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

[Wakefield Turntables]

Well I'm enjoying this exercise more and more as I'm slowly learning How the amp works. I'm sure Glenn has some fantastic ideas as to how the amp could be improved and that's what I like. I love the idea that I can talk and discuss the mods and see how they work. Part of the whole hifi experience is knowing that I tailored my equipment to my needs it's very satisfying seeing how your ideas turn out especially at the end of a long winters night when your completely chilled out listening to your favourite tunes.

[brian2957]

Well I'm enjoying this exercise more and more as I'm slowly learning How the amp works. I'm sure Glenn has some fantastic ideas as to how the amp could be improved and that's what I like. I love the idea that I can talk and discuss the mods and see how they work. Part of the whole hifi experience is knowing that I tailored my equipment to my needs it's very satisfying seeing how your ideas turn out especially at the end of a long winters night when your completely chilled out listening to your favourite tunes.

With a favourite tipple of course Andrew I like this type of thread since it points the way to people who buy 2nd hand gear ( in this case Croft ) and want to upgrade it .

[Wakefield Turntables]

With a favourite tipple of course Andrew I like this type of thread since it points the way to people who buy 2nd hand gear ( in this case Croft ) and want to upgrade it .

Usually a big glug of single malt Brian! I hope you enjoy the thread and I'll be posting some pictures later.

The part in bold is it... couldn't agree more.

Thanks!

Well I got another email and the fully monty includes :-

Seiden selector switch.
Eichmann phono sockets.
Khozmo attenuator.
SCR Teflon output caps.
Rike PIO coupling caps.
Clarity Cap TC4 power supply caps.
Separate transformer box with separate 500VA transformers for each channel.
Separate hybrid ht supplies for each channel.

Precision wirewound resistors.

Individual heater regulators for each valve.


I'm not sure if Glenn can push things further but sounds pretty exhaustive. I still don't know how he's going to populate the Khozmo attenuator, I'd like to know his resistor selection. Additionally I have no idea what " Individual heater regulators for each valve" are and God only know's what "Separate hybrid ht supplies for each channel." can be . I presume that they must have something to do with the SS regulation that some of these high end Crofts seem to have around here . I have some pictures for later so I'm off for an hour to get some work done.

[Jimbo]

Usually a big glug of single malt Brian! I hope you enjoy the thread and I'll be posting some pictures later.



Thanks!

Well I got another email and the fully monty includes :-

Seiden selector switch.
Eichmann phono sockets.
Khozmo attenuator.
SCR Teflon output caps.
Rike PIO coupling caps.
Clarity Cap TC4 power supply caps.
Separate transformer box with separate 500VA transformers for each channel.
Separate hybrid ht supplies for each channel.

Precision wirewound resistors.

Individual heater regulators for each valve.


I'm not sure if Glenn can push things further but sounds pretty exhaustive. I still don't know how he's going to populate the Khozmo attenuator, I'd like to know his resistor selection. Additionally I have no idea what " Individual heater regulators for each valve" are and God only know's what "Separate hybrid ht supplies for each channel." can be . I presume that they must have something to do with the SS regulation that some of these high end Crofts seem to have around here . I have some pictures for later so I'm off for an hour to get some work done.

Err that sounds pretty comprehensive to me.

Might be up there with your spec Jo

[Firebottle]

Usually a big glug of single malt Brian! I hope you enjoy the thread and I'll be posting some pictures later.



Thanks!

Well I got another email and the fully monty includes :-

Seiden selector switch.____________\
Eichmann phono sockets.__________\
Khozmo attenuator._______________\ All good quality stuff Andrew
SCR Teflon output caps.___________/
Rike PIO coupling caps.___________/
Clarity Cap TC4 power supply caps. /
Separate transformer box with separate 500VA transformers for each channel.
Separate hybrid ht supplies for each channel.

Individual heater regulators for each valve.

Additionally I have no idea what " Individual heater regulators for each valve" are and God only know's what "Separate hybrid ht supplies for each channel." can be .

The separate transformers feeding separate ht supplies is the best approach for minimum crosstalk between channels. The 'Separate hybrid ht supplies' just means that valves and FETs are being used in the power supplies to give maximum performance.

Individual heater regulators are very easy to implement, just a 3 terminal regulator chip, also I imaging to ensure no crosstalk between different stages.

Very similar approaches that I incorporate in my designs.

[Wakefield Turntables]

The separate transformers feeding separate ht supplies is the best approach for minimum crosstalk between channels. The 'Separate hybrid ht supplies' just means that valves and FETs are being used in the power supplies to give maximum performance.

Individual heater regulators are very easy to implement, just a 3 terminal regulator chip, also I imaging to ensure no crosstalk between different stages.

Very similar approaches that I incorporate in my designs.

Alan, many thanks for the reply. I've bought a couple of simple electronics books so that I have some grasp of what I'm talking about. I need to re-read the passive amp thread of Marcos with regarded attenuators but I think the basic principles of these are quite simple to understand. I just need to get my head around FETs and how they work with a valve to regulate the power. I understand what "cross talk" so I can see why some of the components are being used. Looks like I need to do some reading around heater regulators, maybe tonight's homework?!