[Shpongle_Dongle]

Quote:

Originally Posted by daggerlee /img/forum/go_quote.gif Have been rolling opamps - so far I have to say my favorite is the LM4562, it has the nice roundedness of the OPA627 sound, but sounds as 'fast' as the AD8620. Although truth be told, at least to these ears the differences are minimal, and I'd be happy with any of the three - OPA627, AD8620, or LM4562.

LM4562 is a superb sounding opamp. A good friend of mine (with golden ears) is auditioning a CanAmp at the moment and will be rolling his LM4562, OPA627 and AD-823 in over the next few days, I'll try to get him over here with his impressions. My own impressions were AD-823 sounded the most organic and natural, the AD8620 slightly rounded and bass shy NE5532 full, bloomy but musical OPA627 chocolaty, rose tinted inoffensive LM4562 slightly more presence to the sound, extremely musical (toe tapping) but slightly less bass extension. Other opamps worth trying here have to be OPA2107, OPA2111 (nice) OPA2132P, OPA2134P, OPA2604 etc etc Too many to list and, as daggerlee says the differences will be "minimal" and not night and day. There's not a lot you can do externally (outwith the confines of the op amp) apart from trying different capacitor types / values (I think someone already mentioned that replacing the 4700uF power caps with 10,000uF made an audible improvement.... yes, it will) Diodes seem to have been covered too, ultrafast much better than the standard 1N4002 types that are fitted. Nobody seems to have mentioned the fact that the PSU section is "unregulated" I'd lose that onboard 9V encapsulated transformer and feed the CanAmp with a good quality regulated / linear offboard dedicated PSU... we are getting into two box territory here (PSU / Amp) but must sound better with a regulated PSU instead of 9V straight from a 110AC to 9DC encapsulated transformer. Maybe not, maybe there's method in Heed's madness and Raw DC power is the reason this guy sounds so good... the jury is out, I'll see what she sounds like with a dedicated "regulated" PSU and report back.

Great thread by the way.

 

[daggerlee]

Quote:

Originally Posted by Shpongle_Dongle /img/forum/go_quote.gif LM4562 is a superb sounding opamp. A good friend of mine (with golden ears) is auditioning a CanAmp at the moment and will be rolling his LM4562, OPA627 and AD-823 in over the next few days, I'll try to get him over here with his impressions. My own impressions were AD-823 sounded the most organic and natural, the AD8620 slightly rounded and bass shy NE5532 full, bloomy but musical OPA627 chocolaty, rose tinted inoffensive LM4562 slightly more presence to the sound, extremely musical (toe tapping) but slightly less bass extension. Other opamps worth trying here have to be OPA2107, OPA2111 (nice) OPA2132P, OPA2134P, OPA2604 etc etc Too many to list and, as daggerlee says the differences will be "minimal" and not night and day. There's not a lot you can do externally (outwith the confines of the op amp) apart from trying different capacitor types / values (I think someone already mentioned that replacing the 4700uF power caps with 10,000uF made an audible improvement.... yes, it will) Diodes seem to have been covered too, ultrafast much better than the standard 1N4002 types that are fitted. Nobody seems to have mentioned the fact that the PSU section is "unregulated" I'd lose that onboard 9V encapsulated transformer and feed the CanAmp with a good quality regulated / linear offboard dedicated PSU... we are getting into two box territory here (PSU / Amp) but must sound better with a regulated PSU instead of 9V straight from a 110AC to 9DC encapsulated transformer. Maybe not, maybe there's method in Heed's madness and Raw DC power is the reason this guy sounds so good... the jury is out, I'll see what she sounds like with a dedicated "regulated" PSU and report back. Great thread by the way.

Hmm maybe I'll give the AD823 another try over the next few days. It was the one opamp which I didn't like too much but maybe my opinion will change. I have heard that great gains can be gotten by swapping out the power resistors (the two ones inside the heatsinks) with some nice big ones (the one I saw used NOS sprague koolohms, 100 ohm 10W) which is supposed to improve dynamics. Let us know how you make out with the rest of your mods

 

[leener]

Rav , DexDexter, thanks a lot for help.
So, if I want to use just one EQ with two sources (a better CDP1 and HIFI 5,1 Stereo / CDP2) + CanAmp , here is what I can do, right?


