The balanced Krell KRS-1 carried a total of 5 dozen Roederstein EK caps.
4-case preamp, a 2-deck Spectrol 702 volume pot in each case, comparable with a stereo Penny & Giles rotary pot, the KRS-1 cost ~$10K in the mid '80s.
A 470uF/25V EK cap cost about $0.25 each for 100-up in the mid 1980s.
Ask yourself why so many manufacturers chose to use that part for so long, all across the globe, when it wasn't all that expensive.
4-case preamp, a 2-deck Spectrol 702 volume pot in each case, comparable with a stereo Penny & Giles rotary pot, the KRS-1 cost ~$10K in the mid '80s.
A 470uF/25V EK cap cost about $0.25 each for 100-up in the mid 1980s.
Ask yourself why so many manufacturers chose to use that part for so long, all across the globe, when it wasn't all that expensive.
Spragues will get replaced too
Yep, they'll get replaced too =D
The Roederstein EK (Bakelite) type of caps are so different that I want to make sure I get a replacement that will not change the sonic signature of the receiver. It's been recommended I use a low-leakage cap like the Nichicon KL which are great caps.
Yep, they'll get replaced too =D
The Roederstein EK (Bakelite) type of caps are so different that I want to make sure I get a replacement that will not change the sonic signature of the receiver. It's been recommended I use a low-leakage cap like the Nichicon KL which are great caps.
Aluminum bodied caps sound quite a lot like aluminum, due to the field integration with the casing, under delta load. Which is what a cap does, in an audio circuit.... thus, a notable amount of the sound of an aluminum cased cap is coming from the leads and the casing.
Getting away from aluminum casings for electrolytics is a GOOD thing for the final overall sound quality of the final/complete device.
Preaching to the Pew in this thread:
The problem is that so many people are used to hearing phase smeared transients as micro-detail that they confuse this obscuring noise with the signal that it just covered up, dislocated, and destroyed. Since these problems are throughout the given systems, in every trace, component and implementation, to some degree or another - most folks have no idea about where to start.
The place to start, is where you can, and begin the process of getting it done, step by step. Wherever you can. Then the windows that are stacked on top of one another, like 10-20-30-40 dirty filters, will finally begin to clarify. One by one. And one day, you find you can actually begin to see (hear) something through that mess.
oddly enough, the complaint is that the sound is 'darker' But somehow, much more detail, much more harmonically richer. Well, if we go back to the start,and we recover the question and answer we were told back at the beginning, we know we are on the right track with the darker bit. We were told that the best we can ever get to is a minor bit of subtraction of signal. That the least interference that we can ever get to with audio components, is one of a slightly darker sound, a minor subtraction. Anything that is peaky and harsh, with falsified micro-detail is is exactly that. Noise. Obscuring noise.
The problem is that the people who have money in audio purchasing, have generally not made it to this understanding as of yet, and thus the money in audio, like may other hobby markets (like road bicycles) belongs to the monied and mediocre/half way semi-literate crowd. That the things touted as the best rarely are the best, as they are only the best to the buying public, a buying public which is semi-literate in the subject, at best.
A sad state of affairs if one is only trying to create the best, as It gets little no traction in the marketplace. Sad that you have to be mediocre in some way, to make it big. When looking at the world and how it works, in all areas.....not unexpected. Sadly.
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"Bakelite" and related plastics
Bakelite is a brand of Phenol-formaldehyde resins and moulding compounds. It's thermosetting, like Epoxy, Unsaturated Polyester and Alkyd resins. That means it needs heated dies to manufacture products and likely, with large numbers of cavities with very high capital costs. It stands to reason that manufacturers would want to maximize utilisation and just change to other thermoset materials that lend themseves to light colours, better strength and electrical properties etc. as need arose.
Urea and Melamine-formaldehyde plastics are akin to Phenolics but can be light coloured and once found wide application in lighting, switchgear, industrial components homewares, even still as tableware and benchtop laminates surfaces and MDF surfacing like Corinite, Laminex, Formica etc. Let's not forget our commercial PCB laminates and Stripboard either.
Any of the above resins, incuding Bakelite, could have been filled or "loaded" with a variety of inert minerals such as powdered clay, silica, mica, asbestos, glass or carbon and advanced fibrous materials or even humble cotton flock to make a moulding compound. Woodflour is a filler for only the cheapest cost with some reinforcement in general products, not so much those required to be heat resistant or have good electrical properties. The choice of filler also affects cost and processing efficacy so naturally, there is going to be compromise and thus unforseen ageing effects such as case cracking and leakage as reported earlier. Electrical and mechanical properties can be greatly improved with filler choice but always there is short-sighted compromise in design wherever there is ignorance and a penny to be pinched.
When the point at which thermoplastic materials became generally more competitive in the 1970s, thermoset dies were pensioned off and usually newer, high performance thermoplastic materials and their different machinery introduced. Unfortunately, there always was a fundamental problem with making a reliable fluid seal for an open ended container such as an elco in these thermoplastic materials and we don't see much variation from aluminium cases even now. Maybe, just as well.
