[Herakleitus]

I would like to order my parts now, and this is my list. **Do I have the quantities for one amp correct?** (Yes, I will probably make a triple order, but I need to know what quantities to triple!) Any other final recommendations? Thanks for any suggestions!
(If it matters, I will be using the amp to drive a set of Etymotic ER4S)

www.Mouser.com
Resistors:
$0.16 for 1x [Vishay/Dale] 100 ohms, 1/8w (Part# 71-RN55D-F-100K)
$0.16 for 1x [Vishay/Dale] 332 ohms, 1/8w (Part# 71-RN55D-F-332)
$0.16 for 1x [Vishay/Dale] 1k ohms, 1/8w (Part# 71-RN55D-F-1.0K)
$0.16 for 1x [Vishay/Dale] 2k ohms, 1/8w (Part# 71-RN55D-F-2.0K)
$0.16 for 1x [Vishay/Dale] 2.2k ohms, 1/8w (Part# 71-RN55D-F-2.21K)
$0.16 for 1x [Vishay/Dale] 4.7k ohms, 1/8w (Part# 71-RN55D-F-4.75K)
$0.32 for 2x [Vishay/Dale] 10k ohms, 1/8w (Part# 71-RN55D-F-10K)
$0.16 for 1x [Vishay/Dale] 100k ohms, 1/8w (Part# 71-RN55D-F-100K)
Other:
$0.72 for 1x [CW Industries] SPST rocker switch (on/off) (Part# 629-GRS401116)
$3.43 for 1x [Dialight] LED – Green (3.8mW) (Part# 645-558-1301-007)
$1.60 for 2x [DGS] DGS Phone Jacks 3.5mm Stereo (Part# 161-3502)
$0.84 for 2x [Xicon] Low-leakage radial electrolytic capacitator 25v 220uf 20%(Part# 140-LLRL25V220)
IC Sockets (Part# 575-113308)
[ $8ish +S/H ]

www.Digikey.com:
$4.80 for 2x [Burr-Brown] OPA2134 Opamp (Part# OPA2134PA-ND)
$2.69 for 1x [Panasonic] Potentiometer 10k ohms (volume) (Part# P2G1103–ND)
Capacitators:
$0.90 for 2x [Panasonic] .1 uF Metallized Polyester Film (Part# EF2104-ND)
$1.16 for 2x [Panasonic] .22 uF Metallized Polyester Film (Part# EF2224-ND)
$0.74 for 2x [Panasonic] .047 uF Metallized Polyester Film (Part# EF2473-ND)
$0.98 for 2x [Panasonic] .12 uF Metallized Polyester Film (Part# EF2124-ND)
[ $12ish +S/H ]

JMT@Head-fi
$10 (w/S&H) for 1x Hansen PCB

 

[Tomo]

Hello,

Your parts list is pretty complete. You should be able to build a pretty wonderful sounding amplifier. However, I would like to make few more suggestions.

Instead of your polyester caps should be polypropylene caps. Polyesters are good elsewhere but it can resonate at high audio freq. (ringing) It cost more and take up more space but it is worth the change.

This is a personal preference but I prefer using Panasonic Electrolytic (HFQ ... FC) than Xicon electrolytic caps. Besides, you can get them at digikey at good price.

We would like to see your completed amp. Why? Well we like pictures. (Right guys?)

Tomo

 

[Ctn]

pictures yes yes

Do you know if the JMT hansen board supports oversized caps?
Just wondering if it would fit compared to "normal" caps

 

[Herakleitus]

Ctn: Are the caps on my parts list oversized for the Hansen PCB?!

Tomo: Thanks for the advice! Checking into polypropylene caps... do you mean these, Panasonic P-Series with a working voltage of 50?
$0.64 0.047 uF P3473-ND/ECQ-P1H473GZ
$0.84 0.100 uF P3104-ND/ECQ-P1H104GZ
$1.06 0.120 uF P3124-ND/ECQ-P1H124GZ
$1.28 0.220 uF P3224-ND/ECQ-P1H224GZ

The reason I chose the Xicon cap is that the Panasonic one is unavailable at Digikey, it is listed as obsolete.

** Do I have the number of parts right, or am I going to end up short of something? **

And *of course* I will submit pictures, once I am done and

 

[Ctn]

Hehe nono Herakleitus

I mean I have massive Solen and ME caps

alot bigger than the ones that Jaycar sells.

 

[Tomo]

Ctn -

Size of capacitance should be the biggest concern for builders and designers are alike.

Solen is good for large capacitance. However, it is not wrapped tight enough really for signal coupling. It is far better signal coupling cap than electrolytics but it is NOT that good.

Please read the capacitor articles at:

http://www.capacitors.com

It tells more about the issues that you must know.

Herakleitus -

Availability is important. You do not have to stick with exact 220uF. I used 470uF for my first one because I could not find it at the stockroom. Later I used 1000uF because I had just sooo many of them. The capacitance is not important as long as the cap fit the board / the case and it is close or a little bigger than the design shows.

