Peter Daniel said:
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.
Peter, I have just seen this and it 'crossed' with my last comments.
I have just been called for dinner, which, on Sunday here, is a big Do! nod:
I will post again in a couple of hours.
Regards,
Mark A. Gulbrandsen said:
Well, phase shift is rather meaningless as typical phase plots are the result of both frequency dependent and frequency independent delays. What matters is whether or not all the frequencies are arriving at the same time. And that question is answered in a plot of group delay, or as Jensen refers to it, deviation from linear phase (DLP).
Taking a look at the DLP plot of the Jensen JT-11P-1 shows a difference of just 0.6 degrees at 20 Hz. Sure, a resistor won't have such an effect because there is no high pass filter function involved. But this needs to be considered in the proper context. We don't just listen to preamplifiers and amplifiers. Y'ever see a group delay plot of a loudspeaker?
Core saturation is a concern but is dealt with by using an appropriate core size for the task at hand. You wouldn't want to slap an input transformer on the output of a power amplifier.
Ringing isn't a problem for properly designed and properly loaded transformers. However this is one concern I have about transformer-based attenuators. Each position gives you what amounts to a different transformer, yet every position will be loaded exactly the same as every other position.
Last time I talked to the folks at Jensen, they had no interest whatsoever in doing any sort of transformer-based attenuator. Jensen only pushes transformers for what they've always been superior at; ground isolation and noise rejection.
And as far as I'm aware, Sowter and S&B only produced their transformer attenuators at the behest of Thorsten Loesch, who is the preeminent transformer attenuator proponent.
Which leaves me wondering just what it is that you're wondering.
se
Hi Peter,
I don't fully understand what you mean by the input or output here, but I assume it may be related to the BOSOZ (or one of these preamps) which has some attenuation at both input and outputs.
If that is the case it doesn't apply with me as my (active!) preamp is a much modded Spectral, which strictly-speaking has the attenuator in the middle of it!
It is perhaps a rather unusual arrangement in the Spectral, but there are two very similar stages (in each channel) with the first being an RIAA stage of almost identical topology to the second stage (except for the passive feedback RIAA) which is merely to amplify the signal.
Between the two stages, there are several switches which permit the connection of other inputs, and this then feeds directly on to the attenuator, which 'fronts' the second stage dual FET input.
This attenuator (third version!) is now a dual mono Shallco/Vishay job with a mechanical 'tandem' arrangement I made using plastic gears, with a 'swing arm' central sprocket which can be lifted out of engagement to permit shifting balance etc., if ever needed. I only use this balance provision normally for testing purposes, as all of my sources are well balanced anyway, and all of my equipment has lids which are never screwed down, so I can carry out mods easily.
In fact the Spectral has a rather attractive (in my opinion) smoked Perspex see-through lid which I made because the gold-plated circuit board looks so pretty!
You may empathise with this, but the sound is also a little nicer with this lid than with the original aluminum one!
In addition, I have a separate dual mono A/S type of passive attenuator in a small alumium enclosure which can be plugged into the system in place of the (active) preamp, even for vinyl, as I have a separate (from the Spectral) HQ RIAA and pre-preamp stage, also in an aluminium box.
Finally, to complete the lineup (apart from about 5 other DIY passives using differing pots and resistors!) I have the choice of using an A/S Passion Ultimate, which is the latest version from A/S with a remote control, which I use when I am (infrequently) feeling lazy!
This is the passive I mentioned which was slightly less good sonically than the 'old' manual Shallco/Vishay passive, because it is optically switched using "a single Vishay foil resistor leading to a light controlled shunt resistor driven by an accurately programmed and balanced light source." instead of a Shallco switch.
Although I say "slightly less good", it was described by Martin Colloms in HFN (Aug 2001) for what this is worth, as "top of the class"... "its great clarity and low level resolution, plus stereo images, fine depth and a very natural character, both in mid and treble, are all on its side. The Ultimate was *free from artifice* and very easy to live with."..and... "This is one of the worlds best remotely controlled passive line units". These comments, apart from my own findings, are what makes me rather tend to doubt that Fmak has had any worthwhile experience of these units.
