Bugle with an active MC step up

guest3264 · « **on:** 21 Feb 2006, 08:04 pm »

Hi folks,
I am looking at an inexpensive solution for putting an MC step up between my new Denon DL103 and my stock Bugle.

Although I would like to use transformers - in order to save some pennies I am looking at some of the active plans posted by Marshall Leach

http://users.ece.gatech.edu/~mleach/headamp/

I was wondering if anyone had built any of these plans, what they might have found regarding selection of values for load resistors etc., and if the standard Bugle AC power supply might be adapted to drive both devices.

I am tempted to rebuild my Bugle with both MC and MM input jacks.

regards - SteveS in North Vancouver

PatOMalley · « **Reply #1 on:** 22 Feb 2006, 12:57 am »

you don't want to change resisters so the Bugle can boost up to 60dB?

that 60dB delivers 300mv which is should be ok for the dl-103.

guest3264 · « **Reply #2 on:** 22 Feb 2006, 03:38 pm »

Hey thanks for the reply.

I had planned to do that - but I was concerned that the boost may be only _just_ enough, and besides why tweak the bugle when I can build a whole new piece of hardware!

Since the cartridge is probably going to arrive well before I get my s**t together to build a step up device I'll report back on how it works with the 60db setting on the Bugle.

I've also looked at the DL103R which only has an output of 0.25mV versus the 0.3mV of the regular DL103. So I may need the extra 20dB boost of a step up in the long run anyway.

Steve

PatOMalley · « **Reply #3 on:** 4 Mar 2006, 03:31 pm »

if you use a sut you can set it for 1:20 to get a bit more db for the 103R. i am considering using the Lundhal LL9206 when I get the DL-103*. you will have less resistance though at around 200ohms. Most Denon DL-103 'heads' claim best results in the neighborhood of >100oms & <1000omhs so you are sill in there.

analog97 · « **Reply #4 on:** 4 Mar 2006, 08:10 pm »

Hi. I am using the Denon 103 with a Denon 1:10 sut (20db), the Cornet2 (44db) and recently added the Clarinet. IMHO, +60db total is all you need for the 103(R). I can shake the house down...who needs more? I still remain confused (despite JH's numerous writings) about how to achieve the "correct" cartridge loading. The instructions for this on the Bugle appear very straightforward, however. I have not changed any resistors from stock on the Cornet2. That means (I think) my Denon 103 is seeing 47K. It sounds pretty darn good. So, I gave up on this hunt. Also, I checked my Denon 103 manual and it says the loading should be ">10 ohms". Nothing else was specified. I think it's just up to you, your sytem and your ears.

hagtech · « **Reply #5 on:** 4 Mar 2006, 10:27 pm »

Your denon will see 470 ohms. The reflected impedance seen by the cart (at audio frequencies) is 47k divided by the turns ratio squared. Or 47,000 / 100 = 470. That works out pretty good for most MC carts. Some like it lower. Usually they are of the even lower output variety, so 26dB step-up gives a loading closer to 120 ohms.

jh

analog97 · « **Reply #6 on:** 5 Mar 2006, 03:20 am »

Great news about 470 ohms for the Denon. That's pretty darn close to 100. I stand corrected by the Doctor of Analog Circuitry (now that's what I call a good DAC)....