OT difference ?

[MWJB]

"If you want my $.02... Don't go there! Just believe that the only things that matter about a capacitor are its value, voltage rating, and whether it's electrolytic or not. It'll make your life a whole lot easier and save you money." We got a bunch of similar amps together (all 6G12A Concerts, serviced, same brand of tubes, biased similarly), on more than one occasion, with yellow Astrons, blue Mallories, Astron PIO, and cheapo E. European axial MKT metalised polyester caps from RS Components...there was no outstanding tone attributable to the caps...the only caps that I felt stood out in the amp in question (as well as other amps) were the NOS PIO, because I felt they lacked character & were slightly sterile in an A/B test.

[daz]

Well, so much for that idea. LOL! I guess placebo effect is rampant among builders, but no big surprise there. I have to watch myself closely in that regard, it can be tricky. But i just feel my amp lacks some articulation, and with all the high end enhancing i recently did in the first stages i would have thought that would do it. the fact that it didn't made me start looking to the trannys because i've tried everything else. (including big filters which made it hard and sterile except for the main can which i kept as 100/100uf)

[MWJB]

I wouldn't really call it placebo effect...if you think about guys who are selling $2-4K amps, prospective buyers will want to peek inside & when they do, they'll expect to see something that gives them peace of mind & meets expectation...if you offer an amp commercially, at the same price as a Victoria or a Clark, but fit $0.20 caps you'll undoubtedly lose customers. Just like if all the other cars in the price range have chrome internal trim and yours has sprayed silver plastic...practical difference may be negligible, but comfort level & expectation will make a difference when you are putting down your hard earned cash.

It's a competitive market.

I have also seen brown Fenders factory fitted with ceramic disc caps as preamp coupling caps...no one suspected a thing until the amps were opened up & they saw the caps! Premier amps have their fans too, ceramic disc caps in them too.

For the home builder, use what's available quickly and reasonably cheaply...here in the UK we have to pay through the nose for Mallory & Sprague, so I use the MKT (reasonable price, sound great, on my doorstep the next day) for general applications, if someone brings in a vintage Fender & wants to maybe sell on E-bay one day, with guts shots...then he gets whatever makes him happy.

[daz]

When i said "builders" i didn't mean to imply those who's business it is. Rather just all the people building amps as a hobby today, and among those there seem to be quite a few who swear there are tonal benefits to boutique caps. So in that regard i thing there is a lot of placebo effect going on, at least assuming they really don't sound any different.

[MWJB]

Sure, plus (as I'm confident that you are aware) by the time you have powered down an amp, heated the iron, pulled the old cap, soldered in the new one, reassembled, powered up again...it can be hard for many folks to really hold the original sound in the memory (it took me years)...it usually gets "overwritten" with the new sound...

You hear this from time to time - "Changed the caps in my amp...it sounds great now"...good for you, but it's very unlikely that it sounded crap before, or if it did, it wasn't purely due to having the "wrong" brand of cap.

...of course, that is, if you have simply replaced caps with the same value & rating, just a different brand, without tweaking anything else whilst you are in there - if you're anything like me, that doesn't happen often! :-)

As with any development work, it is a good idea to build 2 versions & use one as a datum for A/B tests, even if they don't sound identical at any point, you still get a reference.

[daz]

Agreed, and for me, unless it's a huge difference that can't be denied, i always either A/B things immediately one of several ways, or i will try both ways many times over day or weeks till the difference becomes very obvious to me. But i always try to hear both ways with no more than maybe 30 seconds between them, and even thats more than i;'d like. But i have the chassis out and plugged in and the iron hot. And i'll have wire sticking up i can attach them to in seconds, or use clip leads when possible, or a switch. But one way or another i don't trust my own hearing till i can hear them next to each other almost instantly or each for long periods over time. I never underestimate the power of placebo effect no matter how much i seem to thing i know the difference between two things. I've gotten much much better, but never would allow myself to feel i'm sure w/o the real test.

[kldguitar]

I agree with you

There is a problem with that "all other things equal", like others said, they're not and never will be. There are about 20 other design parameters in an OT and the designer can set them however he likes, but he only tells you two of them. The other 20 are his secret recipe that he charges you the hefty margin for.

So when you say some OT is "a 3.2k 50 watt one" then that tells you about 10% of what there is to know about it. You probably wouldn't understand the other 90% anyway, it's all voodoo that only old, grizzled transformer designers can perform. Choice of material for the core, wire gauge and fill factor, interleavings, and so on.

Having said that, you can probably count on the following...

A bigger, heavier one will have more iron and more copper. That means less power loss, and bigger bass. And a larger power rating usually means a bigger, heavier unit, so we could guess the 50 watt OT might make the amp a little louder and chunkier sounding.

The 3.2k impedance will get a different sound out of the power tubes compared to the 4k. I don't know any more about this, because every EL34 amp I've ever used had a 6.6k primary, and I always thought 3.2k was really low. It would be like running one of my 6.6k amps with an 8 ohm speaker in the 16 ohm jack.

Some people argue that no modern production OT can ever be a true clone of a vintage one, because they didn't have grain-oriented silicon steel back in those days, and even when it first came out, amp builders might not have used it because of the price premium. But now GOSS has taken over and you can't get transformer laminations made out of anything else! The guys over in the Pickup Makers forum agonize over what kind of steel alloy their pole screws are made of, and I bet the kind of steel alloy used in an OT core is just as important as that.

Paper bobbins don't sound any different to the modern nylon ones. Not in my 3dB Club anyway

I agree with you. heavey OPT will cause chunkier sounding. but heavey OPT will cause cost higher. so many factory make OPT smaller now.
otherwise, Prime Impedance relationship with bass FRQ. The thinne of coil, the turns of coil , how to turn coil effct sound also.Tube Guitar amplifier,effect pedal and studio gear manufactory kldguitar

[Wilder Amplification]

Gotta love all the cork sniffing that seems to go on in the guitar community these days.

While things like plate load differences, Sozos vs Mallorys, etc etc may/may not exhibit SLIGHT tonal differences depending on how discerning your ear is, it's nothing night and day that would matter on a live stage with the whole band playing anyway.

Now speakers on the other hand are a different story. They are what deliver your tone and they all have different frequency response characteristics/power ratings and will undoubtedly have a profound effect on your tone.

Transformer/chokes and things of that nature to me affect the dynamic "feel" of the amp more than anything. Output transformers can have varying degrees of low end due to core size, inductance, etc etc.

As Merlin Blecowe states...real tonal control comes from choice of circuit topology and component values used, not from the "gimmick number" of the tube or vintage of a certain component.

[Joey Voltage]

As Merlin Blecowe states...real tonal control comes from choice of circuit topology and component values used, not from the "gimmick number" of the tube or vintage of a certain component.

Does, or should?

I'm of sound mind that the player is the first thing in the signal path, which to me has the most significant effect, and control over how the amplifier sounds.(and I don't just mean the playing)