RE: Feedback cap. It could e the 47uF/25v ZA next to the large power resistor. You could try a bigger Silmic here** (68/100uF) and if it has a big effect its very likely your feedback cap. When you changed this cap can you remember what the value of the original was?
What are the opamp's on sockets over by the poweramp's? (is the preamp stage in the same area as the poweramp's?)
**EDIT: Or a tantalum.
2ND EDIT: 220uF would be too big for a feedback cap, so its probably not that one. As far as I know they are usually between 47 - 100uF
What are the opamp's on sockets over by the poweramp's? (is the preamp stage in the same area as the poweramp's?)
**EDIT: Or a tantalum.
2ND EDIT: 220uF would be too big for a feedback cap, so its probably not that one. As far as I know they are usually between 47 - 100uF
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Stage = section. Different 'stages' of the overall circuit etc...
Im fairly certain those are your preamp opamps then. LM4562's are very detailed bit lack a bit of musicality IMO, to me they sound sterile. I had similar issues when I modded my Cambridge 340A, changing from LM4562 to OPA2107 was an improvement. The amp sounded warmer but still had good detail.
Im fairly certain those are your preamp opamps then. LM4562's are very detailed bit lack a bit of musicality IMO, to me they sound sterile. I had similar issues when I modded my Cambridge 340A, changing from LM4562 to OPA2107 was an improvement. The amp sounded warmer but still had good detail.
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opa2107.... quite expensive.
Must sleep, thanks for your help. I'll put the elnas back in the cdp and see what happens.
I'll try to summarise all this into one post for you.
There are a few tings you could do to get a more balanced musical sound and reduce the brightness:
*Change signal path caps in Amp to Silmics. Other caps worth trying are Tants (10uF) bypassed with 100nF film (taked under the PCB acroos the Tant). Also worth a shot are 4.7-10uF Wima MKS2-XL, if these are hard to find try 3.3uF Wima MKS2.
*Feedback cap. Agian try a larger value (no more than 100uF) Simic, or a Tantalum. (Going bigger can improve the bass response)
*Opamps (in both CDP and Amp). Read up or ask about, thee are warmer, more musical sounding opamps around.
*Main powersupply caps in the Amp. I know those Mundorfs were expensive but... You could fit bigger caps in that position. Bigger caps store more energy for transients and dynamic swings. Having more capacitance can improve the bass and dynamics.
Remember to only make one change at a time. Try alternative caps until you find the one thats best. Then move on to the next mod. Take your time! 🙂
There are a few tings you could do to get a more balanced musical sound and reduce the brightness:
*Change signal path caps in Amp to Silmics. Other caps worth trying are Tants (10uF) bypassed with 100nF film (taked under the PCB acroos the Tant). Also worth a shot are 4.7-10uF Wima MKS2-XL, if these are hard to find try 3.3uF Wima MKS2.
*Feedback cap. Agian try a larger value (no more than 100uF) Simic, or a Tantalum. (Going bigger can improve the bass response)
*Opamps (in both CDP and Amp). Read up or ask about, thee are warmer, more musical sounding opamps around.
*Main powersupply caps in the Amp. I know those Mundorfs were expensive but... You could fit bigger caps in that position. Bigger caps store more energy for transients and dynamic swings. Having more capacitance can improve the bass and dynamics.
Remember to only make one change at a time. Try alternative caps until you find the one thats best. Then move on to the next mod. Take your time! 🙂
As I've been saying, the LME49723 is my favorite dual and there's a reason...
If you find LM4562 and LME49720 lacking musicality... try this. It would be worth trying the LME49725 too, though this -might- be more similar to the 4562.
P.S. The OPA2107 is a modest opamp... much better a pair of OPA132UA at this point
If you find LM4562 and LME49720 lacking musicality... try this. It would be worth trying the LME49725 too, though this -might- be more similar to the 4562.
P.S. The OPA2107 is a modest opamp... much better a pair of OPA132UA at this point
Hello, Nad
I think Ruby ZA may cause problem with brightness (like ZL too). I recommend You trying Elna Silmic on power bypass and decoupling (opamps). Silmics are famous for "softening effect"...
I think Ruby ZA may cause problem with brightness (like ZL too). I recommend You trying Elna Silmic on power bypass and decoupling (opamps). Silmics are famous for "softening effect"...
Ive not heard the OPA132 but I can vouch for the 2107. Its a much better opamp than the NE5532 sounding more detailed and natural, with a smooth slightly warm presentation that may suit the overall balance of Nad's equipment.
