BOB, JONATHAN AND PETER
Hi,
Bob,
Sorry if you feel you wasted your time...both of us are aware of Ben D's work and it is beyond doubt extraordinary.
I'm,myself however no big fan of passive preamps, preferring the active stages.
Naturally the same priciples for VC can be applied...It's easier for me to have a more universally usable device.
Attention to detail always pays and that's where the Audio Synthesis stand out.
Jonathan,
No comment really...I expect the nudes to sound better and from the 'feedback" I get they do.
They're more fragile...so be it.
In a semi-conductor environment I'd expect the SMDs to even sound better...me I think tubes and hardwiring,you know that,don't you.
Peter,
I hear enthusiastic comments from Benny Glass at Aquablue,Brett,John and others...mostly this is tube oriented stuff though and not easy to implement at all.
I have no idea whether anything usable for semi-conductor based gear is available...unless of course the emperor is changing clothes...and turns tubes???
One situation I consider is in a phono preamp using LCR RIAA correction where I think xformer coupled stages may be the more "elegant" way to go.
That's still in the pipelines though,so don't hold your breath.
That's what I use now,only one R in the signal path and a fixed R as input R, balanced or not it is to my ears the better arangement bar perhaps the xformer.
Mind you,in my system the attenuator is looking at the gridleak R of the buffer,so you can't call that passive.
You'll need to figure out what works best for you here,IMO.
I adhere to the minimalist filosophy,not everyone agrees though.
Cheers,
Hi,
Bob,
Sorry if you feel you wasted your time...both of us are aware of Ben D's work and it is beyond doubt extraordinary.
I'm,myself however no big fan of passive preamps, preferring the active stages.
Naturally the same priciples for VC can be applied...It's easier for me to have a more universally usable device.
Attention to detail always pays and that's where the Audio Synthesis stand out.
Jonathan,
No comment really...I expect the nudes to sound better and from the 'feedback" I get they do.
They're more fragile...so be it.
In a semi-conductor environment I'd expect the SMDs to even sound better...me I think tubes and hardwiring,you know that,don't you.
Peter,
I hear enthusiastic comments from Benny Glass at Aquablue,Brett,John and others...mostly this is tube oriented stuff though and not easy to implement at all.
I have no idea whether anything usable for semi-conductor based gear is available...unless of course the emperor is changing clothes...and turns tubes???
One situation I consider is in a phono preamp using LCR RIAA correction where I think xformer coupled stages may be the more "elegant" way to go.
That's still in the pipelines though,so don't hold your breath.
That's what I use now,only one R in the signal path and a fixed R as input R, balanced or not it is to my ears the better arangement bar perhaps the xformer.
Mind you,in my system the attenuator is looking at the gridleak R of the buffer,so you can't call that passive.
You'll need to figure out what works best for you here,IMO.
I adhere to the minimalist filosophy,not everyone agrees though.
Cheers,
Hi Jonathan,
Thanks for yours comment, which shows my assumption about your choice for attenuators to be correct. My own view is that, when you get to the level of refinement we are dealing with here, the switches become the limiting factor, and I have not so far seen any better way of doing this than the 'old-fashioned' rotary 'self cleaning' style which we use.
As I mentioned to Frank, my 'old' A/S Shallco switch based attenuator still outperforms the newer A/S Passion Ultimate, which (apart from the switching) uses much the same 'ingredients'.
However, the convenience of having remote operation with the latter is not to be ignored, but for all of my serious listening tests on components etc. (except where front-end phono gear is concerned, of course), I always revert to the 'old' manual 'L' pad attenuator, as it is simply more revealing.
Regrettably, I have not yet been very impressed, sonically, with any solid-state switching which I have tried.
I know nothing about transformer-based attenuators save that I prefer to avoid transformers wherever possible (as they can be problematic in construction for good-sounding ones, and they are expensive etc.), but common-sense tells me that there must still be some associated switching, so we are back to the very same limitations here.
If my understanding about this is anything like right, I wouldn't favour swapping out a Vishay with a coil of wire of the quality found in most transformers! I'd rather keep the resistor.
Hi Frank,
Where did "wasted Time" come from?
