No. Short lead closer to TP9/TP10, closer to the plates of the 6SL7’s, closer to the Lundahl anode choke connection.
Best,
Anand.
Hello kind sirs, for this part of the directions:
"connect a 2ft length of twisted blue 20AWG solid core wire to pins 2 and 10"
would that be 2+ ft of blue wire times two? and when twisted together, the resultant length is 2 ft? OR 2 ft of straight wire times two, then twist as directed per instructions (about 1cm per twist)?
"connect a 2ft length of twisted blue 20AWG solid core wire to pins 2 and 10"
would that be 2+ ft of blue wire times two? and when twisted together, the resultant length is 2 ft? OR 2 ft of straight wire times two, then twist as directed per instructions (about 1cm per twist)?
Should work fine as a preamp, the two headphone output settings would effectively act as two different gain settings. Alternatively, you could omit the switch and wire for one or the other turns ratio. Obviously you would want to wire the transformer outputs to RCAs or your preferred line out connection. You could also consider changing the output transformers to line output transformers, but they would need to be gapped for 60mA and series resistance might need to be adjusted such that the DCR and series resistor add to 350ohms.
@stretchneck
The LL7903 is a microphone input transformer not output transformer. I think you are wondering about using a different output transformer for linestage use, yes?
Best,
Anand.
The LL7903 is a microphone input transformer not output transformer. I think you are wondering about using a different output transformer for linestage use, yes?
Best,
Anand.
@stretchneck
Member @Algar_emi measured his Aegis a while back. He did measure for overall gain, but no mention of peak to peak output voltage. Might want to ping him and see if he did those measurements. Moreover, you want to do those measurements over a similar load to what an F4 would be, primarily 47K ohms since the peak to peak voltage swing will be higher. With a headphone load (33 ohms which he used), the swing will be much lower.
The gains he measured are 13dB-16dB, so very useable for a linestage! You can play with the turns ratios, 3:1, 6:1 or 12:1 to adjust for overall gain, peak to peak voltage swing and different output impedances.
All the best,
Anand.
Member @Algar_emi measured his Aegis a while back. He did measure for overall gain, but no mention of peak to peak output voltage. Might want to ping him and see if he did those measurements. Moreover, you want to do those measurements over a similar load to what an F4 would be, primarily 47K ohms since the peak to peak voltage swing will be higher. With a headphone load (33 ohms which he used), the swing will be much lower.
The gains he measured are 13dB-16dB, so very useable for a linestage! You can play with the turns ratios, 3:1, 6:1 or 12:1 to adjust for overall gain, peak to peak voltage swing and different output impedances.
All the best,
Anand.
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@stretchneck
The other option is to keep the switch as is, but use the 3:1 and 6:1 ratios especially if you are going to use it with a follower amplifier like the F4 which has no gain. The F4 with the 47K ohms input impedance can handle higher source impedances with little to no loss of high frequency bandwidth (and you already know the Aegis with the output transformer has a low output impedance since it was designed to drive headphones).
But like L0rdGwyn states, if you wanted to have all 3 turns ratio options, you'll need a new switch design.
Best,
Anand.
The other option is to keep the switch as is, but use the 3:1 and 6:1 ratios especially if you are going to use it with a follower amplifier like the F4 which has no gain. The F4 with the 47K ohms input impedance can handle higher source impedances with little to no loss of high frequency bandwidth (and you already know the Aegis with the output transformer has a low output impedance since it was designed to drive headphones).
But like L0rdGwyn states, if you wanted to have all 3 turns ratio options, you'll need a new switch design.
Best,
Anand.
My apologies…Totally forgot you had designed a pcb for this! And of course Lundahl always has interesting wiring permutations to accommodate different turns ratios…thanks for the correction…yes a new pcb design would be needed to for 3:1 and 6:1.
I usually just flywire so that’s where my mind was going…hence the oversight and confusion and I usually select one turns ratio at a time, listen, then reassess, etc…
Best,
Anand.
I usually just flywire so that’s where my mind was going…hence the oversight and confusion and I usually select one turns ratio at a time, listen, then reassess, etc…
Best,
Anand.
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A little announcement for aspiring builders - without getting into details, for some medical reasons, chassis from Landfall are going to be unavailable for a period of time. Dave and Saer plan to get back up and running as soon as possible (projected mid to late summer) and will update their website homepage when they're taking orders again.