The OPA132UA is the (single and) revised version of the original OPA2132. It sounds more neutral (better balanced bass) and somewhat more transparent. It's a great FET opamp, I even prefer it to the rather sterile (and questionably more transparent) OPA827.
Well, the OPA2107 can be fine, but it's not one of the opamps with the most tonal richness (the NE5532 has more, for instance). In the end I prefer the LME49723, which is bipolar thus more transparent sounding than all these FET-input's, yet isn't relatively sterile like the LME49720/LM4562.
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Are you kidding? The 2107 was much more natural sounding than the 5532 in the preamp I used it in. It was warm but didn't have that artificial 'silicon' 5532 sound.
Anyway, were trying to help Nad get a better overall tonal balance to his system. I dont think a 'transparent' opamp is the solution. Hes already got transparent with the 4562. We actually want to 'color' the sound here to create some warmth and musicality. Were trying to restore the tonal balance of his system.
Can you suggest any other opamps which have a bit of warmth and bass?
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I haven't listened to a 5532 for a long time. I said "colorful", which it is. Natural is a much more complex sum of different things. The OPA2107 may be more natural in many ways but it's also less colorful than a 5534 or 5532, for my ears.
Well, to color an LM4562 (but maintain a correct sound) I'd use something like the OPA132UA, or... let me think. There's always the LT1028, which has passion along with transparency.
Well, to color an LM4562 (but maintain a correct sound) I'd use something like the OPA132UA, or... let me think. There's always the LT1028, which has passion along with transparency.
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As mentioned, I'm looking to add warmth to the system by cap choice and not by opamps. I've just had a look in the CDP an there are Nichicon Fine Golds in the signal path before the opamps and a single ZA positioned inbetween but connected negative to ground..... is this a feedback cap for the D/A?? there used to be an Elna there, I'll put it back in and see what happens.
Back to the Amp, there's panasonic FC's all over for decoupling and some in the path. I've heard they're bright caps???? I'm going to change the signals to silmics but shal I leave the decoups???
Back to the Amp, there's panasonic FC's all over for decoupling and some in the path. I've heard they're bright caps???? I'm going to change the signals to silmics but shal I leave the decoups???
Found this photo here: http://farm4.static.flickr.com/3330/3420658713_b21c1d9e9c_o.jpg It's full of FC's but I can't read the crazy text. Wonder how that sounds? Seems some of the FC's are alot larger than in mine. The caps that MikeSnowdon said could be the feedback caps seem to be the only ones that havn't been swapped (big black/silver cap at bottom left between the pot and big resistor)
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Pana FC are nice caps. I cant say that they are bight, they just good caps, I prefer them in power supply. Some people says FC makes sound a bit harsh ( compared to Elna and FM).
Outside of the amplifier feedback loop any caps to ground will be for power supply decoupling/smoothing.
Id start with trying some different caps in the signal path, Like the Silmics.
I would concentrate on the amp to begin with. Remember, that feedback cap can make a big difference. Try a bigger Silmic instead of the ZA. Id go for 100uF as it should help the bass.
Remember to do one thing at a time and have a listen, and evaluate whether its a positive change or not before moving on to another mod.
Id start with trying some different caps in the signal path, Like the Silmics.
I would concentrate on the amp to begin with. Remember, that feedback cap can make a big difference. Try a bigger Silmic instead of the ZA. Id go for 100uF as it should help the bass.
Remember to do one thing at a time and have a listen, and evaluate whether its a positive change or not before moving on to another mod.
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I suggested the 2107 as its warmer sound would counteract the overly bright sound he now has, and dosent like. From what I can tell Nad's taste is more toward PRaT and dynamics rather than ultimate transparency.
I agree that transparency is a good thing (isnt the only factor for good sound though) but in this instance we actually want to add some warmth and bass to the the system so a transparent opamp might not be the ideal. However, if changing a few caps brings about a more balanced sound then trying the opamps you suggest could be a worthwhile activity.
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I'll do just that, thanks. You're right in saying start with the amp, plugged my destiny into it and it sounded harsh and bad. Run out of solder.....argggghhhh.
I'll get some tomorrow and swap a few caps back (signal/feedback) and see what happens and if it's calms, then I'll go for silmics.
So all caps to ground are decoupling, then there's the signal caps and last but not least, anything not in those 2 (decop/signal) are feedback??
Just wanted to say that to me transparency is supposed to sum up everything, i.e. it's a synonym of the very idea of sonic fidelity. In that sense the LT1028 is transparent, less so the LM4562.
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