AudioCircle
Industry Circles => ModWright Instruments (MWI) => Topic started by: modwright on 28 Oct 2004, 05:00 pm
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By way of explanation for those who are waiting for us to finish their units:
I have two technicians, in addition to myself that do the mods. One tech is pretty much exclusively doing the Sony 999ES mods, as well as P-3A DACs, Link DAC mods. My other technician is pretty new to us and is helping primarily with building power supplies and will be helping me build the preamps.
That pretty much leaves me personally doing the Pioneer DV-59AVi mods as well as the Denon mods. Some of these are behind and I apologize, but in addition to doing the mods, I also have to answer the phone, run the business, oversee the final details of the preamp production and also keep up with new technologies. I am stretched pretty thin right now and I apologize.
The most important thing I want all of you to know, is that I AM working to get everything done and with the same level of quality and performance that we are known for. I will not rush a product out the door and I won't compromise the quality of our work.
Thanks for your patience,
Dan W.
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Dan,
Thanks for being both forthright and talented. The delays have been due to circumstances not of your making, yet you have been very gracious to those of us who have pushed you to the limit to keep up with your backlog of orders.
I just received my modded Pioneer 59avi (signature + LC Audio clock) and even after just five hours of burn in, the sound is glorious.
Best wishes for continued success and I hope you get some sleep!
Bayside Bomber (aka David Dranove)
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I appreciate the support, thank you very much.
Dan W.
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Dan,
Its a nice problem that you guys are so busy. I'm sure everyone appreciates your firm refusal to finish work hastily - quality really is job 1.
Cheers,
- Jay
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Agreed...it needs to be done RIGHT, more importantly thant to be done QUICKLY. It is hard when there are delays, but I DO firmly believe that a job that leaves our shop should be done to our highest standards.
Thanks,
Dan
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By way of explanation for those who are waiting for us to finish their units:
I have two technicians, in addition to myself that do the mods. One tech is pretty much exclusively doing the Sony 999ES mods, as well as P-3A DACs, Link DAC mods. My other technician is pretty new to us and is helping primarily with building power supplies and will be helping me build the preamps.
That pretty much leaves me personally doing the Pioneer DV-59AVi mods as well as the Denon mods. Some of these are behind and ...
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Well, I have been working with various tube circuits as part of the mods and I arrived at a circuit type that sounded particularly good to me. I worked with it further and consulted with Alan Kimmel on various aspects, arriving at a sound that I simply had to make into a preamp.
I feel that our preamp bridges the gap between overly tubey tube designs and hard/clinical SS designs. I prefer a sound that is accurate, detailed and dynamic with good bass response and high-end sparkle, but WITHOUT a hard, cold and clinical sound. I found that I loved the sound of tubes, but some designs were simply too warm and soft for my liking.
I had others listen to the early prototypes in my home and their response was favorable enough that I decided to pursue it. The Beta testing progress simply confirmed my feelings. The very first Betas were loved by some, liked by others and some were returned. Over the evolutionary process of the design however, EVERY Beta that was sent out was REALLY appreciated.
I guess I didn't necessary set out to make a preamp initially, but it was the next logical progression. Building our own CDP or SACD player is just not practical, due to the rapidly changing technology. DACs are also a bit too 'fad'ish at this time too. I know more about line-level signal design than I do about amp design, so it left the preamp as the logical choice.
I am very pleased about the unit. It offers the same options as most flexible linestage/preamp designs. I believe what sets it apart is its sound and performance, especially relative to its price-point.
I don't expect that it will suit EVERYONE's tastes, but those who like it will REALLY be pleased with it.
Thanks,
Dan
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Well, I have been working with various tube circuits as part of the mods and I arrived at a circuit type that sounded particularly good to me. I worked with it further and consulted with Alan Kimmel on various aspects, arriving at a sound that I simply had to make into a preamp.
I feel that our preamp bridges the gap between overly tubey tube designs and hard/clinical SS designs. I prefer a sound that is accurate, detailed and dynamic with good bass response and high-end sparkle, but WITHOUT a hard, co ...
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I opted for SS rectification for sound. I like the fast and dynamic sound of SS rectification. Tube rectification softens the sound too much for my taste. There is some additional cost, but really cost was not the deciding factor.
I really like the sound of HEXFREDs.
I also chose SS voltage regulation for the same reason.
