OLD: Parks Audio Budgie SE - updated 8/21/14

a 3W single ended EL84 amp for home, work & school

OLD: Parks Audio Budgie SE - updated 8/21/14

Postby Shannon Parks » Sat Sep 15, 2012 1:20 pm

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Manual and BOMs:
Budgie SE Manual- The parts list is broken down into three sections: Mouser PCB, Mouser Chassis, and other vendor parts. The first two sections are complete with the BOM instant entry links, while the third section is not. But everything - every last nut - should be in that list. I still plan to draw a separate drawing of the audio input cabling (RCAs to volume pot to board) and the 120VAC wiring (with lengths and fast on connector info).

Purchase:
Budgie SE board set (chassis plate and Budgie PCB) - $78 plus $5.25 shipping:
Budgie SE (PCB only) - $39 plus $2.75 shipping:

Cost at a glance:
Mouser PCB parts.........$37
Mouser chassis parts....$103
Other suppliers parts....$145
Budgie SE boards.........$78
Total.............................$363 (plus shipping costs)
There are a lot of ways in trimming that much lower. I'll post a thread on that later.

*NEW* Front Panel Express Top Plate File

Rev History:
8/21/14 - Added forum link to Front Panel Express file.
10/25/12 - Updated the Mouser Instant Entry for the PCB due to three backordered resistors. Note that schematic has the grid reistsors for the EL84s as 220K - this needs to be updated to match parts list (475K is correct).
Last edited by Shannon Parks on Thu Oct 25, 2012 6:34 am, edited 3 times in total.
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Postby EWBrown » Sun Sep 16, 2012 7:33 pm

I see two different Edcor part numbers for the power trannie:
XPWR128-120 and XPWR136-120.

Update: I just checked the Edcor site, there is no "128" only the "136".

XPWR136-120

Power transformer for a 120V, 60Hz. line to 500V (250-0-250) at 60mA center tapped and 6.3V (3.15-0-3.15) at 2A center tapped.



Also, where does the C24X choke mount ? (I'd presume, on the bottom, inverted chassis).

/ed B
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Postby Shannon Parks » Mon Sep 17, 2012 6:37 am

For some reason they changed the part number - maybe to correspond to the dual voltage version. It really threw me for a loop as I was gathering together the docs this weekend. But the parts list is correct. I'll fix the forum mentions.

The choke needs to be nestled in the rear right corner of the chassis in order to fit beside the board, behind the power switch and clear of protruding bolts from the power tranny mount (and walnut side panel), all while still allowing easy access to the mounting bolts.

Fortunately, the dims are straight-forward. Use a 9/32" drill for the mounting holes (we are using #6-32 machine screws). Put the first hole .5" in from the back and 1" in from the metal side (without any walnut sides on). Then you can use the choke to mark the next hole, or measure another 2.375" inches (i.e. the choke uses 2 3/8" mounts).

Note that the other additional machining you'll have to do is for the four additional top plate screws (#6 1/2" sheet metal screws), as four are already predrilled. You can screw the top plate down and easily mark the four holes. These require a 3/32" drill bit (you can use 7/64", but you get a little more grip with 3/32")..

I see that these screws are missing from the parts list - I'll fix that tonight:
Qty 8................ #6 1/2" sheet metal screw SS 18-8 Bolt Depot pn# 2300

Shannon

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Postby TerrySmith » Tue Oct 02, 2012 9:00 am

What is the size of this board (L x W)?
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Postby Shannon Parks » Tue Oct 02, 2012 11:07 am

TerrySmith wrote:What is the size of this board (L x W)?


Which one? The chassis top plate is 5.9" by 9.9" for the 6x10 Hammond chassis. If you wanted your own chassis, you could still get the plain $12 Hammond and drop it into a wood frame.

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Postby EWBrown » Tue Oct 02, 2012 2:06 pm

The circuit board is 5 inches by 4.2 inches, I just measured it to verify it.

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Postby TerrySmith » Tue Oct 02, 2012 9:41 pm

The circuit board is 5 inches by 4.2 inches, I just measured it to verify it.


That's what I needed, Thanks!
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Postby jollyrogr » Wed Oct 24, 2012 2:13 pm

Hello, I'm interested in this little amp, and thinking about building it. I'm new to this and have a couple questions. 1. How does it sound? Pretty subjective I know, but is it quiet? Better than a push-pull? 2. Any suggestions for speakers to use with this? I'm assuming anything 8ohm that is rather efficient? 3. A few items on your Mouser BOM are on backorder. Are there any substitutions that can be made? I think the POT is an easy one - 20mm shaft is on B.O., 25mm shaft is in stock. Not sure about some of the resistors though.