The slightly better sounding 'stand alone' manual version I have has a series resistor of 7k5 and the shunts vary from 3R8 to 47k, generally to give 1.5 dB steps (not 0.5 which I notice I incorrectly typed earlier). My Spectral ones, do have some differences in resistor values necessary to obtain the correct impedances, but, otherwise they are the same in construction and components.
As you may see from this , I have had a little experience of passives at the high-end (and many lesser passives over some 15 years!) and if you want any further info, like some of the intermediate step resistor values, let me know, and I will look at them.
I would urge you to try a Shallco switch if you are after the very best, Peter, but I warn you now, they are very bulky and take up quite a lot of space.
Its now 1.30 AM, and time for bed!
Regards,
I don't fully understand what you mean by the input or output here, but I assume it may be related to the BOSOZ (or one of these preamps) which has some attenuation at both input and outputs.
If that is the case it doesn't apply with me as my (active!) preamp is a much modded Spectral, which strictly-speaking has the attenuator in the middle of it!
It is perhaps a rather unusual arrangement in the Spectral, but there are two very similar stages (in each channel) with the first being an RIAA stage of almost identical topology to the second stage (except for the passive feedback RIAA) which is merely to amplify the signal.
Between the two stages, there are several switches which permit the connection of other inputs, and this then feeds directly on to the attenuator, which 'fronts' the second stage dual FET input.
This attenuator (third version!) is now a dual mono Shallco/Vishay job with a mechanical 'tandem' arrangement I made using plastic gears, with a 'swing arm' central sprocket which can be lifted out of engagement to permit shifting balance etc., if ever needed. I only use this balance provision normally for testing purposes, as all of my sources are well balanced anyway, and all of my equipment has lids which are never screwed down, so I can carry out mods easily.
In fact the Spectral has a rather attractive (in my opinion) smoked Perspex see-through lid which I made because the gold-plated circuit board looks so pretty!You may empathise with this, but the sound is also a little nicer with this lid than with the original aluminum one!
In addition, I have a separate dual mono A/S type of passive attenuator in a small alumium enclosure which can be plugged into the system in place of the (active) preamp, even for vinyl, as I have a separate (from the Spectral) HQ RIAA and pre-preamp stage, also in an aluminium box.
Finally, to complete the lineup (apart from about 5 other DIY passives using differing pots and resistors!) I have the choice of using an A/S Passion Ultimate, which is the latest version from A/S with a remote control, which I use when I am (infrequently) feeling lazy!
This is the passive I mentioned which was slightly less good sonically than the 'old' manual Shallco/Vishay passive, because it is optically switched using "a single Vishay foil resistor leading to a light controlled shunt resistor driven by an accurately programmed and balanced light source." instead of a Shallco switch.
Although I say "slightly less good", it was described by Martin Colloms in HFN (Aug 2001) for what this is worth, as "top of the class"... "its great clarity and low level resolution, plus stereo images, fine depth and a very natural character, both in mid and treble, are all on its side. The Ultimate was *free from artifice* and very easy to live with."..and... "This is one of the worlds best remotely controlled passive line units". These comments, apart from my own findings, are what makes me rather tend to doubt that Fmak has had any worthwhile experience of these units.
The slightly better sounding 'stand alone' manual version I have has a series resistor of 7k5 and the shunts vary from 3R8 to 47k, generally to give 1.5 dB steps (not 0.5 which I notice I incorrectly typed earlier). My Spectral ones, do have some differences in resistor values necessary to obtain the correct impedances, but, otherwise they are the same in construction and components.
As you may see from this , I have had a little experience of passives at the high-end (and many lesser passives over some 15 years!) and if you want any further info, like some of the intermediate step resistor values, let me know, and I will look at them.
I would urge you to try a Shallco switch if you are after the very best, Peter, but I warn you now, they are very bulky and take up quite a lot of space.
Its now 1.30 AM, and time for bed!
Regards,
TYPOS....
Hi,
Ah,those flamin' typos...happens to me all the time.
I was wondering already how all these 0.5 dB steps would fit the Shalco.
Personally I use 2dB steps with a 24 pos. Elma switch and since I use the 10 to 12 o'clock positions most of the time,I only fit Vishay S102s there.
The shunt R is a Holco which is not varied anyway,the other positions are fit with the same non-magnetic Holcos.
BTW,where can one buy these Shalco switches in the EC?
Cheers,
P.S.First you eat for hours,now you go to bed?
