[OcdMan]

Hi guys,

I'm new to the forum here. I am definitely still a novice when it comes to DIY electronics. I've had a partially completed Bugle on the back burner for quite a while now. I bought it a number of years ago already pre-assembled. It's in a foil-lined box (which eliminates a minor EMI buzz) with small cut outs for the existing RCA jacks, access to the power switch, etc. It's hooked up to two 12-volt SLA batteries. I feel it's long overdue to be put in a proper metal box.

So I've come up with this parts list (with links) that will hopefully finish the job. Does it look like I have it covered? Any alternative parts to recommend or other suggestions?


Description                                                      Qty.           Mouser Part#                    Price (each)

Aluminum Box w/lid & screws (black)               1               546-1590DE                       $21.29
     (7.83" x 4.73" x 2.37")

Self-adhesive Feet (12.7 mm, square)             4               517-SJ-5018BK                 $0.18
                     
Strain Relief (for battery cable pair)                 1               836-1280                          $0.34

Ground Binding Post                                        1               530-111-2223-001           $2.20

Op-Amps                                                          3               926-LM4562NA/NOPB       $2.68

RCA Jacks (red)                                                2               502-BPJF02AUX                $2.37

RCA Jacks (white)                                             2               502-BPJF03AUX                $3.00

RCA Jack insulating washers (fiber)                 4                502-S1564                       $0.52

RCA Jack insulating washers (plastic)              4                502-S2207                       $0.53

SIP Sockets (for loading resistors)                   1               575-113132                     $3.18
      (photo is generic) (datasheet)

Toggle Switch (DPDT, ON/ON, 30V DC)             1               633-S6A-RO                     $5.25


A few questions:

1. What gauge of hook-up wire is recommended for the RCA jacks? And for the power switch? Stranded wire should be a little easier to work with and to solder, right?

2. Does the toggle switch need to be insulated from the box?

3. Using SIP sockets to change the loading was recommended to someone else on another forum. My primary cartridge uses a 100k load for best sound. I have another cartridge that I occasionally swap in but it sounds best at 37k. Right now I have resistors soldered onto RCA plugs and use Y-connectors to adjust the load. But now I want something cleaner and I think a pair of sockets would do the trick for that once-in-a-while swap. Do those sockets look like they would fit the bill? I've heard that the life-span on their internal contacts isn't too long but they would be used sparingly.

4. Are the LM4592 op-amps worth it? I have a chip puller, so it should be fairly easy to remove the existing OPA2134s. There shouldn't be any incompatibilities swapping the OPA2134s directly for the LM4562s, right?

Thanks for the help.

[Speedskater]

1] For low voltage, low power inside a box wiring, a small solid wire is best. If you have some spare Cat3 or Cat5 cable, that would be good.
     In the past I would use a slightly thicker 4 conductor cable 'doorbell' or 'telephone' or 'intercom'. I would separate the 4 wires.

2] You don't need insulation.

3] pass

4]pass

[Folsom]

Go with LME49720HA (aka LM4562HA), they are more than worth it. They are cheap through Mouser. But they need heatsinks. The heatsinks, some are a bit big for the Bugle.

These are best suited for the Bugle with the impressive LME49720HA.

[OcdMan]

I will consider those op-amps especially if I feel comfortable enough to desolder the existing sockets. Thanks for the heatsink link too.

I have plenty of CAT 5 solid-core cable. I don't think I have anything thicker right now. So CAT 5 will work for both the RCA jacks and power switch? I don't have any problems buying something thicker if it's worth it.

The breakaway SIP sockets are going into the R16 and R34 spots. The datasheet  (Fig. 1) says the contacts are gold-plated and they accept .015 - .025" diameter pins. That seems like what I'd need for resistors. That has to be better than the Y-connector/RCA plug combo I'm using now.

[Folsom]

If you have the stock sockets leave them. The cans can go into them just fine.

[OcdMan]

Okay, that's very interesting. I may give that a shot. Thanks.

[kylek]

Go with LME49720HA (aka LM4562HA), they are more than worth it. They are cheap through Mouser. But they need heatsinks. The heatsinks, some are a bit big for the Bugle.

These are best suited for the Bugle with the impressive LME49720HA.

Do they really need heatsinks?

[Folsom]

I don't know why but they get real warm, a little hot. Can't say I noticed the same kind of heat from other opamps. The sound difference may be a little bit of refinement.

[kylek]

Thanks.  The smaller heatsinks look good.