Thanks,
Dan
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I opted for SS rectification for sound. I like the fast and dynamic sound of SS rectification. Tube rectification softens the sound too much for my taste. There is some additional cost, but really cost was not the deciding factor.
I really like the sound of HEXFREDs.
I also chose SS voltage regulation for the same reason.
Thanks,
Dan
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I opted for SS rectification for sound. I like the fast and dynamic sound of SS rectification. Tube rectification softens the sound too much for my taste. There is some additional cost, but really cost was not the deciding factor.
I really like the sound of HEXFREDs.
I also chose SS voltage regulation for the same reason.
Thanks,
Dan
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I see ;)...sorry.
I really like the 5687 tube because it is linear, handles high-current and sounds exceptional in my opinion. Other options included the 6H30 and ECC99. The ECC99 I couldn't get consistent quality tubes and wasn't crazy about the sound. The 6H30 is good, but I found it to be a bit darker than the 5687 and also difficult to source.
The 6SN7/6CG7 were also viable alternatives, but I still preferred the 5687. I was concerned about availability, as they are only NOS, but I found a good supply and bought a large enough quantity for this not to be a problem.
I have never been a fan of 6DJ8/6922 tubes, despite their popularity.
Thanks,
Dan
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My 2 cents regarding tube choice.
After hearing the 5687 in various applications now and comparing with some of the other tube options mentioned, I can also say my preference would be with the 5687 with the 6SN7 and similar taking a very close second.
I have not heard the 6H30 at this time so cannot comment here but I do have the same feelings in regard to the 6DJ8/6922, not at the top of my list.
There is always the ever so popular "12" series tubes, 12AX, 12AT, 12AU and so on but I do not feel this preamp, nor Dan's other work, would have that special magic if these tubes were utilized. I will say, of this series, the 12AU would be my first preference.
Everyone has their preferences and I have heard very good designs based on many of these tubes.
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Regarding the 12-- series tubes, I too prefer the 12AU7. The 12AX7 and 12AT7 tubes are meant for high-gain applications, such as phono stages and mic preamps. In this application, they are excellent, but in a linestage application, where voltage gain is secondary to current buffering, these tubes are not ideal.
The key is to look at the tube curves for the tubes in question. You will find much greater linearity in the 5687, 6SN7, 6CG7, 6H30, 12AU7 and ECC99. Compare this to the curves for the 12AX7 and you will see what I mean.
The other thing to consider is the amount of current that the various tubes can deliver, as well as factors such as plate resistane, transconductance, etc.
The popularity of the 6DJ8 is a bit of a mystery to me. It is a medium gain triode and has decent but not great specs. It IS however, readily available and mfd. currently by different companies. I don't think that it is a bad tube, just that it isn't as musical as others that I prefer.
Dan
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Regarding the 12-- series tubes, I too prefer the 12AU7. The 12AX7 and 12AT7 tubes are meant for high-gain applications, such as phono stages and mic preamps. In this application, they are excellent, but in a linestage application, where voltage gain is secondary to current buffering, these tubes are not ideal.
The key is to look at the tube curves for the tubes in question. You will find much greater linearity in the 5687, 6SN7, 6CG7, 6H30, 12AU7 and ECC99. Compare this to the curves for the 12AX7 a ...
Hi dan, Probably because the 6DJ8 is so readily available is probably why it is used. On a construction level, why did you choose point to point versus a PCB? Any advantages here? Thanks. always wondered about that. Ray
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I've heard a great sounding 5751 (Sylvania Gold Brand gold-pin gray plate) that was substituted for a 12AX7. I just bought a pair of Amperex Orange Globe NOS 6DJ8s... which I can use in my Scott Nixon TubeDac... and which Dan's website mentions can be used instead of the 6H30 in the Ultimate Truth output stage of his modded Denons...
That said, I think you've got a good point that some tube families are inherently better than others.
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I've heard a great sounding 5751 (Sylvania Gold Brand gold-pin gray plate) that was substituted for a 12AX7. I just bought a pair of Amperex Orange Globe NOS 6DJ8s... which I can use in my Scott Nixon TubeDac... and which Dan's website mentions can be used instead of the 6H30 in the Ultimate Truth output stage of his modded Denons...
That said, I think you've got a good point that some tube families are inherently better than others.
