bugle questions, cap upgrade and LOMC compatibility.

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jmpiwonka

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i've already seen where you can bump the gain up to run lower output cartridges.
i've got grado gold1 ~4mv output. i'm gonna have soon a soundsmith retipped statement sonata ~.5mv output.

i have resistors to set gain at 50db, 55db, 60db and 65db.
i'm going to wire up the hagtech power supply soon too.

is anyone successfully running LOMC cartridges with the bugle without stepup tranny?
did you add resistors in the two empty slots? i don't think my grado will need it but if i were to use another LOMC cartridge...

also, has anyone replaced the caps in the bugle and noticed any improvement in performance?
which did you replace?
i was considering a replacing the stock caps with something of the same value in perhaps jantzen crosscaps or something.

oh yeah, what about opamps?
someone told me the national semiconductor LM4562 worked well in the U3 position. anyone tried that?

thanks.

PatOMalley

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Re: bugle questions, cap upgrade and LOMC compatibility.
« Reply #1 on: 5 Aug 2009, 12:04 am »
I like the LM4562.

What you need to do is use it at U3 and add caps to pin 4 and 8 then run that to ground.



That stabilizes the opamp, drives down noise, and winds up being pretty impressive.

If you up the gain on the Bugle you may increase noise.

jmpiwonka

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Re: bugle questions, cap upgrade and LOMC compatibility.
« Reply #2 on: 5 Aug 2009, 12:06 am »
what size caps did you use?

PatOMalley

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Re: bugle questions, cap upgrade and LOMC compatibility.
« Reply #3 on: 5 Aug 2009, 12:56 am »
.1uF stacked film - DigiKey part number: P4525-ND

reuben

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Re: bugle questions, cap upgrade and LOMC compatibility.
« Reply #4 on: 5 Aug 2009, 01:24 pm »
I put sockets in the empty resistor slots to make cartridge loading changes easy.

After messing with the gain a couple of times, I soldered the resistors in for the lowest gain I would need. To increase gain, 'piggyback' parallel resistors are used. They are easy to swap out without risk of damage to the PC board.

An LM4562 or OPA2228 in U1 lowered the noise floor enough to make my LOMC cart enjoyable, but I still couldn't live with it and picked up an SUT. The Piccolo would be a better choice for a low output Grado because of the cartridge loading options.

In my Bugle, C2 and C5 are each bypassed with a 470pf polystyrene. This shifted the EQ slightly, got rid of that 'in your face' effect, and made everything sound more natural. The improvement may be system dependent. Then C1 and C4 were similarly bypassed (1800pf), with a much less dramatic result.

Regards,
Tom

jmpiwonka

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Re: bugle questions, cap upgrade and LOMC compatibility.
« Reply #5 on: 7 Aug 2009, 12:43 pm »
well after thinking about it. i'll probably just build a piccolo, should have a few months atleast before i get the grado back from soundsmith.

does hagerman sell the case for the piccolo too or am i on my own with that if i DYI the build?

would it be beneficial to replace any of the caps in the bugle with something nicer? which ones?

jmpiwonka

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Re: bugle questions, cap upgrade and LOMC compatibility.
« Reply #6 on: 9 Aug 2009, 06:57 pm »
well my PS isn't working right. kinda turned out to be a big pain in the butt.
went to radio shack to get "hook up wire" and got home. noticed it's some super tiny solid wire. kept breaking and voltage wold drop to the 115v taps on the PS board.

replaced all that wire with something better.
so i got proper voltage to the PS and i see 15v and -15v at the ps output, 30v at the LED without it hooked up to the bugle.
hook the wires up to the bugle and that voltage will drop at the -15v (about 4volts).
at the +15 it stays around 15v, end up with 15v at the LED too.
notice the heatsink on the negative side regulator will get warm quickly.

the bugle works fine if i hook it back up with the batteries...


jmpiwonka

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Re: bugle questions, cap upgrade and LOMC compatibility.
« Reply #7 on: 9 Aug 2009, 07:54 pm »
oh nevermind  :duh: i was hooking up the -15v to the positive to the bugle... :duh:

wired it up right and it's playing great now.
got so frustrated with that for a bit there. just had to step back and take a break and check everything over.

izerbi

Re: bugle questions, cap upgrade and LOMC compatibility.
« Reply #8 on: 10 Aug 2009, 09:41 am »
I use the bugle boosted to 60db to run an ortofon mc 15 super II and yes I?m very happy with the results, though, like I was expecting there is a small hum produced because of such high gain but this doesn?t gets in the way of the music whatsoever. Could have managed with 55db only but it?s a pain to change things around, the same with the opamps, got a couple of LM?s to try out but as the OPA?s are soldered on the pcb? just leave it, it?s great like it is.
I?ve used some modest orange drops and solen caps on the build, again I?m delighted with the sound coming from my LP?s. Praise the bugle and it?s creator!
One day I may build the cornet2 and the piccolo or maybe not, for me hifi it?s only a means to an end and not an end in itself.
Cheers

jmpiwonka

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Re: bugle questions, cap upgrade and LOMC compatibility.
« Reply #9 on: 10 Aug 2009, 12:33 pm »
i did replace most of the caps on the board and i do like the sound a bit better. the treble sounds better and the presentation isn't so forward. the caps weren't that much so i figured i'd give it a try. i even ran the bugle on batteries after the caps swap to listen for the differences. used jantzen crosscaps, two audiocaps, and two zcaps. the zcaps were so large that i put them on the under side of the board.

the PS gave the bugle more dynamics which is nice. i'm real happy with it.