I did not recommend overly high quality caps like Orange Drops because these are really big and will not fit your board. However, if you are crafty, you might be able to devise something to fit them in. The size is 1~1.5 inch long, 3/4~1 inch wide and 1/2~3/4 inch width.

Panasonic metalized polypropylene caps are very compact and will fit your board ... They are still big but you only have to very little compromise.

Lastly, please always check specs for your parts. Sometimes parts marking and names can be very very confusing. For example, film cap does NOT mean it is polypropylene caps. It could be myler or polyester which you do not want.

Cheers,

Tomo

P.S. Myler is bad because its capacitance changes durastically over uses.

 

[Ctn]

Hi Tomo,

dang how bad is it really? compared to other caps?

Kewl nice articles, going to read

 

[Daniel Pumphrey]

Hi,
You really need to order some 50 ohm Vishay resistors to. The RN55 or CMF 55 will be fine.
These go in the current opamp loop to give the amp a constant impedence.
You need to try different gain settings too. I like 2 to 2.5K for the feedback resistor to ground. 10X gain is a little high for the ER4-S.
I don't see any enclosure on your list either. Get the dual 9V Pactec from Mouser. It is not in the catalog but they have it. Don't use the Altoids box, it probably will not hold all the parts you are getting and definately not the dual 9V batteries which is nice.
The hansen board fits perfectly in the Pactec box. Are you usinf the TLE 2426? It is also highly recommended, but can be added later too. If you want both levels of crossfeed, (which I don't use at all) you will need a triple pole triple throw switch too.
Dan

 

[Herakleitus]

Thanks for the advice Daniel. I put in an order for enough parts for 3 amps today. I kept asking if I had the *amount* of parts right, but no one was answering, so I went with the numbers I had, and I supposed that after I made one, I could make another small order for spare parts for the other two if I had used 'theirs' already. If I had seen your post before I ordered, I would have added the 50 ohm resistors. I will see if Mouser will let me modify my order after the fact, and before they put it together.

I am a complete newbie at this.

To be honest, I don't really know what I am doing, but I am diving in. I learn quickly, but I have zero electronics background, which all of the project articles assume. That is why I wanted to know exactly how many parts I would need, and which ones. There is no step by step guide for people who are new to this.

So, like I said, I am diving in, and hoping that I haven't just wasted $100. If anyone knows of a step by step guide that could help me out I would very much appreciate it if you could direct me to it!

As for the case and volume knob, I am going to be casting my own case from RTV (room temperature vulcanization) silicone. It doesn't get to be a closer fit than exact. This will let me make a perfectly customized casing which can also be as hard or as flexible as I would like, and any color I like, depending on the mixture. -- If I can make any kind of positive contribution from all of my questions here, it will be by showing off the custom case, which other people may be interested in making.

 

[Daniel Pumphrey]

Dive right in. The waters great. If you have any problems, just ask here or at Headwise, or email me.
Please document the enclosure and how you made it too.
The Hansen board used to have good instructions for parts whan Carl had them. Hopefully these still come with the boards. If not somewhere I have a schematic from Apheared.
Dan

 

[JK1dotNET]

Is it just me, or wouldn't you need to double most of the resistor quantities? The project page for the CMOY amp gives parts for a single channel, so since you probably want a stereo amp, you'll need twice as many caps and resistors for everything in the amp section. Of course, you'll only need one of everything in the power supply section, and one pot, since it's a stereo pot. The op-amp IC has two op-amps on one chip. Sorry I didn't see your post earlier to catch this before you ordered.

Good luck!

 

[tangent]

Quote:

wouldn't you need to double most of the resistor quantities?

Yes, his resistor list is badly off. This thread is also on headwize.com, where I replied with a correct resistor list.

There's one other serious problem with his parts list: he's missing the .022 uF cap (DigiKey #P3223), and he's over-ordered the .047 uF cap -- you only need one per amp, since it's in the crossfeed section. (The same goes for the .022 cap -- only one per amp.)

Some minor nits:

1. He's ordering a $3.50 LED, when a ten cent part will do just fine. (DigiKey 160-1078, for example.) To be fair, his part has a mounting ring, but my cheap part you have to glue into the case somehow. Me, I don't mind a bit.

2. In retrospect, I'd bump up the electrolytics' values to 330 to 470 uF, since you can find 10mm diameter versions, which is what the Hansen board is designed for. Even moving from the nice-ish Panasonic NHG 220s to generic Rat Shack 470s was a noticeable improvement to the bass in the one amp I tried it in. Going to a good brand might help even more.

3. He's ordering two of both .1 and .12 uF caps -- simpler to just get four of one kind.

4. Daniel Pumphrey pointed out that he needs a switch to use the crossfeed. However, a 3P3T switch apparently doesn't exist, at least in toggle versions -- NKK and Tyco don't make them, and that's a big pair of suppliers. You have to settle for a 3PDT, or go to a rotary switch. 3P3T rotaries are hard to find, too, but you can get 4P3Ts easily and simply not wire the fourth pole. Or, you can use three 3PSTs. I have two you can have if you want to buy a third.