Excited about new Budgie SE build!

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

Excited about new Budgie SE build!

Postby Audiophyle » Fri Aug 09, 2013 8:27 pm

This will be my very first adventure into tube anything, and I chose this board (& forum) because of the support. I must also say that the quality of this board is just incredible, and matches the service I received after ordering it too. Ive repaired several car audio amps in the last few years (old school PG, SS, & RF gear) and their boards dont hold a candle to this one

I am mostly interested in the headphone option but thought it was pretty cool that it could also power speakers. I will be using this at work, which is an open studio & I spend a lot of time listening to my headphones. I will retain the output option for speakers just in case, but probably wont use them.
I will be fabricating my own chassis, and want to make something very cool to decorate my desk, show it off to colleagues, and above all else enjoy the hell out of it.

I will be using my Iphone 5 as the source, and want to incorporate a dock into the chassis. Im open to ideas on the simplest way to accomplish this. I figured I would dissect a cheap dock to retrofit it into the chassis, but what Im not sure about is if I need preamp level audio or headphone out level audio to feed into the Budgie. I also need to look into the best way to get a reliable 5v DC from 120vAC for charging that I can build myself.
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Re: Excited about new Budgie SE build!

Postby Shannon Parks » Sun Aug 11, 2013 7:10 am

Sounds like great idea! From a KISS standpoint, I think the easy route would be to add a rear mounted AC socket on the Budgie SE chassis (like old stereo amps) and have it non-switched (i.e. always on, so that the iPhone would always be charging whether the amp was off or on). Then the iPhone charger would plug into that. A car-type cradle could be affixed to the left side of the chassis.

Note that using the spec'd transformer and supply to power the iPhone would create a lot of problems. The extra current for a charge is probably fairly appreciable, and the ground reference of the audio circuit is set already by the filaments 6.3VAC connected to the power tube cathode's DC (i.e. lifted). So using an off the shelf SMPS for the iPhone is the way to go.

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Re: Excited about new Budgie SE build!

Postby Audiophyle » Sun Aug 11, 2013 1:12 pm

I figured everything associated with the amp needed to remain as is & not manipulated at all.
I was planning on splitting the 110v AC inside the chassis and letting it power the amp as needed but also provide for the iPhone charging, which would be entirely its own circuit.

I'm also thinking a pair of gauges on the front with their warm incandescent bulb glow would look right at home with the glow of the tubes, and be more for looks than anything. What I'm not sure of is what type of gauge I should use. I'd like to run a pair of VU or mA gauges on the audio signal, but I don't want to degrade the sound at all. I'm thinking I'll end up just running voltmeters since they are easy to implement, but I'd like to have bouncing needles. Lol
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Re: Excited about new Budgie SE build!

Postby Audiophyle » Wed Aug 21, 2013 9:31 pm

So I am in the middle of soldering the parts onto the Budgie board & I noticed that the resistors for R1,R2,R11,R12 are listed as 475kohm 1/2W on the schematic, but the parts in the Mouser BOM are 475Kohm 1/4W.
Also R7 & R8 are listed as 100ohm 1/2W but the Mouser BOM contains 1/4w 100ohm resistors.

Can I use the 1/4W resistors or should I reorder & replace them with the 1/2W as indicated by the schematic?
(fingers crossed the 1/4w will be fine)
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Re: Excited about new Budgie SE build!

Postby Shannon Parks » Thu Aug 22, 2013 11:06 am

Audiophyle wrote:So I am in the middle of soldering the parts onto the Budgie board & I noticed that the resistors for R1,R2,R11,R12 are listed as 475kohm 1/2W on the schematic, but the parts in the Mouser BOM are 475Kohm 1/4W.
Also R7 & R8 are listed as 100ohm 1/2W but the Mouser BOM contains 1/4w 100ohm resistors.

Can I use the 1/4W resistors or should I reorder & replace them with the 1/2W as indicated by the schematic?
(fingers crossed the 1/4w will be fine)


The BOM and parts are 100% correct and you are OK. Those parts are MILSPEC, so under 70C they are double rated. (y)

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Re: Excited about new Budgie SE build!

Postby Audiophyle » Thu Aug 22, 2013 8:48 pm

Music to my ears.... or will be soon enough [:) lol
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Re: Excited about new Budgie SE build!

Postby Audiophyle » Thu Aug 22, 2013 9:52 pm

Ive got another quick question.
The on/off switch is rated for 16A 250VAC, but I found a switch I really like that is only 5A 250VAC.
Can I run the lower rated switch? Or should I stick to the 16A capacity?
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Re: Excited about new Budgie SE build!

