solderdude
Administrator
measureutternutter
Posts: 4,886
|
Post by solderdude on Mar 18, 2015 18:47:41 GMT
Yes, that's what it solves.
I thought Mick and Dicky have an HE-6 + filter
It should give the same improvements on HE500.
The opamps ICx02 are gyrators.
They 'mimic' an inductor.
An inductor is needed to create a narrow bandfilter (for the treble peak) where the trebl lifting is a simple shelving filter.
It is easy to 'configure' a gyrator and it is easy to mimic large inductors that way.
All analog (graphic) equalizers work with gyrators, only a few witb real inductors.
Inductors can pick up hum, gyrators generate noise.
When the filter is before the volume control the noise should not be a problem but you may hear it without music and the volume turned up all the way.
If that bothers you than an inductor can take the place of the gyrator circuit.
|
|
|
|
Post by chris1967 on Mar 18, 2015 19:56:15 GMT
Thanks Frans, i have already contacted Javier in order to acquire a populated board!  |
|
solderdude
Administrator
measureutternutter
Posts: 4,886
|
Post by solderdude on Mar 18, 2015 20:07:00 GMT
Javier already contacted me.
Will be looking into the HE500 filter once more and see if I can make it using an inductor as well.
Need to redo the HD650 filter for newer pads anyway so a good reason to update the article.
|
|
solderdude
Administrator
measureutternutter
Posts: 4,886
|
Post by solderdude on Mar 20, 2015 6:16:50 GMT
|
|
|
|
Post by chris1967 on Mar 21, 2015 8:56:00 GMT
Yes, that's what it solves. I thought Mick and Dicky have an HE-6 + filter It should give the same improvements on HE500. The opamps ICx02 are gyrators. They 'mimic' an inductor. An inductor is needed to create a narrow bandfilter (for the treble peak) where the trebl lifting is a simple shelving filter. It is easy to 'configure' a gyrator and it is easy to mimic large inductors that way. All analog (graphic) equalizers work with gyrators, only a few witb real inductors. Inductors can pick up hum, gyrators generate noise. When the filter is before the volume control the noise should not be a problem but you may hear it without music and the volume turned up all the way. If that bothers you than an inductor can take the place of the gyrator circuit. Because Javier asked me what i prefer, what would be your recommendation for lower distortion (i understand an inductor)? I have a very high power headphone amp (Schiit Mjolnir) i hardly ever go past the 11-12 o'clock position, and usually listen with moderate levels. Do you think under these conditions that i would have a problem with hum ?(which i absolutely don't want to... at the moment my amp at full volume is dead silent). I mean will this be audible at the volumes i listen and/or will it interfere with the extraction of minute detail in low levels form my recordings? |
|
solderdude
Administrator
measureutternutter
Posts: 4,886
|
Post by solderdude on Mar 21, 2015 9:07:10 GMT
Javier can use the BOM list in the latest upload.
This contains the inductor for the HE-6 filter ensuring lowest possible noise (LM4562 amount of noise and distortion)
There should be no hum or noise added (provided it is built correctly in a metal enclosure which is connected to ground internally)
The filter is designed to 'amplify' 1x and can be bypassed by a switch so it can remain in line when not in use.
Given the efficiency of the HE-6 it is unlikely background noise of the filter will reach audible levels.
With the filter on the HE-6 you will hear more minute detail extraction.
Not HD800 level as that one exaggerates detail retrieval but far better than currently.
|
|
|
|
Post by chris1967 on Mar 21, 2015 9:23:18 GMT
I have the HE-500's but i recon it is very similar in frequency response.
Thanks Frans!
|
|
sekar
quite active
Posts: 161 
|
Post by sekar on Mar 24, 2015 18:21:46 GMT
Frans,
Could your filter correct known feature ( don't want to use word problem ) of AKG K601 concerning their "ringing" vocals and some coldness of voice of the singers and may be to add some warm but preserve unique feeling of 3D soundstage ? Some special op amps needed ? I saw K601 in the list of HP supported. I feel i could surely complete this new project now and i've got some appetite to begin something new.
|
|
solderdude
Administrator
measureutternutter
Posts: 4,886
|
Post by solderdude on Mar 24, 2015 19:25:44 GMT
I only have the K612 here and IMO it improved with a firmer 'bottom'and less 'trebly'.
The 'ringing' can't be addressed by the filter though and will remain but slightly less prominent.
The felt in front of the driver does lower the ringing and lowers the treble.
It will be easy to 'modify' the filter so it only corrects the subbass.
How far the K601 and K612 are 'apart' Ian can answer, he owns both. The K612 I have here is Ian's.
I could investigate how far the K601 and K612 are apart in bass response and adjust the filter accordingly if needed.
I suspect the K612 is close to the K601 but possibly the K612 has more 'bottom' and 'bass'
|
|
Rabbit
Administrator
Posts: 7,091
|
Post by Rabbit on Mar 24, 2015 19:52:20 GMT
The K612 has just a slight more warmth in the bass. The K601 and K612 are extremely close and I thought the 612 would be a better idea for you Frans since most would be buying that one now and it's as close as dammit to the 601 in any case.
There's no really deep bass with them both though unfortunately. There's a typical hump bass although it's less than others.
The felt trick probably does a lot for them both I would imagine. I do it by changing the pads. I sent mine to you with stock though.
|
|
sekar
quite active
Posts: 161
|
Post by sekar on Mar 24, 2015 19:54:14 GMT
Thank you Frans.
Could i use LM4562 opamps in filter or it may be OPA2132-34 family or AD826-23 IC ?
|
|
solderdude
Administrator
measureutternutter
Posts: 4,886
|
Post by solderdude on Mar 24, 2015 20:06:13 GMT
In the correction filterboard you can use the LM4562 or OPA2132-34 family.
The filter for the K612 is for the Kameleon amplifier though.
Should you want to make the filterboard I could have a close look on the K601 filter again, knowing what I know now of the K612.
|
|
sekar
quite active
Posts: 161
|
Post by sekar on Mar 25, 2015 10:47:16 GMT
Frans,
I've found my old and unused HP amp in solid metal case, no use of amplifier section more. It has 12cm x 7cm free space for PCB is that enough for filter ?
PS section provides ~15v of regulated floating voltage as it supply PCB only, has very simple design diode bridge and LM317T but I think that small outer PSU i has for external HDD enclosure rated at 12VDC 2A would be OK and most simple way ?
|
|
solderdude
Administrator
measureutternutter
Posts: 4,886
|
Post by solderdude on Mar 25, 2015 12:58:29 GMT
The dimensions are no problem the PCB is 8.5 x 5.5cm
You can use the power supply that is already in there if it is regulated.
12V or 15V regulated will be fine.
Use the power option with the DCDC converter in that case.
|
|
solderdude
Administrator
measureutternutter
Posts: 4,886
|
Post by solderdude on Mar 31, 2015 17:38:53 GMT
I am currently 'converting' these PCB's so they become the SeNNator !
The purpose is build a HD650 dedicated amp only.
Currently building the PCB in various configurations.
|
|