What I said was "but it was *worth spending the time* to compare my experiences with those of the others"
I am certainly not omniscient in *any* audio-related matters, and there is nearly always something to be learnt from what others have to say for themselves. Also, unlike some people, I am always prepared to give up the necessary time to carefully read about what others have to say, even if I don't happen to agree with it.
However, in this case, (unusually) I didn't learn anything new about attenuators, as it happened, but I felt that I could have perhaps added some value to what had been said, as passives have been an interest of mine for 15+ years, and I do have a little experience with them.
As you know, I admire and get on well with David Heaton of A/S, simply because I empathize with his approach towards audio matters, and like me, he is passionate about details, and will go to the ends of the earth to get things right!
Also, whilst he's very much into choosing components by ear, he will not put up with any b*l*s*i* or 'snake oil', and it is interesting (now I think of it) that he is another staunch supporter of BGs!
Regards,
Thanks for yours comment, which shows my assumption about your choice for attenuators to be correct. My own view is that, when you get to the level of refinement we are dealing with here, the switches become the limiting factor, and I have not so far seen any better way of doing this than the 'old-fashioned' rotary 'self cleaning' style which we use.
As I mentioned to Frank, my 'old' A/S Shallco switch based attenuator still outperforms the newer A/S Passion Ultimate, which (apart from the switching) uses much the same 'ingredients'.
However, the convenience of having remote operation with the latter is not to be ignored, but for all of my serious listening tests on components etc. (except where front-end phono gear is concerned, of course), I always revert to the 'old' manual 'L' pad attenuator, as it is simply more revealing.
Regrettably, I have not yet been very impressed, sonically, with any solid-state switching which I have tried.
I know nothing about transformer-based attenuators save that I prefer to avoid transformers wherever possible (as they can be problematic in construction for good-sounding ones, and they are expensive etc.), but common-sense tells me that there must still be some associated switching, so we are back to the very same limitations here.
If my understanding about this is anything like right, I wouldn't favour swapping out a Vishay with a coil of wire of the quality found in most transformers! I'd rather keep the resistor.
Hi Frank,
Where did "wasted Time" come from?
What I said was "but it was *worth spending the time* to compare my experiences with those of the others" I am certainly not omniscient in *any* audio-related matters, and there is nearly always something to be learnt from what others have to say for themselves. Also, unlike some people, I am always prepared to give up the necessary time to carefully read about what others have to say, even if I don't happen to agree with it.
However, in this case, (unusually) I didn't learn anything new about attenuators, as it happened, but I felt that I could have perhaps added some value to what had been said, as passives have been an interest of mine for 15+ years, and I do have a little experience with them.
As you know, I admire and get on well with David Heaton of A/S, simply because I empathize with his approach towards audio matters, and like me, he is passionate about details, and will go to the ends of the earth to get things right!
Also, whilst he's very much into choosing components by ear, he will not put up with any b*l*s*i* or 'snake oil', and it is interesting (now I think of it) that he is another staunch supporter of BGs!
Regards,
Peter Daniel said:
I used this arrangement (U attenuator) before I went to the S&B transformers.
At wide open throttle, there is little to choose between the two (Tx still best), but as you attenuate, the Tx gets better and better. I set my system up so that I'm listening at around the -20 to -25dB range for most material, at most times, or around 80dB SPL. The difference between the two is even greater when you have long cables to drive.
It would be interesting to hear the S&Bs driven by some sand, like the BalZen. Later I want to add a tape monitor output to my pre, using a BZ or one of the Aleph P designs, so I'll try it then. There simply isn't any more room in my pre for more tubes and transformers, and besides, I have all the parts in my parts box.
Re: Re: PASSIVE.
The only attenuator which might be marginally better would be if the Vishays (or similar bulk-foils) had been surface-mount jobs, thus avoiding the (very short) leads, and I do believe that Jonathan Carr uses this arrangement in his Connoisseurs.
Regards, [/B][/QUOTE]
--------------------------
Not necessarily, I have not heard Jonathan Carr's but the Danish Audio DACT? ones don't sound good to me (rather dim and muted) compared with the Audio Synthesis ones (tends slightly to be dry and brighter than neutral). The Carver Lightstar Direct balanced passive is excellent. Do a serach in Stereophile archive.
