The Official "Build" thread for the V4 WYN Phono preamplifier
- Thread starter j!m
- Start date
MuseChaser
Super Member
"..clamp the workpiece!"
"..clamp the workpiece!"
"..clamp the workpiece!"
"..clamp the workpiece!"
Boy does that bear repeating. I learned the hard way the first time I tried to drill a hole through a clock mainspring.
"..clamp the workpiece!"
"..clamp the workpiece!"
"..clamp the workpiece!"
Boy does that bear repeating. I learned the hard way the first time I tried to drill a hole through a clock mainspring.
AvFan
Super Member
Another option is a plunge router with a carbide straight bit on the inner face. Set the final plunge depth so the remaining thickness works with your switches but take a few passes to reach that depth. It is counterintuitive but I found slowing the router speed caused chatter when edge routing aluminum so I'd use a higher speed. As noted always clamp the workpiece, have a real firm grip on the router and take very light cuts since this will be a freehand operation.
MuseChaser
Super Member
AvFan
Super Member
I'll be doing the layout of the front and back panels of the enclosure soon and I'm wondering based upon the info above if there is a preferred location for the four switches: Mute, +6dB Gain, +9dB Gain, Stereo w/Warp-Stereo-Mono. I'd prefer that the wires between the switches and pins on the PCB cross as few times as possible . The Power switch will be on the left with a nearby hole for a on/off LED.
The MM/MC switch is between the L and R input on the PCB but I imagine the input jacks can be moved to either side of that switch so long as the wire or coax doesn't interfere with the operation of the switch.
I plan to provide a ground lug for the tonearm ground but should it be isolated from the enclosure? Also, might a ground lug connected to the enclosure be beneficial to allow a ground wire to my house or other ground?
wyn palmer
Addicted Member
The control wires are physically related as shown on the earlier posted schematic.
The power switch is independent.
I don't understand the question.
The ground lug from the tonearm should be connected to the chassis. The system ground should be "grounded" through the phono outputs.
AvFan
Super Member
Thanks, I will plan the control wiring/switches according to the diagram on the schematic.
I clearly don't understand how to ground V4.0. From what I've read it is different than earlier versions and in my case I'm running two V1 or V2 preamps off the same, but separate power supply. In that case the PS case is tied to the ground from my house then to the preamp enclosures. That ground is separate from the ground on the PCBs and the tonearm is tied to that ground that is isolated from the enclosure. My confusion is that I thought it was the same as earlier versions. It is not a concern at the moment but when I start assembling I will need to better understand how to ground V4.0.
wyn palmer
Addicted Member
V4.0 uses a floating 18v AC source, with no mains ground connection. One side of the AC source (the ring) is connected to the board analog ground, which is shorted to the output phono socket grounds and the chassis. The output phono sockets are intended to provide the system ground through the preamp that the phono stage provides signal to. The TT ground wire should be isolated from the phono signal wires, and preferably from mains ground.
AvFan
Super Member
Thank you for explaining how to ground V4.0. With my current V1 and V2 preamps the mains ground provided, in my layman's terms, shielding for the preamp. If I understand it the shielding provided by the V4.0 enclosure is from the system's preamp ground. Are those comparable ways to provide shielding?
wyn palmer
Addicted Member
Yes.
Tim Grindell
New Member
Thank you Wyn
I'm still getting my head around the GND/0V connections.
Could GND/0V, instead, be connected to the chassis via J67 and the 10R resistor?
tim
I'm still getting my head around the GND/0V connections.
Could GND/0V, instead, be connected to the chassis via J67 and the 10R resistor?
tim
wyn palmer
Addicted Member
Ultimately, I don't care what you do. There is no connection between mains supply and the unit, so there is no need for mains ground, but if you want to connect it whatever way you wish and see what happens it's fine with me. However, if you are going to do anything different then the AC panel socket and the line outputs will have to be isolated from the chassis.
Tim Grindell
New Member
Yes, I know you don't care Wyn.
You and I have had similar discussions previously.
Thank you for the design
You and I have had similar discussions previously.
Thank you for the design
AvFan
Super Member
I'm laying out the switches and jacks on the enclosure, deciding where engraving will go and I may have to find equivalents for a couple of parts.
- DIP Switch: I'm going to cut a couple of holes in the bottom of my enclosure and mount the load DIP switches aimed down. The current BOM uses a "piano" style DIP switch from OMRON that might be awkward to adjust through a hole when aimed down. OMRON makes what looks like equivalent switches with either raised or flatted individual switches, Models A6E-8104-N or A6E-8101-N. From what I can tell these two switches are the same as the spec'd switch except for the actuator type. Correct?
