Originally Posted by ThinkCenter
RishiGuru, great review of Z-2300. Hands down, the best I have read so far. I wanted to post in your "Logitech Z-2300 : Mega Review" thread, but it was locked thanks to some loonies making some wild comments. But the problem is, the review is kinda heavy on material, and one needs to be technically sound to understand it to the full. You should have posted it in technology forums.
When some body said that you wasted time in analyzing & writing a review on Z-2300 since they are cheap, I got a good measure of their, as you say --> "intellect". Actually they did not understand what you wrote. They just read the intro & conclusion.
I am an engineer like you and I do understand how much effort it takes to analyse each components and how they were used. Your analysis of power amps was spot on.
From what I knew, you get x4 power of a single amp in bridged mode. Does the TDA7295 allows impedance less than 8 in bridged mode? Also I am astounded that Z-2300 uses a toroid instead of a EI to power the amp module. They ripples seems quite beefy. CapXon are quite okay for me but you could have upgraded to Nippon. 150.9VA? That is quite a strange value.
It seems the control pod is quite important. Do you have the schematic of how the pins of D-sub are used? I have heard the Z-2300 and they are quite good. Actually at $110 they are awesome.
Hope you contribute more.
Thanks for appreciating my review: Logitech Z-2300 : Mega Review
Yes, I quite amazed by the quality hardware Z-2300 uses for its mere $110 price. Logitech must have been selling them at ultra thin profit margins since the competition have reached a new level among this 2.1 PC speakers. All these companies have to downgrade their product line.
The highly downgraded version of Klipsch Promedia is the latest example. They have to downgrade in order to reduce the price & garner higher sales. Logitech did the same with Z-623. Currently Z-2300 garner maximum sale figures followed by Altec Lansing MX-6021 in the premium PC speakers segment. Now the Promedia are all of a sudden available at $110 so the picture is going to change again.
x4 power is a myth. Basically it's all about speaker impedance and supply voltages, it gives you higher power in to a higher impedance speaker from a lower supply voltage.
There's no 'magic' involved - each amplifier is simply providing the same power in to the same impedance as before.
For an example - a standard car amp, running off 12V
Stereo - 2x4W in to 4 ohms (total 8W to two speakers
Bridged - 1x8W in to 8 ohms (total 8W in to one speaker)
Stereo - 2x8W in to 2 ohms (total 16W to two speakers
Bridged - 1x16W in to 4 ohms (total 16W in to one speaker)
So this is where the 'myth' comes from the bridged amplifier will provide 16W in to one 4 ohm speaker, but one amp will only supply 4W to the same single 4 ohm speaker (so it is 4 times the power, and how most car stereos work).
The 'snag' with that is because the amplifiers have to be capable of driving 2 ohms, and if you had a 2 ohm speaker on one amp, it would deliver 8W - exactly half of what a bridged amplifier feeding 4 ohms would. And the two amps feeding two 2 ohm speakers would give the same 16W.
If you paralleled the two amps, and fed a 1 ohm speaker, you would get the exact same 16W as bridging them with a 4 ohm speaker - like I said, it's to do with speaker impedance more than anything else.
TDA7295 does not allow less than 8 ohms in bridged mode. You can go higher say 16 ohms.
Regarding those ripple filters they are actually quite sufficient at 10,000uF, 35V used with the 150.9 VA manufacture specific toroid. Truly speaking I was astounded to find that there can be toroids at $110 sets. Z-2300 power supply is very robust which is the reason why it can pump so much power through the speakers. Never thought of upgrading the caps though.
Yeah I do have the schematic of the Control pod & how the pins of the D-sub plug are used.
The truth is Z-2300 have a very potent amp & the use of low quality drivers blunts its performance to a certain level. Use of better quality drivers would have definitely created a much superior sounding set & much better sound stage but at the cost of increased price.
Still at $110 the Z-2300 is a formidable performer.Edited by RishiGuru - 1/26/11 at 6:52am