The only attenuator which might be marginally better would be if the Vishays (or similar bulk-foils) had been surface-mount jobs, thus avoiding the (very short) leads, and I do believe that Jonathan Carr uses this arrangement in his Connoisseurs.
Regards, [/B][/QUOTE]
--------------------------
Not necessarily, I have not heard Jonathan Carr's but the Danish Audio DACT? ones don't sound good to me (rather dim and muted) compared with the Audio Synthesis ones (tends slightly to be dry and brighter than neutral). The Carver Lightstar Direct balanced passive is excellent. Do a serach in Stereophile archive.
"I've been hearing comments that transformer based attenuators are the way to go. Never tried them though."
___________________________________________________
Transformers are just ok in my book, even if they are really high quality. There will ALWAYS be more phase shift in a transformer and be sure not to saturate the core , especially at low frequencies. With added features like phase shift, ringing, and possible core saturation in ones system that ought to add some special effects....
Personally I'd stay away from using them and use a simple resistor attenuator...you'll find it does less to an audio signal then even the best of the best audio transformers. Companies like Jensen are pushing their use, and to me its probably more due to the fact that so many devices have been made transformerless(for good reasons too!). These companies have to explore new inroads to keep their sales up. I believe Jeff Rowland uses some Jensen transformers, but then they also use I.C.'s in the output stages of at least one of the high priced amplifiers they sell. Leaves me wondering.........
Mark
___________________________________________________
Transformers are just ok in my book, even if they are really high quality. There will ALWAYS be more phase shift in a transformer and be sure not to saturate the core , especially at low frequencies. With added features like phase shift, ringing, and possible core saturation in ones system that ought to add some special effects....
Personally I'd stay away from using them and use a simple resistor attenuator...you'll find it does less to an audio signal then even the best of the best audio transformers. Companies like Jensen are pushing their use, and to me its probably more due to the fact that so many devices have been made transformerless(for good reasons too!). These companies have to explore new inroads to keep their sales up. I believe Jeff Rowland uses some Jensen transformers, but then they also use I.C.'s in the output stages of at least one of the high priced amplifiers they sell. Leaves me wondering.........
Mark
Re: Re: Re: PASSIVE.
Quote.***
Not necessarily, I have not heard Jonathan Carr's but the Danish Audio DACT? ones don't sound good to me (rather dim and muted) compared with the Audio Synthesis ones (tends slightly to be dry and brighter than neutral). The Carver Lightstar Direct balanced passive is excellent. Do a serach in Stereophile archive. [/B][/QUOTE]***
Hi,
I agree entirely with your findings on the DACT attenuators but they (or at least the one I listened to, did!) have much poorer quality metal film resistors in them and a much less good Elma type of switch, so this should be no surprise.
Bulk foils and coin silver switches 'sound' much better, in my experience, and Jonathan's Connoisseur will be in a different league from a DACT, as a result of this.
I, also, have not heard Jonathan's Connoisseur, but according to the recent comments in Hi-Fi+, he must have got most of it right!
I don't agree at all, with your suggestions over the Audio Synthesis (manual passive, as opposed to the latest remote-based Passion Ultimate) as I find this extremely neutral. If quoting reviewers' opinions as a 'reference' holds any merit, it seems that Martin Colloms agrees with me.
By neutral, *I* mean compared with a 'straight wire' which can be done as a comparison. Have you done this 'direct' comparison in forming your opinions, or, if not, what was the yardstick you used in reaching this conclusion?
I regret to say that I am not overly impressed with some of what I have seen recommended in 'Stereophile', but I have not read the comments to which you refer about the Carver Lightstar Direct. Many of the opinions seen therein appear to be purely subjective and based on comparisons (if any) with other similar equipment, which in my view has little real merit as the yardstick is merely one of 'familiarity', as opposed to being truly 'neutral'.
I will, however, reiterate that the Shallco/Vishay attenuator is IMHO extremely neutral, and it is hard to imagine how this could be much improved upon, as I had said.
Regards,
Quote.***
Not necessarily, I have not heard Jonathan Carr's but the Danish Audio DACT? ones don't sound good to me (rather dim and muted) compared with the Audio Synthesis ones (tends slightly to be dry and brighter than neutral). The Carver Lightstar Direct balanced passive is excellent. Do a serach in Stereophile archive. [/B][/QUOTE]***
Hi,
I agree entirely with your findings on the DACT attenuators but they (or at least the one I listened to, did!) have much poorer quality metal film resistors in them and a much less good Elma type of switch, so this should be no surprise.
