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Post by dean0 on Oct 24, 2009 18:23:44 GMT
Just got myself some HD650's , problem; volume does not go high enough on certain tracks using SCHA amp. My source is a Y2 Gamma Dac; www.amb.org/audio/gamma2/ Using RK27 50K impedance Pot, would changing this to a different value solve the problem? Thanks dean0
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Post by Deleted on Oct 24, 2009 21:08:13 GMT
Dean I will send you an email Alex
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Post by dean0 on Oct 24, 2009 21:19:39 GMT
thanks for the info, will increasing the gain have any adverse effects on sq?
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Post by Deleted on Oct 24, 2009 21:58:17 GMT
thanks for the info, will increasing the gain have any adverse effects on sq? Dean0 There will be a minor reduction in SQ only if you increase the gain as far as SC suggests in the original article. However, if you later use a JLH in line, the differences will be quite obvious. Alex
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Post by dean0 on Oct 25, 2009 16:11:32 GMT
thanks for the info, will increasing the gain have any adverse effects on sq? Dean0 There will be a minor reduction in SQ only if you increase the gain as far as SC suggests in the original article. However, if you later use a JLH in line, the differences will be quite obvious. Alex Im already using JLH PSRR, so its not worth increasing the gain, becuase of the drop in SQ? Also read the HD650's require more voltage than most headphones, is this the reason for lower volume levels or because 300ohm
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Post by Deleted on Oct 25, 2009 17:06:26 GMT
Speaking from a listening point of view only (electronic knowledge meager and unreliable!). I found no decrease in SQ (with JLH) when I changed my gain resistors from 1K to 1K5. This gave me the little extra volume I required on HD600. Roughly equivalent to 2 more "notches" on the vol pot. (Number 11 ) Whether this would be enough for you I can't say. Though, if I had a choice between not enough volume (unit falls into disuse) or marginal drop in SQ, I'd pick the latter. You may even regain lost ground with any remaining mods you have yet to implement. ....puts on surplus army gear and waits to go "under-fire".
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Post by Deleted on Oct 25, 2009 20:36:39 GMT
Dean0 There will be a minor reduction in SQ only if you increase the gain as far as SC suggests in the original article. However, if you later use a JLH in line, the differences will be quite obvious. Alex Im already using JLH PSRR, so its not worth increasing the gain, becuase of the drop in SQ? Also read the HD650's require more voltage than most headphones, is this the reason for lower volume levels or because 300ohm DeanO Chris is correct. The suggested gain changes from Silicon Chip are a MAJOR increase. The ones I suggested in my email are quite minor, and unlikely to be noticed, even with a JLH in line. Alex
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Post by Deleted on Oct 26, 2009 1:35:14 GMT
Alex, if I can buy a cheap computer I may pick up a new orthodynamic can from Head Direct. However I am told they are very power hungry, so do you remember the gain you set my Jaycar at? I believe it was low. Thanks. Miguel I can't remember if it was the original 2 x, or perhaps 3.2 times. I left it fairly low because of your prefence for relatively low listening levels. I can certainly talk you through any gain changes needed, as it will only involve changing 2 resistors. It is also easy to increase drive to the headphones by changing 2 other resistors. . i.e. The 68 ohm series output resistors.This is all well within your capabilities. Alex
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Post by dean0 on Oct 26, 2009 11:08:14 GMT
What are orthodynamic headphones?
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toad
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Post by toad on Oct 26, 2009 15:10:44 GMT
They look rather nice Miguel. Eeek at the price though.
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Post by clausdk on Oct 26, 2009 21:30:23 GMT
What are orthodynamic headphones? It is a system that Pioneer was using about 20 years ago. I am not into the tec, but it should be like a electrostat crossed with a dynamic in sound.
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robertkd
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Post by robertkd on Oct 27, 2009 0:46:56 GMT
Orthodynamic is just a variation of dynamic type transducer according to,.. en.wikipedia.org/wiki/HeadphonesAs for increasing gain, I'm running an AV of 4 (3K0R in feedback loop) with no perceivable change to SQ what so ever.
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Post by yhong on Oct 4, 2010 8:01:34 GMT
newbie here,the SCHA can drive well the orthodynamic headphone?
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Post by Deleted on Oct 4, 2010 8:22:12 GMT
newbie here,the SCHA can drive well the orthodynamic headphone? I haven't tried it with very low impedance headphones, or the types that are more often used with power amplifiers due to their drive requirements. . You could try using the original version with links as per the SC article for 8 ohm headphones. With the modified version you could try reducing the 68 ohm output resistors to 4.7 or 10ohms. Alex P.S. Has anybody tried the SC HA with these types of headphones ?
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Post by yhong on Oct 4, 2010 17:07:33 GMT
newbie,what is the meaning of silicon chip?what is the different with discrete amp?if compare with CKKIII or M3?
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Post by Deleted on Oct 4, 2010 21:39:39 GMT
newbie,what is the meaning of silicon chip?what is the different with discrete amp?if compare with CKKIII or M3? Hi SiliconChip, as referred to here, is the Australian Electronics magazine called "Silicon Chip" Alex
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mrarroyo
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Post by mrarroyo on Oct 4, 2010 23:43:27 GMT
Alex, I did but I lost the review notes and I no longer have the HE5 from Head Direct. Sorry.
