• 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.

6V6 line preamp

diyAudio Chief Moderator
Joined 2002
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So not especially prone to highlight hiss though sensitive enough. If its the source and the gain surfacing it, and because you had been listening with no line gain before, its not a bad idea to check the system with the bootstrap buffer option too before you settle. Just a rewiring, not major.
 
fellas,
I need your advice...
I "have lost the ball" concerning the transformer.I find output/amp/driver/preamp/blabla transformers and I have no clue what the differences are...
Can you suggest one to me for the 6v6?
And also an inductor (choke??) cause I haven't found anything yet at 20H@>100ma..
Maybe a link or two?
 
built one

A very simple box with parts I had at hand. Went overboard on two serial regs (were laying idle) and NOS Fivre tubes. Just one input (ha); I need the preamp's amplification to drive a small poweramp. No hiss or hum (after I connected the heaters to ground). These are old parts and certainly no boutique products so I won't comment on initial reproduction quality. It's alive and it works smoothly, not bad for a days work.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.


Somehow PSUD simulated out of the ballpark. I use a voltage doubler which was calcutated for 480V but the thing delivers 530V. Of cause this strains the capacitors on the raw voltage so I had to series connect some, this not the way I normally work things out. The PSU has low capacitance and gives almost 2V ripple which is swamped by the regs to less than 1mV (on the Fluke that is).

An externally hosted image should be here but it was not working when we last tested it.


Promising design Salas, I like it and will like it more once built to higher standards.
 
reg questions

I have been following this thread on and off for a while. Salas et al, I have a few questions:

I gleaned from the responses to Buzzforb that the circuit sounds best with 2X the Salas SSHV2 instead of the Maida referenced on the schematic?

Buzzforb mentioned effects on his heater voltage due to something he did to the SSHV2 (it was late when I read this). Was he talking about the LV Salas regulator or just the regulated heater circuit shown on the schematic?

I have just in the last week become aware of the group buy for the SSHV2, which is already closed but I see that some Johnny-come-latelys have been advised to contact Teabag anyway – which I plan to do. Here is my question – is the SSHV2 the same as the circuit shown by Salas in his link to Maida circuit – or is Salas’ SSHV2 design shown somewhere else? I ask in case I cant get boards from Teabag.

Salas – this thread really makes me want to build this circuit. ;) In fact, I have been thinking about trying to figure out how to combine it in one box with DanL’s version of Hagerman’s octal coronet phono circuit.

regards

mike