Bulk foils and coin silver switches 'sound' much better, in my experience, and Jonathan's Connoisseur will be in a different league from a DACT, as a result of this.
I, also, have not heard Jonathan's Connoisseur, but according to the recent comments in Hi-Fi+, he must have got most of it right!
I don't agree at all, with your suggestions over the Audio Synthesis (manual passive, as opposed to the latest remote-based Passion Ultimate) as I find this extremely neutral. If quoting reviewers' opinions as a 'reference' holds any merit, it seems that Martin Colloms agrees with me.
By neutral, *I* mean compared with a 'straight wire' which can be done as a comparison. Have you done this 'direct' comparison in forming your opinions, or, if not, what was the yardstick you used in reaching this conclusion?
I regret to say that I am not overly impressed with some of what I have seen recommended in 'Stereophile', but I have not read the comments to which you refer about the Carver Lightstar Direct. Many of the opinions seen therein appear to be purely subjective and based on comparisons (if any) with other similar equipment, which in my view has little real merit as the yardstick is merely one of 'familiarity', as opposed to being truly 'neutral'.
I will, however, reiterate that the Shallco/Vishay attenuator is IMHO extremely neutral, and it is hard to imagine how this could be much improved upon, as I had said.
Regards,
Re: Re: Re: Re: PASSIVE.
By neutral, *I* mean compared with a 'straight wire' which can be done as a comparison. Have you done this 'direct' comparison in forming your opinions, or, if not, what was the yardstick you used in reaching this conclusion?
-------------------------------------------
Straight wires sound different and so how does one do a comparison? I have not tried the new Passions but I understand it is more 'neutral'.
=======================
I regret to say that I am not overly impressed with a some of what I have seen recommended in 'Stereophile', but I have not read the comments to which you refer about the Carver Lightstar Direct.
Regards, [/B][/QUOTE]
------------------------------------------
Many Sterophile reviews are fine. I have the Carver and it is truly excellent, one of the few with balanced remote operation.
I am not impressed by the reviews in HI Fi+. Seems to be a 'selling' mag with reviewers of unknown pedegree. I find some of their exhaltations to be rubbish, from personal experience.
By neutral, *I* mean compared with a 'straight wire' which can be done as a comparison. Have you done this 'direct' comparison in forming your opinions, or, if not, what was the yardstick you used in reaching this conclusion?
-------------------------------------------
Straight wires sound different and so how does one do a comparison? I have not tried the new Passions but I understand it is more 'neutral'.
=======================
I regret to say that I am not overly impressed with a some of what I have seen recommended in 'Stereophile', but I have not read the comments to which you refer about the Carver Lightstar Direct.
Regards,
[/B][/QUOTE]------------------------------------------
Many Sterophile reviews are fine. I have the Carver and it is truly excellent, one of the few with balanced remote operation.
I am not impressed by the reviews in HI Fi+. Seems to be a 'selling' mag with reviewers of unknown pedegree. I find some of their exhaltations to be rubbish, from personal experience.
Hi Fmak,
I don't mind at all if we don't see eye to eye on some of these matters, since our experiences have been rather different, but, as before, I will answer the points you have raised.
For the comparison test I suggested, merely set up different value 'fixed' attenuators elsewhere (immediately before or after the passive) so that in order to balance out (accurately) the overall sound levels, the DUT is in one circuit, but not at all in the other. (i.e. fully rotated, so no *variable attenuator* resistors are in the signal path on one side)
However, it is adviseable here to ensure that everything else possible is in a similar 'state' and that both identical (mono) signals pass through exactly the same cables and components etc.
I also tried this with three different types of resistors for the 'fixed' attenuation arrangement (Vishays, Caddocks, and Holcos) in case the results might be skewed by any 'synergy' or untoward 'clashes' between the resistive elements in the attenuators and the resistors used for the 'fixed' arrangements.
Fortunately, I have never heard of any claims that resistors of the same type vary noticeably in accordance with their values in their sonic attributes, and, indeed in my own long-term experiments, I find that they all have a family semblance based more on the type of construction and materials used, whatever their individual values may be.
