Tubed RIAA phono stage

[shif]

I wish to share photos of my Cornet phono stage DIY project:



The excellent electrical design by Jim Hagerman yields a tubed phono stage that is simple to build and sounds wonderful. I packaged my project in a custom machined aluminum enclosure that I designed to compliment my DIY audio furniture.

"The amplification stages are all single-ended class A with zero feedback. RIAA equalization is implemented using a split, passive RC design. A cathode follower provides low output impedance to capably drive any interconnects."

Link to more photos

Link to Hagerman site

I am not affiliated with Hagtech. I am simply a happy customer who believes in their excellent products and service.

[analog_sa]

single-ended class A

They may be wonderful but i still cringe when i read something like that. Does the clueless competition use exclusively class B? Or maybe G?

[dhaen]

The case loooks looks lovely

[ungie]

VERY nice casework!!
I love the fact that your design has made this tube phono pre look like something modern. I am not very big on the "tubes on top" look of the suggested casework! One question though: The PCB was designed to have the tubes mounted on the backside of the board in order to stick out the chassis. All other components would be mounted on the opposite side. What, if anything, did you have to change in order to have all components mounted on one side of the PCB?

Cheers!

Andrew

[shif]

Andrew, nothing had to change in order to mount all the parts on the back side of the board. There is slightly less room for boutique caps, but I don't have any other than a few Auricaps in the signal path. No giant caps like can be seen in other Cornet stages posted on the Audiocircle forum.

The hole in the top panel allows for use of rectifier tubes having vintage tall glass envelopes. A typical 5Y3GT is about flush with the top surface as shown. This polished aluminum lid lifts off for easy access to all the tubes for rolling.

A tiny blue LED is mounted in the front panel and is powered by the heater circuit.

[hybridamp]

I don't guess you would be willing to machine me an enclosure like that? LOL

I would be willing to pay of course...

[benny]

They may be wonderful but i still cringe when i read something like that. Does the clueless competition use exclusively class B? Or maybe G?

i absolutely agree... i saw an add for a guitar amp just the other day advertising as having a SE Class A preamp...

technically, this is correct, so they can get away with it, but i think for the uninformed consumer, this is a little bit misleading... ethically, i think this kind of advertising is wrong, especially in a guitar magazine where there are the majority of readers that have been programed to know that SE class A is good for certain reasons, so see that spec and go, oh wow... i want one, it's got SE class A preamp!!!

but they don't even know what they're talking about, and don't realise that their PP 50W class AB amp also has a SE class A preamp...

what's worse, is that for quoting this spec, the manufacturer who i wont name, is probably adding another couple of hundred dollars onto the price, despite the fact this is the cheapest to build preamp anyway... imagine the unnescesary cost of a push pull preamp... and even better, i wanna hear a class AB or class B SE amp!


that's all i got to say... by the way, nice case... i hate people like you with nice cases, and here i am, i just chuck mine into ordinary steel and aluminium boxes... your presentaion makes me look like i put in sooooo much effort into my presention...

nice work

cheers

[hybridamp]

that's all i got to say... by the way, nice case... i hate people like you with nice cases, and here i am, i just chuck mine into ordinary steel and aluminium boxes... your presentaion makes me look like i put in sooooo much effort into my presention...

LOL

I have to agree, my case on my diy headphone amp is crap. I would LOVE to have a nice machined aluminum case as you have...