That's what i understand also from reading Oliver when he swaped from Charcroft to the Rhopoint GR102 ... as the GR102 are more expensive than the Rhopoint 5 & 8 wirewound series...
Founded strange than the tubes which has a higher noise floor than transitors let allow to hear a difference between this two excellent resistors... but in reallity rhopoint give a better subjective sounding than TX2575 Charcroft and all bulk foil as I/V with both tubes & transistor output solution !
So John here and Thorsten use Rhopoint in their devices not for nothing ! One with transistor the other with tubes !
Founded strange than the tubes which has a higher noise floor than transitors let allow to hear a difference between this two excellent resistors... but in reallity rhopoint give a better subjective sounding than TX2575 Charcroft and all bulk foil as I/V with both tubes & transistor output solution !
So John here and Thorsten use Rhopoint in their devices not for nothing ! One with transistor the other with tubes !
You are right, we are limited by the facility to source and the monney we have. here in France we have so few off shelves shop and like so many countries, Mouser and like web shop are easier ! But Maybe if people ask they can add some ref to the catalog ?
Did you find the Neohms as good or better in i/V than the wirewound rhopoint ?
What are the ref you think about when talking about PS caps ?
Did you find the Neohms as good or better in i/V than the wirewound rhopoint ?
What are the ref you think about when talking about PS caps ?
My comparisons
I went thru a few options for I/V on 1541a with Lampizator 6n2p tube buffer.
I have used standard metal film, then Takman REY (better). Tried Amtrans. At first interesting as if it would have potential once burnin complete. It got better over time but always muffled. Then stepped up to Caddock USF340. Very nice step up. it is clear clean and still musical. Final was the hand made Manganin bifilar winding. Clear winner on all subjective measures and will not be leaving the system. All were 50R.
One DIY claims that in his experience only the Rhopoint betters them so I suspect that Thoerston/Oliver/John et al are on the winning track if you do not mind paying the price.
I went thru a few options for I/V on 1541a with Lampizator 6n2p tube buffer.
I have used standard metal film, then Takman REY (better). Tried Amtrans. At first interesting as if it would have potential once burnin complete. It got better over time but always muffled. Then stepped up to Caddock USF340. Very nice step up. it is clear clean and still musical. Final was the hand made Manganin bifilar winding. Clear winner on all subjective measures and will not be leaving the system. All were 50R.
One DIY claims that in his experience only the Rhopoint betters them so I suspect that Thoerston/Oliver/John et al are on the winning track if you do not mind paying the price.
The I/V resistor type not only depends on the type of circuit that you are using (ie valve and/or fet) but your whole system preference - some people run quite soft sounding amps/speakers and prefer a brighter sounding source while other folks like the opposite.
For my system and an example of the 2 types, I've found that the Neohms seem to fit really well as the gate stopper resistors for buffers but I've used the Rhopoints in the Aikido gain stage for an added presence in the lower mid/upper bass area - I also use the Rhopoints as the 1541A o/p stage I/V resistor as the sound matches up with requirements but some of the guys here actually find they prefer the extra brightness that you get from the TC2575 - I think you have to just try them in your own system.
There's a Sfernice range that's common in France/Europe that's well worth a try too.
I'm playing with a copper wire resistor that's a bit different again - possibly the most neutral of them all but a real PIA to wind as the #36 wire is very thin - tried to do one of those 'cotton reel' formers like John's but wire too fragile & keeps breaking (ham fisted too!)
You can buy something that'll act as 'resistance wire' from all sorts of places - doesn't just have to be Isotan or Manganin - this was a 'hot topic' about 10 years ago and isn't mainstream these days so you perhaps will find a lot of useful info in the Archives
Small quantities of resistors are available from Rhopoint Company direct but does attract a service charge - might be cheaper to get them thru someone like Farnell/Element 14, RS Components, etc - not sure about stocked values and the costs seem to be all over the place, so worth a quote/query - don't forget about Elfa too.
There's now some higher value film caps that are rather useful for power supply filter caps - big and expensive, but available - mostly European, I think.
For my system and an example of the 2 types, I've found that the Neohms seem to fit really well as the gate stopper resistors for buffers but I've used the Rhopoints in the Aikido gain stage for an added presence in the lower mid/upper bass area - I also use the Rhopoints as the 1541A o/p stage I/V resistor as the sound matches up with requirements but some of the guys here actually find they prefer the extra brightness that you get from the TC2575 - I think you have to just try them in your own system.
There's a Sfernice range that's common in France/Europe that's well worth a try too.
I'm playing with a copper wire resistor that's a bit different again - possibly the most neutral of them all but a real PIA to wind as the #36 wire is very thin - tried to do one of those 'cotton reel' formers like John's but wire too fragile & keeps breaking (ham fisted too!)
