The more I read about the analogue audio the more I see references to transformers being part of the "tube Sound". Tube preamps are less about fullness and more about angry distortion. Plus its a heavy piece of kit.
Now, you will counter with "if you want a tube sound, get a tube amp". yada, yada, yada. I have the amp I want. Its mostly solid state, Lightweight, reliable and flexible. I can take it on the London underground with a bass and a speaker cab. I would like a little more bass warmth though(not fuzz, or overdrive)
So I read that putting a transformer in the chain will often do that. I don't know it that means finding most transparent component or the cheapest and worst. I don't know if I need to generate saturation, in a tiny tranny or if a higher power rated one is best? I make the assumption that a 600 OHM 1:1 device place in my send/return loop is the target.
Who can tell me about the appropriate theory?
Now, you will counter with "if you want a tube sound, get a tube amp". yada, yada, yada. I have the amp I want. Its mostly solid state, Lightweight, reliable and flexible. I can take it on the London underground with a bass and a speaker cab. I would like a little more bass warmth though(not fuzz, or overdrive)
So I read that putting a transformer in the chain will often do that. I don't know it that means finding most transparent component or the cheapest and worst. I don't know if I need to generate saturation, in a tiny tranny or if a higher power rated one is best? I make the assumption that a 600 OHM 1:1 device place in my send/return loop is the target.
Who can tell me about the appropriate theory?
where did you read this? i bet it was on the internet!!!
so you really don't have the amp you want 'cuz it needs a little more bass warmth!?
and as far as "saturating a tiny tranny" that does sound like something that happens on the underground mostly late at night.
seriously i don't think that adding a tranny in line is going to "warm up " the sound without additional drawbacks like insertion loss and response /gain anomalies requiring more engineering workarounds that it's worth.(unless something like saturation or frequency response changes produce a useable effect musically)
so you really don't have the amp you want 'cuz it needs a little more bass warmth!?
and as far as "saturating a tiny tranny" that does sound like something that happens on the underground mostly late at night.
seriously i don't think that adding a tranny in line is going to "warm up " the sound without additional drawbacks like insertion loss and response /gain anomalies requiring more engineering workarounds that it's worth.(unless something like saturation or frequency response changes produce a useable effect musically)
Naturally the internet is a good resource. Is it worse that the hyperbole used to advertise equipment that we don't need or doesn't work and that we don't understand? Well this talks about output transformers:- Valve Amps: Output transformers
This deals with recording level parts:- Using Transformers to Transform Audio | Allen Farmelo
Analogue warmth in general:- Analogue Warmth
So I'm working on the basis that its real and that the folks on the DIYaudio forum know more than accepted tube legend. If there is a different section I should be in please advise and I'll post there.
This deals with recording level parts:- Using Transformers to Transform Audio | Allen Farmelo
Analogue warmth in general:- Analogue Warmth
So I'm working on the basis that its real and that the folks on the DIYaudio forum know more than accepted tube legend. If there is a different section I should be in please advise and I'll post there.
Hi,
You are basically correct. I gave up on understanding tranny guitar
amplifiers a long time ago, (compared to hifi), but Peavey for one
company used a small transformer in the driver stage in their bass
combo's for no good reason other than sound. AFAICT no overall
feedback and a very progressive overload characteristic.
Small interstage transformers can give interesting output drive options.
TBH though its been many years since I looked at the Peavey schematics.
rgds, sreten.
Typical send/return loop impedances won't remotely stress a 600 ohm 1:1.
Even loading the return to 600R won't mean the Send struggles way before
the transformer does.
You are basically correct. I gave up on understanding tranny guitar
amplifiers a long time ago, (compared to hifi), but Peavey for one
company used a small transformer in the driver stage in their bass
combo's for no good reason other than sound. AFAICT no overall
feedback and a very progressive overload characteristic.
Small interstage transformers can give interesting output drive options.
TBH though its been many years since I looked at the Peavey schematics.
rgds, sreten.
Typical send/return loop impedances won't remotely stress a 600 ohm 1:1.
Even loading the return to 600R won't mean the Send struggles way before
the transformer does.
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So which is more "interesting" in HiFI Cheap and nasty or expensive and clean? Which would make the bottom end go "boof"? (completely undesirable in HIFI).