Having done these trials, I also set up another test which used *only* the fixed resistive attenuator in one side, and with the passive in the other, but (as I had made the passive anyway and I had other similar phonos and jacks to hand) I used these connectors in exactly the same way to replicate those used in the Vishay/Shallco attenuator, in an effort to avoid any other unnecessary variables.
With some care, full details of which I won't reiterate as I have shown this elsewhere in several places on the Forum, but which include siting speakers together in the middle of a large room, and because no two speakers even with hand matched components (like mine) ever sound *exactly* alike, and neither do two channels of (also matched component) amps or preamps, you do need to 'ring the changes' from time to time, by swapping these components around.
It is then merely a matter of patiently switching from one channel to the other, however many times as is found necessary, in order to identify any *differences* which must be due to the DUT, when compared with 'nothing'. (i.e about as close as one can practically get to a straight wire.)
This kind of arrangement is a little less easy with attenuators such as here, but similar methods are used (by me, at least) frequently in any such 'comparison trials', as I have said before.
Having done this, I could detect no *significant* differences repeatably and consistantly, between having the Shallco/Vishay attenuator, in circuit or not, over many many hours of careful listening. Of course, there will be *some* albeit minor differences, as this is inevitable with using *any* different component, but even in my own very revealing system, they were not significant enough to be able to identify and describe properly.
I am therefore satisfied that as much as is humanly possible, these were very effective 'straight wire' comparisons, in the same manner as all others which are undertaken in similar circumstances, and it is not possibly IMO to do any better.
If any others have developed an easier or more effective method of carrying out such tests, I will be grateful to learn of them.
Certainly, the above tests will outdo any such ordinary subjective 'sit back and listen' tests (which I have also been conducting for about 30 yrs, and which definitely have their place in audio development), which are more about whether one *prefers* the sound or whatever, rather than if it is more *accurate*.
As I indicated by my earlier comments, I don't take much notice of *any* reviews, preferring to find out for myself in such cases, and I am sure that many Stereophile Reviews are "fine", as you suggest.
I just wished to know, and I still don't as you have omitted to say so, whether your opinions (or maybe Stereophile's, as you mentioned this mag and appear to hold them in esteem) were based on *comparisons* with other gear (frequently so with Stereophile), or whether, like me, you (or they) have attempted to conduct any more *valid* tests in deciding that the A/S attenuators exhibit the problems to which you referred?
Regrettably, your comments on the two A/S devices should be completely reversed, since as mentioned by me earlier (and, again, for what it is worth, by Martin Colloms) the 'old' A/S Passion is sonically a couple of points *ahead* of the later remote Passion Ultimate (both of which I use, as also advised), which reinforces my view that either you are not very familiar with these devices, personally, or that you have never done an A/B comparison between them.
The remarks relating to Jonathan's Connoisseur, were in relation to the comments made by Roy Gregory in Hi-Fi +, and Roy is very well known and has been on the audio scene for many years.
Interestingly, for anyone who is not familiar (perhaps like yourself?) with the review concerned, the article was all about Boulder equipment, but Roy simply raved about the Connoisseur in that review!
It is the first time in some 45 years that I have ever seen such a situation, where so much praise was awarded (and so much space allotted) to another make of equipment within a review of an alternative manufacturer, incidentally, whose (Boulder's) products were also thought quite highly of.
As I said originally, merely from my own knowledge and experience of the components used by Jonathan in his attenuator, it *will* be in an entirely different league, sonically, from a DACT , with which you had drawn some comparisons.
Maybe, Jonathan might care to add something here, since as I said, I have never heard his preamp, although I am aware that it is considered to be at the very 'top of the heap' within knowledgeable audio circles.
Regards,
I don't mind at all if we don't see eye to eye on some of these matters, since our experiences have been rather different, but, as before, I will answer the points you have raised.
For the comparison test I suggested, merely set up different value 'fixed' attenuators elsewhere (immediately before or after the passive) so that in order to balance out (accurately) the overall sound levels, the DUT is in one circuit, but not at all in the other. (i.e. fully rotated, so no *variable attenuator* resistors are in the signal path on one side)
However, it is adviseable here to ensure that everything else possible is in a similar 'state' and that both identical (mono) signals pass through exactly the same cables and components etc.
