Post by michaelw on Oct 25, 2019 9:29:26 GMT 12
A not E ?
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Pundit
Post by LinnBoy on Aug 21, 2020 14:03:57 GMT 12
It’s a straightforward circuit built with high end materials and parts. Nothing a good NZ tech like Clarry couldn’t do. I have the schematics here. I am in the market for an (up)market MC phono stage. Wots this 2 box thing being talked about?
I am a non-recovering audioholic, and Ivor is my higher power.
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Post by cartridgeguyonline on Aug 21, 2020 16:39:23 GMT 12
Best you have a chat to colinf about it. Its a 2 box valve MC one he made for a mate in the Wairarapa to match his Hana SL. I ran it here briefly before deciding that I really couldnt afford to listen to it any more !
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Post by colinf on Aug 21, 2020 20:14:44 GMT 12
It’s a 2 box (power supply and phono unit) MC-only phono stage. It has no transformers in the signal path, the cartridge is connected straight to the valves. I just think that’s the most transparent way sonically. It’s reasonably hard to get ultra low noise with a valve MC headamp so it’s best used with cartridges of 0.4mV output and greater. (But that hasn’t stopped me using the Top Wing cartridge at only 0.2mV!) My Dynavector XX2 has lower noise with this pre though from having higher output. It’ll never have as low noise as a transformer or solid state stepup though. I just like the transparency of an all-valve circuit. A bit of maintenance involved as well, you need to change the headamp valve every now and then to maintain low noise. I have plenty of replacement 417s here. It has dual mono power supplies with valve rectification, opamp regulation with individual stages, a combination of Audionote tantalum resistors and Amtrans resistors in the places where they work best, the high end Mundorf coupling capacitors as well as Amtrans paper-oil EQ caps, partly direct-coupled circuit, brass valve supports, solid aluminium casing and Perspex front panels. Also microprocessor-controlled warm-up and muting circuit for no clicks or thumps when switching on or off. Unbelievably I never took any photos of the outside after they were done! But here’s one before they were painted silver, and another of the completed insides. I have parts to make them in stock here.
AMR-iFi R&D
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Post by Owen Y on Aug 21, 2020 20:51:03 GMT 12
WE417A / 5842 - I'm reminded of the 'Arthur Loesch' phono stage I thought of building back then - before I decided on Diego Nardi's 'Phi-42' phono stage.
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Pundit
Post by LinnBoy on Aug 21, 2020 23:29:28 GMT 12
It’s a 2 box (power supply and phono unit) MC-only phono stage. It has no transformers in the signal path, the cartridge is connected straight to the valves. I just think that’s the most transparent way sonically. It’s reasonably hard to get ultra low noise with a valve MC headamp so it’s best used with cartridges of 0.4mV output and greater. (But that hasn’t stopped me using the Top Wing cartridge at only 0.2mV!) My Dynavector XX2 has lower noise with this pre though from having higher output. It’ll never have as low noise as a transformer or solid state stepup though. I just like the transparency of an all-valve circuit. A bit of maintenance involved as well, you need to change the headamp valve every now and then to maintain low noise. I have plenty of replacement 417s here. It has dual mono power supplies with valve rectification, opamp regulation with individual stages, a combination of Audionote tantalum resistors and Amtrans resistors in the places where they work best, the high end Mundorf coupling capacitors as well as Amtrans paper-oil EQ caps, partly direct-coupled circuit, brass valve supports, solid aluminium casing and Perspex front panels. Also microprocessor-controlled warm-up and muting circuit for no clicks or thumps when switching on or off. Unbelievably I never took any photos of the outside after they were done! But here’s one before they were painted silver, and another of the completed insides. I have parts to make them in stock here. Sounds interesting. I have a HANA ML cartridge, so it squeaks in there. Is a balanced output possible? My preamp has a balanced input. Just a thought. Cost?
I am a non-recovering audioholic, and Ivor is my higher power.
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Post by colinf on Aug 22, 2020 1:47:21 GMT 12
Hi Linnboy, thanks. It’s single ended only, I’d have to add another valve for balanced. It would just invert the signal from the output to generate the negative phase so might not sound any better. You could always use an XLR connector though, if you have balanced cables. The negative phase would just be connected to ground. Which preamp do you have? Hana ML should be fine, it has similar output to the Dynavector at 0.4mV. The background noise is slightly quieter than typical record noise. I’ve just been thinking about the cost, I can most likely keep it around $4k.
AMR-iFi R&D
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Post by cartridgeguyonline on Aug 22, 2020 8:02:29 GMT 12
Which is why I stopped listening to it 😊
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Pundit
Post by LinnBoy on Aug 22, 2020 16:47:34 GMT 12
Hi Linnboy, thanks. It’s single ended only, I’d have to add another valve for balanced. It would just invert the signal from the output to generate the negative phase so might not sound any better. You could always use an XLR connector though, if you have balanced cables. The negative phase would just be connected to ground. Which preamp do you have? Hana ML should be fine, it has similar output to the Dynavector at 0.4mV. The background noise is slightly quieter than typical record noise. I’ve just been thinking about the cost, I can most likely keep it around $4k. It sounds fantastic, but sadly way - I mean way - out of my budget.
I am a non-recovering audioholic, and Ivor is my higher power.
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Post by cartridgeguyonline on Aug 22, 2020 17:30:06 GMT 12
Yes it was for me too and tbh I'm more than happy with either of the other preamps which colin built for me.
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Post by colinf on Aug 22, 2020 20:08:40 GMT 12
Sure....I made it with no compromises (of which I’m aware :-) ) and the cost of high end is dear! Even I can’t afford it really, high end parts are expensive and the law of diminishing returns with price is in evidence. So I made a preamp which has elements of the high end preamp in it but with much more affordable parts, and less maintenance needed, and single power supply instead of dual mono, all in one case. But I had to retain the valve rectifier both for sonics and slow warmup, making the audio valves last longer. I designed it in 2016 and it became the one I made for Cartridgeguyonline. I built that one hardwired and labour was very high. So I decided to make it more affordable and designed it on a circuit board, which is far neater and faster to put together. This one is a full function pre with MM input and phase-true line stage. It can be built with a headphone amp like this one, and with MC input. You can specify a transformer MC stepup or my preference, a very low noise opamp, both to keep cost under control and flexibility for cartridge loading. It’s in a wooden case with shielding inside. It also has microprocessor-controlled warmup and muting. Depending on options I can make it for about $1k, a little less for MM and no headphone amp.
AMR-iFi R&D
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Post by cartridgeguyonline on Aug 23, 2020 8:22:31 GMT 12
Let me know if you want a listen to mine Linnboy, as im not far away from pulling it out of my system. Long story but due to the situation of my listening room upstairs with double glazed windows etc it gets too warm in summer to use the valve amps for long periods so I have a SS set up of colins that I use in summer.
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Pundit
Post by LinnBoy on Aug 23, 2020 20:30:49 GMT 12
Let me know if you want a listen to mine Linnboy, as im not far away from pulling it out of my system. Long story but due to the situation of my listening room upstairs with double glazed windows etc it gets too warm in summer to use the valve amps for long periods so I have a SS set up of colins that I use in summer. Very keen. Get that heater out of the room, global warming and all lol. Need the heating here in Invercargill. Which one do you have?
I am a non-recovering audioholic, and Ivor is my higher power.
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Post by cartridgeguyonline on Aug 23, 2020 22:50:55 GMT 12
Will send you a PM but best to have a chat to colin first he will tell you the technical details of both of mine, happy to send you either but they are both pre amps with phono stages MC and MM
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