C'mon.. as a beginner /bungler I've asked a Lot of foolish questions too.
Start with the DIY shoppe bits and proceed from there.
Jensens and PCB's are the Basic ingredients.. ALL else follows.
Get the PS pcbs at the same time
Antek.com sells a 4218 transformer for ~50$ + shipping.. bargain pricings.
Are there better units.. Undoubtably.
But the antek.. will work, acceptably well.
In fact more than acceptably. They are a high quality unit...I have used a bunch of them in Pass Amplifiers, preamps and phono preamps. None vibrate, all amps and preamps, etc. are totally silent...no hum buzz or fizz. For my F-6 I sprung for a couple more bucks and got the 5218, 500 VA. I also prefer Teabag's power supply board for these amps, holds a lot of capacitance, very heavy duty. See his blog, I think they are $20.00.
Russellc
If you look at their website you will notice the 500 VA series comes in only the AN (no shield) instead of the AS (has a shield). If you do not want to settle with the size of the AS-4218 (400 VA), then email them and they probably can work out a deal where you buy a AN-5218 and they will ship the shield along with tape and you attach it.
Everybody worries to much about this. Same with the transformers on the boards, both F6 and M2. I built both, transformers both Antek 5218, no shield, internal or "Ham can" external, both in DIYstore Deluxe 4U boxes. I built it (F6) just like 6L6 did, except I didn't mount the transformer up on its side. The only shielding of any sort is the input wiring from the RCA jacks. I used Silver Sonic BL-1 interconnect cable, as I had it on hand. It is shielded, but I let shield float at both ends. Both amps are dead silent, no hum, buzz fizz or anything, just flat silent. No turn on turn off transient noises either.,
No shield over the main transformer, transformers on the boards, F6 or M2.
If yours hums, you laid something out wrong, or your transformer is wonky. I have heard people who had to rotate the transformer slightly, I did not...or just got lucky. Every build, so I doubt it was luck. All mine use Antek, with the exception of the BA3 amp, it used a 1000VA unit from SUMR or something like that, which was part of Buzz's F5 turbo kit group buy.
My BA3 preamp also used Antek, it did have a shield ( both of the BA3 preamps I have built) which was connected to the ground where the power supply and IEC plug ground attached to chassis floor.
Just build it and don't over think it. Most people that have trouble think they have some better idea than standard and it just makes it more likely you will have problems, and less likely anyone will know how to undo it.
In short, get the F6 boards and transformers from DIY store, you will need them. Do not buy non Pass approved crap off ebay and expect folks here to figure it out for you. Get your Jfets from the store or from Spencer, or the guy in Israel who IS on ebay, I forget his name, but nowhere else.
Get your power transformer from Antek, Plitron or SUMR. Get board parts from Mouser or Digikey. Sometimes searches there are picky, so ask questions if you don't find what you want, it is there somewhere.
As to a case, I can not suggest more highly those from the Diystore. Deviate from this at your peril and frustration.
I found the F6 to be the easiest and most straight forward of the builds I have done. Also in terms of firing it up. Same with M-2.
Just follow established build guides, don't deviate to "improve" it. Once it is built and properly working, then if you must, start to monkey with it. Then at least you will know what the source of the problem is. Start out with a bunch of changes and good luck figuring it out! Start simple, do it right, then play, and ask questions. Most of peoples ideas have been tried here by someone. Lay your wiring out properly, and twist what should be twisted and so forth.
Enjoy,
Russellc
Yes, I have efficient horn speakers, both Econowave and Altec, (Altecs are over 100 dB efficient.) as well as "regular" type speakers of various types.
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Welll.. the Anteks may be Functionally High Quality.
But visually, these are Uninspiring.
My 400va is a misshapen egg shaped Lump. I was annoyed/surprised.
(Odd as my 300va version was/is mostly round)
But in truth, it is visible in their Site photos, if one looks carefully.
Unlike a Piltron Or Torroidy which are beautifully made efforts
Mucho Mo' $$ though
But visually, these are Uninspiring.
My 400va is a misshapen egg shaped Lump. I was annoyed/surprised.
(Odd as my 300va version was/is mostly round)
But in truth, it is visible in their Site photos, if one looks carefully.
Unlike a Piltron Or Torroidy which are beautifully made efforts
Mucho Mo' $$ though
Are you interested in a different transformer in search of something better?
It's very doubtful you'll be successful.
I was simply curious. I was researching phono stages and ran across Cinemag transformers. Then I saw teabag's daughter boards for his version of the F6 boards. You know how the mind wanders. Finding reasons not to tweak always ends up saving me money.
I was simply curious. I was researching phono stages and ran across Cinemag transformers. Then I saw teabag's daughter boards for his version of the F6 boards. You know how the mind wanders. Finding reasons not to tweak always ends up saving me money.
Always best to start with stock and start tweaking from there so you have a valid reference point to compare with.
Start with the Jensen.