Hi,
Not so. Bass distortion in valve amplifiers makes
bass lines easier to follow though clearly wrong.
You have to run a transformer at its limits which
is clearly the case for valve output transformers.
Lower level transformers are usually not pushed
to the limit, and are relatively transparent used
properly, they need misusing to distort usefully.
rgds, sreten.
Not so. Bass distortion in valve amplifiers makes
bass lines easier to follow though clearly wrong.
You have to run a transformer at its limits which
is clearly the case for valve output transformers.
Lower level transformers are usually not pushed
to the limit, and are relatively transparent used
properly, they need misusing to distort usefully.
rgds, sreten.
'Warmth' is a completely meaningless term - and has no application in audio.
If you mean distortion, then say so - which is the main effect valve amps give you, along with greater noise levels and poor frequency response.
Personally, although you asked not to be told this 😀, I would say get a valve amp if you want the valve sound - it's the ONLY way - but as such sound is entirely subjective you probably wouldn't like it anyway.
Adding a transformer isn't going to help, the lower quality is caused by overdriving the valves and transformers.
In a push pull tube amp the "warmth" is often low frequency end 2nd harmonic distortion. It occurs when the inductive impedance of the output tranny primary inductance falls (with frequency) and approaches (and finally dips below) the rp of the output tubes.
That is why you often see the claim that no output tranny means no tube amp sound.
That sound is the subjective "artificially" strong bass sound due to that low frequency 2nd harmonic distortion. AS the frequency goes up and the impedance from the primary inductance becomes much larger than the output tubes rp, this type of distortion disappears.
This (in my opinion) is the principal "tube sound" that people talk about, even when they don't know what it is that they are talking about. ONLY one mans opinion.
Can you get that sound using an interstage tranny? Probably but you need to use a "compromised" design to get that same low primary impedance vs driver rp at the low frequency end. Either a high rp driver or a low primary inductance tranny would probably work.
Cheers,
Ian
EDIT: Do I have experimental evidence of this "opinion", well yes, I built a pair of monoblocks each with a quad of KT88 into Hammond 1650T output trannies which have 57H primary inductance. I then replaced the output trannies with Plitron Torroidal output trannies with 560H primary inductance. The bass went deeper but was subjectively weaker and the "tube amp warmth" disappeared. I ended up putting the Hammonds back in coz I liked that sound.
That is why you often see the claim that no output tranny means no tube amp sound.
That sound is the subjective "artificially" strong bass sound due to that low frequency 2nd harmonic distortion. AS the frequency goes up and the impedance from the primary inductance becomes much larger than the output tubes rp, this type of distortion disappears.
This (in my opinion) is the principal "tube sound" that people talk about, even when they don't know what it is that they are talking about. ONLY one mans opinion.
Can you get that sound using an interstage tranny? Probably but you need to use a "compromised" design to get that same low primary impedance vs driver rp at the low frequency end. Either a high rp driver or a low primary inductance tranny would probably work.
Cheers,
Ian
EDIT: Do I have experimental evidence of this "opinion", well yes, I built a pair of monoblocks each with a quad of KT88 into Hammond 1650T output trannies which have 57H primary inductance. I then replaced the output trannies with Plitron Torroidal output trannies with 560H primary inductance. The bass went deeper but was subjectively weaker and the "tube amp warmth" disappeared. I ended up putting the Hammonds back in coz I liked that sound.
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It is possible to put something interstage (the effect loop is between preamp and power section). Yes I know that it would be a distortion of the pure bass sound, but the note creation process is not supposed to be HIFI.
Typically transformers used in balanced line and DI boxes are 1:1 600 Ohm, although the quoted input impedance is 33KOhm! This much I know. My real question is "what do I do now?"
Typically transformers used in balanced line and DI boxes are 1:1 600 Ohm, although the quoted input impedance is 33KOhm! This much I know. My real question is "what do I do now?"
Have a look at this Application note to understand transformer impedances.
Your "knowing" is incorrect.
Jensen AN002
"transformer itself has no intrinsic impedance. It simply reflects
impedances, modified by the square of the turns ratio, from one
winding to another."
