Viola Forte Mono Powers.

[rnsa2000]

Hello,

recently I acquired the Viola Forte mono powers, although his "little" power, these mono powers are phenomenal.

I would like to exchange information with other owners of these beautiful amplifiers.


Nice regards,
Ricardo Nonato.

 

[LL21]

Hello,

recently I acquired the Viola Forte mono powers, although his "little" power, these mono powers are phenomenal.

I would like to exchange information with other owners of these beautiful amplifiers.


Nice regards,
Ricardo Nonato.

Congratulations. Viola is great equipment. I have not been able to find it to hear for myself, but i have spoken with a few people who find their sound among the best. Hopefully Gary Koh, a member here, can join this thread. He is very knowledgable about Viola as he uses them sometimes with Genesis, his speaker company, at trade shows.

 

[rnsa2000]

Hi Iloydelee21,

thank you for the message.

Before buying these powers I had heard many times in the system of a friend, he used AR CD7, AR LS27 and SF Amati Anniversary. This combination was fantastic.


Nice regards,
Ricardo Nonato.

 

[LL21]

Hi Iloydelee21,

thank you for the message.

Before buying these powers I had heard many times in the system of a friend, he used AR CD7, AR LS27 and SF Amati Anniversary. This combination was fantastic.


Nice regards,
Ricardo Nonato.

i could believe it.

 

[flez007]

I heard those amps some years back at RMAF or CES (not sure) with Ocean View speakers (modded RCAs), the BOS for me! Congratulations!

 

[rnsa2000]

What most strikes me these powers it is refinement. The combination with SF and AR, in my opinion, is very good.

In the next week I'll be doing a AxB between AR CD8, the MCD1100 and Esoteric X-03 SE.

 

[wizard]

View attachment 9001

View attachment 9002
Some pics

 

[wizard]

View attachment 9003
Inside

 

[rnsa2000]

WOW!!!!!!! Excellent picturess!!!

Thank you!

 

[opus111]

It looked to me at first glance of the pics that they're using two toroidal transformers. But a read of their web page indicates one of those toroids may well be a choke. Seems they're using a valve-style choke-input PSU to get a very low noise supply. Excellent idea

 

[mep]

Are these Class D ice boxes?

 

[garylkoh]

No, they are not Class D. Mark, I need to send you one of my amps to try out - not all Class D amps are "ice boxes".

The hallmark of the Viola design is the choke-filtered power supplies. In some instances, the choke is the same size as the power transformer. In some cases, the choke is larger than the power transformer. I recall Viola telling me that the choke in the Bravo power supply weighed almost 20kg.

I should get the Viola Bravo back on Wed. It will be interesting to compare it to the Burmester 909 - although I think that Jeff Dorgay might have already done that for Tone Audio.

 

[LL21]

No, they are not Class D. Mark, I need to send you one of my amps to try out - not all Class D amps are "ice boxes".

The hallmark of the Viola design is the choke-filtered power supplies. In some instances, the choke is the same size as the power transformer. In some cases, the choke is larger than the power transformer. I recall Viola telling me that the choke in the Bravo power supply weighed almost 20kg.

I should get the Viola Bravo back on Wed. It will be interesting to compare it to the Burmester 909 - although I think that Jeff Dorgay might have already done that for Tone Audio.

Thanks, Gary...i saw someone else post that earlier today....what exactly does such a gigantic choke do? I understand that choke filters can keep out unwanted noise from entering the rest of the signal path. Is that really what this 'choke' is doing? Thanks for a non-technical/dummie explanation.

 

[wizard]

View attachment 9014

Bravo inside - this is a powerhouse - it can deliver 635/1160 watt pp in 8/4 ohms.
The transformers are 2 KVA each.

 

[garylkoh]

Thanks, Gary...i saw someone else post that earlier today....what exactly does such a gigantic choke do? I understand that choke filters can keep out unwanted noise from entering the rest of the signal path. Is that really what this 'choke' is doing? Thanks for a non-technical/dummie explanation.

Lloyd, it's going to be really tough to keep it to a non-technical explanation........ chokes (why oh why is it called a choke??) store energy just like capacitors store energy. In the old days of tube amps, because large capacitors at very high voltages are not available, chokes were used.

However, you can't just use the largest choke you can afford. There is a minimum current needed for a choke to work properly. There is also a maximum current that a choke can supply. In a power supply like Viola's designer Paul Jayson has done, there is a fine balance between the size of the choke, and the size of the capacitor bank. The math is quite a bit more difficult for a choke-filtered power supply. You could go into oscillation and have exploding capacitors if you're wrong. Hence, it's far easier to use brute-force capacitor power supplies. Just insert as many capacitors in parallel as you can afford.

 

[garylkoh]

Bravo inside - this is a powerhouse - it can deliver 635/1160 watt pp in 8/4 ohms.
The transformers are 2 KVA each.

A powerhouse, but not that big.....

In stereo mode, 350W into 8 ohms, 700W into 4 ohms, 1400W into 2 ohms. Running into 2 ohms, the Bravo draws 25A at 120V from the wall.

A Bravo also allows mono operation in bridged or half-bridged (parallel) mode. Bridged, it delivers 1200W into 8 ohms and 1600W into 4 ohms. Parallel, it delivers 400W into 8 ohms and 1000W into 4 ohms.

All power ratings given at <0.1% THD and <0.075% IMD.

 

[wizard]

A powerhouse, but not that big.....

In stereo mode, 350W into 8 ohms, 700W into 4 ohms, 1400W into 2 ohms. Running into 2 ohms, the Bravo draws 25A at 120V from the wall.

A Bravo also allows mono operation in bridged or half-bridged (parallel) mode. Bridged, it delivers 1200W into 8 ohms and 1600W into 4 ohms. Parallel, it delivers 400W into 8 ohms and 1000W into 4 ohms.

All power ratings given at <0.1% THD and <0.075% IMD.

Measurements from an Italian magazine:

Correct peak to peak power output should be 460/880/1300 watt in 8/4/2 ohms,
and 400/710/1150 watt continuous.

Output current - 44A
Output voltage cont. in 8/4/2 ohms - 55/52/48V
Freq. Response - 10-50k -2dB, 10-100k -5dB.
Damping factor in 8 ohm 10 kHz - 465
Slew rate - up 30V, down 40V
S/N - 126 dB Aw

 

[rnsa2000]

It looked to me at first glance of the pics that they're using two toroidal transformers. But a read of their web page indicates one of those toroids may well be a choke. Seems they're using a valve-style choke-input PSU to get a very low noise supply. Excellent idea

Exactly!!!

 

[LL21]

Lloyd, it's going to be really tough to keep it to a non-technical explanation........ chokes (why oh why is it called a choke??) store energy just like capacitors store energy. In the old days of tube amps, because large capacitors at very high voltages are not available, chokes were used.

However, you can't just use the largest choke you can afford. There is a minimum current needed for a choke to work properly. There is also a maximum current that a choke can supply. In a power supply like Viola's designer Paul Jayson has done, there is a fine balance between the size of the choke, and the size of the capacitor bank. The math is quite a bit more difficult for a choke-filtered power supply. You could go into oscillation and have exploding capacitors if you're wrong. Hence, it's far easier to use brute-force capacitor power supplies. Just insert as many capacitors in parallel as you can afford.

IOW, leave it to the experts!...thanks, Gary!

 

[rnsa2000]

Hi garylkoh,

thank you for the explanations about the functioning of Viola.

I've done several internet searches on Viola and don't usually find much, so I created this little space.

Thank you also to all who are participating in the topic!!!


Nice regards for all,
Ricardo Nonato.