I also tried this with three different types of resistors for the 'fixed' attenuation arrangement (Vishays, Caddocks, and Holcos) in case the results might be skewed by any 'synergy' or untoward 'clashes' between the resistive elements in the attenuators and the resistors used for the 'fixed' arrangements.
Fortunately, I have never heard of any claims that resistors of the same type vary noticeably in accordance with their values in their sonic attributes, and, indeed in my own long-term experiments, I find that they all have a family semblance based more on the type of construction and materials used, whatever their individual values may be.
Having done these trials, I also set up another test which used *only* the fixed resistive attenuator in one side, and with the passive in the other, but (as I had made the passive anyway and I had other similar phonos and jacks to hand) I used these connectors in exactly the same way to replicate those used in the Vishay/Shallco attenuator, in an effort to avoid any other unnecessary variables.
With some care, full details of which I won't reiterate as I have shown this elsewhere in several places on the Forum, but which include siting speakers together in the middle of a large room, and because no two speakers even with hand matched components (like mine) ever sound *exactly* alike, and neither do two channels of (also matched component) amps or preamps, you do need to 'ring the changes' from time to time, by swapping these components around.
It is then merely a matter of patiently switching from one channel to the other, however many times as is found necessary, in order to identify any *differences* which must be due to the DUT, when compared with 'nothing'. (i.e about as close as one can practically get to a straight wire.)
This kind of arrangement is a little less easy with attenuators such as here, but similar methods are used (by me, at least) frequently in any such 'comparison trials', as I have said before.
Having done this, I could detect no *significant* differences repeatably and consistantly, between having the Shallco/Vishay attenuator, in circuit or not, over many many hours of careful listening. Of course, there will be *some* albeit minor differences, as this is inevitable with using *any* different component, but even in my own very revealing system, they were not significant enough to be able to identify and describe properly.
I am therefore satisfied that as much as is humanly possible, these were very effective 'straight wire' comparisons, in the same manner as all others which are undertaken in similar circumstances, and it is not possibly IMO to do any better.
If any others have developed an easier or more effective method of carrying out such tests, I will be grateful to learn of them.
Certainly, the above tests will outdo any such ordinary subjective 'sit back and listen' tests (which I have also been conducting for about 30 yrs, and which definitely have their place in audio development), which are more about whether one *prefers* the sound or whatever, rather than if it is more *accurate*.
As I indicated by my earlier comments, I don't take much notice of *any* reviews, preferring to find out for myself in such cases, and I am sure that many Stereophile Reviews are "fine", as you suggest.
I just wished to know, and I still don't as you have omitted to say so, whether your opinions (or maybe Stereophile's, as you mentioned this mag and appear to hold them in esteem) were based on *comparisons* with other gear (frequently so with Stereophile), or whether, like me, you (or they) have attempted to conduct any more *valid* tests in deciding that the A/S attenuators exhibit the problems to which you referred?
Regrettably, your comments on the two A/S devices should be completely reversed, since as mentioned by me earlier (and, again, for what it is worth, by Martin Colloms) the 'old' A/S Passion is sonically a couple of points *ahead* of the later remote Passion Ultimate (both of which I use, as also advised), which reinforces my view that either you are not very familiar with these devices, personally, or that you have never done an A/B comparison between them.
The remarks relating to Jonathan's Connoisseur, were in relation to the comments made by Roy Gregory in Hi-Fi +, and Roy is very well known and has been on the audio scene for many years.
Interestingly, for anyone who is not familiar (perhaps like yourself?) with the review concerned, the article was all about Boulder equipment, but Roy simply raved about the Connoisseur in that review!
It is the first time in some 45 years that I have ever seen such a situation, where so much praise was awarded (and so much space allotted) to another make of equipment within a review of an alternative manufacturer, incidentally, whose (Boulder's) products were also thought quite highly of.
As I said originally, merely from my own knowledge and experience of the components used by Jonathan in his attenuator, it *will* be in an entirely different league, sonically, from a DACT , with which you had drawn some comparisons.
Maybe, Jonathan might care to add something here, since as I said, I have never heard his preamp, although I am aware that it is considered to be at the very 'top of the heap' within knowledgeable audio circles.
