Hagerman Bugle 2

[6L6]

Building the Hagerman 'Bugle 2'

I recently bought the Hagerman Bugle 2 phono preamp as a DIY kit, and this shows how, step-by-step. It's also available assembled. http://hagtech.com/bugle2.html

This phonostage sounds absolutely wonderful! It shows exactly how good of a quality you can get from modern opamps and some very clever engineering.

Where the original Bugle used two 9-volt batteries for power, the Bugle 2 uses a universal AC-DC power adapter, and a very smart design in the preamp's PSU. It's quiet, cool, and simple.

http://cdn-1.dastatic.com/forums/gallery/data/500/medium/IMG_1899.jpg
Opening the package the first thing to do is locate the paperwork. Included are a very nice manual, covering assembly and testing, a resistor stuffing guide, and a piece of paper for sorting the resistors.

http://cdn-2.dastatic.com/forums/gallery/data/500/medium/IMG_1900.jpg
Here is the full contents of the kit - manual, very neat looking translucent case, power adapter, circuit board, and a bunch of parts.

http://cdn-1.dastatic.com/forums/gallery/data/500/medium/IMG_1901.jpg
The first job is to sort the resistors. Sort by color code, or better, measure them and verify the color.

http://cdn-2.dastatic.com/forums/gallery/data/500/medium/IMG_1902.jpg
The resistors are the first to install on the PCB. Do yourself a big favor and align all the brown stripes in the same direction. This will greatly help with troubleshooting if you make an error.

I also strongly suggest that you measure every resistor again before placing in the PCB. You will make mistakes, and the only way to catch them before they turn into a problem is to measure.

http://cdn-1.dastatic.com/forums/gallery/data/500/medium/IMG_1903.jpg
Trim the leads once soldered. (It sounds obvious to say this, but I have an obviously amateur -built Heathkit multimeter that has a forest of un-cut leads on it's PCB… Go figure.)

http://cdn-2.dastatic.com/forums/gallery/data/500/medium/IMG_1904.jpg
Keep following the instructions to stuff the PCB.

http://cdn-2.dastatic.com/forums/gallery/data/500/medium/IMG_1915.jpg
A quick note on the opamps, the DIP-8 package (these little computer-chip looking things) have the dot at pin 1. Easily seen here.

http://cdn-1.dastatic.com/forums/gallery/data/500/medium/IMG_1916.jpg
The PCB has a square pad at pin 1.

http://cdn-1.dastatic.com/forums/gallery/data/500/medium/IMG_1918.jpg
So the proper orientation looks like this.

BUT BEFORE YOU INSTALL THE OPAMPS, it's actually a good time to make a few quick checks.

Checking PSU voltage and polarity.
This kit is quite simple and very well laid-out, but it never hurts to check along the way and make sure you are building it correctly.

Before applying power make sure the 'can' capacitors have all been installed correctly - they have a polarity. The + lead is marked with the longer lead, and the label itself will have a marking on the - side.

Also make sure that the stripe on the diode aligns with the stripe on the PCB. It's there to protect against a backwards PSU, but if it's installed backwards it's not going to do any good.

Now plug it in. Does the LED light? Good! (The provided one is yellow. I used this color because I like it better and happened to have a couple laying around.)

Now place the minus (black) lead of your multimeter on the ground screw thing and set the meter to DC volts.

http://cdn-2.dastatic.com/forums/gallery/data/500/medium/IMG_1913.jpg
Read the voltage from the top of the resistor in-between the two can caps. It should read +12V (or probably just a bit lower)

http://cdn-1.dastatic.com/forums/gallery/data/500/medium/IMG_1914.jpg
Reading from the bottom of the resistor opposite the one you measured in the previous step should show just a bit less than -12V

If your voltages are good and of proper polarity, install the opamps and continue.


A geeky diversion -

What attracted me to this phono preamp is the use of the LM4562 (an opamp I've been interested in for some time) and the very clever PSU to power everything.

The DC starts from a little switch-mode AC-DC adapter outputting 24V DC. It being a SMPS, it has very nice DC coming out from it but it does have some high-frequency hash like they all do.

Here is what it looks like -
http://cdn-2.dastatic.com/forums/gallery/data/500/medium/IMG_1908.jpg
The base line is nice and stable, but there is high frequency junk at the beginning of the wave.

Ok. So what does that mean? It means that at high frequency that PSU rings and makes some 'noise'. (Ultrasonic, BTW, way above the audio band.) This is very common modern in wall-warts.

So how the heck is it fixed? Simple - inductors! (Also known as chokes) Because the current draw of this preamp is fairly low, some high-value chokes can be placed on the PSU input and all the junk and grime hits a brick wall.