Hi,
Ah,those flamin' typos...happens to me all the time.
I was wondering already how all these 0.5 dB steps would fit the Shalco.
Personally I use 2dB steps with a 24 pos. Elma switch and since I use the 10 to 12 o'clock positions most of the time,I only fit Vishay S102s there.
The shunt R is a Holco which is not varied anyway,the other positions are fit with the same non-magnetic Holcos.
BTW,where can one buy these Shalco switches in the EC?
Cheers,
P.S.First you eat for hours,now you go to bed?
Trying to prove you're an insomniac, again!
Hi Frank,
I don't know, here we are on the brink of war, and I am just enjoying myself all the while!
Sorry about the typo, but you must agree it is rather unusual for me.
Actually, whilst I can hear 0.5 dB changes readily, the difference is so small that it would hardly be a sensible way of making a switched passive, in my view.
The Shallcos, are simply the best IMHO, but they are a problem to get hold of in small quantities.
Last year, I spent ages researching this, and came up with sweet nothing, regrettably, so I too would be interested in hearing of any others' positive experiences with supplies of these.
David Heaton has none of them left, as he only uses the newer optical arrangements now, and when I enquired from Shallco direct, and some USA suppliers, the minimum quantities in all cases was 10 off.
Michael Percy does have some, but their configuration didn't suit my requirements, unfortunately.
In the end, I had a UK company make me up a special, which was not any cheaper than a Shallco, and it appears to be of almost identical rugged construction. Very similar large body, and silver contacts, and very well put together, but although it seems to be very good sonically, I have not done a true A/B comparison with a Shallco, as I don't have a 'counterpart' to compare it with.
This switch was for input (source) switching, and only (at my choice) had six positions, whereas all of my Shallcos have 31 posns.
I guess, if there was sufficient interest, that this would be an ideal candidate for a WIKI (or whatever it is called!) purchase, possibly direct from Shallco, themselves.
Your 'hybrid' idea with different makes of resistors is a very good way of keeping costs down, and one of my (very many!) 'intermediate' attenuators was made this way.
I started out with all Holcos, and wishing to see (hear!) what difference Vishays would make in practice (but as a 'dipping the toes into the water' for the first time exercise), I merely substituted some Vishays for the middle few resistors.
In fact, as I had already said that I might have added somewhat to the earlier thread had I been around then, I will mention the following, which (from memory, and I am not going to spend another 90 mins checking back!) I don't think was covered.
In my experience, I found that (generally) with 'fixed' resistors, the series resistor accounted for say two-thirds of the sonic benefit, and the shunt about one third. So if costs need to be kept down, use a higher quality R for the series, rather than for the shunt.
The same was apparent with law-faking resistors used with pots, and here a similar ratio was observed, with it seeming to be more advantageous to spend proportionately more on the fixed resistor than the pot.
A quite average (Alps Black Beauty) bypassed with a Vishay will sound better than say a (normally better sounding when used alone) Panasonic 'For Audio' pot used with a Holco law-faker. As a complete 'off-topic' aside, I have regularly read that the name 'Holco' stems from: wHOLe COpper: which is another complete audio myth. It comes from the fact that the company making them was called Holdsworthy Co (in Devon, UK) before it was taken over by (or merged with) Meggitt, and about twenty years ago I used to get my Holcos direct from them!
Incidentally, I am still awaiting fmak to come back on this thread to tell us all about his experiences (after criticising the Shallco/Vishay types), and I hope he will let us know which method of switching, and what the resistive elements are, in his 'favoured' Carver job.
Regards,
fdegrove said:Hi,
Ah,those flamin' typos...happens to me all the time.
I was wondering already how all these 0.5 dB steps would fit the Shalco.
Personally I use 2dB steps with a 24 pos. Elma switch and since I use the 10 to 12 o'clock positions most of the time,I only fit Vishay S102s there.
The shunt R is a Holco which is not varied anyway,the other positions are fit with the same non-magnetic Holcos.
BTW,where can one buy these Shalco switches in the EC?
Cheers,
P.S.First you eat for hours,now you go to bed?
Hi Frank,
I don't know, here we are on the brink of war, and I am just enjoying myself all the while!
Sorry about the typo, but you must agree it is rather unusual for me.