Bakelite is a brand of Phenol-formaldehyde resins and moulding compounds. It's thermosetting, like Epoxy, Unsaturated Polyester and Alkyd resins. That means it needs heated dies to manufacture products and likely, with large numbers of cavities with very high capital costs. It stands to reason that manufacturers would want to maximize utilisation and just change to other thermoset materials that lend themseves to light colours, better strength and electrical properties etc. as need arose.
Urea and Melamine-formaldehyde plastics are akin to Phenolics but can be light coloured and once found wide application in lighting, switchgear, industrial components homewares, even still as tableware and benchtop laminates surfaces and MDF surfacing like Corinite, Laminex, Formica etc. Let's not forget our commercial PCB laminates and Stripboard either.
Any of the above resins, incuding Bakelite, could have been filled or "loaded" with a variety of inert minerals such as powdered clay, silica, mica, asbestos, glass or carbon and advanced fibrous materials or even humble cotton flock to make a moulding compound. Woodflour is a filler for only the cheapest cost with some reinforcement in general products, not so much those required to be heat resistant or have good electrical properties. The choice of filler also affects cost and processing efficacy so naturally, there is going to be compromise and thus unforseen ageing effects such as case cracking and leakage as reported earlier. Electrical and mechanical properties can be greatly improved with filler choice but always there is short-sighted compromise in design wherever there is ignorance and a penny to be pinched.
When the point at which thermoplastic materials became generally more competitive in the 1970s, thermoset dies were pensioned off and usually newer, high performance thermoplastic materials and their different machinery introduced. Unfortunately, there always was a fundamental problem with making a reliable fluid seal for an open ended container such as an elco in these thermoplastic materials and we don't see much variation from aluminium cases even now. Maybe, just as well.
Hi, how did you solve the problem with substitution of EK capacitors? I'm facing the same issue with my Tandberg TR 2075. On top of yours I have one small, most probably 10/63 - it's quite difficult to read it since this small one and one 220/16 is covered by kind of yellowish salt from leaking capacitor...
Sorry for the late reply. I wound up using Nichicon KL 10% 105C caps to replace the the ROE EK caps. I have recapped two Tandberg 2075's recently and the ROE EK caps on the Program Voltage boards had unacceptable ESR when checked with my BK 879. The ROE EK caps on the Preamp and RIAA boards were still barely ok. I changed them all out while I was in there to avoid problems.
I'd really like to get the datasheet for the ROE EK caps but I keep coming up empty online. I guess I should just contact Vishay and see if they can provide it or info on a good replacement. I think the following maybe the Vishay replacement for the ROE EK but not entirely sure.
http://www.vishay.com/docs/28313/013rlc.pdf
Japan was considered a major treath to the survival of European (maybe american too) audio/video industry. In those days manufacturers took pride in NOT using Japanese parts in their products. Roederstein could have been almost as good as Elna or Rubycon in those days and still get 95% of orders.
Regarding spec sheets, sorry I cannot help you there. Many Roe''s elco capacitance were specified like -10%/+50% and even -20%/+175% i recall, I would not know when those +values occured and how best to aproach that.
Regarding spec sheets, sorry I cannot help you there. Many Roe''s elco capacitance were specified like -10%/+50% and even -20%/+175% i recall, I would not know when those +values occured and how best to aproach that.
The Bakelite can is far superior to the metal cans. this is a given, and is not deflatable as a reality, or point in the logic of the fundamentals of signal.
Metal and the complex fields that have to integrate with it, makes for a problem, a slurring of the signal, and out phase aspect, which is easily heard.
Any metal can capacitor is automatically attempting to run a race with a leg cut off. It cannot help but lose. The metal can is good for many aspects, but it is fundamentally a move in the exact wrong direction - when it comes to audio signal fidelity.
Metal and the complex fields that have to integrate with it, makes for a problem, a slurring of the signal, and out phase aspect, which is easily heard.
Any metal can capacitor is automatically attempting to run a race with a leg cut off. It cannot help but lose. The metal can is good for many aspects, but it is fundamentally a move in the exact wrong direction - when it comes to audio signal fidelity.
And the replacement of all those capacitors (compared to new), with modern metal can caps.... made for a giant step backward in fidelity for that Krell Pam1 preamp.
I have a potential replacement for the Bakelite body, that in some aspects, may just be superior to the metal cans of today. To put modern electrolytic design in can that is not metal. But yet, performs in some ways, superior to the metal, regarding safety/reliability concerns.
One in a long list of projects that never get the attention they need....
One in a long list of projects that never get the attention they need....
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Bakelite, now commonly called phenolic comes in a multitude of "grades". The really old ones were mfg'd using bakelite housing because it was cheap. The "tin cans" were/are typically aluminum or tin plated brass.
For the last 40 years, inexpensive capacitors were/are manufactured using polyester tape, preformed epoxy cases, or molded using some type of epoxy. Now electrolytics are mfg'd primarily using aluminum cases.
Not having a lot of experience with older electrolytics, perhaps the bakelite ones used a solid electrolyte, hence the sonic resonance.
For the last 40 years, inexpensive capacitors were/are manufactured using polyester tape, preformed epoxy cases, or molded using some type of epoxy. Now electrolytics are mfg'd primarily using aluminum cases.
Not having a lot of experience with older electrolytics, perhaps the bakelite ones used a solid electrolyte, hence the sonic resonance.
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