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Post by Deleted on Oct 5, 2010 5:08:38 GMT
Alex, I did but I lost the review notes and I no longer have the HE5 from Head Direct. Sorry. Hi Miguel Just a brief recollection will do. Alex
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mrarroyo
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Post by mrarroyo on Oct 6, 2010 1:51:20 GMT
Well, I just set up the SCHA, which I have not used for a couple of months. I had forgotten how GREAT it sounds! I do not have a Senn HD650 but I do have a Senn HD580 with a set of stock cables from an HD650 and I used it for these impressions. BTW, the source was a Meridian 506.20 cd-player and the I used the December 1976 recording of "Jazz At The Pawnshop".
For those who do not know I personally do not care much for the HD650 sound and much prefer the HD580/600 presentation. I also listen at very low levels and even though my SCHA has a low gain of around 2-3 I do not go higher than 9 o'clock on the volume pot of the SCHA. BTW, zero volume is at 6 o'clock and I use an stepped attenuator, that is about 5 to 7 clicks to go from 6 o'clock to no more than 9 o'clock.
The sound is fast, very fast with excellent micro-detail and it renders the note to note transition with crispness and smoothness. The hi-hat notes at about 7 minutes into Limehouse Blues are so detailed/realistic it feels like you have a drummer playing next to you. The overall presentation is dynamic and very articulate with no harshness to speak off.
The clarinet at the beginning of I'm Confessin' is so mellow yet the notes cut right through that if I closed my eyes I feel like I am in an small jazz club listening to live music. Hope this short impressions help.
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Post by Deleted on Oct 6, 2010 2:02:05 GMT
Well, I just set up the SCHA, which I have not used for a couple of months. I had forgotten how GREAT it sounds! I do not have a Senn HD650 but I do have a Senn HD580 with a set of stock cables from an HD650 and I used it for these impressions. BTW, the source was a Meridian 506.20 cd-player and the I used the December 1976 recording of "Jazz At The Pawnshop". For those who do not know I personally do not care much for the HD650 sound and much prefer the HD580/600 presentation. I also listen at very low levels and even though my SCHA has a low gain of around 2-3 I do not go higher than 9 o'clock on the volume pot of the SCHA. BTW, zero volume is at 6 o'clock and I use an stepped attenuator, that is about 5 to 7 clicks to go from 6 o'clock to no more than 9 o'clock. The sound is fast, very fast with excellent micro-detail and it renders the note to note transition with crispness and smoothness. The hi-hat notes on the end of Limehouse Blues are so detailed/realistic it feels like you have a drummer playing next to you. The overall presentation is dynamic and very articulate with no harshness to speak off. The clarinet at the beginning of I'm Confessin' is so mellow yet the notes cut right through that if I closed my eyes I feel like I am in an small jazz club listening to live music. Hope this short impressions help. Miguel Thanks. That should help. BTW, if you want a little more oomph at the very low end, then you should replace those 4 x 2,200uF electros in the SC HA JLH with low ESR 4,700uF 10V types , and give 48 hours for the electros to fully form. Regards Alex
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mrarroyo
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Post by mrarroyo on Oct 6, 2010 22:44:36 GMT
Alex, last time I attempted to mess w/ the SCHA I "fudged" it! No I am not going to mess with it ... unless I ship it back to you ...
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XTRProf
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Post by XTRProf on Oct 8, 2010 4:48:59 GMT
Alex, last time I attempted to mess w/ the SCHA I "fudged" it! No I am not going to mess with it ... unless I ship it back to you ... Miquel, it's quite simple to change those E-caps. Just make sure the +ve and -ve are put correctly. Before you remove the E-caps just note the -ve orientation (mark) on the caps. The new caps just put them in the same direction as the removed caps. That's it. Bingo! Done correctly there will be no Bango ..........
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Post by petef on Oct 9, 2010 0:45:23 GMT
I am using the SCHA with the 300 Ohm HD-650s and the volume is MORE than loud enough! Initially to test I ran the source CD player directly into the RCA inputs without attenuation and it was very loud even driving 300 Ohms. I now have a 50K pot on the input and can still achieve very high volume levels, so I'm surprised you say you need more gain.
Pete
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Post by Deleted on Oct 9, 2010 2:09:21 GMT
Hi Pete and welcome. Is your SCHA a standard build or had any/all of the modifications available? I also found I needed more gain (just a tad) though that is with HD600 and AKG701. Any which way, don`t be shy, lets be having some photos
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Post by petef on Oct 9, 2010 2:42:46 GMT
At the moment it's completely stock, with the exception of it being DC coupled to the CD player (very carefully!) I have some 1.5uF ANSAR caps here and may use them on the input once I have this thing sorted out. Sorry no point in any photos, it looks just like the photographs on the construction pages, except mine is screwed to a piece of melamine while modding and coming up with some ideas for a case. I am feeding this with an Arcam Alpha 9 CD player and have an Alpha 10 amp as a reference. I used the 2K resistor in the feedback loop. I have it on the bench at the moment looking at things with the CRO, but can't recall what the gain was. Around 2??? I can check if it's important? As I say, it's more than enough output to drive the HD-650s to a level that if you're seriously listening to them like that you probably want to rethink things a bit as you won't have your hearing much longer I spoke to Alex before/after building this, and as I mentioned to him, I thought the SCHA is "ok" as it stands now. At first I must admit I was a bit under-whelmed as I expected it to be significantly better than the Alpha 10. Both the A9 CD player and A10 amp are a bit dated now of course, but far from the POS end of the spectrum. But I must admit I still feel something in that chain is lacking. The vocals are definitely a bit clearer however. It seemed that the performance was very rapidly changing, as it's brand new and literally only had 30-60 minutes or so on it so far. Some of the caps are still sorting themselves out I suspect. I may just leave it on the bench powered up for the day to settle things down and have another listen later. Pete
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