I. CDP1 > EQ >Amplifier / CDP2 > Tape Out > CanAmp


...............CanAmp........................
..................^............................
II. CDP1 > EQ <=>Amplifier / CDP2

It is nice that there is always someone who is willing to help,
Thnx again, leener

 

[Dexdexter]

Quote:

Originally Posted by leener /img/forum/go_quote.gif Rav , DexDexter, thanks a lot for help. So, if I want to use just one EQ with two sources (a better CDP1 and HIFI 5,1 Stereo / CDP2) + CanAmp , here is what I can do, right? I. CDP1 > EQ >Amplifier / CDP2 > Tape Out > CanAmp ...............CanAmp........................ ..................^............................ II. CDP1 > EQ <=>Amplifier / CDP2 It is nice that there is always someone who is willing to help, Thnx again, leener

Yes, I believe that either configuration would be possible.

 

[Chops]

Quote:

Originally Posted by Shpongle_Dongle /img/forum/go_quote.gif To prevent roll off you'd need at least a 220uF value in series with the output with nearer to 1000uF being preferable as a catchall for all 'phones from 32R to 600R a simple calculator where you enter the impedance as that of your headphones (ie: Grado would be 32 ohm in the resistor field) http://www.muzique.com/schem/filter.htm So film caps are pretty much no go as output caps due to the sheer size of them, a 220uF film cap would be the size of a house, non polar electrolytics are best in this application IMO.

This is what I did in my 708B amp. I pulled out the old cheap 150uF - 200V ecaps and replaced them with much better (and much much larger) Mundorf M-Lytic 200uF - 450V caps.

 

[Mikesul]

Does all this talk of moding the Canamp mean I will be unhappy with it if I ever get one?

 

[carlosgp]

I sincerely doubt it

 

[daggerlee]

Quote:

Originally Posted by Mikesul /img/forum/go_quote.gif Does all this talk of moding the Canamp mean I will be unhappy with it if I ever get one?

No, the stock unmodded Canamp probably sounds 90-95% as good as the modded versions..

 

[Shpongle_Dongle]

As the man said

the law of diminishing returns kicks in at anything over $100 and throwing $300,000 at it will not bring about $300,000 worth of difference. To those with golden ears like that Pink Flute guy these mods may bring about an improvement (and a seemingly very low price) but to us mere mortals I bet you couldn't hear the difference between the standard HEED and a gold plated fully Pink fluted Heed if you were blindfolded and strapped to a chair. I may be wrong but my experiments with the canamp have only reaped a perceptible 7% improvement, cost me about $40.... I think it would be hard to get 100%, 9% tops. Some may say that +1% is worth striving for at ANY cost...... whatever rocks your boat.

Edit 4% may be a more workable percentage.... 11.71% max tho.

 

[brianth]

I have a Heed on order, but haven't heard a ship date yet. My question, once it arrives, is whether most owners leave the unit powered on all the time, and whether you've noticed any difference in sound from leaving it on vs. frequent on/off cycles.
Thanks.

 

[Dexdexter]

Quote:

Originally Posted by brianth /img/forum/go_quote.gif I have a Heed on order, but haven't heard a ship date yet. My question, once it arrives, is whether most owners leave the unit powered on all the time, and whether you've noticed any difference in sound from leaving it on vs. frequent on/off cycles. Thanks.

I'm expecting mine sometime this week. But since it outputs in Class A, my instinct would be to switch it on maybe 30 minutes before a listening session and then switch it off afterwards.

But I'd be interested in hearing from other CanAmp owners about this as well.

 

[RasmusseN]

I want the Heed CanAmp

I just need to save the money can't spend all my money as I need to save for a car and insurance.

 

[daggerlee]

Quote:

Originally Posted by Dexdexter /img/forum/go_quote.gif I'm expecting mine sometime this week. But since it outputs in Class A, my instinct would be to switch it on maybe 30 minutes before a listening session and then switch it off afterwards. But I'd be interested in hearing from other CanAmp owners about this as well.

I leave mine on 24/7, since it is solid state after all and doesn't have any high risk failure parts...

But it does get pretty hot, which can shorten component life, so perhaps I should turn it off at night then?

 

[hansel_ng]

why do you guys want to kill the environment by doing stupid things such as this? let it run in for 15-30 minutes before you want to have a serious listen and that's enough!

 

[daggerlee]

Quote:

Originally Posted by hansel_ng /img/forum/go_quote.gif why do you guys want to kill the environment by doing stupid things such as this? let it run in for 15-30 minutes before you want to have a serious listen and that's enough!

Are you saying it's stupid to leave it on 24/7 because it uses too much power? Well first of all being a SS amp I doubt it uses THAT much power - I would be very surprised if it uses more than 15W of energy. You waste far more energy leaving a TV plugged in (not on, off) or leaving your computer on.