ilfungo

Re: esoteric audio reserch - EAR 660
« Reply #20 on: November 29, 2017, 05:15:58 AM »
Yes I've tried with different termination
This is the frequency response with 600R termination.
In this circuit the better result I can have is with 220R termination.
Now I want to try with Sowter Fairchild transformers...
Thanks!
« Last Edit: November 29, 2017, 06:43:32 AM by ilfungo »


ilfungo

Re: esoteric audio reserch - EAR 660
« Reply #21 on: December 07, 2017, 01:04:39 PM »
Hi
mounted new transformer and now the gain staging is the same!!!
But the frequency response is not better :'(
Today I have tried to mount the sowter 8344e to real unit and the frequency response is the same of my unit....
This confirm me that the problem is  output transformer.


The big difference I can see with some misurations are this:


EAR 660 output transformer: resistance of each primary is about 750R - secondary 12.5R
Sowter 8344                        : resistance of each primary  is about 300R/ 250R - scondary 6.6R


There is a way to change something in the tubes area to suite better the new transformer?

Thanks!!!

ilfungo

Re: esoteric audio reserch - EAR 660
« Reply #22 on: December 09, 2017, 12:25:03 PM »
Hi
this is the link to 2 files:
( the song is from a disc and it's a mastered version, just L channel)
no processing
processed : 4 db compression/ position 6
https://drive.google.com/drive/folders/1XEXbtgEg6RJUKs3rq4pMZ4JXN5SnlofD?usp=sharing

Now the unit is 100R teminated and sound good ( I hope it's not a problem for the output stage  ???)

what do you think?

thanks!
« Last Edit: December 09, 2017, 12:29:21 PM by ilfungo »

bluebird

Re: esoteric audio reserch - EAR 660
« Reply #23 on: December 09, 2017, 05:50:01 PM »
In any varimu, tube matching is very important. If your tubes are mismatched you will have problems. If you don't have a way to test the tubes, try just switching them around in different sockets. Maybe you will see better response...or worse.

ilfungo

Re: esoteric audio reserch - EAR 660
« Reply #24 on: December 10, 2017, 04:32:04 PM »
Thanks Blebird!
I will try...

ilfungo

Re: esoteric audio reserch - EAR 660
« Reply #25 on: December 11, 2017, 09:50:52 AM »
Hi Bluebird
with matched tube the situation is much Better!!!
150R terminated.
Now I have only -0.2db at 100HZ -0.6db at 40hz and the rest flat.
I think could be good but I don't understand why I have this attenuation on low frequency...
Suggestions?
THANKS!!!

ilfungo

Re: esoteric audio reserch - EAR 660
« Reply #26 on: January 17, 2018, 03:08:41 PM »
NEWS!!!!
Work and sound great!!!
sorry for a crappy images...
« Last Edit: January 18, 2018, 01:38:29 PM by ilfungo »

ilfungo

Re: esoteric audio reserch - EAR 660
« Reply #27 on: January 18, 2018, 01:38:52 PM »
Front

ilfungo

Re: esoteric audio reserch - EAR 660
« Reply #28 on: January 18, 2018, 01:40:26 PM »
Thanks to all for great help!!!
First as possible I will post some sound samples...

ilfungo

Re: esoteric audio reserch - EAR 660
« Reply #29 on: June 22, 2018, 07:38:54 AM »
I would like to understand if it's normal or why this happens?
the positive half-wave is more controlled while the negative one has strange peaks,
but I've seen some samples
Dry drum and Analog _Tube 670 and I see the same behavior

Attached 2 screenshots from pro tools (dry drum and processed 8db compression Time 1 pos)
Thanks!!!
« Last Edit: June 22, 2018, 07:43:38 AM by ilfungo »


scott2000

Re: esoteric audio reserch - EAR 660
« Reply #30 on: June 22, 2018, 08:00:58 AM »
Interesting.... Maybe some kind of bias movement??? Doesn't bias affect this behavior??


ilfungo

Re: esoteric audio reserch - EAR 660
« Reply #31 on: June 22, 2018, 08:36:26 AM »
Hi Scott2000
thanks for your answer
sorry I'm not an electronic exerpert but how the bias is set accordly with schematics?
Thanks!
« Last Edit: June 22, 2018, 08:50:58 AM by ilfungo »

scott2000

Re: esoteric audio reserch - EAR 660
« Reply #32 on: June 22, 2018, 05:40:04 PM »
I'm sorry... I was just throwing a quanswer out there to get some momentum and ask.....I was more or less asking about tube bias.... I'm pretty sure it can affect the symmetry in ways??

That thing's crazy... How did we get here??

Hopefully someone can be helpful.....

How does it sound???

What are those AC DC threshold pots doing???
« Last Edit: June 22, 2018, 06:42:43 PM by scott2000 »

ilfungo

Re: esoteric audio reserch - EAR 660
« Reply #33 on: June 22, 2018, 09:12:56 PM »
The sound is good!!!
But I'm trying to understand why this happen....
Could be a simple matching tubes problem ( i've bought them as matched but I don't have tube tester to see if is real).

ilfungo

Re: esoteric audio reserch - EAR 660
« Reply #34 on: June 23, 2018, 08:53:44 AM »
does anyone have any ideas?

ilfungo

Re: esoteric audio reserch - EAR 660
« Reply #35 on: June 23, 2018, 01:34:03 PM »
News
I've found online:
1: dry drum samples
2 :same processed with Anamod 660 ( with all settings)

after I have processed the samples with my unit , the result is the same.
Also the Anamod have the same behaviour
At this point I think it's normal, but why this happen?

Dmichel123

Re: esoteric audio reserch - EAR 660
« Reply #36 on: August 25, 2018, 10:11:53 PM »
I think maybe you're seeing the first transient that gets through while the timing cap charges. Attack time  is .2mS, about 1/4 of a 1kHz wave. I think.