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Regarding our choice of construction methods, I actually chose PCB over point-point. The reason here is actually two-fold.
1) Cost. Construction cost goes up exponentially due to labor/time.
2) Consistency. It is difficult to get the same consistency when building units point-point. Spatial alignment of wires/conductors, etc., actually is very important with respect to RFI/EMI, ground loops, etc. I have actually built prototypes with point-point wiring and found that in the end I preferred the PCB based designs.
So, ultimately, even if cost was not an object, I would still build the design with a PCB and would simply focus the cost and effort on parts quality and design.
Thanks,
Dan
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Regarding our choice of construction methods, I actually chose PCB over point-point. The reason here is actually two-fold.
1) Cost. Construction cost goes up exponentially due to labor/time.
2) Consistency. It is difficult to get the same consistency when building units point-point. Spatial alignment of wires/conductors, etc., actually is very important with respect to RFI/EMI, ground loops, etc. I have actually built prototypes with point-point wiring and found that in the end I preferred the PCB b ...
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Regarding our choice of construction methods, I actually chose PCB over point-point. The reason here is actually two-fold.
1) Cost. Construction cost goes up exponentially due to labor/time.
2) Consistency. It is difficult to get the same consistency when building units point-point. Spatial alignment of wires/conductors, etc., actually is very important with respect to RFI/EMI, ground loops, etc. I have actually built prototypes with point-point wiring and found that in the end I preferred the PCB b ...
This was about ten years ago, and a friend of mine who was a repair tech was always constantly fixing Conrad Johnsons. There was always some problem or other with solder joints on the circuit board. So was wondering how you got around that. Is there any advantage to point to point wiring? RayC.
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Interesting about the C.J.'s needing constant repair. It could have had to do with the solder they used or too thin of traces.
We do use fiberglass boards with good thick traces. The relationship is largely between current and trace width. The same is true with wire gauge. Voltage has more to do with dialectric strength, while current directly relates to power and thus heat generation. If too hig of a current is forced through a wire of inadequate gauge, heat will be generated. Likewise, if a PCB trace is two thin, the same will occur. The main high-current portion of a tube preamp is the heaters and these are larger in comparison to everything else. The actual signal current is pretty minor - on the order of 25mA-80mA, while the heater current in this case is closer to 500mA to 1A. Compare this to amplifiers (especially SS), where current can range from mA to 15A+ and you can see the diff.
Dan
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I see ;)...sorry.
I really like the 5687 tube because it is linear, handles high-current and sounds exceptional in my opinion. Other options included the 6H30 and ECC99. The ECC99 I couldn't get consistent quality tubes and wasn't crazy about the sound. The 6H30 is good, but I found it to be a bit darker than the 5687 and also difficult to source.
The 6SN7/6CG7 were also viable alternatives, but I still preferred the 5687. I was concerned about availability, as they are only NOS, ...
Hi Dan, Are 6SN7's drop in replacements for the 5687 tubes? Just thinking in case something were to happen and you were not available to supply the tubes? Thanks. Ray
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Are 6SN7's drop in replacements for the 5687 tubes?
No, these are not the same at all. Besides electrical parameters, the 6SN7 uses an 8 pin base (same as the EL34, 6550 type tubes) and the 5687 utilizes a standard 9 pin such as a 12AX, 12AU, etc. And no, these tubes are also not a replacement for the 5687.
As far as availability, there are still plenty of these tubes around. Another alternative is the JAN Philips 5687 which I also really like. I wouldn't worry too much about running out of these tubes
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Are 6SN7's drop in replacements for the 5687 tubes?
No, these are not the same at all. Besides electrical parameters, the 6SN7 uses an 8 pin base (same as the EL34, 6550 type tubes) and the 5687 utilizes a standard 9 pin such as a 12AX, 12AU, etc. And no, these tubes are also not a replacement for the 5687.
As far as availability, there are still plenty of these tubes around. Another alternative is the JAN Philips 5687 which I also really like. I wouldn't worry too much about running out of these tubes
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So these have the old octal socket like a 6l6? Don't know that much about tubes. just remember my boyhood days replacing a 6l6 in an old Helicrafters shortwave receiver.
NO, the 6SN7 has the same octal base as the 6L6. The 5687 is the same as any of the 9 pin input tubes as mentioned. The 5687 looks the same as any 12AX7, 6922, etc.