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DIY amplifier for current hungry speakers question.

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Posted on January 5, 2017 at 08:21:17
Iczerman
Audiophile

Posts: 121
Joined: July 23, 2000
I got current hungry speakers.

If I bias kt120 tubes to over 100ma in a push-pull amplifier...would the speaker "see" over 200 ma of current?

Or would I need to look into the 6c33c tube?

 

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RE: DIY amplifier for current hungry speakers question., posted on January 5, 2017 at 09:16:13
Paul Joppa
Industry Professional

Posts: 6694
Location: Seattle, WA
Joined: April 23, 2001
That's what output transformers are for.

 

RE: DIY amplifier for current hungry speakers question., posted on January 5, 2017 at 12:38:37
used-hifi
Audiophile

Posts: 529
Location: Surprise AZ
Joined: March 18, 2003
Thats not totally correct tranformers are voltage step or step down devices not current step up or step down.


Lawrence

 

First things first, posted on January 5, 2017 at 12:42:24
drlowmu
Manufacturer

Posts: 9706
Location: East of Kansas City
Joined: January 10, 2005
The very first thing you must attend to is to be sure you have good transfer efficiency, between the amp, the speaker crossover, and the wiring from the crossover to the individual drivers.

There are huge "dividends' by having speaker wiring, all the way to the driver, optimized for transfer efficiency. That is THE starting point, in optimizing high or low efficiency speaker implementations.

It need not be e the most expensive wiring, to have optimized transfer efficiency, but it must be executed well, and with good thinking behind the choices.

Think of it as asking us about a supercharged large block Hemi engine, but the car you use has bald tires, and thin tires, on the drive wheels. Fix 'de tires first.

If you need cost effective solutions, ask us, or even me. First things first. Good luck.

Jeff Medwin

 

Huh? , posted on January 5, 2017 at 12:47:26
gusser
Audiophile

Posts: 2406
Location: So. California
Joined: September 6, 2006
The power ratio through a transformer always remains the same negating small internal losses.

So how do you keep the power ratio the same by only changing the voltage and not the current?

To answer the OP, the power on the OPT secondary will be that of the power into the primary minus some slight resistance loses.

 

No, stop., posted on January 5, 2017 at 12:51:30
Chip647
Audiophile

Posts: 1703
Location: The South
Joined: December 24, 2012
Read up a little on transformers. A filament transformer will take 1 amp at 120 volts to create 12 amps at 10 volts. Both current and voltage "transformations" are characteristics of transformers. You may be thinking of a resistor network.

 

RE: DIY amplifier for current hungry speakers question., posted on January 5, 2017 at 13:09:14
Triode_Kingdom
Audiophile

Posts: 6089
Location: Texas
Joined: September 24, 2006
Speakers can only consume current in proportion to their impedance. Unless the impedance falls to considerably less than their rating, particularly at low frequencies, they're not "current hungry."



--------------------------
Buy Chinese. Bury freedom.

 

RE: DIY amplifier for current hungry speakers question., posted on January 5, 2017 at 13:38:47
Chip647
Audiophile

Posts: 1703
Location: The South
Joined: December 24, 2012
Some speakers with widely swinging impedance that drops below 2 ohms can be too much of a challenge without altering the speaker some what with a zobel network or some such. Some speakers are not tube friendly (Apogee et. al.)

 

RE: DIY amplifier for current hungry speakers question., posted on January 5, 2017 at 20:37:02
hahax@verizon.net
Audiophile

Posts: 3087
Location: New Jersey
Joined: March 22, 2006
What are your current hungry speakers?

 

I think you mean voltage-hungry, as in reactive nt, posted on January 6, 2017 at 06:26:23
Frihed89
Audiophile

Posts: 15185
Location: Copenhagen
Joined: March 21, 2005
nt

 

This is how I determined my speakers are current hungry.., posted on January 6, 2017 at 08:28:20
Iczerman
Audiophile

Posts: 121
Joined: July 23, 2000
Same approximate listening levels.
Two different amps that sound so different...
Tube amplifier- Sophia electric baby amplifer- bad match.
Solid state amplifier- Parasound Halo 23- Good match, but I miss the sound of tubes.

