[Jaypetermen]

Does any one have a currently BOM with component quantities for the Millit-Hybrid?

I have looked at the parts list at http://hybrid.fluidlight.com but it does not show the quantities needed for each component.

 

[drewd]

Quote:

Originally Posted by Jaypetermen Does any one have a currently BOM with component quantities for the Millit-Hybrid? I have looked at the parts list at http://hybrid.fluidlight.com but it does not show the quantities needed for each component.

The parts placements are shown in the first column. Add up the total number of placements and that's the number of parts that you need. For example, the first row is for C1, C9L/R, C10L/R. That's 5 caps.

Also, it appears that Welborne does not carry the Wima film caps that are listed in the parts list, but TAW Electronics does, and for MUCH less (as has been posted earlier). I would really suggest ordering the film caps through TAW because, for the money, you won't get a better cap. You have to call them on the phone, but it's well worth it.

Also, the Cerafines are out of production, so I guess that the Welborne parts listed there are going to be going away, too, so I'll work on updating the parts list with something else.

-Drew

 

[Finch&Music]

Quote:

Originally Posted by drewd The parts placements are shown in the first column. Add up the total number of placements and that's the number of parts that you need. For example, the first row is for C1, C9L/R, C10L/R. That's 5 caps. Also, it appears that Welborne does not carry the Wima film caps that are listed in the parts list, but TAW Electronics does, and for MUCH less (as has been posted earlier). I would really suggest ordering the film caps through TAW because, for the money, you won't get a better cap. You have to call them on the phone, but it's well worth it. Also, the Cerafines are out of production, so I guess that the Welborne parts listed there are going to be going away, too, so I'll work on updating the parts list with something else. -Drew

I have looked at the latest version of the partslist. That gives reason to make two remarks:

1. I could not find C4 L/R (2x 0.222 mu Wima) anymore in the partslist (version 23 may). Is that on purpose or just an omission?

2. When I try to observe the partslist it shows itself a little strange on screen. Text is spread on a much broader space than is usefull and it rolls over different cells. Older versions of the list had not that problem and could be printed out by me very easily.

Greetings.

 

[drewd]

Quote:

Originally Posted by Finch&Music 1. I could not find C4 L/R (2x 0.222 mu Wima) anymore in the partslist (version 23 may). Is that on purpose or just an omission?

The parts are included in the range of C3L/R-C5L/R. I can see the potential for confusion, so I will edit the parts list to show each part separately.

Quote:

2. When I try to observe the partslist it shows itself a little strange on screen. Text is spread on a much broader space than is usefull and it rolls over different cells. Older versions of the list had not that problem and could be printed out by me very easily.

I see that problem sometimes as well. I'm not sure what the cause is. It may be a combination of the HTML editor that I use and the web browser. I'll look at the HTML code and see if there is some redundant or missing code that might be causing the problem.

Thanks for the input!

-Drew

 

[Finch&Music]

Quote:

Originally Posted by drewd The parts are included in the range of C3L/R-C5L/R. I can see the potential for confusion, so I will edit the parts list to show each part separately. I see that problem sometimes as well. I'm not sure what the cause is. It may be a combination of the HTML editor that I use and the web browser. I'll look at the HTML code and see if there is some redundant or missing code that might be causing the problem. Thanks for the input! -Drew

Thanks for your answer.

May be the second point is due to cell-properties of your document section. When you use (if at all) MS Excell than you have to install the correct cell-properties.

May be that is the cause after you have alter a new (copy-)version of the partlist?

If not so, than I do not have any knowledge of what could be the cause. I am just a simple reader of what is shown on screen.

Succes with searching into the fault.

Greetings

Pieter.

 

[drewd]

The parts list table should show up correctly now. The problem was from some extra code that probably came from the Excel spreadsheet.

-Drew

 

[n_maher]

Looking good to me!

 

[Finch&Music]

Quote:

Originally Posted by n_maher Looking good to me!

I have looked at the new version also and it looks very good now to me.

I strongly advise to add a second collumm to the partslist called 'qty', so there can be no cause anymore to make a fault when one is to order the number of the components. Not everyone is expierienced enough to 'read electronic specs language' immediatly in the right way. I am one of them!

Greetings,

Pieter

 

[drewd]

Quote:

Originally Posted by Finch&Music I strongly advise to add a second collumm to the partslist called 'qty', so there can be no cause anymore to make a fault when one is to order the number of the components.

It is so added.

I'm working on new and improved pages that will go through the construction, a little (very little) tube theory and some ideas on parts selection and a few tweaks. I really wanted to have all of that finished a few days ago, but, alas, I find that I have a life outside of this project

Thanks again for the input!

-Drew

 

[kilkil]

I was looking at Welborne for Wima's and noticed that there are two caps that have the size requirements:

Wima MKP-10 and Roederstein Metallized Polypropylene Capacitors, WM210 .10uf/160V as listed in the part selection guide and

Wima FKP-2 Polypropylene Film Capacitors, WM15 .10uf/63V

I don't know much about caps, but would think the non-metallized cap would be better, is it better?