You can buy something that'll act as 'resistance wire' from all sorts of places - doesn't just have to be Isotan or Manganin - this was a 'hot topic' about 10 years ago and isn't mainstream these days so you perhaps will find a lot of useful info in the Archives
Small quantities of resistors are available from Rhopoint Company direct but does attract a service charge - might be cheaper to get them thru someone like Farnell/Element 14, RS Components, etc - not sure about stocked values and the costs seem to be all over the place, so worth a quote/query - don't forget about Elfa too.
There's now some higher value film caps that are rather useful for power supply filter caps - big and expensive, but available - mostly European, I think.
I think some of quite exotic parts are still available in France via the military supply network - not sure how it works now but it used to be via approved forwarding houses, indirect, industrial supply systems, etc - Siemens gear is a bit the same - they don't like small retail sales much.
thanks james for the advices. I think the same as you about parts and compensation with the whole system... differences can be huge; I spent a lot of time e.g. on the Subbu 3 which have few parts, only playing with caps maid a incredible better sound. Never played with resistors...
Yes we have some surplue industrial & miltiray stocks... I knew a shop but forget the name : some parts were fabulous : caps used in satelites, railways, etc... Some brand are fabulous like EUROFARAD ! when you read the industrial catalog of caps it's like Christmass !
Via Farnel element 14, the rhopoint is less expensive than the TC2575
will surf on EFA, thanks for the hints.
But did you said we can ask them for a better price if less than 10 units are buyed, i believe I didn't understand what you wrote about that !
@Wlovles,
Peter Daniel liked very much the cadock TF020... what a pity you didn't test it for the testimonial... the AMTRANS is said to be very good in signal path of a DAC... maybe as some carbon comp, the filter HF effect matter ?!
Yes we have some surplue industrial & miltiray stocks... I knew a shop but forget the name : some parts were fabulous : caps used in satelites, railways, etc... Some brand are fabulous like EUROFARAD ! when you read the industrial catalog of caps it's like Christmass !
Via Farnel element 14, the rhopoint is less expensive than the TC2575
will surf on EFA, thanks for the hints.
But did you said we can ask them for a better price if less than 10 units are buyed, i believe I didn't understand what you wrote about that !
@Wlovles,
Peter Daniel liked very much the cadock TF020... what a pity you didn't test it for the testimonial... the AMTRANS is said to be very good in signal path of a DAC... maybe as some carbon comp, the filter HF effect matter ?!
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Hi Ceglar,
The reason I/V resistors change the output spectrum and related sound is that these are driven by low level, large bandwidth signals.
50 Ohm passive I/V resistor with TDA1541A resuts in 200mVpp full scale and LSB corresponds to 3uV.
The Rhopoints consist of two counter wound windings with non-ideal magnetic coupling, so these are stil inductive. Noise properties (mainly depends on weldings) on the other hand are excellent.
What we need for transparent sound reproduction is an I/V resistor with lowest noise and lowest inductance.
Here is an article about resistor noise:
Resistor Noise » Resistor Guide
Good wire wound resistors offer even lower noise compared to bulk metal foil.
The weak spot is the welding or bonding between resistor wire or resistive element and the lead wires. This may be (one of) the reasons why bulk metal foil resistors disappoint as I/V resistor.
During development of the new projects I built my own 50 Ohms non-inductive (twisted bifilar winding) wire wound SMD resistors. Attached picture shows the tiny wire wound resistor that is placed on a CNC milled PCB coil former.
The reason I/V resistors change the output spectrum and related sound is that these are driven by low level, large bandwidth signals.
50 Ohm passive I/V resistor with TDA1541A resuts in 200mVpp full scale and LSB corresponds to 3uV.
The Rhopoints consist of two counter wound windings with non-ideal magnetic coupling, so these are stil inductive. Noise properties (mainly depends on weldings) on the other hand are excellent.
What we need for transparent sound reproduction is an I/V resistor with lowest noise and lowest inductance.
Here is an article about resistor noise:
Resistor Noise » Resistor Guide
Good wire wound resistors offer even lower noise compared to bulk metal foil.
The weak spot is the welding or bonding between resistor wire or resistive element and the lead wires. This may be (one of) the reasons why bulk metal foil resistors disappoint as I/V resistor.
During development of the new projects I built my own 50 Ohms non-inductive (twisted bifilar winding) wire wound SMD resistors. Attached picture shows the tiny wire wound resistor that is placed on a CNC milled PCB coil former.
