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Author Topic: Hagerman Bugle  (Read 6733 times)

Offline xcortes

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Hagerman Bugle
« on: January 27, 2009, 11:49:54 am »
The Hagerman Bugle is a little battery operated phono stage kit (SS) with good press. A "half kit" (a PCB with a parts list with Digikey parts numbers) costs $39.

http://www.hagtech.com/bugle.html [nofollow]

The interesting point for us is that the passive RIAA network can be modified to other EQs. It looks like a very good solid state option to substitute internal electronics and add IEC eq to any machine. There's even a java calculator that tells what resistor values to substitute. Of course one needs to know the desired frequency breakpoints (turnovers) for NAB or IEC which I don't:

http://www.hagtech.com/equalization.html [nofollow]

I'd love to hear opinions and/or help on calculating the values for tape.
Xavier Cortes

Offline Tubes n tapes

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Re: Hagerman Bugle
« Reply #1 on: January 28, 2009, 06:02:04 pm »
Xavier,

The corner frequencies for NAB and IEC are mentioned in my NAB to IEC converter article on the LAOCAS website.

http://laocaudiosociety.net/tech/NABtoIEC.pdf [nofollow]

Maybe that is of some use for you.
Arian Jansen.

SonoruS Audio.
VP of technology of the Los Angeles and Orange County Audio Society (LAOCAS).
ESL/OTL builder and modest Studer/ReVox collector.

Offline xcortes

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Re: Hagerman Bugle
« Reply #2 on: January 29, 2009, 03:12:34 pm »
Thanks Arian. I knew I had seen that information somewhere!



So for NAB we have a bass zero at 50 hz and a bass pole at 40hz (the minimum allowed). On the treble side pole is 3,150 hz and zero at 50 khz. So maintaining Ca and Cb (C3 and C2 on the schematic) stock at 0.22 and 0.01uF and solving for resistors Ra, Rb, Rc and Rd (R10, R14, R8 and R13 on the schematic) we get 3.62k, 14.47k, 4.73k and 0.32k.

For IEC we maintain the bass response of NAB (ala Seduction) and set a treble pole at 4,500 hz getting 3.62k, 14.47k, 3.21k and 0.32k.

Of course R17 must be changed to a value more in accordance to each tape deck heads but, building on the Seduction 100k should be a good value to start.
« Last Edit: January 29, 2009, 03:21:37 pm by xcortes »
Xavier Cortes

Offline xcortes

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Hagerman Bugle. Instructions to build a Tape Head Preamp
« Reply #3 on: January 29, 2009, 03:28:36 pm »
I intend this post as a summary of the above that can be used for reference for anyone trying it.

Disclosure: I have no relation with Hagerman neither have I listened to the Bugle phono stage nor have I performed the mods here proposed. Having said that I will try them soon.

The Hagerman Bugle is a little battery operated phono stage kit (SS) with good press. A "half kit" (a PCB with a parts list with Digikey parts numbers) costs $39.

http://www.hagtech.com/bugle.html [nofollow]

The interesting point for us is that the passive RIAA network can be modified to other Eqs. It looks like a very good solid state option to substitute internal electronics and add NAB and/or IEC equalization to any machine.

To build a NAB version build it exactly as the RIAA version and substitute resistors R10, R14, R8, R13 and R17 with the closest you can get to the following: 3.62k, 14.47k, 4.73k, 0.32k and 100K.

To build an IEC version for your TP tapes build it exactly as the RIAA version and substitute resistors R10, R14, R8, R13 and R17 with the closest you can get to the following: 3.62k, 14.47k, 3.21k, 0.32k and 100K.

Of course a version with both eq options can be built by building the NAB version and paralelling a 10k resistor to R13 with a switch in series. Switch open you get 4.73k (NAB) and switch closed you get 3.21k (IEC).
Xavier Cortes

Offline steveidosound

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Re: Hagerman Bugle
« Reply #4 on: January 29, 2009, 04:49:51 pm »
Wow. the surprising thing there is that there is only about 1.5K (give or take) change in one resistor between NAB and IEC !
BTW, if your list is consistent are you not changing the value of R8 not R13 ?
Steve Williams

you don't want to know what equipment I listen to...

Offline ironbut

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Re: Hagerman Bugle
« Reply #5 on: January 29, 2009, 08:44:59 pm »
Nice work Xavier! Jim's kits are really well thought out too ( I've built a couple without a hitch). The only thing is check the quality of the female rca jacks he has listed before you order them. You'll probably wanta sub whatever your favorite is. I've never heard the Bugle but I did have the loan of a little battery powered phono pre-preamp that Mark Levinson Audio Labs put out a gazillion years ago. It kicked the crap out of the step up I had at the time and I sure was sorry to see it go. A friend of mine down in LA has been working on a little ss phono stage for a while and he says that it's sounding better than his John Curl Vendetta (which is good since the last time I heard it, it was a little too euphonic for me). So, even though I'm a die hard tubes fan, I have to admit that there's some places that it does a nice job.

steve koto
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Offline drdeaner

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Re: Hagerman Bugle
« Reply #6 on: March 04, 2013, 11:26:44 am »
I built the bugle with the values shown above, and the EQ was way off.   I contacted Jim Hagerman and he provided the values relative to a stock phono bugle:
R10=14.3 K
R14= 226 ohm
R8= 0 ohm
remove R13 and C2 

The bugle now works great, far better than the Otari electronics.  There are 3 stages of gain, and you could vary any of them for higher gain if needed.  It is close enough as is. No, this will not equal an EF86 telefunken input stage, but it is great bang for the buck

Dean

Offline Ki Choi

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Re: Hagerman Bugle
« Reply #7 on: March 04, 2013, 03:39:08 pm »
Excellent thread.

Any discussions that will lead to infecting another unsuspecting tapeheads are good.

I had also contacted Jim earlier and asked about the conversion and have ordered his new phono preamp that I find it very intriguing:

http://www.kickstarter.com/projects/1907446723/bugle2-a-diy-phono-preamp?ref=email [nofollow]

Five days to go... according to the site.

I am pretty sure (although I have not looked at the schematic) the R value are applicable to both models.

Now I had a chance to read your post more carefully, I have few questions:

1) did you change the R17 to 100Kohm or left it alone?
2) would R13 value change to 3.12K ohm for IEC EQ would still be valid?

Thanks,

Ki
« Last Edit: March 04, 2013, 03:56:15 pm by Ki Choi »
Ki Choi

Offline Hxt1

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Re: Hagerman Bugle
« Reply #8 on: September 19, 2017, 08:56:23 pm »
Hey guys, I know this is an old thread,
I had a couple of bugle 2s modded for tape preamp use with my a807's and
I must say, they have been keeping me happy so far.
I'm now working on putting a battery power supply together for them.
Ki, did you build one up yet?'and if so, what do you think?
Cheers
Harvey.
Harvey X Thomison
Lencos, Leicas, and Lyrecs.....
Studer A807 Archival, Sony tc766-2, Revox B77,Ampex AG350,Crown 'Staggerd Head' transport, Lenco G99, Bent Audio TAP AVC, Almarro a205MkII, Bottlehead Eros Phono, etc. Lots of "Charmingly Imperfect" DIY Stuff