Actually, whilst I can hear 0.5 dB changes readily, the difference is so small that it would hardly be a sensible way of making a switched passive, in my view.
The Shallcos, are simply the best IMHO, but they are a problem to get hold of in small quantities.
Last year, I spent ages researching this, and came up with sweet nothing, regrettably, so I too would be interested in hearing of any others' positive experiences with supplies of these.
David Heaton has none of them left, as he only uses the newer optical arrangements now, and when I enquired from Shallco direct, and some USA suppliers, the minimum quantities in all cases was 10 off.
Michael Percy does have some, but their configuration didn't suit my requirements, unfortunately.
In the end, I had a UK company make me up a special, which was not any cheaper than a Shallco, and it appears to be of almost identical rugged construction. Very similar large body, and silver contacts, and very well put together, but although it seems to be very good sonically, I have not done a true A/B comparison with a Shallco, as I don't have a 'counterpart' to compare it with.
This switch was for input (source) switching, and only (at my choice) had six positions, whereas all of my Shallcos have 31 posns.
I guess, if there was sufficient interest, that this would be an ideal candidate for a WIKI (or whatever it is called!) purchase, possibly direct from Shallco, themselves.
Your 'hybrid' idea with different makes of resistors is a very good way of keeping costs down, and one of my (very many!) 'intermediate' attenuators was made this way.
I started out with all Holcos, and wishing to see (hear!) what difference Vishays would make in practice (but as a 'dipping the toes into the water' for the first time exercise), I merely substituted some Vishays for the middle few resistors.
In fact, as I had already said that I might have added somewhat to the earlier thread had I been around then, I will mention the following, which (from memory, and I am not going to spend another 90 mins checking back!) I don't think was covered.
In my experience, I found that (generally) with 'fixed' resistors, the series resistor accounted for say two-thirds of the sonic benefit, and the shunt about one third. So if costs need to be kept down, use a higher quality R for the series, rather than for the shunt.
The same was apparent with law-faking resistors used with pots, and here a similar ratio was observed, with it seeming to be more advantageous to spend proportionately more on the fixed resistor than the pot.
A quite average (Alps Black Beauty) bypassed with a Vishay will sound better than say a (normally better sounding when used alone) Panasonic 'For Audio' pot used with a Holco law-faker.
As a complete 'off-topic' aside, I have regularly read that the name 'Holco' stems from: wHOLe COpper: which is another complete audio myth. It comes from the fact that the company making them was called Holdsworthy Co (in Devon, UK) before it was taken over by (or merged with) Meggitt, and about twenty years ago I used to get my Holcos direct from them!Incidentally, I am still awaiting fmak to come back on this thread to tell us all about his experiences (after criticising the Shallco/Vishay types), and I hope he will let us know which method of switching, and what the resistive elements are, in his 'favoured' Carver job.
Regards,
HOLSWORTHY.
Hi Bob,
You know I was only teasing you,don't you?
It appears that once again our experiences concur nicely.
BTW,FYI Holsworthy is actually a place in Devon where I assume the factory is located.
Didn't you just love the way they did/do the packaging?
Lovely old fashioned little carton boxes,the resistors laying on a piece of soft paper?
And even when they only stated a 1% tolerance they were always spot on from what I measured.
Too bad they have abandoned the copper endcaps and leadouts.
I think I know this company,I once browsed through their website and they got me confused there,not clear what to order at all.
I suppose having them custom made or, as you suggest ordering them in quantities from Shalco may be the best way to go.
Could it be that Fmak is *carving* up the beef?
Cheers,
Hi Bob,
You know I was only teasing you,don't you?
It appears that once again our experiences concur nicely.
BTW,FYI Holsworthy is actually a place in Devon where I assume the factory is located.
Didn't you just love the way they did/do the packaging?
Lovely old fashioned little carton boxes,the resistors laying on a piece of soft paper?
And even when they only stated a 1% tolerance they were always spot on from what I measured.
Too bad they have abandoned the copper endcaps and leadouts.
I think I know this company,I once browsed through their website and they got me confused there,not clear what to order at all.
I suppose having them custom made or, as you suggest ordering them in quantities from Shalco may be the best way to go.
Could it be that Fmak is *carving* up the beef?
Cheers,
Re: Trying to prove you're an insomniac, again!