Attachments
In particular for the RS and Farnell's, I think these sorts of components are quite low volume so the prices probably are set some time ago and when an enquiry is sent to them, the sales people have a fresh look at stock movement and can offer more consistent prices (I could also be quite wrong about this)
[some values are priced at twice other values and a simple enquiry can sometimes get better prices all over]
I don't buy many of them nowadays and if I get enough on one order to offset the 20GBP handling charge from Rhopoint, I prefer to get them direct - if I just require 2, maybe 4, I go looking for Farnell, RS Component, etc
I'm now using the OCC copper wires for Interconnects and this has led to some changes in preferred resistor and capacitor types so I haven't gone back to try the Caddocks as signal line Rs - I do use some mp930s but usually prefer the Isabellenhutte PBH in power Rs for F5 amp, for example (hence the ELFA reference)
Again, it seems to me that where you use the particular types in the circuit has nearly as much effect on the result as the type
My reference is the old modded AKG701 headphones (not the more exotic planar types, etc) with Patrick's DAO headamp or the Cavalli, so maybe that gives you a better idea of 'my ears' - the new LCD-X Audeze planars are on my 'wish list' but ....
[some values are priced at twice other values and a simple enquiry can sometimes get better prices all over]
I don't buy many of them nowadays and if I get enough on one order to offset the 20GBP handling charge from Rhopoint, I prefer to get them direct - if I just require 2, maybe 4, I go looking for Farnell, RS Component, etc
I'm now using the OCC copper wires for Interconnects and this has led to some changes in preferred resistor and capacitor types so I haven't gone back to try the Caddocks as signal line Rs - I do use some mp930s but usually prefer the Isabellenhutte PBH in power Rs for F5 amp, for example (hence the ELFA reference)
Again, it seems to me that where you use the particular types in the circuit has nearly as much effect on the result as the type
My reference is the old modded AKG701 headphones (not the more exotic planar types, etc) with Patrick's DAO headamp or the Cavalli, so maybe that gives you a better idea of 'my ears' - the new LCD-X Audeze planars are on my 'wish list' but ....
Dear Jameshillj wrote:
OCC copper rules. I use it everywhere: mains; power; IC; speaker cable....and hopefully on handmade honeycomb resistors soon...
I found a good machine-tool mechanic that can do the resistor formers of smaller size for me, as mine resulted too big:
https://picasaweb.google.com/lh/photo/pf08g41H6u3y3GctjpjTldMTjNZETYmyPJy0liipFm0?feat=directlink
Best wishes to you all,
M.
PS: for the person that asked before, I am one of the guys willing to buy -EC's-DAC but I plan to go there and meet the gurú in person in the future, if he receives...
OCC copper rules. I use it everywhere: mains; power; IC; speaker cable....and hopefully on handmade honeycomb resistors soon...
I found a good machine-tool mechanic that can do the resistor formers of smaller size for me, as mine resulted too big:
https://picasaweb.google.com/lh/photo/pf08g41H6u3y3GctjpjTldMTjNZETYmyPJy0liipFm0?feat=directlink
Best wishes to you all,
M.
PS: for the person that asked before, I am one of the guys willing to buy -EC's-DAC but I plan to go there and meet the gurú in person in the future, if he receives...
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thanks James,
My old brother had this AKG headphones, if it is the same, age device is 30 ore more years old ????
Saw a wirewound with the link given by John could be good HF filtering at output analog stage also : no more than 50 k hz.... (ok a little high for a NOS TDA1541).
carbon film are said to be bad candidat because current noise and Jonson noise sensivity but at less than 2 V do we worth about it ? they are said to act like HF filtering... do their value swings at so low voltage in a dry environment ?
John in your design you have no resistor in serie after the TDA1541 ? Will you say that a wirewound with its so small inductance in the case of the Rhopoint can be used in the signal path of the analogic stage also , or value like 100 to 1 k Ohms in serie after the 2 volts (for impedance matching with the next input stage; pre, amp) can not be hearable ?
I've had the 701s for about 5 years now, done a bit of work on the 'cases', new pads and Chimera Labs wires (4) - it suits me well, particularly with a heavy current drive headamp - not thin or toppy any more - they're a bit fussy.
I also use Patrick's CEN o/p stage so we're talking about 1k5R for the I/V resistor - not the same setup as John's, so the different resistor types mightn't have same sound effect - a lot of 'iffs' here - sorry I can't give more definite answer
Riedon's are a crazy price - think they've got Platinum wire or something - never heard or seen one, so no help here either - anyone else know them? Space or Military Instrumentals?
I also use Patrick's CEN o/p stage so we're talking about 1k5R for the I/V resistor - not the same setup as John's, so the different resistor types mightn't have same sound effect - a lot of 'iffs' here - sorry I can't give more definite answer
Riedon's are a crazy price - think they've got Platinum wire or something - never heard or seen one, so no help here either - anyone else know them? Space or Military Instrumentals?
I use the ec design sd 1, its just a amazing dac. I doubt you can do much better then ec design dac.
only pita is the transfer to sd cards. So I use a cheap dac to listen to new music and when I like enough a new record, I get it in flac then transfer it in a sd card.
Why did you change of avatar with a new one in June 2014 ? Very curious to know why / I know just one canadian here who like Dinosaur Jr and have a SD1 !
At Max; Hi, Max Lorenz: as already said, we have to see you in your country, if people could know how beautiful it is, The DAc will come to you !
2 cents...