Regards,
Peter Daniel said:
Most defenitely 'L' type, Peter.
I had already tried about half a dozen of both styles using different resistors (like Holcos) and the Swiss Elma switches, and, always, the 'L' types were markedly superior, except when running at (almost) full volume, which I rarely do!
Otherwise, I guess it is the fact that the signal goes thro far too many separate resistors and soldered joints, which, as we all should know, will not help with the very best sonics.
The main problem with these jobs is getting hold of (small quantities of) the necessary frequently obscure values of resistors of this quality level, in order to get the steps correctly matched.
Mine are in 0.5 dB steps down to -42 dB, and then in 3 steps down to '0', although apart from '0', I don't ever use these last few steps. They are very 'usable' gradations, and the channel balance due to the use of 0.1% tolerance bulk foils, is as near as one can get to perfect!
I was very fortunate, when I made this attenuator in '95, in being friendly with David Heaton of Audio Synthesis (a smashing chap, and very talented!) as he used these components in attenuators which he built for sale, and he very kindly sold me the relevant bits.
I can never thank him enough, as my system resolution then took an almighty jump, even though it was quite good before.
Regards,
I also think that L Pad is more prefferable choice, yet when looking at Connoisseur production photos (below), it seems like their attenuator is of a series type using 39 resistors (although, I might be wrong here). Because of both surface mount and naked type, they probably less intrusive sonically, even when so many are in series. I would be interested in Jonathan's comments on choices made here.
My approach to preamp is that when you don't need it, don't use it. This narrows my selection to only one source component, but this is what I mostly listen to, so why make sacrifices by complicating signal path with switches and additional wiring and jacks?
I'm using CD source and separate DAC with a volume built in at the output. It consists of a fixed series resistor (50 ohm Vishay) and variable switch with 24 resistors selection to ground. Some may think that it's not enough, but for my needs it's more than enough. I'm mostly using selection between 15 and 20th position. The switch is based on Elma and I like it because of a small size. Initially I had some pops but after spraying contacts, they are fine. Resistors are variable between 0.5 - 500 ohm and the output resistance is usually 100 ohm.
My approach to preamp is that when you don't need it, don't use it. This narrows my selection to only one source component, but this is what I mostly listen to, so why make sacrifices by complicating signal path with switches and additional wiring and jacks?
I'm using CD source and separate DAC with a volume built in at the output. It consists of a fixed series resistor (50 ohm Vishay) and variable switch with 24 resistors selection to ground. Some may think that it's not enough, but for my needs it's more than enough. I'm mostly using selection between 15 and 20th position. The switch is based on Elma and I like it because of a small size. Initially I had some pops but after spraying contacts, they are fine. Resistors are variable between 0.5 - 500 ohm and the output resistance is usually 100 ohm.
Attachments
Hi Peter,
Don't be too hasty in thinking that Jonathan's attenuator is a 'series' job, merely from the picture.
I hope Jonathan will share some more of his valuable comments with us, but, in the meantime, I don't know if you are aware of it but a 'true' 'L' pad (impedance matched) should switch a different shunt resistor *and* a different series resistor into the circuit at each stage. This is needed to preserve the same input and output resistances seen by the cables and the surrounding components (i.e. source and amp) to suit their output and input impedances.
Most, (including mine!) don't because of the doubling of the already high cost, and the poor availability of good-sounding resistors in the required values.
In normal positions of rotation, the use of only one 'fixed' series resistor is a reasonable compromise, but, as I kept on telling Rarkov, such things are still a compromise, nevertheless, and the input and output impedances of the passive will vary according to rotation etc., which can have bad effects on the surrounding gear.
Somehow, I cannot see Jonathan going for any such compromise, and it is my guess that he uses the full 'L' pad arrangement, but this is only a guess and we will have to wait and see if he kindly replies to us.
Regards,
Edit: Incidentally, that picture you show looks to me like a Shallco, alright, and they are superb switches from the sonic aspect!
Don't be too hasty in thinking that Jonathan's attenuator is a 'series' job, merely from the picture.
