• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Aegis DIY Tube Headphone Amplifier

One quick question on the output transformer specs: neither the Earhard transformer specifcation pdf, nor the Lundahl site shows the gap current, and Don Audio's page says it's a 30ma gap. Does the LL2765 get ordered with a 60ma gap, or are they all 60ma and the DA page isn't 100% accurate?
 
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One quick question on the output transformer specs: neither the Earhard transformer specifcation pdf, nor the Lundahl site shows the gap current, and Don Audio's page says it's a 30ma gap. Does the LL2765 get ordered with a 60ma gap, or are they all 60ma and the DA page isn't 100% accurate?

You can order almost any transformer or choke from Lundahl with whatever gap current you require. Check the BOM, the gap currents are included there. You simply need to communicate to the Lundahl distributor what gap current variation you are ordering. In this case, the LL2765 is gapped for 60mA.
 
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I may use a different chassis :) I have an external power supply for B+ that may work well, and I think I have an angled case with interior room for the 6SL7s & power/driver tubes.

I'm thinking Hiwatt-style and quality layout. I'll probably get it working quickly, then rebuild it to that level of quality using the initial experience.
 
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No I didn't. Keep in mind you are entirely dependent on the input tube for voltage gain in this circuit, so you need an input tube with a medium to high gain to reach any considerable amount of power. 6SL7 was chosen as it is high gain, widely available, and very linear. But you can definitely experiment with others, just make sure you use the appropriately spec'd anode choke. You could also use a CCS load, but the B+ needs to cover the bias voltage plus the peak AC voltage swing plus the dropout voltage of the CCS in that case.

As an aside, since I was very happy with the sound of this amplifier, I am going to be building myself a one off transformer coupled variation. It will use triode strapped E810F or D3a inputs, Dave Slagle 1:1 ISTs, and a triode strapped HY69 directly heated pentode output stage with Dave Slagle output transformers. Probably will be my last headphone amp, assuming it turns out well.
 
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I purchased the last set from the guy I was buying from. I would scoop a set from Metaldogg99 while they last.
Bill
I did! Thanks gents. Got the xformers on order too. I really like Landfall Systems but I'm thinking I may do my own chassis this time around. I've nearly forgotten what a PITA it is to cut out an IEC sized hole out of thick gauge steel so it's time to remind my lazy ***.

The Lundahl covers are very unique looking so I'm ordering those and will probably powder coat them. Could be robin's egg blue, brick red, white metallic... we'll see what the powdercoater has languishing on the shelf.

Thanks again L0rdGwyn, it's been a while since my last project.
 
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Started the project for a friend. Received most of the parts, except the Lundhall and the ELMA Switch. Started the assembly, superb instructions manual.
 

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