knew you were cooking up
some goodies over there but would never have picked
a DHT heater voltage reffed current source, smart thinking!

OK, here's a question, WRT differential audio current generated
in the heater, is it better to reference one end of the heater,
or would a theoretical centre point be better, sort of pseudo
balanced?

Good luck, I'm sure the implemetation is first class.

Terry
Hi Terry

Thanks for your kind words

The "where to connect heater to ground question" is a fundamental one.

We couldn't hear major differences between tying either end to ground, in a fixed bias setup.

Any kind of balancing, like done with a humpot, decreases the differential impedance, which we don't want.......

So far I prefer having the + side of the heater to ground, but there still is many ways to experiment

all the best
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