I hope Jonathan will share some more of his valuable comments with us, but, in the meantime, I don't know if you are aware of it but a 'true' 'L' pad (impedance matched) should switch a different shunt resistor *and* a different series resistor into the circuit at each stage. This is needed to preserve the same input and output resistances seen by the cables and the surrounding components (i.e. source and amp) to suit their output and input impedances.
Most, (including mine!) don't because of the doubling of the already high cost, and the poor availability of good-sounding resistors in the required values.
In normal positions of rotation, the use of only one 'fixed' series resistor is a reasonable compromise, but, as I kept on telling Rarkov, such things are still a compromise, nevertheless, and the input and output impedances of the passive will vary according to rotation etc., which can have bad effects on the surrounding gear.
Somehow, I cannot see Jonathan going for any such compromise, and it is my guess that he uses the full 'L' pad arrangement, but this is only a guess and we will have to wait and see if he kindly replies to us.
Regards,
Edit: Incidentally, that picture you show looks to me like a Shallco, alright, and they are superb switches from the sonic aspect!
It may be true that having a fixed series resistor and changing only shunt resistor's value is a compromise, but to me the impedance change between let's say 60 ohm and 250 ohm (this is what I'm mostly using) is much less compromise then having a switch in a signal path and a longer path as well. Please correct me if I'm wrong.
Peter Daniel said:It may be true that having a fixed series resistor and changing only shunt resistor's value is a compromise, but to me the impedance change between let's say 60 ohm and 250 ohm (this is what I'm mostly using) is much less compromise then having a switch in a signal path and a longer path as well. Please correct me if I'm wrong.
As I said, I am quite content with the same kind of arrangement as you, and if it wasn't for the impedance matching with surrounding gear, there would be no issue here, so it will (to some extent) depend on the parameters of what you use. Again, this was why it was impossible to give Rarkov any definitive advice over this.
You do really need to know the various impedances involved, to ensure proper and adequate signal transfer.
I only mentioned my thoughts on Jonathan's setup (and I could still be wrong, here!) bearing in mind that it is possible at extra cost and complication, to avoid this particular compromise, and I don't see Jonathan doing much in the way of unnecessary compromising, if I am any judge!
I hope he will tell us.
Regards,
Bobken said:
I don't see Jonathan doing much in the way of unnecessary compromising
I noticed that too.
Bob,
Are you using your attenuator at the input or output? It's been sugested by Nelson Pass that actually the better placement is at the output, providing you don't present too much signal at the input. And what value of resistance are you using in your setup? I'm asking, because knowing your experience in that matter I might built something similar, maybe even using Shallco switch. With having so many choices in resistance selection it's quite hard to spend $400 or more for premium parts, only to learn later that the choice was inappropriate.
Hi Peter,
Thinking again about what you said, I guess it will depend also on the quality of the switch, and as I believe you had already probably posted before my edit, you may not have seen my comment on the Shallco (?) switch picture you posted.
These (or something similar with coin silver contacts, perhaps) are really a step ahead of *all* others I have tried (including Elmas, which are not bad) and they are just about as transparent and reliable in use as it is possible to go.
I guess they were developed for military use originally, where maybe lives are at stake if they don't work well (!), but by chance, as they are so well made and put together with sonically good materials, they also 'sound' superb.
In such a case, I am (only) guessing that a double-switching arrangement with a proper two resistor 'L' pad, would sound as good as the types we use, and there is the added advantage of completely avoiding the otherwise varying impedance issue, which is more elegant, and (I am also guessing) would be more 'aesthetically' appealing to Jonathan.
Regards,
Thinking again about what you said, I guess it will depend also on the quality of the switch, and as I believe you had already probably posted before my edit, you may not have seen my comment on the Shallco (?) switch picture you posted.
These (or something similar with coin silver contacts, perhaps) are really a step ahead of *all* others I have tried (including Elmas, which are not bad) and they are just about as transparent and reliable in use as it is possible to go.
I guess they were developed for military use originally, where maybe lives are at stake if they don't work well (!), but by chance, as they are so well made and put together with sonically good materials, they also 'sound' superb.
In such a case, I am (only) guessing that a double-switching arrangement with a proper two resistor 'L' pad, would sound as good as the types we use, and there is the added advantage of completely avoiding the otherwise varying impedance issue, which is more elegant, and (I am also guessing) would be more 'aesthetically' appealing to Jonathan.
Regards,
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