 

[drewd]

Quote:

Originally Posted by kilkil I was looking at Welborne for Wima's and noticed that there are two caps that have the size requirements: Wima MKP-10 and Roederstein Metallized Polypropylene Capacitors, WM210 .10uf/160V as listed in the part selection guide and Wima FKP-2 Polypropylene Film Capacitors, WM15 .10uf/63V I don't know much about caps, but would think the non-metallized cap would be better, is it better?

In a perfect world, yes, the non-metallized cap would be a better performer, but in the specific case of this amplifier, the sonic difference is probably inaudible. The 0.10uF caps will definitely work - the specific value of the cap is not critical in this amplifier, but you're probably not going to hear a difference. Of course, the price difference isn't too terribly much, so if you're considering populating the other cap positions with high performance models (like the Elnas), then it's no great expenditure to go with the FKP-2 caps - it's only something like a $3.00 difference for the entire amplifier.

Also, TAW Electronics stocks the 0.22uF Wima cap as listed in the parts sheet for something like 80 cents each. They also carry the FKP-2 caps, but they don't list a 0.10uF part on their web site.

-Drew

 

[Finch&Music]

Quote:

Originally Posted by amb drewd, you forgot something in the denominator... the formula should be: f = 1 / (2 * pi * R * C) For a 100uF output cap, -3dB point is 5.3Hz for 300 ohm load or 49.7Hz for 32 ohm load. For 470uF, it's 1.1Hz and 10.6Hz, respectively.

Some questions:

1. What is from an audio-quality standpoint a practical -3db corner frequency for a headphone with respectively low (30-100), middle (approx >120) and high (>300) ohm caracteristic?

2. Is in the case of a sennheiser 650 a -3 db point of 8 a 10 Hz (more than) enough for an appropiate bandwidth? Or is it 18-20 Hz or even higher?

3. Or is a -1 db refference point more disirable? If that is the case, what is than the formula? (The already given formula for -3 db points is workable for me; I could find the same results with the elements you give without any schooling on that point! So the other formula shall also be understandable).

4. When you install the outputresistor in the Milletamp should you take that little amount of ohm also into account? If yes, how? Simply adding to the ohm's of the phone?

I am asking this because it is most likely that I mostly use a high impedance phone with the Millet. So it is to contemplate to go for a higher value filmcap instead of a quality electrolyte. I have several 30 mf available from a former speakerproject, so why not reuse those. In the case for the amp there is ample room available.

IMO, it is also possible to take a double route: one jack with a high value electrolytic/bypassed outputcap for low/high and one with a single filmcap only for high impedance phones. Only one phonejack will be used at the same time. The board has more than one outputposition. Or is that a dangerous route to go with too much pitfalls?

Greetings,

Pieter Vink

 

[steinchen]

you want to have the corner frequency as low as possible, from an audio-quality standpoint I'd say 10Hz or lower (output capacitor with headphone impedance works like a highpass filter). The higher the output capacitance the lower the corner frequency.

for f=10Hz @ -3dB
300Ohm -> 50uF minimum
120Ohm -> 130uF minimum
75Ohm -> 220uF minimum
32Ohm -> 470uF minimum

 

[drewd]

Quote:

Originally Posted by Finch&Music 3. Or is a -1 db refference point more disirable? If that is the case, what is than the formula? (The already given formula for -3 db points is workable for me; I could find the same results with the elements you give without any schooling on that point! So the other formula shall also be understandable).

-3dB is the standard measurement point for frequency response. The first order high pass filter that is being used falls off at 6dB per decade, so if the corner frequency is at 10Hz, the -1dB point is probably around 20Hz - that's not derived from any formula, it's just from experience.

Quote:

4. When you install the outputresistor in the Milletamp should you take that little amount of ohm also into account? If yes, how? Simply adding to the ohm's of the phone?

The output resistor acts only as an attenuator - it has no function in the high pass filter. The 1K resistor to ground, in parallel with your headphones, though, does count. At low impedances (Grado-style low), that resistor has little effect, but at high impedances (Sennheisers), it's worth calculating the parallel resistance of the headphones and the 1K resistor if you want to be exact. However, if you just place a 470uF electrolytic cap, you'll have a corner frequency below 10Hz in all cases (for headphones that the amplifier is capable of driving).

Quote:

IMO, it is also possible to take a double route: one jack with a high value electrolytic/bypassed outputcap for low/high and one with a single filmcap only for high impedance phones. Only one phonejack will be used at the same time. The board has more than one outputposition. Or is that a dangerous route to go with too much pitfalls?

You'll have to use a switch and a single set of outputs because even though there are two sets of outputs on the board, any capacitors that are installed will be in the circuit all the time. The caps will have to be wired after the switch. It might be easier to visualize of you draw it out on paper. When I put the second set of outputs in, I didn't think about using them for headphones of differing impedances, just as a convenience for panel wiring.

Another method that might work a bit better than a switch would be to use switched headphone jacks like the Re'an or Neutrik stacking jacks. You would put the paralleled 30uF caps in the normal cap positions, then a high quality electrolytic after the first jack. That way, when a set of headphones are plugged into the first jack, the caps going to the second jack are disconnected. Again, a picture on paper would make it more clear, I think.

-Drew

 

[Erik S.]

Wondering if Mouser Part #: 505-M100.1/160/5 is the same Wima caps that are in the parts list? If so, they're alot cheaper than Welborne.