Postby Shannon Parks » Fri Aug 23, 2013 4:40 am

Audiophyle wrote:Ive got another quick question.
The on/off switch is rated for 16A 250VAC, but I found a switch I really like that is only 5A 250VAC.
Can I run the lower rated switch? Or should I stick to the 16A capacity?


Your sub will be fine.

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Re: Excited about new Budgie SE build!

Postby Audiophyle » Sat Sep 07, 2013 12:15 pm

Time for a little update, I have sourced most (but not all) of the parts I need, waiting mostly on funds to continue gathering parts. So far, here is the progress of my amp.

Image

Image

Image
The Budgie SE board is complete & ready to go, and Ive picked up pretty much everything needed except the parts to fabricate a chassis & the Edcor transformers. The odd pieces in that pic are dual VU meters with a driver board (to not impact audio signal), an Iphone dock which will be integrated into the chassis, and a DC output power supply that will provide the needed 5v DC to charge the Iphone & 12v DC to drive the VU meter driver.


This is a sketch of what I am planning to fabricate....
Image
Im thinking an aluminum top case and bottom case with finished Mahogany end caps. Im picturing an ash or black toned wood finish and a matte/brushed aluminum finish. Still trying to decide how to mount everything to the chassis in a clean manner, I dont want to have lots of fasteners puncturing through the chassis case in a seemingly random arrangement (because components wont be visible), but that is probably me just being overly picky.

Cant wait to have this thing done & rocking on my desk at work, bosses will be jealous. lol
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Re: Excited about new Budgie SE build!

Postby Shannon Parks » Sun Sep 08, 2013 3:37 am

Looking good!
A note on the docking power: in my earlier post suggesting a SMPS, I was thinking wall wart (like every phone charger on the planet). If you are planning to squeeze that supply into your chassis, I fear you will have horrible noise. Shielding would help a little, but the sensitive Budgie circuit will soak up all that switching noise.

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Re: Excited about new Budgie SE build!

Postby Audiophyle » Sun Sep 08, 2013 10:01 am

My goal is to have everything integrated, I don't want two power cords leading to the amp.
Do you think the noise would be picked up from being in close proximity to the DC inverter, or do you think the Inverter would be introducing noise into the AC line?
What if I were to isolate the DC inverter inside the amp chassis with a thin copper casing, a makeshift Faraday cage grounded to the chassis & insulated from both the amp & inverter?

I'm also curious, if I am using the analog headphone output from my iPhone can I eliminate the volume pot from the budgie & instead rely on the iPhone volume setting to control overall volume? I would probably keep a pot in circuit, but mount it inside as more of a gain control VS a volume knob. Thoughts?
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Re: Excited about new Budgie SE build!

Postby Shannon Parks » Thu Sep 12, 2013 9:32 am

Audiophyle wrote:Do you think the noise would be picked up from being in close proximity to the DC inverter, ...What if I were to isolate the DC inverter inside the amp chassis with a thin copper casing, a makeshift Faraday cage grounded to the chassis & insulated from both the amp & inverter?


The radiated currents through the switching transformer will get into all the high impedance circuits in the audio path. I think shielding will help, but I think the easiest route would be to use a second power switch so it could just be switched off with the amp is switched on. That would be the easiest solution, and could be implemented after the fact, too. You could even use a SPDT or DPDT switch, but then you could never completely shut off everything without pulling the plug.

Audiophyle wrote:I'm also curious, if I am using the analog headphone output from my iPhone can I eliminate the volume pot from the budgie & instead rely on the iPhone volume setting to control overall volume? I would probably keep a pot in circuit, but mount it inside as more of a gain control VS a volume knob. Thoughts?


Yes. That is how I use mine quite often as well.

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Re: Excited about new Budgie SE build!

Postby Audiophyle » Sun Dec 29, 2013 11:21 pm

Time for an update on my progress!

I opted to simplify, so I dropped the idea of incorporating the iphone dock, and picked up a much smaller 12v psu (compact wall wart) to power the VU driver board & gauge illumination. Im still waiting on a power button, and need to start wiring everything up, then fabricate the finished wood end panels, but the mock up of the components has me even more excited than before.

Image

Image
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Re: Excited about new Budgie SE build!

Postby AmadeusMozart » Mon Dec 30, 2013 12:26 am

Very nice looking, well done, nice job so far. But... should the 12AX7 not be on the right side or am I mistaken?
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Re: Excited about new Budgie SE build!

Postby Audiophyle » Mon Dec 30, 2013 7:59 pm

Thanks, & you are correct. The 12ax7 should be on the right, I just threw them in for the photo op. lol
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