The Croft Epoch - A Tale of developing a MoFo of a pre amp..........

[Vinyl turner]

Thanks Jim,

Your wise words are always much appreciated

[Firebottle]

Hi Mark, there are a few common upgrades that can be applied to most valve based circuitry that can improve performance.

As indicated adding power supply regulation is a good move as it improves the 'loading' on a valve stage, providing a more stable environment for the valve to work under.
There are other mods that can remove some or all of the non-linearity of frequency response of capacitors, particularly electrolytic types.

By far the best approach to improve performance is to engineer the valve circuitry to operate in the best linear fashion possible. All active devices, solid state or valve, have non linearities in their operating characteristics. By adding additional circuitry the operating conditions of a valve stage can be manipulated to force the valve to operate in a much more linear fashion, reducing distortion and giving a cleaner and more open sound.

I apply this approach in the valve/hybrid circuits I use.

[Vinyl turner]

Hi Mark, there are a few common upgrades that can be applied to most valve based circuitry that can improve performance.

As indicated adding power supply regulation is a good move as it improves the 'loading' on a valve stage, providing a more stable environment for the valve to work under.
There are other mods that can remove some or all of the non-linearity of frequency response of capacitors, particularly electrolytic types.

By far the best approach to improve performance is to engineer the valve circuitry to operate in the best linear fashion possible. All active devices, solid state or valve, have non linearities in their operating characteristics. By adding additional circuitry the operating conditions of a valve stage can be manipulated to force the valve to operate in a much more linear fashion, reducing distortion and giving a cleaner and more open sound.

I apply this approach in the valve/hybrid circuits I use.

Thanks Alan, That is all sensible sounding advice ......... and before I get totally out of my depth, I suppose the points that have been mentioned throw up a simple question from me (and I am half anticipating the answer) : is it cost driven criteria that prevents such 'improvements' being built into the pre-amps in the first place ?
i.e. would a £600 unit double in price if it was built with such refinements ?

Another schoolboy question from me - if these elements are altered, is there a pay off elsewhere down the line - such that (say for instance) clarity is improved but bass is reduced or are we always improving the baseline unit ?

I don't always ask a stream of questions and these are probably the only over-riding queries that apply to the whole range of potential upgrades.

Thanks everyone.

[Wakefield Turntables]

Croft now going to be potentially Firebottled!

[Jimbo]

Croft now going to be potentially Firebottled!

FrankenBottleCroft!

[Firebottle]

@ Mark. Generally the price will be more if the build is more complex, so simple answer is yes.

There isn't any payoff further down the line providing there isn't a bottleneck anywhere. Improvements to one stage need to be replicated in further stages as necessary.

[Bigman80]

Croft now going to be potentially Firebottled!

What you having done?

[Firebottle]

Secret, I'll make it up as I go along

[Bigman80]

Lol, fair enough.

[Jimbo]

Can you elaborate? I know what voltage regulation is, but I'm not sure what you mean by valve regulation.

I was referring to the fact you can have preamp either valve regulated or non regulated. I believe fets can be used rather
Than valves?