100W iron

[Funkalicousgroove]

There are a couple sweet spots IMHO, but for standard fare I am a really big fan of twin Iron.

The thing about the Onetics stuff is they are WAY over rated, so there is no drop in the b+ under load, and you'll end up with about 500v on the plates, and a VERY stiff feel.

[Guitar James]

Brandon has built a bunch of these high voltage amps. Superb tones with a special wooliness in the low mids.

First off, the B+ is way too High on that PT, and it's the size of my head- Not a good choice.

Funk could you elaborate a bit so I can understand this apparent conflict? dogears is saying Music Man trannies with redic high B+ (but reduced screens) achieve grail tone but you're saying Bud's PT yields a B+ that's too high at (I'm guessing) ~485-ish. Or maybe my numbers are wrong and Bud's PT will yield higher B+ than ~485-ish (Bud said 350-0-350 @ 400mA). Or maybe you two are talking about two different versions (i.e. BM vs. high-plate/Skyliner vs. HRM)?

I haven't even received my SLOclone tranny set yet but...as big as a man's head? Holy Terrell Owens batman! I guess I'm glad SLO's mount the trannies at opposite ends of the chassis (so he says now...before he's even built it ).

THe SLO Hi-Def trannies are awesome if you are building an amp that will be run REALLY hard. In a Dumble style of design, if you are playing with your masters on less than about 6, they are tonally a bad choice. Don't ask me how I know.....I just do. THat said if you are building an amp to run real loud all day and all night, nothing beats these in my opinion. THey run cooler than any other transformer set I've used. Fantastic build quality, just heed the warning about low volume use. These are serious 'on-the-road, beat the crap out of, work every night without failure, not for the faint hearted' transformers that weigh about as much as a mid size SUV. With an aluminium chassis hanging upside down, they may have a tendency to make it look more like a relief map of the Alps.

I love the SLO-100 one of my favourite amps, but you are right. It does sound it's best when cranked. Built like a tank too.

['67_Plexi]

There are a couple sweet spots IMHO, but for standard fare I am a really big fan of twin Iron.

The thing about the Onetics stuff is they are WAY over rated, so there is no drop in the b+ under load, and you'll end up with about 500v on the plates, and a VERY stiff feel.

Yeah, I totally agree. THats why I was saying the amp doesn't sound or feel as well unless driven really hard. For the 6L6 amp we were talking about on the phone recently I used the O-Netics OT with a Marshall JCM-800 style PT with 470V on the plates. That made a good combination with a ton of headroom, but not as stiff. It still has to be run hard though to sound great.

The O-Netics PT works better with a 4xEL34 setup IMHO with their heavier current draw.

[Fischerman]

Thanks for the responses. Bud did tell me that these trannies were very stout and that the amp would be very, very loud. But I was thinking; "This is a master volume amp...etc. etc." and didn't really think that was an issue. I think I can see how it could be now. We'll see how my SLO sounds (still awaiting trannies...all dressed up and nowhere to go ) but I'm not really into VOLUME that much anymore...however I always seem to prefer 100W amps over 50W amps. The chassis I got is pretty kickass (16ga steel) so I think it will be OK.

Already I'm having to up the PI filter from 450v to 500v and I don't feel comfortable using 400v 225Ps between the PI and power tubes because the bias voltage is added to the B+ and when unloaded those caps would be well over 400v I think (probably anytime the PI tube is pulled). I'm gonna use my last two 1000v Solens there and I hope 225Ps will be OK elsewhere.

The O-Netics PT works better with a 4xEL34 setup IMHO with their heavier current draw.

That's good to know...I'm gonna try different power tubes and let my ears decide.

FWIW...there is a guy who has built lots of SLOs and he likes the New Sensor Marshall 100W replacement OT over just about anything (he hasn't tried the O-netics yet though). Dunno how one of those would sound with an ODS but it's not the first time I've heard that those New Sensor Marshall replacements sound good.

With an aluminium chassis hanging upside down, they may have a tendency to make it look more like a relief map of the Alps.

Funny you mention that because I was thinking that I would build my 100W ODS 'upside down'...I just really don't like 'tubes down'...especially in a 100W amp. They just get too hot and I'd rather not use a fan if I don't have to.

['67_Plexi]

Thanks for the responses. Bud did tell me that these trannies were very stout and that the amp would be very, very loud. But I was thinking; "This is a master volume amp...etc. etc." and didn't really think that was an issue. I think I can see how it could be now. We'll see how my SLO sounds (still awaiting trannies...all dressed up and nowhere to go ) but I'm not really into VOLUME that much anymore...however I always seem to prefer 100W amps over 50W amps. The chassis I got is pretty kickass (16ga steel) so I think it will be OK.

Already I'm having to up the PI filter from 450v to 500v and I don't feel comfortable using 400v 225Ps between the PI and power tubes because the bias voltage is added to the B+ and when unloaded those caps would be well over 400v I think (probably anytime the PI tube is pulled). I'm gonna use my last two 1000v Solens there and I hope 225Ps will be OK elsewhere.

The O-Netics PT works better with a 4xEL34 setup IMHO with their heavier current draw.

That's good to know...I'm gonna try different power tubes and let my ears decide.

FWIW...there is a guy who has built lots of SLOs and he likes the New Sensor Marshall 100W replacement OT over just about anything (he hasn't tried the O-netics yet though). Dunno how one of those would sound with an ODS but it's not the first time I've heard that those New Sensor Marshall replacements sound good.

With an aluminium chassis hanging upside down, they may have a tendency to make it look more like a relief map of the Alps.

Funny you mention that because I was thinking that I would build my 100W ODS 'upside down'...I just really don't like 'tubes down'...especially in a 100W amp. They just get too hot and I'd rather not use a fan if I don't have to.

You know, I never got such high voltages from the O-Netics SLO PT. I think it was around 470V on 4xEL34's. It physically looked like it was going to 1000000000V, but I remember being suprised. Maybe it was a different spec. ?

[Fischerman]

You know, I never got such high voltages from the O-Netics SLO PT. I think it was around 470V on 4xEL34's. It physically looked like it was going to 1000000000V, but I remember being suprised. Maybe it was a different spec. ?

I dunno Alan...the sheet that Bud sent me only had one 100W PT listed and then several different OT flavors (the most expensive being the Hi Def OT). Not much for specs on the PT but I asked Bud and he said the HT was 350-0-350 @ 400mA. I'd run it through Duncan's PSC but that never seems to give me the right numbers (pilot error I'm sure). I was just basing it on what Funk said about the voltage...I drilled/staked my circuit board for a 450v PI filter and the 500v is def bigger so I'd rather use a 450v there.

BTW - if you check out the picture log on that site with the chassis that I posted above you can see the trannies mounted. The guy seems to be very familiar with SLOs but I can tell he's fairly green when it comes to electronics (I had to 'splain to him how the switching worked)...but he's very open about that. He def doesn't half-ass it if he can avoid it...it rubbed off I guess since I'll be using 4% silver solder and I just spent $$ on a bunch of teflon wire. But I finally 'splurged' on a Weller.