How good? Look - (and the oscilloscope settings are haven't been changed)
http://cdn-1.dastatic.com/forums/gallery/data/500/medium/IMG_1909.jpg
Wow - that's significant. The hash is now gone. What's different? Only that I am measuring downstream of the chokes.

As long as the scope is hooked into the PSU, let's 'zoom in' quite a bit until we can see the residual of DC ripple.
http://cdn-1.dastatic.com/forums/gallery/data/500/medium/IMG_1910.jpg
The scale is now 20 millivolt/division (the previous photo were .5V or 500millivolt/division) and you can see a very nicely behaved DC supply with no leftover weirdness. And this is measured near the output opamp, which has the least amount of filtering!

But there are still more tricks left to show - the PSU as an additional layer of RC filtering for each opamp, meaning that the input circuit has a much quieter supply. This is important because it's the one that handles the teeny little delicate signal off the cartridge.
(One thing to keep in mind is that opamps have very good PSRR, or power supply rejection ratio, meaning how much PSU noise the device (opamp) can reject all by itself. So making a supply this quiet is icing on the cake. I like that!)

Look at this last scope shot - it is the same scale as the photo above, but the probe in now placed near the input opamp.
http://cdn-2.dastatic.com/forums/gallery/data/500/medium/IMG_1911.jpg
Ripple? What ripple? :cool:

That's good engineering.

Ok, back to building. :)

I'm a card-carrying member of the "Can't leave anything alone" club, and made a couple substitutions on my project.

http://cdn-2.dastatic.com/forums/gallery/data/500/medium/IMG_1919.jpg
As I am wanting to use this preamp with both MM and MC cartridges, it makes sense to have the resistors that set the gain changeable somehow. Instead of wiring up a switch, which would look kludgey no matter how it's done, I opted to use these pins. Stolen from a really nice DIP socket, they are soldered in, and now the leads from the resistors can be inserted and removed from those pins. A simple solution, and quite handy when I feel like using a low-output moving coil.

http://cdn-2.dastatic.com/forums/gallery/data/500/medium/IMG_1922.jpg
Here is is with the resistors installed. Why none on R23? I ran out of pins. :) (And also because it's left empty for the 40dB setting)
Remember, these pins are not supplied with the kit, so if you are confused because you are not reading the text, that's why.

Also, some of you are probably wondering about the silver flying saucers that are now on the board --- remember how I mentioned I was attracted to this preamp because of the LM4562? Well I had the idea of making my own phono pre with them, and got some in the fancy (and expensive) TO-99 package. Then I found this project, scrapped the plans to make my own and in memory of that idea, used the fancy-pants opamps in this circuit. They are completely the same on the inside as the ones in the plastic. They just look cooler and are harder on the wallet. (Almost 8 bucks each.)

http://cdn-1.dastatic.com/forums/gallery/data/500/medium/IMG_1921.jpg
I thought the ground lug was pretty cool. Here's a photo.

http://cdn-1.dastatic.com/forums/gallery/data/500/medium/IMG_1923.jpg
The last thing to do is put the case on, screw it together and place the sticky feet on the bottom.

http://cdn-2.dastatic.com/forums/gallery/data/500/medium/IMG_1924.jpg
The translucent case looks very cool lit up.

So… How does it sound? In a word, Wonderful. It is quiet, supremely musical, and unobtrusive. As I've been writing this guide my turntable has been spinning, and I am really, really liking it. Dynamic, transparent, the Bugle 2 is just getting out of the way and letting the music flow. This thing punches so far above it's weight class it's ridiculous.

[Thing Fish]

Neat job Jim...:)

[Batty]

I built one a couple of months ago, swapped R3 and R8 on both channels for 560 Ohm resistors and used 200 ohms in R23 mine is now 54db gain and input impedance of 200 ohms. I also changed the 3rd op amp for 2x OPA627s on a brown dog adaptor, I think this gives it more detail and will eventuall get around to replacing the other 2 if I can bear removing it from my system.

10384
Pre modification.

[Firebottle]

Great write up Jim. It's good of you to put the time in to show others how easy it is to assemble these type of kits :thumbsup:

:cool:Alan

[Batty]

There is more, Jim Hagerman is great to deal with and answers all emails very quickly. He gave me the info on how to change the gain on mine.
This has to be one of the easiest kits I have ever built and his price includes delivery anywhere in the world.

[6L6]

Thanks all for the comments. :)

Yes, Jim has a great product here, and if you have been interested in doing a kit this is a reasonable place to start. (It has some fine soldering required, but there is nothing complex.) He responds very promptly to queries and this product's price/performance rating is genuinely astounding.

