Funny about the bleed tool , I just modified a cheap Chinese amp PCB to have a bleed resistor! I got feed up of getting a belt every time I went near it. Thanks for your time and work good video well presented.
@LawsonsStudio
3 жыл бұрын
Right, you've convinced me to convert my amp to dual mono. I have a spare dual transformer and the psu is built on turret board so it's quite easy to do.
@imnewtothistuff
3 жыл бұрын
Glad I found you! I used to build Heath Kits purchased at Allied Radio in Chicago when I was a younger man. I have tube guitar amps and would LOVE to build another amp/pre-amp! (dual mono of course)
@tubelab194
3 жыл бұрын
Welcome! I got my start with Heathkit as well when I was 14. Believe it or not I built an entire fairly complicated preamp without a voltmeter, just a soldering iron and a resistor chart!
@jeffcatalano2518
Жыл бұрын
Thank you so much. I enjoy your videos and I like your clear explanations. BTW, your audio sounds perfect to me. I've been scouring the web for just the right 12SN7 preamp and I'm pretty sure I've found it here. Question; I followed the link in this video to find the two schematics dated 2/5/21 - Rev-3. When I went to your website I found cad generated schematics with a later date (8/6/22) but with an earlier revision of 2.4 Which schematics do you recommend I use- the hand drawn ones or the cad drawn ones? Thank you,
@tubelab194
Жыл бұрын
Always build to the highest revision number, this would hold true for almost any technical drawing.
@jeffcatalano2518
Жыл бұрын
@@tubelab194 Ok, I'll build to older pencil drawing labeled Rev. 3. It doesn't seem right to me but I'll trust you. Thanks.
@tubelab194
Жыл бұрын
@@jeffcatalano2518 just to clarify the cad drawings are the official releases, the hand drawn schematics are all working drawings. The correct schematic and most up to date is the one in the store under information.
@paulstubbs7678
3 жыл бұрын
Nice pre-amo, I love how people talks about dangerous high voltage in valve/tube gear, then put out their designs with exposed tubes & no cover, over them. I tend to think tubes are too fragile to be used like that. Also, why the separate external heater supple? that means two power outlets for one amp - weird.
@tubelab194
3 жыл бұрын
Thanks for your comments! No high voltage is present on the exterior of most common audio tubes, the glass and plastic base don't conduct. Yes the pins are "live" but they are buried in the socket. The separate heater supply allows the use of 6 or 12v heated 6sn7's (same tube different filament voltage). This allows you to use the more affordable 12v version of the 6sn7 and opens up a much larger selection!
@LawsonsStudio
3 жыл бұрын
@@tubelab194 I think the external heater voltage is a neat idea providing noisy cheapo switch modes aren't used. I tried it once with a 12v wall wart and the noise on the heater rail could actually be heard. On the scope, the output was sooo bad. I now use two small lt1083 boards one at 6.3 and one at 12.6. With a switch.
@tubelab194
3 жыл бұрын
@@LawsonsStudio Yes, cheap SMPS are to be avoided. When I first decided to use a SMPS for an external filament supply, I scoped about a dozen different brands and found some of the generic Chinese brands to be very noisy and poorly filtered. A few are very quiet, those made by large computer companies tend to be the quietest.
@AlejandroLopez-qd3xm
3 жыл бұрын
Man, for such a audiophile you are, you need to improve your microphone audio. Keep it up
@tubelab194
3 жыл бұрын
My apologies, I love my wide angle high def camera , But it only has a directional stereo mic and when I look away, I fade out! As soon as valvesNmore can afford it, I'll purchase a new camera that can take an independent quality mic.
@sethjohnson1590
3 жыл бұрын
Finally a mono design! I have been looking for a DECADE for a pre like this. I want one! Seriously! Seth
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