F6 Amplifier

[Zoran]

does anybodu have a Spice model for SS jfets?

 

[flg]

Do you realize what is effectively inside the TL device? A zener and an opamp with lotsa gain
Sayin it's better without any reason or data is dumb! Yep you ZM!
Sayin below 100Hz the JFET and Zd is better without any circuit description etc. etc. is just as dumb as ZM!
Sorry
I need more convincing info than a basic sim and a Dummy...

 

[flg]

does anybodu have a Spice model for SS jfets?

I don't but, some have said they do. Try the www.site? Or search...

 

[lhquam]

I have been using the Spice model referred to in this post:
http://www.diyaudio.com/forums/pass-labs/179116-semisouth-spice-models-2.html#post2843791

does anybodu have a Spice model for SS jfets?

 

[flg]

You appear to be correct about that. Here is a Spice simulation of the two. The plot shows the ripple rejection of the two approaches. As you can see, the LED+CCS has a much lower corner frequency than the TL and is about 16dB better at frequencies about 100Hz.

I don't know. Must be Dumber than me? I read: Led+ccs VB2 ripple= 40uVp-p. Quite good in fact.
But, I also read:
TL431 VB1 ripple=17uVp-p???
Who is Dumber? Forgive me ZM
Not tryin to be Dumber

 

[flg]

as far as below 100Hz, I think you might wanna play with the values biasing the TL part a little???

 

[lhquam]

Those captions are poorly stated. What they represent is the ripple rejection without the capacitors, which is the rejection of changes in the DC level of the power supply, ie. the ripple rejection at Zero Hz.

I don't know. Must be Dumber than me? I read: Led+ccs VB2 ripple= 40uVp-p. Quite good in fact.
But, I also read:
TL431 VB1 ripple=17uVp-p???
Who is Dumber? Forgive me ZM
Not tryin to be Dumber

 

[flg]

I don't even know why I'm in this thread????
Don't get me wrong though. I want to know how good a bias ref the TL is??? and how to optimize for that purpose

 

[Zen Mod]

no big fuss

make it with whatever you want , as long it works



we are not going to hear difference between TL and LEDs , in bias nets

what If I'm gonna to use Jfet CCS + LM336-Z5 .........

 

[Antoinel]

Peace my dear DIYers. I hope this ongoing rapport lowers our blood pressure, soothes our soul and stimulates our intellect. We are seeking/sharing ideas and knowledge for a beneficial and unprecedented cyber camaraderie.

 

[buzzforb]

Last night I switched the .47R source resistors out for a 1R resistor. I was wanting to see what effect it had on sound. To me, it killed some of the space and seperation from original attempt. I have been told before that these parts sound better with less source resistance. I will try .33R tonight ans see if stereo image and spaciousness improves. I agree with Ilquam, that the bass is surprising, although it reminds me of the AJ. The thing this amp foes well, IMO, is space and certain natural feel to voices. Lucinda Williams, Shawn Colvin, Patricia Barber sound wonderful.
@Ilquam
Can you play flac files? I want to send you a couple tracks.

 

[lhquam]

I made some measurements one of my Teaser-6 bias circuits using a variac to modify the AC line voltage. My measurements are the current through the source resistor and VGS vs. line voltage with zero voltage input to the channel.

The reduced numbers give:

delta_source_current / delta_line_voltage = 5.6mA/V

delta_VGS / delta_line_voltage = 0.67mV/V => 63.5dB

 

[buzzforb]

How much of this AC fluctuation would you see with a big cap bank?

 

[Zen Mod]

all of it , if fluctuation is slow enough

especially in case of brown out

 

[lhquam]

Cap bank will not help with very low frequency (cycles/minute) power line fluctuations. This is a DC stability issue.

How much of this AC fluctuation would you see with a big cap bank?

 

[Zen Mod]

90% of existing amps will have bias fluctuation while mains fluctuate

nature of the beast

 

[buzzforb]

Cap bank will not help with very low frequency (cycles/minute) power line fluctuations. This is a DC stability issue.

Sorry, I thought you were trying to draw a parallel with DC bias and AC fluctuations.

 

[Melon Head]

Last night I switched the .47R source resistors out for a 1R resistor. I was wanting to see what effect it had on sound.

Just go straight to 0.1R if you have it
Or try 2 x 0.47 in parallel

 

[buzzforb]

Gonna move slowly down the plane and listen. Have resistors to try it all.

 

[Antoinel]

I don't even know why I'm in this thread????
Don't get me wrong though. I want to know how good a bias ref the TL is??? and how to optimize for that purpose

flg. Is the Avatar you show your living pet Jack Russell? I hope I named the right breed. He/she is handsome/pretty. This breed has a long life which is a blessing. My neighbor has one. It loves to chew on sticks. Smart dog. Takes in all the anti oxidants [vegetable extracts] it needs to live long!. I have a female Old English Sheepdog puppy named Bella. I'll figure out how to upload her picture as my new Avatar; if she behaves!