[Incidentally, I am still awaiting fmak to come back on this thread to tell us all about his experiences (after criticising the Shallco/Vishay types), and I hope he will let us know which method of switching, and what the resistive elements are, in his 'favoured' Carver job.
Regards, [/B][/QUOTE]
----------------------------------------------
I have never criticised the Shallco/Vishay type; you have read that into my post. I said that the AS passives I have are not totally neutral. Part of the reason is the existence of the rec switch and part due to the kind of wiring used. On the former, check with AS if you like.
I am happy to make short contributions of views but do not intend to be involved in long debate.
[Incidentally, I am still awaiting fmak to come back on this thread to tell us all about his experiences (after criticising the Shallco/Vishay types), and I hope he will let us know which method of switching, and what the resistive elements are, in his 'favoured' Carver job.
Regards, [/B][/QUOTE]
----------------------------------------------
I have never criticised the Shallco/Vishay type; you have read that into my post. I said that the AS passives I have are not totally neutral. Part of the reason is the existence of the rec switch and part due to the kind of wiring used. On the former, check with AS if you like.
I am happy to make short contributions of views but do not intend to be involved in long debate.
Buffered passive preamp
[QUOTE
If you must stick with 100k vol pot you should think about
going the active-passive-pre-amplifier route
with a
unity gain buffer]
Look at :Aunt Corey's Homemade Buffered Passive Preamplifier
http://www.stereophile.com/showarchives.cgi?54
It a very intereresting story about a buffered preamp.
I will take a BUF 634 instead of an BUF 03 or a BUF 04.
I made a buffer after my CD-player with the BUF 634.
Compared with the X10D from from Musical Fed. it is mutch better
and very cheap.
You find also a story on fast soft recorery diodes and the importance of dual mono powersupply.
Peter.
[QUOTE
If you must stick with 100k vol pot you should think about
going the active-passive-pre-amplifier route
with aunity gain buffer]
Look at :Aunt Corey's Homemade Buffered Passive Preamplifier
http://www.stereophile.com/showarchives.cgi?54
It a very intereresting story about a buffered preamp.
I will take a BUF 634 instead of an BUF 03 or a BUF 04.
I made a buffer after my CD-player with the BUF 634.
Compared with the X10D from from Musical Fed. it is mutch better
and very cheap.
You find also a story on fast soft recorery diodes and the importance of dual mono powersupply.
Peter.
----------------------------------------------fmak said:[Incidentally, I am still awaiting fmak to come back on this thread to tell us all about his experiences (after criticising the Shallco/Vishay types), and I hope he will let us know which method of switching, and what the resistive elements are, in his 'favoured' Carver job.
Regards,
I have never criticised the Shallco/Vishay type; you have read that into my post. I said that the AS passives I have are not totally neutral. Part of the reason is the existence of the rec switch and part due to the kind of wiring used. On the former, check with AS if you like.
I am happy to make short contributions of views but do not intend to be involved in long debate. [/B][/QUOTE]
Hi,
If you wish to be pedantic about it, yes, you are absolutely correct that you did not "criticise the Shallco/Vishay type", and this being the case, I owe you a most sincere apology.
However, if your clearly-stated criticisms are brought about as you *now* say by the "rec switch and kind of wiring used" why did you bring this up in direct response to (and actually quoting!) my earlier comments which were all about the use of a Shallco/Vishay arrangement? (Irrespective of wherever I sourced the necessary parts)
Now being similarly pedantic myself, you also did *not* say that "the AS passives *you have* are not totally neutral."
What you did say was a sweeping generalisation relating to AS passives (without any qualification, like perhaps you constructed it, yourself, so this could be why) which included "dry and brighter than neutral".
This (unqualified) statement was to my knowledge an incorrect and misleading comment applied to A/S passives generally, in the same manner as your subsequent comment "understand that the new Passion is more neutral", when the converse is actually true!
Again, I don't mind differing in opinion with anyone over such matters, but it is all too easy for someone to toss in some crumbs of unsubstantiated 'wisdom' in a thread, in an apparrently authoritative manner, but this will doubtless have some (possibly incorrect) influence on the future thoughts of other readers.
I note with regret that (unlike me) you decline to offer any further explanations about these *conclusions*, nor do you even comment on how the suggested 'comparisons' were made, in a similar way that I did when I explained my methodology at great length. i.e. Was the suggested "dry and brighter" result heard in comparison with what you are familiar with, or was it in comparison with some *known* reference, as I had tried to do?
