Need a few more good photos of the inside of the preamp, can't make out how much of anything is grounded, and only kinda-sorta the input connections.
Also you seem to have only 2 connections from the PSU to the BA2018 PCB, a bipolar supply needs positive/ground/negative...
Anyway, more photos will help a ton, we'll figure it out.
😀
Also you seem to have only 2 connections from the PSU to the BA2018 PCB, a bipolar supply needs positive/ground/negative...
Anyway, more photos will help a ton, we'll figure it out.
😀
You now that I know Andy wasn’t talking about a hydrogen generator 😜, I’m interested in possibly messing with P3 pot in the F5T to achieve more to see what that does before jumping to the BK1 or H2v2. I have about adjusting P3. As a newer builder, never doing this type of adjustment, will I need any special equipment to see my adjustment or is this something done by ear? I have both of the pots set to their mid position from the initial build.
P3 adjustment is best done with a distortion analyzer. See for example 6L6's video demonstration: Adjusting P3, Nelson Pass Burning Amplifier BA-3 - YouTube
HP distortion analyzers are expensive when you can find them. REW software is free to load on a laptop, you will need a good external sound card along with:
1 - A high wattage 8 ohm resistor mounted on a heat sink
2 - A way to decrease the voltage out of the amp to protect the sound card. It can handle low voltage.
There is a thread for REW software use that has all the information you need to learn how. I started with preamps first, then went on to amplifiers. Burned up my first sound card thinking I would be careful enough without using a resistor box shown in the REW thread.
I need to learn how to attach thread links so you can just click on the link to find the REW thread.
1 - A high wattage 8 ohm resistor mounted on a heat sink
2 - A way to decrease the voltage out of the amp to protect the sound card. It can handle low voltage.
There is a thread for REW software use that has all the information you need to learn how. I started with preamps first, then went on to amplifiers. Burned up my first sound card thinking I would be careful enough without using a resistor box shown in the REW thread.
I need to learn how to attach thread links so you can just click on the link to find the REW thread.
Do watch the YouTube video 6L6 made, I watched it several times before I tried to adjust P3.
I forgot to add you will need a very low distortion 1K Hz sine wave generator. I built the kit discussed in the REW thread, not very expensive and easy to build.
I forgot to add you will need a very low distortion 1K Hz sine wave generator. I built the kit discussed in the REW thread, not very expensive and easy to build.
So one does not have to switch the speaker leads with the BA2018 like with either the B1K or with the H2/H2V2?
Thanks
Thanks
Correct, one does not. B1K and H2gen inverts phase, that’s why swapping connections is mandatory iot keep the intended phase of harmonic distortion. OTOH, not swapping might be just as pleasing, so trying both is probably smart.
Think of it a bit like Kama Sutra. Choosing position of the day, is dependant - amongst other things - on mood and partnering equipment and accessories. Like with H2 level and phase
Think of it a bit like Kama Sutra. Choosing position of the day, is dependant - amongst other things - on mood and partnering equipment and accessories. Like with H2 level and phase
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Up and running
@cubicincher: Good eye! I feel very silly admitting this, but I wired up two "left" outputs from the TentLabs Volume control to the inputs of the BA18. Oops. I knew I wouldn't get this project done without making at least one stupid mistake. That solved it. Thanks, Dirk!
@elwood625: The RCA jacks next to the power jack are "tape out/pass-thru" jacks, labeled as such because they are taken before the volume control but after the source switching circuitry (from a "Vol In" on the TentLabs attenuator). Thus, they function the same way a tape out would, but I have no intention to use them with a tape recorder -- they'll go to the auxiliary input of my old Lafayette tube receiver. Just a way to let me have fun and select the source with the preamp unit, but not touch the attenuator before reaching the destination. The resistors are just 110R Takmans I had lying around to prevent weird noises and such. If you think this could cause problems, please let me know!
@6L6: The orange wire is Power+ and the black wire is Power-. The ground is shared between both channels and goes to the star ground point via a brown wire. The outputs of the preamp board are brown wires only because I ran out of white wire 😀 Hey, it works!
Listening right now and I have to say, it's sounding quite good! Thanks to you all for your help. Last question: it should be alright to leave it running, right? At only a few milliamps, leaving it on shouldn't be any problem I presume, but I want to ask before I let it go for an extended period.
@cubicincher: Good eye! I feel very silly admitting this, but I wired up two "left" outputs from the TentLabs Volume control to the inputs of the BA18. Oops. I knew I wouldn't get this project done without making at least one stupid mistake. That solved it. Thanks, Dirk!
@elwood625: The RCA jacks next to the power jack are "tape out/pass-thru" jacks, labeled as such because they are taken before the volume control but after the source switching circuitry (from a "Vol In" on the TentLabs attenuator). Thus, they function the same way a tape out would, but I have no intention to use them with a tape recorder -- they'll go to the auxiliary input of my old Lafayette tube receiver. Just a way to let me have fun and select the source with the preamp unit, but not touch the attenuator before reaching the destination. The resistors are just 110R Takmans I had lying around to prevent weird noises and such. If you think this could cause problems, please let me know!
@6L6: The orange wire is Power+ and the black wire is Power-. The ground is shared between both channels and goes to the star ground point via a brown wire. The outputs of the preamp board are brown wires only because I ran out of white wire 😀 Hey, it works!
Listening right now and I have to say, it's sounding quite good! Thanks to you all for your help. Last question: it should be alright to leave it running, right? At only a few milliamps, leaving it on shouldn't be any problem I presume, but I want to ask before I let it go for an extended period.
It grows soundwise the first hours, maybe up to 100+, dunno. So yea, leave it on.
That said, ensure offset is reasonably stable first 🙂
That said, ensure offset is reasonably stable first 🙂
to bonacciomj #2931
Hello bonacciomj,
you can be sure, that I made a lot of stupid mistakes in my life.... 🙄
Some were painful and some gave me fun...😀
Enjoy the sound!
Cheers
Dirk
Hello bonacciomj,
you can be sure, that I made a lot of stupid mistakes in my life.... 🙄
Some were painful and some gave me fun...😀
Enjoy the sound!
Cheers
Dirk
you betcha! ThanksI opted for a bit more room than the Hammond case you chose (post # 1428). ;>)
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sounds great but low volume
hi
I have a general question for the group I built this ba-2018 and it sounds great and very clear, but the volume will not go very loud, it fills the room but not near as loud as when I hook up the Dac direct to the amp, pass labs F6
is there a resistor I can change or something to fix
thanks
hi
I have a general question for the group I built this ba-2018 and it sounds great and very clear, but the volume will not go very loud, it fills the room but not near as loud as when I hook up the Dac direct to the amp, pass labs F6
is there a resistor I can change or something to fix
thanks
