Jump to content

KG Balanced Dynahi build discussion thread


Vortex

Recommended Posts

  • 1 month later...

Hello

 

I can hear a little "ufffffff" without music on a channel (Balanced and SE output). I read that normally this type of noise is associated with the input transistors. In this case, Is it possible to be produced by the THAT340?

 

Regards

Link to comment
Share on other sites

Thanks Dr. Gilmore. It´s only on a channel and I can hear it if I use a headphone sensitive.

 

I get lucky because I bought some THAT340 (around 20 units). I've been changing one by one until I found one that does not make noise but I discarded 10 for this reason   ???  ???

 

I believed that the THAT340 had a better quality ???

Link to comment
Share on other sites

  • 2 months later...
  • 1 month later...

I'll be using a 10K balanced volume control. Balanced gain will be 10 by changing R52, R56 to 50K and C1, C3 to 5 pf.

 

Can somebody help me by confirming this ?

 

I'm populating my boards right now, and still don't know if this way to obtain a balanced gain of 11 ( (50k/10k)+1 <-> 5+5+1) is OK, especially for the compensation capacitor.

Unfortunately I don't have no scope and not much skills to guess this...

 

More generally, is a balanced gain of 11x more friendly to run headphones between say 30-300 Ohm ?

 

Best regards.

Link to comment
Share on other sites

that is close to right, because of the way supersymmetry works. i will when i have

time get you the exact values. using this amp with 300 ohm headphones is probably

pretty goofy, as the voltage swing will easily fry both the headphones and your

ears. put mainly your ears.

really designed for low impedance low efficiency phones.

he6, that kind of thing.

new supersymmetry dynalo is much better for high efficiency high impedance headphones

Link to comment
Share on other sites

Thank you Dr. Gilmore.

I'm trying orthos for now (LCD-2 = 50 Ohm / 91dB), so I think they'll take benefit from the Dynahi with lowered gain. I'll probably try HE-6 and / or K-1000 in the future, so this upcoming balanced Dynahi will be on duty.

 

When I switch to dynamic headphones (or higher efficiency stuff), I'll build a dynalo (or dynamid) for sure, thanks for the tip !

Link to comment
Share on other sites

that is close to right, because of the way supersymmetry works. i will when i have

time get you the exact values. using this amp with 300 ohm headphones is probably

pretty goofy, as the voltage swing will easily fry both the headphones and your

ears. put mainly your ears.

really designed for low impedance low efficiency phones.

he6, that kind of thing.

new supersymmetry dynalo is much better for high efficiency high impedance headphones

Yikes, so I shouldn't use my HD650's or 250 Ohm Darth Beyers?

Link to comment
Share on other sites

  • 3 weeks later...

Hello all,

 

Managed to source balanced dynahi and PSU boards from Lil Knight and am in the process of orderings components for the boards. Long journey ahead.

 

Just wanted to confirm: Are 2 x 2sa970's a direct replacement for 1 x 2sa1349 on the amp PCB? 

 

I'm quite sure it is based on the datasheet, reading through this forum and googling, but just wanted to quadruple check :) And matching isn't a necessity with this amp is it? I'll be getting BL versions from bdent.com, think I saw a comment from spritzer saying something to the effect of 'its ok'...

 

Thanks for your help :)

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.