Prima luna Prologue 4 or 5

[Colin2040]

I am thinking of purchasing a valve power amp ,I am missing my valves!, what I am looking at is a 4 or 5 Prima Luna . The question I have is does anyone have any experience of them. Both seem to have the facility to use different valves so I am not sure if there is any particular benefit over the other? Thoughts please.

Colin

[JohnJo]

The 5 has higher quality components. Diodes and capacitors AFAIK.

[hifi_dave]

I stock Prima Luna so I am familiar with the products but the 4 and 5 are old models, aren't they ?

[Colin2040]

Yes they are not current models

[Haselsh1]

I know that the current models can use different valves by just flicking a switch on the right side of the amp to set the bias. I use EL34's in mine by JJ which are way superior to the stock valves but KT88's are also supposed to be excellent.

[Colin2040]

Thanks John ,I am not too fused about that as I will probably consider upgrading as well so it does give me some useful info

[Colin2040]

As far as I am aware the 4 and 5 use auto bias so can accomodate different valves.

[Haselsh1]

Yeah, they all use auto bias but there is a switch at the front on the right of the unit for valves such as KT88/KT120 & KT150. I know that this applies to the Dialogue Premium as that is the one I use.

[Colin2040]

Thanks Shaun I thought that was the power switch. Can I ask if you have had it long?

[JohnJo]

Although both amps can use a variety of output valves the 4 was designed to run EL34s and the autobias has a slightly lower set point than the 5 which was designed to run KT88s.
The set point can be adjusted via a small trim pot on the auto bias board.
If you have the relevant knowledge of the dangers involved, remove the base plate, turn the amp on its side, and make adjustments. Make sure the amp is plugged into a 30mA RCD, in the event of a balls up this could save your life.
Here's a link to the instructions. I took my 5 up slightly when running KT120s.
https://www.primaluna-usa.com/tube-rolling-legacy/