It now seems most unlikely that you will let the rest of us know anything worthwhile about what the resistive elements and switching arrangements are in your 'favoured' Carver passive, so I guess like me, many other readers will be wondering quite what was the point of your posting in this thread at all!
Playing devil's advocate must be a very rewarding experience!
Regards,
Re: HOLSWORTHY.
Hi Frank,
Yes!
Yes!
And yes!
In fact I knew as I have been through the village many times as my brother retired to Devon quite near there some years ago, but I also knew from their address when I needed to send Holsworthy some money!
It is said that "there is no future in nostalgia", Frank, but I still keep many of these Holcos in the original little brown envelopes, which looked rather like the very first wage packets I got 40+ years ago!
Right again about the tolerances, but they were also available in tighter tols than the nominally 1% (I had some 0.1%) which probably measured at 0.01%, or similar! Oh, those were the days when they were a couple of pennies each!
I don't know from any experience about the change in endcaps, apart from reading somewhere about it, as I haven't bought any for maybe ten years. I used to get them in tens or hundreds from the factory, and I still have most useful values left.
Now that my system is Vishay throughout (save for a few Caddocks for higher PD) I don't use Holcos any more except if I am trying out some new circuit, which I will develop to finalisation, and then swap out with Vishays.
Actually, in all the years I used them, I never had any failures, nor excessive noise etc., but I am always careful not to bend *any* leads close to the body of components as this is simply asking for trouble, anyway.
The work-hardening stresses (effectively the opposite of annealing!) resulting from all tight bends in leads will also badly affect the sonics, because of the breakdown of the crystalline structure, exactly as it does with wires like we have discussed before.
I don't presently recall (but will look it up on request) the name of the switch company I referred to who were in Wales I believe, and I don't think they had a website (last year) from memory. They needed (then) to fax me most of their tech info.
However it could be the same place, as this firm's info was rather alarming to look through with many hundreds of possible variations, all coded with numbers or letters, and which you had to get right when ordering anything!
I cheated, and had several chats with a tech guy there as I wanted to know more about the consuction (i.e. what was the contact pressure, were the contacts welded or riveted, the quality of silver used, how long and what was the 'path' made of between the contacts themselves and the tags etc.) so he simply did the job for me.
These kind of details are all too easy to overlook, but will be just as responsible for the ultimate 'sound' as some of the more obvious parameters like contact resistance, and mean-time before failure etc.
Whenever I look at non-audiophile bits for the first time, I think about these matters, since for say military use, what is important to us, simply may not matter at all in combat!
Regards,
fdegrove said:Hi Bob,
You know I was only teasing you,don't you?
It appears that once again our experiences concur nicely.
BTW,FYI Holsworthy is actually a place in Devon where I assume the factory is located.
Didn't you just love the way they did/do the packaging?
Lovely old fashioned little carton boxes,the resistors laying on a piece of soft paper?
And even when they only stated a 1% tolerance they were always spot on from what I measured.
Too bad they have abandoned the copper endcaps and leadouts.
I think I know this company,I once browsed through their website and they got me confused there,not clear what to order at all.
I suppose having them custom made or, as you suggest ordering them in quantities from Shalco may be the best way to go.
Could it be that Fmak is *carving* up the beef?
Cheers,
Hi Frank,
Yes!
Yes!
And yes!
In fact I knew as I have been through the village many times as my brother retired to Devon quite near there some years ago, but I also knew from their address when I needed to send Holsworthy some money!
It is said that "there is no future in nostalgia", Frank, but I still keep many of these Holcos in the original little brown envelopes, which looked rather like the very first wage packets I got 40+ years ago!
Right again about the tolerances, but they were also available in tighter tols than the nominally 1% (I had some 0.1%) which probably measured at 0.01%, or similar! Oh, those were the days when they were a couple of pennies each!
I don't know from any experience about the change in endcaps, apart from reading somewhere about it, as I haven't bought any for maybe ten years. I used to get them in tens or hundreds from the factory, and I still have most useful values left.
Now that my system is Vishay throughout (save for a few Caddocks for higher PD) I don't use Holcos any more except if I am trying out some new circuit, which I will develop to finalisation, and then swap out with Vishays.
