Monica2/Amp5

[tomcuk]

Hello all!

I am in the last stages of planning my audio system which i plan building myself (first year EE student). I have decided on a simple DAC --> tripath amp configuration however I have a few questions.

I intend to use the Monica 2 DAC from diyparadise.com with the Amp 5 from www.41hz.com (i like the minimum THD+N figures of both).Now here are my questions:

1) I have heard the output of the monica may be too small to effectively drive the tripath, would this be true for the proposed setup? If so does anyone have any recommendations on a suitable preamp, preferably with as low THD+N as a semi skilled DIYer can do?

2) I have heard alot of people recommending batteries/smps for DACS, I would be using my system as the audio side of my home theatre setup and it would be used for extended periods of time <12 hours, would a battery last this long and would the charge/discharge cycle kill the battery quickly? If so would running the DAC of a modular smtp (ie you plug in only the cables you need) be better?

Many thanks for your help,
Tom

[eVITAERC]

The first question depends on the sensitivity and impedence of your speakers. The Monica can drive the Amp5 with no problems, but the question is whether the voltage amplification of the Amp5 will be enough for your speakers. It'll be better if you quote us some numbers.

Remember the sensitivity is in dB/W @ 1m and the power flow into the speaker is P=I^2 R and I is determined from the impedence of the speaker roughly from Ohm's law. So remember your first year classes and you can even derive the maximum output loudness (in dB) yourself! The Monica outputs ~2Vpp and the Amp5 should have a voltage gain of 18x.

The Monica needs around 100ma. A typical 7amp-hour SLA battery can actually run it continuously for 3~4 days(!). Plus it also doesn't really need 12v, and a 9v battery works just as well (the on-board regulators converts them all to 5v anyways, so 9v is enough overhead). So if you don't want to fuss with a seperate SMPS you can try rechargeable 9v-12v batteries if you have them. Just remember to add a power cap ~2000uF in parallel before the DAC, as batteries have poor dynamical performance.


Cheers

[kyselym]

Hi

I also think of amp5 from 41Hz. Ok here are my numbers:

8ohm DIY speakers 2.5way closed(seas drivers)
amp AB DPA380
130W 8ohm 0.00... %THD
monoblock

do you thnink bride amp5 would satisfy me? my DPA380s are very big and hot! This could be really small and cold

sound of DPAs is best I've heared. Can somebody tell me what the difference will be?

[kyselym]

here is some link with some onfo on dpa380

http://www.djpaul.czechian.net/dpa380.php

[HiFiddle]

Or you could try these -

http://members.dodo.com.au/~gregball/guru_004.htm

designed by a fellow Aussie.

[The Saint]

Or these by another fellow Aussie


http://www.aussieamplifiers.com/nx150.htm

[kyselym]

Hi thanks for suggestions NX150 looks pretty good! but i would like to hear some opinions about sound and quality of NX150 and AMP5 compared to DPA380. can sb help me?

ps. DPA380 is the best of! from 1992(the reason you probably cant find any info) mine is lightly modified by author(Pavel Duked) still sound very well!

author of GB150D seems to me non-profesional and I have bad experiences with such people - not saying this is the case but wont try any more

pss. sensitivity of my speakers is moderate about 84db

[HiFiddle]

"author of GB150D seems to me non-profesional and I have bad experiences with such people - not saying this is the case but wont try any more"

You're joking - I was at Greg's lecture on "State of the Art Audio Engineering Techniques" to the Audio Section Of the I.R.E.E. back in 1976 or 7. The guy has been subjected to life threatening suffering in his career, has consulted to renowned audio companies in the US and Thailand and produced Golden Ear award winning designs. He just doesn't suffer put downs well.

His unique amplifier kits are set to become modern classics, setting the standard for others to aspire to. I doubt you could buy anything that comes close at three times the price.

I can't wait to finish mine after hearing one blow away a Krell.

A bargain. DIYA should have more respect for such an accomplished designer.

[kyselym]

Hi

well im sorry. didnt know. it was just a personal feeling gained by first look (havent much time to study more about them yet)

so now it seem s I have new item in my spot(and probably the wining) because that is the same kind of person as Pavel Dudek.

ps. I sayed this doesnt have to be the case