Edit:I hope we are discussing Lundahl vs Jensen. Lol
If we are discussing toroidal power transformers, then I can highy recommend AS4218. Mine are absolutely dead silent.
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Found it. Post #174 in the pictures thread. It had a laptop power supply at the time. Later, I duplicated 6l6's B1 power supply. If you scroll up a few posts there is also a pic of my F5 from the same time. Both those chassis were built from 6061 aluminum. I just use store chassis now.
Russell c
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I have to research the BA-3 preamp. But I already have the B-1 board populated.
Nothing wrong with B1 with F6, unless your source is very low output and you need the extra gain in which case BA3 front end is a very good solution.
I'm in the middle of casing up both a Buffer preamp eg B1 with an F3 type preamp (could also be BA3) in the one case.
2 birds with one stone (one case).
I have to research the BA-3 preamp. But I already have the B-1 board populated.
Where can I find a build guide for the single-ended version of the BA-3 preamp? Does it have enough gain to drive the F6?
There is not a build guide for the SE version. I built the SE version and it does not differ that much so you should not have any problems using the PP guide of 6L6. Great sounding amp by the way.
I have to research the BA-3 preamp. But I already have the B-1 board populated.
Where can I find a build guide for the single-ended version of the BA-3 preamp? Does it have enough gain to drive the F6?
http://www.diyaudio.com/forums/pass-labs/258022-ba-3-preamp-build-guide.html#post3968063
I'm in a small space so even just the B1 was loud enough for me.
Dennis
I have to research the BA-3 preamp. But I already have the B-1 board populated.
Where can I find a build guide for the single-ended version of the BA-3 preamp? Does it have enough gain to drive the F6?
I only know of 6L6 guide, the pre amp is the pre amp...single ended or complimentary refers to the output stage when you build a power amp. The front end is all that is used for the preamp, it is what it is and there is no output section.
The BA3 has enough gain to drive F4. (plenty!) Your F6 has similar gain to F5, around 14 -15 dB. I found the B1 somewhat lacking with that sort of gain, unless high efficiency speakers are being used. Myself, I always find an active buffer like B1 sounds better than just a volume knob-potentiometer alone, and an active pre with gain sounding even better still. Just my opinion, they do vary. My F5 sounded much better with BA3 pre than B1, but everyone is different here.
Here 's a link to my B1: (Post #174) (F5 at #165)
http://www.diyaudio.com/forums/pass-labs/166784-pictures-your-diy-pass-amplifier-4.html#post2254417
Russellc
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Bias setting Source Resistor (0.47) is R12?
Preset Bourne ( same ones as in Build Photos, same orientation ie; 240s below the boards) Bias pot to ? (which direction; CCW ?)
Where can I measure Bias Pot ohms with PCB mounted ?
Yess being silly Cautious, as I don't like the smells of Magic Smoke.. it lingers.
Preset Bourne ( same ones as in Build Photos, same orientation ie; 240s below the boards) Bias pot to ? (which direction; CCW ?)
Where can I measure Bias Pot ohms with PCB mounted ?
Yess being silly Cautious, as I don't like the smells of Magic Smoke.. it lingers.
You can monitor the bias by the voltage across 0.47R resistor at R2. (Target
for about 0.5V initially)
I don't remember which direction to turn the pots, but if you are using something
like 6.2V zeners, you can just set both pots to mid point and then slowly adjust
P2 while monitoring the R2 voltage. You can figure out which direction will
increase the bias by just slowly turning P2. It's best if you have a second
meter across the output to check the DC offset and occasionally trim it as
you adjust the bias.
for about 0.5V initially)
I don't remember which direction to turn the pots, but if you are using something
like 6.2V zeners, you can just set both pots to mid point and then slowly adjust
P2 while monitoring the R2 voltage. You can figure out which direction will
increase the bias by just slowly turning P2. It's best if you have a second
meter across the output to check the DC offset and occasionally trim it as
you adjust the bias.
Forgot to mention that P1 is for trimming DC offset.
Have you soldered in P1 and P2? If not, you can just measure
the resistance of the mid pin to the outer ones to see if you are indeed
close to mid point in resistance value.
I have no knowledge if the pots are shipped near the mid point setting, so
if they are already soldered in place, I would still recommend counting the
total number of turns from end to end and go back half way.
Sounds like you should have it up soon. Also, I remember the bias going up
a bit as the amp warms up so the final bias adjustment should be made after
running it for a while.
Cheers,
Dennis
Have you soldered in P1 and P2? If not, you can just measure
the resistance of the mid pin to the outer ones to see if you are indeed
close to mid point in resistance value.
I have no knowledge if the pots are shipped near the mid point setting, so
if they are already soldered in place, I would still recommend counting the
total number of turns from end to end and go back half way.
Sounds like you should have it up soon. Also, I remember the bias going up
a bit as the amp warms up so the final bias adjustment should be made after
running it for a while.
Cheers,
Dennis