- Just verifying that 2 of the 8 DIP switch positions are for MM capacitive loading and if both are left off then zero capacitance is added? Also verifying that the 100kΩ resistor is not one of the six selectable resistors on the DIP switches.
- MM/MC Switch: Is the preamp in MC mode when the switch is depressed/locked? Also, the current switch in the BOM is an E-SWITCH PHB4UEENAG1RBLK and the edge of the switch (at or very close to the edge of the PCB) will be about 10mm from the back panel to allow about 5mm of the button (3mm of travel) to protrude beyond the back panel. 10mm between the PCB and back panel is pretty tight to wire up RCAs so is there an alternate pushbutton switch with a longer actuator? Is there a part that can extend the round cap on the actuator in the BOM? Last question re: this switch: The data sheet does not spec the diameter of the push button. Any clue what the diameter is?
- For appearances I want to have the MM/MC pushbutton centered vertically on the back panel of my enclosure that has an internal height of 40mm . The top of the PCB will need to be 15mm off the bottom of the enclosure to centre the push button leaving 25mm between the PCB and the top of the enclosure. Are any parts on the preamp PCB taller than 20mm to 22mm?
- Not a part issue but the notes on the schematic regarding switches shows the MonoR pin has a wire named MonoL and MonoL pin has a wire named MonoR. Not that I could figure out why that would be but it looked odd.
Last edited:
wyn palmer
Addicted Member
Yes, as would the https://www.mouser.com/ProductDetail/TE-Connectivity-PB/ADE08A04?qs=lVCAImbLNkezRarMCRb1Tg==
Yes
@hirscwi will need to answer this
As above. Bill supplied a mounted board in an enclosure which I tested. It has an extension rod.
The tallest components are the two 3300uF 35 v caps. they are 18mm in diameter, radial, and have a lead spacing of 7.5mm.
I do not believe that any available caps meet your height requirement.
Indeed, the BOM cap could be changed to
as the original is essentially unavailable. At 25mm this is the shortest that I can find, but any of the Mouser listed caps meeting the voltage/capacitance/diameter/pitch requirement will do from a design perspective.
You could split the board and mount the power supply closer to the bottom.
Alternatively, the cap can be reduced to 3000uF with minimal impact.
This has a length of 20mm.
The lead identifiers are there to simplify the wiring labelling by associating all of the channel wires. I was hoping to avoid questions such as "why does the monoL go to the right switch" for example. This was not an error, but it seemed that I was wrong in my assumption, and I still got a question...
AvFan
Super Member
Thanks @wyn palmer for the reply.
- I will wait to hear back from Bill @hirscwi on how the MM/MC switch works and where he got the extension. Having the extension will make assembly and layout much easier. He may know the diameter of the hole needed for the push button switch cap.
- The alternate OMRON DIP switches are more expensive so thanks for the less costly TE-Connectivity option.
- I'm going to split the board so the power supply portion will be low enough for those two big caps and then raise the preamp portion of the PCB to hopefully get the MM/MC switch in the middle of the panel so just looking at components on the preamp side. Hopefully Bill will be able to help out.
-
Just shows I'm looking carefully.
Thanks again.
I made an extension from a piece of aluminum tube. I happened to have a piece that slipped over the end of the actuator without the cap attached but you could also put it over the cap itself. The tube I used came from modeling supply but I've had it for several years so I don't have a source. Try hobby supply.Thanks @wyn palmer for the reply.
- I will wait to hear back from Bill @hirscwi on how the MM/MC switch works and where he got the extension. Having the extension will make assembly and layout much easier. He may know the diameter of the hole needed for the push button switch cap.
- The alternate OMRON DIP switches are more expensive so thanks for the less costly TE-Connectivity option.
- I'm going to split the board so the power supply portion will be low enough for those two big caps and then raise the preamp portion of the PCB to hopefully get the MM/MC switch in the middle of the panel so just looking at components on the preamp side. Hopefully Bill will be able to help out.
Just shows I'm looking carefully.
AvFan
Super Member
Thanks. I have a really good hardware store nearby plus some hobby stores so I will look to make my own extension.
- Is the preamp in MC mode when the switch is depressed? I want to have that info engraved on the back.
- When you built the prototype do you recall which component on the preamp side of the PCB was the tallest? I want to move the PCB up about 15mm so the MM/MC switch is in the middle of the 1U (40mm height) Modushop Galaxy enclosure's back panel. I don't want to move it up and then have any components touch the top.