I've had it playing a few more days now, and I am becoming more and more amazed at it's performance. It is simply transparent. No drama, no editorializing, no color, just a stalwart determination to play the music in the grooves. Some electronics that do that are also brutally honest - you know the type, the ones that only sound good on good recordings, and make poor recordings sound awful... That is very much not the case with this. The Bugle 2 will show you that the quality of the recording/mix/pressing/whatever may not be the highest quality, but it still plays the music in a lively and enjoyable manner. (Let's face it, no recording engineer or artist tries to make a poor sounding album... they try to make good music. This preamp always honors their intent.

[DSJR]

My take is that really good gear brings out what good is there in iffy recordings/pressings, but goes into a different league with good ones. The most endearing old vintage stuff does this with ease IMO.

Well done with the kit. Does it come with mains adaptor and case?

[Batty]

My take is that really good gear brings out what good is there in iffy recordings/pressings, but goes into a different league with good ones. The most endearing old vintage stuff does this with ease IMO.

Well done with the kit. Does it come with mains adaptor and case?

Yes it does, and the price includes international postage, mine took 8 days to reach South Australia and most of that was due to Aus Post.

[Barry]

Excellent post Jim!

I admire the the quality of the photos and the practical advice given (such as orientating the resistor colour code bands and checking the resistor values before soldering)

As you say ample room for up-grade tinkering. What cartridge will you be using?

Regards

[6L6]

Currently Denon DL-110 and Ortofon X5-MC.

Am planning on an Audio-Technica AT33-EV or -PTG/II. Haven't decided yet. Or maybe a Shelter 501II if my buddy can swing a good deal on it...

As for upgrading/hot-rodding/gold-plating/etc... There is no doubt at all that this circuit will shine with boutique parts. The supplied bits and pieces are of fine quality, but there were some engineering decisions made - for instance, teflon caps could not be supplied due to space constraints in the chassis.

If you wanted to stuff it completely with nude bulk-film Vishay resistors and gold-foil beeswax paper caps, I think you would have a circuit quite able to show you what modifications like that can do.

Have at it, and don't hold back. :) :) :)

[Aerobat]

How does it compare to your Pearl 2?

[6L6]

It's quite similar, actually.

The Pearl is quieter. The Pearl lets things flow just a little more easily. The Pearl is also about $350 more expensive, in DIY money -- which means that in the real world as a retail it would be at least $2000, probably more like $3000+.

The fact that the Bugle is that close is testament to just how good it really is.

I've got a thing for phonostages. There are currently 5 in my house, the tube "Bench RIAA 5", Pass Pearl, Pass Pearl 2, Hagerman Bugle 2, and Elliott Sound Products P06/P05A. They are all good, and have their own strengths.

When using HOMC and MM cartridges, my overall favorite is still the original Pearl, I think because I built it in a steel chassis and it is freakishly quiet. The Pearl 2 is an extremely close 2nd. The Bugle 2 is quite close in performance to the Pearls, and just trounces the Bench and Elliott.

When I get a low-output MC I will try them all again and report back.

[hal55]

Interesting, the Bugle I presume would kill most of "the usual suspects" in the under $1000 price range, and possibly well above it. Not quite a fair comparison I know since the retail units have to cover very significant extra margins before you even get to dealer markup. Still, that's market reality and the Bugle seems to be at the same price (fully assembled) as the Yaqin 22B that I currently use and quite love. Even if the thing did chew through the very nice Mullard Reissues I put in it in less than 5 months.
So, is the Bugle musical enough to tempt a valve lover like me and I suspect many others that could be tempted by the Yaqin, which has the advantage of being a) valve and b) looks way cool with the tube cages off and valves glowing away nicely.

Hal55

[6L6]

So, is the Bugle musical enough to tempt a valve lover like me ?

Most certainly yes.

[6L6]

Has anybody else heard or built one of these?

[Batty]

Just replaced the input matching resistors for Takman, will give it a good listen to this weekend.

[hal55]

Looking forward to your comments,

Hal55

[6L6]

Do you mean the cartridge load resistors? I'm interested in hearing about your impressions. The cartridge load resistors are always a sticky wicket, as 100% of the resistor's Johnson noise is amplified along with the signal.

[Batty]

Yes, the load resistors, my cart works best with 200 ohms load according to van den Hul

[6L6]

Did you have the loading at 300 ohm or 47K before the change to the takmans? If you had 47K there is going to be a large change. :) :) :)

[Batty]

I went for 200 from initial build