Bugle power supply

SamA · « **on:** 21 Jul 2008, 09:38 pm »

I've been using a 12-volt, 0.3 amp wall wart to power my Bugle (which I love). Recently, I've noticed after playing the seconfdside of an LP,about 20 minutes or so, the sound begins to distort. Indeed, when I look at a recording I'm making on my PC, the signal graphic looks very flat or cut off. It sounds distorted

If I unplug the power supply, count to 10 and plug it in again, it sounds great.

Should I look for a higher amperage power supply? Or is something else going on here?

Theo · « **Reply #1 on:** 22 Jul 2008, 12:01 am »

The recommended power supply for a Bugle is 15V@0.1A.

http://www.hagtech.com/bugle.html#powersupply

hagtech · « **Reply #2 on:** 22 Jul 2008, 05:43 am »

How do you make split supplies? You need both + and - about ground.

jh

SamA · « **Reply #3 on:** 22 Jul 2008, 03:33 pm »

I'm using an older Coleco power supply that is labeled 12v - and 12v + and connecting to the Bugle via alligator clips to the 9v battery connectors - positive on the left side of the board and negative on the right side of the board.

Are you saying that I should be using a separate 12v (or 15v) power supplies on each of the two 9v battery connectors?

jcg0322 · « **Reply #4 on:** 23 Jul 2008, 05:26 pm »

SamA,

I will send you a bugle power supply to test on your system.
I have 2 or 3 untested units and you can help me out.

You will also receive documentation for wiring and hookups for 120 or 230 volts.

This will verify if your old power supply is the culprit. Let me know if you are interested.
You can buy the power supply if you like it, or send it back. I will pay shipping.

Thanks,
Jack

hagtech · « **Reply #5 on:** 24 Jul 2008, 03:50 am »

Very odd, that it takes maybe 10 minutes for the problem to show up. As if there is a leakage path that causes a runaway dc bias shift. Maybe one of the resistors on the opamp inputs are not soldered or broken?

jh

SamA · « **Reply #6 on:** 23 Aug 2008, 02:43 pm »

Jack - Thank you for the very generous offer. Sorry, too, for the delay. I've been out of the country and had no e-mail access. For now, I think I'm going to stick to 9v rechargeable batteries. Eventually, though, I can see myself acquiring a more permanent power supply. especilaly as we get into winter and increased LP listening time. SamA.

PRR · « **Reply #7 on:** 7 Sep 2008, 04:17 am »

> recommended power supply for a Bugle is 15V@0.1A.

It is +/- 15V. This is old shorthand for "two 15V supplies tied together so as you can get positive OR negative voltages".

As jh implied with "How do you make split supplies? You need both + and - about ground."

A "+/-" power supply has three terminals. Internally it may be two power supplies with four terminals with two terminals strapped together. Indeed that is how the stock battery array is connected: four snaps, but if you peek the connections, "+" on one batt connects to "-" on the other batt and to circuit ground/common.

> I'm using an older Coleco power supply that is labeled 12v - and 12v + and connecting to the Bugle via alligator clips to the 9v battery connectors - positive on the left side of the board and negative on the right side of the board.

Does it also have a third wire?

I've seen some odd things on old game supplies. But this is most likely a single 12V supply, polarity marked, but no ground and no midpoint.

Shorn of distractions like most of the audio path, this is how the Bugle is wired:

Each supply rail is solidly set 9V up or down from the output jack shell/common. The opamp can swing maybe 6V up or 6V down relative to common and output jack shell.

This is what SamA seems to have tried:

> about 20 minutes or so, the sound begins to distort.

According to the over-simplified drawing, the mystery is why it ever worked at all. The output jack shell is not connected to anything!

> Very odd, that it takes maybe 10 minutes for the problem to show up.

That's the key clue.

Of course I've over-simplified. The real Bugle has capacitors each rail to ground. At power-up, equal capacitors will set the ground halfway between the rails. The output signal returns on the shell and signal current flows in the rail caps. It "works".

But that initial halfway charge is not "solid". Opamp input bias current starts to pull the common off-center, which is not a problem, until it is so off-center that it can't swing the peaks of one side of the signal. SamA hears distortion. His off-wait-on process re-starts with a new halfway charge.

