Gemstone blue diamond??? - Page 2

Just to be clear (because i am not 100% sure myself), differential means that its internally bridges. So the balanced incoming signal the pos and neg are amped and send in that way to the speakers correct ? So any amp that you can bridge can be differentially used. How well that works depends on the amp's in question since the effect is 1/2 the load (that has effect on snr) and possibly 4x the power coming out.

If fully balanced means, bridged amps (please explain to me if it isn't the same) than yes you will loose any external effects on the signal but you gain possible nasty's as a effect of having them bridged.

Daniel.

PS: i use my 10 channel amp bridged.

The Gemstone amp is a great amp. I like it much better than the Mc 7106. I owned 3 MC-7106's and in bridged mode. The Gemstone is my favorite multichannel amp I have owned. It sounds more powerful than the other 300 watt per channel amps(8 ohm) I have owned. I don't know why, it just does.

I have owned too many amps.

It was a great amp. Sounded much more powerful than my Outlaw and Emotiva amps. If I didn't need the money, I definitely would have kept mine.

I would have bought it from you. That Gemstone was great!!

If you want natural sound, fully differential amp is the last thing you want. It may have lower noise floor but also has low even order harmonics.

OK, the distortion is so low and much lower than any speaker so you will never hear it unless you over drive it.

No problem, I have owned Cinepro, Cinenova, Odyssey, Monarchy, Ada, Krell, McIntosh, Adcom, B&K, Parasound, Sherbourn, Gemstone, Behringer, Samson, Ashly, Crown, etc....

Are you saying you'll only hear the fundamental with this amp unless you over drive it?

I am saying you won't hear any distortion because the speakers will be much higher. Basically if you push an amp at say 200 watts with .01% distortion the speakers will be .1-1% or more. The sound of the speaker will dominate.

Any idea why it sounded better than the other amps ?, Maybe because it was bridged but was using 1 powersupply ?. Seems because of the 1 powersupply when using in stereo the 4 amps in use could use all of the 1.55kva and 129.000uF to reach silly levels for short times ?

Daniel.

I liked it better because for some reason it sound the most clear(meaning all the sounds were easily heard) and dynamic with the speakers I was using at the time(M&K S-5000's). I love my Ashly amps right now as they were built for my speakers and my speakers are a huge upgrade over the M&K's.

No, a differential configuration and a bridged configuration are not exactly the same. Bridged or not, your POA is not a differential amp. Interestingly, though, your AVP is dual differential at the DAC stage.

Because of the numerous disadvantages, I would not recommend bridging unless absolutely necessary. You are much better off getting an amp that meets your power output needs unbridged. See the other thread:

http://www.avsforum.com/avs-vb/showt...php?p=19467765

AJ

The Blue Diamond is not a bridged amp. See above...

AJ

You also won't hear distortion from other average priced amps unless driven to extreme if speaker distortion is not a factor. Even order harmonics and odd order harmonics have more to do with the sound characteristics and fully differential amp is not a good choice for hi-fi sound.

How was the B&K compared to the others? I have the 200.7 and was considering maybe getting something else like a Rotel.

I never said you will hear distortion from other amps. I talking about distortion with all amps within their range. How can odd or even harmonics make an amp sound different when they will be to low to hear?

Hi Fi sound is a matter of preference. I would prefer accurate sound rather than Hi Fi.

I have owned a Gemstone Blue Diamond 7 channel for around 4 years, and for the past 2 years it has been driving giant GR Research Focus LS9 speakers. It has been powered up 24/7 except when a storm approaches, and has never missed a beat.

I'll part with it over my dead body.

I will read that link again (but i think i already did) but please explain to me how its not differential. Both the pos and neg are amped (180degree) by themselves and only 'meet up' at the speaker. If this is not differential what is ?

http://www.audioholics.com/reviews/p...iew_fullscreen

Daniel.

