[canzld]

I've been using a Bugle for about a year now (kicks all previous phono stages i have used by a mile  ) with the standard 9V supply, however at the urging of my brother who also runs a Bugle (actually I stole his first one) I have recently tried running it at 12V. While I find that many things improve quite noticeably at 12V - i.e. staging size and depth and imaging, all good audiophile stuff, there is a distinct shift in frequency range, with 12V. High frequencies become more prominent, with a clear loss of low end information compared to 9V supply. This is most noticeable listening to an instrument such as the cello which completely loses the bottom end on 12V versus 9. I also noticed this while visiting my brother and listening to music through his bugle (at 12V) - although his gear -outside the bugle - is completely different from mine. I found only one previous post here making a similar comment, but I was wondering whether it might be a more general observation as i couldn't see how anyone could fail to notice the change I hear. I like the good stuff the 12V does but I want my 9V bass back (although I am fed up with changing batteries all the time). Welcome all comments - explanations?

[poty]

What type of power supply do you have? Maybe it is the property of the device (I mean power supply)?

[canzld]

alkaline battery in both cases, while my brother was using 12v sla

[poty]

Your observations puzzled me a lot. I tried to model different cases with help of my test PCB and found, that noticeable loses in the bass part for opamps could be the result of some disbalanses in the opamps halves, which in turn can be the result of different voltages of each half of power supply or some external DC on inputs. The more the power voltages - the more the impact of the disbalances. So (I think) your Bugle even at 9V doesn't show all its ability.
I don't know where you can pick the DC from a cartridge (but you always can try to use a capacitor on the input - just to check), so I think it is some problem with batteries connection or batteries themselfes.

[hagtech]

Others have found similar sonic improvements by increasing the supply voltages. 

jh

[poty]

The question was about problem, not improvemets.

[hagtech]

Oops, I misread the post.

jh

[jusbe]

Well at least  you didn't do what I just did this afternoon - blew it up! 

I love the Bugle and have swapped in new opamps to great effect. I assembled an inexpensive battery upgrade (10 x AA per side for 15V) and, in my haste to listen, completely forgot to upgrade the C7 16V/220uF capacitors. Pop! 

[poty]

... I assembled an inexpensive battery upgrade (10 x AA per side for 15V) and, in my haste to listen, completely forgot to upgrade the C7 16V/220uF capacitors. Pop! 

Very strange... I believe you mixed up polarity.

[Aerobat]

I just built a bugle and am currently running it with 2 9v batteries per channel in series.  I think it's a substantial improvement over running at 9v.  9v batteries drop to 8 - 8.5 volts pretty quickly, and that's just not enough - I've been told that 15v is pretty much a minimum to run a phono pre.

After a couple hours of operation, the dual 9v batts are showing 16.7v.

Mark