I can't make out the rail-caps from the published info and am too lazy to look up bias current. You might run those numbers and see if time constant is minutes.

It's a good preamp and I dunno why someone would want to power it with a game-console supply. True, the Bugle will reject a lot of trash; you still have your very weak phono signal intimately connected with every vacuum cleaner and fluorescent lamp in the neighborhood. (At least a digi-game supply will reject RF on the powerlines.) Battery power floats far-away from mundane wall-power trash/hash. The Bugle wall power supply does a lot to damp the hash.

Here's a hasty-hack. Since we only need 30ma and most bricks have 100mA or more, "waste" power to fake a split rail. Two 1K will bleed around 10mA, chip bias currents just vanish in the flood. The output shell sees 500R, so with 50K amp input the crosstalk is 40dB down. I do not like it, do not advise it, but SamA showed that the preamp "works" with "infinite" power supply center-tap resistance, for a while, and this would swamp the lingering drift.

SamA · « **Reply #8 on:** 8 Sep 2008, 09:48 pm »

JCC - Thank you for that very detailed and expert reply. I think I'm beginning to understand what is going on now. Methinks I gotta bite the bullet and build the official Bugle power supply.

I love this pre-amp and I want to get the most I can from it.

Batteries do a good job, but, trying to be an eco-kind-of-guy, I cringe tossing the worn batteries in the trash (no battery recycling here in Central Pa.) and the rechargables don't seem to last that long.

Stay tuned.... and thanks again for your generous reply.

SamA.

SamA · « **Reply #9 on:** 8 Sep 2008, 11:15 pm »

Yikes! I thought ordering the parts from Digi-Key would be easy. But some stuff is on back order and there doesn't seem to be a way to order fewer than 1,500 heat sinks! Two is all I really need.

It seems, too, that some hardware isn't included, like a power cord and it's not clear what cord is appropriate for this application. And screws/nuts? Digi-Key doesn't seem to know them.

Jim, how about an up-to-date parts list?

jcg0322 · « **Reply #10 on:** 10 Sep 2008, 03:49 pm »

SamA,

I have all parts for the Bugle power supply listed in the on-line manual plus the Hagerman circuit board.
The price is $65 plus shipping.

This will save you valuable time and money.

Jim Hagerman has an outstanding reputation for high quality audio (just look at the reviews). Whether they are solid state or vacuum tube components, you know you are getting the best engineering from an audio professional who really cares and knows about his products and the needs of his customers.

I commit to uphold that quality with my complete bugle preamp and matching power supply kits. Check it out for yourself.

All parts are guaranteed.

jcg0324@aol.com

215-300-4009

Thanks,
Jack Gallagher

SamA · « **Reply #11 on:** 10 Sep 2008, 09:35 pm »

Thanks, Jack. You have mail. Sam

PRR · « **Reply #12 on:** 13 Sep 2008, 01:56 am »

> trying to be an eco-kind-of-guy
> ....back order and there doesn't seem to be a way to order fewer than 1,500 heat sinks!
> And screws/nuts? Digi-Key doesn't seem to know them.

Digi-Key can be confusing. What you want, or a viable alternate, probably is in there, but I agree that I find their search overwhelming.

And buying just one or four, when the Main Market orders ten-thousands per box, can be relatively expensive. Some stock-clerk has to open a big box, pull your 4 parts, keep the other 9,996 around hoping for more 4-part orders, and eventually chuck-out 6,789 unsold parts.

Eco-heatsinks, Eco-screws: scavenge and re-use. The world is full of old hi-fi and other electronic carcasses. "Mechanicals" like heatsinks and screws don't wear out. And their exact parameters are rarely critical. I've made heatsinks from several pieces of aluminum roof-flashing. I've re-purposed fins from a 60W loudspeaker amp on a 0.1W headphone amp. Older 486 CPU heatsinks are wonderfully adaptable. Old PC power supplies are full of fins, also screws. (However nuts may be scarce.)

I'm assembling a micro-PC. The case had no power switch, a $6.50 option! I went to my junkpile, ripped the button PCB out of a dead Dell. True, by the time I adapt the wires and rig a mount, I may be up to six bucks of labor; but I thought it was silly to buy a switch when I throw them away in huge piles.