 

LOL, posted on January 6, 2017 at 08:40:26
Triode_Kingdom
Audiophile

Posts: 6089
Location: Texas
Joined: September 24, 2006
Two amps sounding different is evidence that the speakers are "current hungry." Haven't heard that one before.




--------------------------
Buy Chinese. Bury freedom.

 

perhaps POWER hungry would be more appropriate? nt, posted on January 6, 2017 at 11:02:00
vinnie2
Audiophile

Posts: 2731
Joined: September 28, 2013
nt

 

Yup....watts are not the same., posted on January 6, 2017 at 13:38:30
Iczerman
Audiophile

Posts: 121
Joined: July 23, 2000
According to Ohms law.
Tube amps..high voltage/low current.
Solid state amps.. Low voltage/high current.

 

RE: Yup....watts are not the same., posted on January 6, 2017 at 13:51:05
gusser
Audiophile

Posts: 2406
Location: So. California
Joined: September 6, 2006
Again you are failing to understand the function of the OPT.

All modern speakers run on low voltage/high current.

A solid state amp produces that directly.

A tube amp must transfer the developed wattage through a transformer to get the proper voltage to current ratio. However the same amount of audio power is being developed in either case.

As for the differences in tube vs solid state sound, there are many variables that cause this effect.

 

RE: Yup....watts are not the same., posted on January 6, 2017 at 15:43:45
Tre'
Industry Professional

Posts: 12244
Location: So. Cal.
Joined: February 9, 2002
"As for the differences in tube vs solid state sound, there are many variables that cause this effect."

Damping factor for one.


Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"

 

Yup!, posted on January 6, 2017 at 15:50:51
gusser
Audiophile

Posts: 2406
Location: So. California
Joined: September 6, 2006
Caused by that nasty OPT once again!

 

RE: DIY amplifier for current hungry speakers question., posted on January 7, 2017 at 15:45:47
6bq5
Manufacturer

Posts: 2245
Location: SF Bay
Joined: August 16, 2001
Contributor
  Since:
September 14, 2012
If you have a tube amp with multiple taps - say 2, 4 & 8 Ohms, and your current hungry speakers are currently connected to the 8 ohm taps - you can go down to the 4 or 2 ohm taps you will get more current - at the expense of voltage-
Ohm's Law (AC) Current = Voltage / impedance

The tube amp output function is fixed by the circuit and the OPT-
adjusting the bias will not affect the output.
Happy Listening

 

RE: DIY amplifier for current hungry speakers question., posted on January 7, 2017 at 16:02:17
sony6060
Audiophile

Posts: 728
Location: SE MI
Joined: August 8, 2014
Tilte states a DIY amplifier. I would use four KT88 per channel with 525 volts plate and 300 volts screen for 120 watts per channel amplifier. I would use Lundahl LL1693 audio transformers and a 6SN7 driving a twin tail phase invertor. 6SN7 are very linear tubes. Sylvania 6SN7 GTA are excellent.

 

RE: Yup!, posted on January 9, 2017 at 04:38:39
PakProtector
Audiophile

Posts: 11353
Joined: May 14, 2002
Limited by that nasty OPT perhaps. For sure if you take a global loop of NFB around it. In the extreme the limit is certainly the DCR of the windings...assume the secondary is aero resistance, the primary DCR will still have a non-zero reflected value.

While I disagree in principle with him, Geddes said that two amps that measure the same will sound the same. I do not believe his set of measurements include all the required components for this to be true, let alone the impracticality of attempting to get two amps to measure the same in even the gross values...LOL
cheers,
Douglas

Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

 

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