PS: ill google some on this topic myself who knows maybe ill get it by myself

PS2: well i guess i am not the only one who is confused about the terms, ill move to the other thread and stop being offtopic in this one :

http://www.profusionplc.com/images/a...notes/an12.pdf

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Bridged (Differential Amplifiers)
The primary difference between single-ended output amplifiers and bridged (or differential) output amplifiers is that the negative terminal of the bridged-output amplifier is active, supplying a voltage equal in amplitude and opposite in phase to the positive terminal. This effectively doubles the available voltage to the speaker load, quadrupling the output power capability (P=E2/R). However, since the negative terminal is active just as the positive terminal is active, the negative terminal must never be connected to ground, to chassis, or to any other amplifier terminal, at any time. Figure 2 shows a typical configuration for one channel of a bridged-output amplifier. Note that connection of the negative terminal to another negative terminal or to ground or even to chassis would short out the V2 voltage source, causing a very high current condition. Under such conditions, an amplifier without over-current protection would likely be damaged. As mentioned above, such a connection should never be made.
-------

From that diagram, the POA does appear to utilize a differential topology. However, Denon makes no apparent mention of that in its specs.

AJ

ehmm well they call it the only fully balanced setup from input to output (source, processor and amp(s)). And they provide you a way to join 2 amps to get 10 fully bridged paths. So bridged and differential are the same ?

Daniel.

No, again, bridged & differential are not exactly the same. The POA is apparently differential and can be optionally bridged. Each POA channel is inherently differential. If two POA channels are bridged together, then the resulting channel is both differential & bridged.

AJ

I have had a gemstone for 3 years now. I have upgraded all my equipment several times ( i have a sickness ) The gemstone is the one thing i will never upgrade. I have an onkyo 5007 receiver. It sounds great without the gemstone. When i add the gemstone it takes it to a whole new level. My wife can even tell the difference. When i bought mine i bought a "scratch and dent " model and it was about 2k. I cant find the scratches or dents though.

It's seems that you are misunderstanding terminology of acoustics. Try Google search on harmonics.


You also seem to not understand the term high fidelity (hi-fi). I suggest you look it up in the dictionary.

Nevermind, you missed the point. Please add something to this thread rather than telling people that the Gemstone won't sound natural. If you think so(without ever hearing it) you need to state what you think is natural and give a recommendation in it's place. The OP is clearly looking for a multichannel amp and specifically asking about the Gemstone. Have you ever owned one?

I've already explained what and why. You are the one who's missing the point. You still haven't understood those terms, obviously. Until you do, all this will be foreign language to you. I would suggest you read and understand those terms for your own benefit.


I've listened to and have studied the measurements of single ended, push pull and fully balanced amps. What about you?

Other than the noise floor, I cannot hear the difference with a differentially balanced circuit versus single ended. Meaning, I hear a difference with no signal (with your ear to the speaker). With a signal, it's a tie (to MY ears anyways).

The subjective differences comes into play because of lack (or enhancement) of filtration as well as bandwidth. Those are the two big players. The other subjective difference is the ability to quickly deliver the current. I'm taking about in the 1/4 watt to 2 watt range. So ignore damping factor, peak current specs etc. IMHO, those specs are positively meaningless. More than enough is merely buying testosterone.

The layout, components used, coupling methodology, feedback, etc will deliver it's "signature". The Gemstone design went out of it's way to use a very low filtration approach as well as using a 300KHZ bandwidth. Bandwidth is KEY. It's why a 40KHZ B&O Ice sounds "tube-like" and 120KHZ NuForce sounds more "solid state". So why does the NuForce cost more?? ONE reason is bandwidth will knock down efficiency increase the cost (heat sinks, power loss needing a bigger supply etc). Note that the bandwidth of tube great is around 40KHZ. So it's signature is high filtration and low bandwidth.

Subjectively, limited bandwidth sounds thicker in the midbase even though the FR is positively linear. Ask any tweaky designer at Nuforce, Krell, B&O, Sim, Class'e etc. You will get this exact answer. This is subjective and audible. Hence Krell CAST is a 600KHZ bandwidth. No. You cannot hear more than 20KHZ but the signature is changed inside of the audible spectrum. Every bit of the information is there on a 40KHZ amp versus a 600KHZ amp. The difference is the effort needed to hear it and subjectively that sounds like "treble". It's why Krell amps are called "bright". The real difference is the Krell is more closely delivering what is on the disk. Great recordings sound better than ever while poor grainy recordings sound worse. I diverge...

The Gemstone has $1440 on the BOM (bill of material). Needless to say, it would sound different if I spent $400 on the BOM like a popular Chinese built model. That's not to say spending more ==better. That Chinese model is an incredible deal. But all things being equal, there is a correlation.

I'm sure there is a correlation subjectively. When things are subjectively viewed, sky is the limit.