Single Ended vs Push Pull tube amplifiers

[heliumflight]

Hari Iyer Sir,

What is the cost of DARED VP-300B SET MONO-BLOCKS?

Thanks
helium

 

[viren bakhshi]

If only it were so simple and straightforward! Take one or two measured parameters, design around them, and viola, you have a perfect audio component. We should all be flooded with perfect audio, if that were the case.

This topic has been explored in great detail on the internet. To get something relevant, read up on what actual designers really say. It's systems that count, because no component acts alone.

Best of all, go listen to systems with the two amplifier topologies. You'll hear differences right away. It's for you to decide which one you prefer.

Regards,
Viren

 

[Hari Iyer]

Hari Iyer Sir,

What is the cost of DARED VP-300B SET MONO-BLOCKS?

Thanks
helium

PM sent. Please check.

 

[Hari Iyer]

I will strongly recommend to check any tube amp with the speakers you are going t0o play with else you will be disappointed (which happened with me initially). I had to do some research and modify my entire speaker design to make them sound great now. I am now extremely happy with the current setup.

My experience again says that speakers meant for SS amp may not sound too good with the tubes if they are not meant for it. Both type of amps work very differently to drive the speakers.

 

[gobble]

Thats interesting. What did you have to change about the speaker design to work better with tubes?
G0bble

 

[GeorgeO]

Barring the drivers, I'm guessing everything else!

 

[Hari Iyer]

Thats interesting. What did you have to change about the speaker design to work better with tubes?
G0bble

FM Kapvin had a pair of unused Tangband mid-woofer and Vifa tweeters and suggested to use them instead of Peerless Kevlar and Aluminium tweeter. Since the driver parameters were similar the box did not have any major modification other than damping coefficient.

The entire cross-over had to be rebuilt . Earlier Peerless drivers had a min impedance of around 3.2 ohms which were quite low for a tube amp. Also the impedance phase change were abrupt at the low end which could have been a difficult load for the amp.

Moving to Tangband did not any of the above issues with a very smooth impedance phase. I have raised the impedance of the speaker system from around 1.2KHz to around 6KHz to tame the mid-range a bit. The impedance is quite constant from around 300Hz till 1.2KHz (5.9 Ohms), rises linearly by around 1.5ohms from 1.2KHz till about 6KHz and then again is constant from 6KHz to around 15KHz(7 Ohms) after which it gradually fall to around 6.7 ohms from 15KHz to 20KHz.

The above profile gives a very smooth transition from low to mid to highs without any associated harshness in any frequency and is very mellow to listen to with minimum hearing fatigue for long listening hours. Also the detail is preserved quite well with a constant energy response at high frequencies.

Will post the simulated response later.

 

[Hari Iyer]

Barring the drivers, I'm guessing everything else!

Yes everything including the drivers and the box damping. Will post images maybe today.

 

[gobble]

Hello
While we are on this topic of speaker load and tube amps I would like to pop a quick question I am curious about conceptually.

If we take two hypothetical speakers with exactly the same impedance and frequency curve and Xmax etc, but one speaker is a 15" driver and the other is a 5" (i.e within the range of low frequency limits of physics for a 5" drivers frequency response) would both the 5 and 15 inch driver present the same load to an amp? For example for a frequency range of 80hz to 20khz which both drivers can play - if an amp were to drive such a signal to either speaker and the impedance curve is exactly matched - would it see a replica of the exact same load between the two speakers?

G0bble

 

[Hari Iyer]

The impedance of the driver should be considered with the speaker inside the box which will be different than the free-air impedance. In case of a 15" woofer i preassume that the resonating freq could be in the range of 30Hz to 40Hz, but in the case of a 5" driver it could be a little higher in the range of 45Hz to 70Hz.

Assuming everything to be same including the Vas (which cannot be for a 15" & 5" driver), Qtc, Qes, Qms, Mms (again would be different) ,Fs etc. etc. then the calculation of the box would not be same due to different Xmax and Sd.
If they are same then the electrical load to the amp will be similar for a 15" and 5" driver is my guess. (I have assumed that the voice coil resistance and inductance is same). Only actual simulation can justify the claim though.