In this case: the regs almost can work without a heatsink. Any old 1"x1" hunk of flat metal (need not be aluminum, but it drills easier) will throw the heat. True, it may not fit the PCB, or may not be supported against vibration. Some DIY cleverness is called for.

OTOH, you may not have the luxury to collect and scavenge old cassette decks, PCs, and other electro-junk. It DOES pile-up. I have to pirouette around the piles in my shop.

If Jack has set up a scheme buying parts by the hundred and kitting them to dozens of customers, it is probably as-cheap and much less stress to get the kit from him.

SamA · « **Reply #13 on:** 13 Sep 2008, 01:33 pm »

PRR - Gone are the days when I had parts boxes in the basement. My significant other has had me on a down-sizing cleanup binge the last year or so and I'm struggling to keep my 6,000 album/CD collection from her "they've got to go" eye. She had a point with the speakers. I mean, who really needs 12 pairs of speakers? I'm down to six and my BA 150s may be next to go.

Long story short, I ordered the kit from Jack and am looking forward to this project. Stay tuned.

sfox50 · « **Reply #14 on:** 14 Sep 2008, 02:48 am »

OK- I've had the Bugle power supply for a couple years, but I've been using 12 volt SLA's because the hookup of the PS had me baffled. Thanks to this thread, I figured out the key to the way to connect it up! I think it sounds better with the 15V +/-! Now I need to find a suitable chassis to mount both boards in.

jcg0322 · « **Reply #15 on:** 15 Sep 2008, 03:30 pm »

PRR,

Those are some great electronic schematics of the + - power supply hookup to the Bugle.

You explained the concepts very well also.

If anyone is interested in other pics, I have some actual photos of the Bugle / power supply hookup.

There are pics of 120 vac and 220/240 attachments to the power supply.

Just email me at jcg0324@aol.com and you will receive this information for free.

Thanks to PRR and Jim Hagerman and especially to all the participants who contribute valuable experiences and information on a day to day basis.

Talk to you later
Jack

SamA · « **Reply #16 on:** 22 Sep 2008, 09:47 pm »

Dilemma solved!

I ordered the complete power supply kit from Jack Gallagher. It arrived perfectly packaged - with additional documentation and photographs and a few pieces of hardware - that made assembly a piece of cake. The only question I had was how to determine the line side side of a wall outlet and Jack answered, in detail, in quick order. On a weekend at that!

Assembly took about an hour. I've been enjoying the heck out of the Bugle pre-amp and Bugle power supply like heck. I've got about 12 hours on the new set up and there's definitely extra oomph in the sound that I wasn't getting from the batteries (or my haphazard wall-wart power supply that fizzled every 30 minutes or so). I swear there's an enhanced soundstage I wasn't experiencing before, too.

I'm kicking myself. I should have built the Bugle power supply the same time I was building the pre-amp. Oh well.

Thanks to Jim and Jack for bringing it all together for me.

jcg0322 · « **Reply #17 on:** 23 Sep 2008, 02:53 pm »

Sam,

Thank you for your kind comments but remember Mr. Hagerman is the engineer of all this excellent audio reproduction, whether it be solid state or tube.
I only try to deliver a quality kit that is fun to build, educational and economical.

If anyone has a question about trying to figure out their AC outlet.....which one is line (hot) and which one is neutral, send me an email and I will show you a fun, easy test if you have an AC voltmeter.

Thanks,
Jack

jameshuls · « **Reply #18 on:** 2 Dec 2008, 08:24 pm »

Hi Jack,

I am thinking of building a Bugle power supply for my Piccolo, and happened to have come across this thread. I was interested to see you had build kits available for $65. Are these still availabe? If so I would like to pick one up in the next month or so. Thanks!

jcg0322 · « **Reply #19 on:** 2 Dec 2008, 09:52 pm »

The bugle power supply kit is still available for $65. I have recently added the recommended 5mm x 20mm 1/16 amp fuse to the kit. Fully built and tested units are also available for $125.

Please email me your zip code to see if you qualify for free shipping.

Thanks,
Jack Gallagher