4 x 6V6

[Smokebreak]

I'm trying to decide on iron. I'll be running reasonable voltages for 6V6s, 330-350V plates.

For the OT I'm looking at Marshall 50W iron at 3K4 http://www.classictone.net/40-18025.html or 50W Bassman iron at 4K2.
Basically, a dude wants a 4x version of this lil 2x6V6 amp I have that runs 330V plates w/ 20V across the shared Rk, and uses 6K6 Deluxe iron. So I'm trying to replicate that, but doubled.
Since I'm using lower plate voltages, does it make sense, generally speaking, to run lower primary impedance?

For the PT, I'm looking at the 370FX 550VCT @ 173mA. Should be enough current eh? The next step is the 370HX @ 230mA.

[randalp3000]

cathode or fixed bias on the 6v6's?

[Smokebreak]

Lovely, lovely sounding 6V6s with low voltage and cathode biased

[randalp3000]

I built a 4 6v6 tweed deluxe with gibson trem circuit. Pretty rockin amp.

If running cathode bias I would recommend at least a 200mA PT

[Smokebreak]

This is similar toplogy w trem also, and simple reverb.

I'd rather have 200mA too, but I came across this. Check Ian Gingertube's report. http://ampgarage.com/forum/viewtopic.ph ... eded+4x6v6

Also, I used something like a 300r shared Rk for the 2x6V6 amp, and at idle I was at something like 55% dissipation ! As nutty as that sounds, it sounded great, so I left it. So since I'm not biasing at 100%, I could get by on less current from a PT eh?

[David Root]

On the OT, check out Musical Power Supplies' OT40PP. Rated 45W.

Has 3k3 AND 4k2 primaries so you can compare and even switch them. American made, less than $50. I've used his iron, very good and good value.

FWIW the one 4x6V6 I've built used a Mercury 4K OT designed for the 60W Jim Kelley amp. Overkill power wise but sounds great at lower voltages too!

On the PT the Hammond is good but the 300 series are awful expensive. I know some say the 200 series tend to hum a bit but I've used quite a few and had no trouble with PT hum. I would think Mag. Cpts. would have something suitable for a lot less.

[Smokebreak]

Thanks David, yea I saw the MPS OT last night. the original 2x amp has Matt's 275PT in there, so those are the voltages I'm shooting for. MagComp doesn't have anything with that low of voltage but higher current unless I overlooked something.

[didit]

For the PT, I'm looking at the 370FX 550VCT @ 173mA. Should be enough current eh? The next step is the 370HX @ 230mA.

Experience on current max Hammond's are quite conservative, particularly 300 series. In country relatively good pricing at http://www.a1parts.ca -- e.g., 370FX listed at CND$102.24, however x-border might prove expensive.

Best .. Ian

[tubeswell]

Run a Fender Tweed Bassman PT (200mA HT winding) and a 40W OT where you can get a 4k-ish reflected load

[Theashe]

Run a Fender Tweed Bassman PT (200mA HT winding) and a 40W OT where you can get a 4k-ish reflected load

Here's one I use in my amp:
http://www.hammondmfg.com/pdf/EDB1750JA.pdf
$57.14 at A1Parts.

Funny enough, I also used the PT from a Bassman.

[gingertube]

The 370FX Hammond was fine in the amp I built for Neale. I do agree that a smidge more current capability may help. He is a vintage rock and blues and folk guy and never pushes the amp.

Continuous Sine Wave testing (400Hz) gave 28 Watts on the edge of clipping. That is right out of what the data book says (14 Watts per pair).
Data book also says 92mA per pair (anode) + 13.5mA per pair (screen) at max output. So for 4 6V6 you should really look for 105 x 2 = 210mA for the power section and then add 10mA for preamp etc.
So at least 220mA to be able to run flat out.

I ran vintage "Coke Bottle" Shape 6V6G in it.

Cheers,
Ian

[shane]

What output transformer did you use Ian?
Cheers
Shane

[Smokebreak]

Not to speak for Ian, but in his report he said he used Marshall output iron at 3K4, but had said that he would have rather used Bassman iron at 4k3, as it would have been better suited.

I'm curious about this too as that was part of my original question - low plate voltages (350 on 6V6) and low primary impedance.

Looks like I'm gonna have to go with the 370HX to be on the safe side. ouch.
Edcor had a nice offering at 200mA but I can't wait 4-6weeks for them to build it.

[Smokebreak]

I'm back on this amp for my buddy , cause he's gotta hit the road soon.
I've got a 370HX to power this cathode biased 4 x 6V6(360ish plates). After all this time, I still can't decide on the OT!
Let's take a vote(and why) and I'll use the winner.
Amp is cathodyne PI, with 3 stages feeding it. Volume between 1 and 2, tone stack between 2 and 3. The dude wants a switchable, variable boost that will be a common cathode triode gain stage in between 2 and 3. Reverb and Tremolo . Boost and trem on relays for instant access.
He sings/plays/fronts in a large-ish country band, and may or may not actually need a giant transformer for output.
I'm leaning towards the vibrolux sized 40W. Even though it's the puniest, that's the one I use for my main rig, as it sounds super in an amp thats turned up halfway, and rules in a medium sized room, in a mix.
Also of note I'm using EH 6V6s. Fuck it.

[rp]

Amp looks Fenderish, player looks Fenderish, when I can't decide I've just gone with an Allen and always was very happy w/ the sound. Heyboers and Allens do the Fender thing well.