Actually, in all the years I used them, I never had any failures, nor excessive noise etc., but I am always careful not to bend *any* leads close to the body of components as this is simply asking for trouble, anyway.
The work-hardening stresses (effectively the opposite of annealing!) resulting from all tight bends in leads will also badly affect the sonics, because of the breakdown of the crystalline structure, exactly as it does with wires like we have discussed before.
I don't presently recall (but will look it up on request) the name of the switch company I referred to who were in Wales I believe, and I don't think they had a website (last year) from memory. They needed (then) to fax me most of their tech info.
However it could be the same place, as this firm's info was rather alarming to look through with many hundreds of possible variations, all coded with numbers or letters, and which you had to get right when ordering anything!
I cheated, and had several chats with a tech guy there as I wanted to know more about the consuction (i.e. what was the contact pressure, were the contacts welded or riveted, the quality of silver used, how long and what was the 'path' made of between the contacts themselves and the tags etc.) so he simply did the job for me.
These kind of details are all too easy to overlook, but will be just as responsible for the ultimate 'sound' as some of the more obvious parameters like contact resistance, and mean-time before failure etc.
Whenever I look at non-audiophile bits for the first time, I think about these matters, since for say military use, what is important to us, simply may not matter at all in combat!
Regards,
Re: Re: Re: Buffered passive preamp
Well, I'm not Steve, but that was HIS commercial version of the Buf03 buffered preamp, which came out before Corey's article.
Hey Steve, I never received my shipment of knobs from that preamp. You were going to send me about a million of them
Cheers,
RonS
mlloyd1 said:
Well, I'm not Steve, but that was HIS commercial version of the Buf03 buffered preamp, which came out before Corey's article.Hey Steve, I never received my shipment of knobs from that preamp. You were going to send me about a million of them
Cheers,
RonS
Re: Re: Re: Buffered passive preamp
It was a commercial product I was selling at the time under the Alpha Logic name.
I had a press release about it in the file area of The Audiophile Network (a dial-up bulletin board system from back in the pre-Internet days). Corey was a regular there and one day he caught me online and said he saw it and thought it was a good idea and asked me if I could help him out with a DIY article for Stereophile (JA had recently recruited a few of the TAN regulars to write for Stereophile, including Jonathan Scull).
So I gave him schematics, parts sources, etc. and along with some Walt Jung-based tweaks, he wrote his Aunt Corey's Buffered Passive Preamp article for Stereophile.
So the pictured AL-1 was the "original."
se
mlloyd1 said:
It was a commercial product I was selling at the time under the Alpha Logic name.
I had a press release about it in the file area of The Audiophile Network (a dial-up bulletin board system from back in the pre-Internet days). Corey was a regular there and one day he caught me online and said he saw it and thought it was a good idea and asked me if I could help him out with a DIY article for Stereophile (JA had recently recruited a few of the TAN regulars to write for Stereophile, including Jonathan Scull).
So I gave him schematics, parts sources, etc. and along with some Walt Jung-based tweaks, he wrote his Aunt Corey's Buffered Passive Preamp article for Stereophile.
So the pictured AL-1 was the "original."
se
Re: Re: Re: Re: Buffered passive preamp
*sigh* My apologies, Ron! Just one of those things I spaced on (you should have given me a kick in the *** to remind me).
The little UPS shipper down the street from me had closed up and between looking for another one nearby and a dozen other things, it slipped through the cracks.
I've got a FedEx account now so there's no excuses. EMail me your mailing address and I'll ship 'em out this week.
Oh, and I seem to have misplaced about 999,930 of 'em as I can only locate about 70 of 'em now.
Again, my apologies.
se
transducer said:Hey Steve, I never received my shipment of knobs from that preamp. You were going to send me about a million of them
*sigh* My apologies, Ron! Just one of those things I spaced on (you should have given me a kick in the *** to remind me).
The little UPS shipper down the street from me had closed up and between looking for another one nearby and a dozen other things, it slipped through the cracks.
I've got a FedEx account now so there's no excuses. EMail me your mailing address and I'll ship 'em out this week.
Oh, and I seem to have misplaced about 999,930 of 'em as I can only locate about 70 of 'em now.
Again, my apologies.
se
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