Thanks

P.S. Small item to note but it looks like on your BOM lists you were trying to include everything. I noticed the fuse holder but the list is missing the fuse itself. I can see from the schematic you had a .75 amp slow blow though.
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Postby EWBrown » Wed Oct 24, 2012 8:34 pm

I have mine all built up, as far as I could go without the Edcor iron.

Today I received notification from Edcor, that the trannies have shipped, so I should have them here, next week, and then be able to finish it up.

==============================

Update:


Finished, I decided to skip the headphones output, and put in a red LED in its place. Classic old Heathkit volume control knob.

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/ed B
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Postby Shannon Parks » Thu Oct 25, 2012 5:40 am

jollyrogr wrote:Hello, I'm interested in this little amp, and thinking about building it. I'm new to this and have a couple questions. 1. How does it sound? Pretty subjective I know, but is it quiet? Better than a push-pull? 2. Any suggestions for speakers to use with this? I'm assuming anything 8ohm that is rather efficient? 3. A few items on your Mouser BOM are on backorder. Are there any substitutions that can be made? I think the POT is an easy one - 20mm shaft is on B.O., 25mm shaft is in stock. Not sure about some of the resistors though.

Thanks

P.S. Small item to note but it looks like on your BOM lists you were trying to include everything. I noticed the fuse holder but the list is missing the fuse itself. I can see from the schematic you had a .75 amp slow blow though.


1) I think it sounds great, and I'll post the frequency response sometime soon. A key factor - particularly for the headphone portion - is noise, and I think the noise performance is superb. Zero hummmmm.
2) I use 91dB efficient speakers in my shop with my Budgie SE. I would consider this a minimum. The Achilles Heel in a design like this is the low frequency (sub 100Hz) distortion caused by the small SE outputs, so higher efficiency speakers alleviate the issue.
3) I'll probably edit the Instant BOM but not the manual for subs. Regarding the pots, I used the ALPS knock-offs on eBay. Same footprint. The Radio Shack pots and Alpha pots will also fit. Whatever the length, some of the shaft will need to be hacksawed off for a close-to-the-chassis fit. Thanks for the fuse heads up.

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Postby jollyrogr » Thu Oct 25, 2012 6:24 am

separks wrote:1) I think it sounds great, and I'll post the frequency response sometime soon. A key factor - particularly for the headphone portion - is noise, and I think the noise performance is superb. Zero hummmmm.
2) I use 91dB efficient speakers in my shop with my Budgie SE. I would consider this a minimum. The Achilles Heel in a design like this is the low frequency (sub 100Hz) distortion caused by the small SE outputs, so higher efficiency speakers alleviate the issue.
3) I'll probably edit the Instant BOM but not the manual for subs. Regarding the pots, I used the ALPS knock-offs on eBay. Same footprint. The Radio Shack pots and Alpha pots will also fit. Whatever the length, some of the shaft will need to be hacksawed off for a close-to-the-chassis fit. Thanks for the fuse heads up.

Shannon


So would different OPT's help some of that low freq distortion you're talking about? I listen to mostly rock music anyway so probably not an issue. How big are your shop speakers?

Ed - very cool. What's the lead time from Edcor? About a month?
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Postby Shannon Parks » Thu Oct 25, 2012 6:32 am

I updated the Mouser Instant Entry for the PCB. You can sub the ALPS pot with 688-RK27112A00CC (as you'll be cutting the shaft down to size anyway).

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Postby EWBrown » Fri Oct 26, 2012 8:56 am

The lead time between placing an order with Edcor , and their shipping it out seems to be approximately 30 days. Add in the UPS transit time, depending on your location, 3 to 5 business days.

Just for simplicity (and because I already have two other tubed headphone amplifiers), I'll leave out the headphone components on this SE Budgie build.
I'll put an LED "power on" light in its place, just to fill the hole..

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/ed B
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budgie

Postby audioray » Fri Oct 26, 2012 10:11 am

hi shannon
is the top plate pre punched and silkscreen.
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Re: budgie

Postby Shannon Parks » Fri Oct 26, 2012 6:33 pm

audioray wrote:hi shannon
is the top plate pre punched and silkscreen.
audioray@hotmail.com


Yes, the top plate is completely done with all the cutouts and silkscreening. Instead of aluminum, it is actually a PCB fabrication around .100" thick, so it is very sturdy and looks great. It makes for a very simple and fast build.

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