Thanks guys, So far we have reached the point where we agree that 1/ transformers are not linear. 2/ Doing this will change the sound. this is good. This brings us back to the original question:-
The reason I don't post this on a musicians forum is that they mostly don't understand the theory either, and would point me at 100 valve distortion pedals - also not the way.
Djgibson - The send/return on Littlemark tube amps are factory set to parallel but I have reset the jumpers to make it series.
The reason I don't post this on a musicians forum is that they mostly don't understand the theory either, and would point me at 100 valve distortion pedals - also not the way.
Djgibson - The send/return on Littlemark tube amps are factory set to parallel but I have reset the jumpers to make it series.
Yes, if you build a tube power amp, you will need an OT to couple it to the speakers, there's no other way.
So yes, it is a part of tube sound, like it or not.
Compared to what?
You do not say so.
If you mean: "tube Pre vs. tube Power amp", yes, in general preamp clipping is buzzier than power amp clipping, for multiple reasons.
One of them being that a Power amp clipping goes through an OT straight into a speaker, not many chances of messing with it, while Preamp clipping (of any kind) still has to go through other stages, which can either improve or worsen the sound.
Also preamp tube clipping in general involves single triode stages and can (and usually does) clip very assymetrically, while power tubes in general are push pull, this cancels a lot of harmonics, and the OT is the reason for that, so you can say that it definitely does modify sound.
Because of internal nonlinearities?
Well, there's some of that, but the main part lies in its architecture, the way it's connected and how it combines 2 out of phase signals into a single one which is fed to the speaker.
See above.
Glad you found your soulmate, pity it's not a tube amp because it will not sound as such.
You also imply it's a very small amp.
Bass unfortunately requires large cabinets, doubly so if you insist on a full, warm, thick sound.
Plain Acoustics, beyond what Electronics can do.
Ok, if a little is enough, you can get some electronically.
Just don't hold way too high expectations.
That bass warmth you wish is in general terms:
* somewhat emphasized low mids , plus a low damping power amp, plus a little natural compression if playing loud, plus an underdamped larger than normal cabinet plus somewhat restricted frequency response, which "rounds" (literally) the somewhat distorted waveforms which otherwise would sound somewhat buzzy*
As you see using a tube power amp, loud, into a large classic cabinet will give you all the tube warmth you wish and then some.
Since you use an SS amp driving a tiny cabinet (any bass cabinet you can carry in your hand in the subway is tiny) it's a huge, almost impossible task, sorry.
Now if you want a modest amount of it, adding a fully adjustable, studio quality compressor, can simulate the compression and even some of the "growl" , and a Parametric EQ can simulate the cabinet resonances and bandwidth limitations.
Just by itself?
I'd love it could be that simple, unfortunately it's not, see above one way to simulate it.
See above one way to simulate it.
No, not at all.
One of your links says so, but it's an absolute truckload of cr*p .
Excuse the French.
Read above.
In a nutshell, it *can* be done, it takes some extra studio quality stuff (even home studio will do) , never as simple as just tucking a line transformer in the effects loop 🙄
If recording, you may use software versions of what I suggest ... although it will be more straightforward to use, say, the SVT emulation plugin and the 8x10" emulation one.
There are many other great classic Bass tube amps which can be used (virtually, that is).
I owned a LittleMark II at some point in time, and it had all the low frequency response I could ever wish for. Sounded way bigger than the small enclosure would let you to believe. It did have the tendency of higher frequency distortion which could be annoying, but the VLE or tweeter volume would take care of that.
'Warmth' is a vague term used to describe many different audible impressions, and to be honest, your definition of 'tube sound' is not correct either. But if you need an extended, powerful low-end response, the amp is not the problem. A cab, small enough to carry on the subway, most likely is. Not knowing what you use now, I'd advice you to forget about transformer trickery (not going to work anyway), and go and listen to your LittleMark on a set of properly sized 12" cabs and be amazed 😀.
'Warmth' is a vague term used to describe many different audible impressions, and to be honest, your definition of 'tube sound' is not correct either. But if you need an extended, powerful low-end response, the amp is not the problem. A cab, small enough to carry on the subway, most likely is. Not knowing what you use now, I'd advice you to forget about transformer trickery (not going to work anyway), and go and listen to your LittleMark on a set of properly sized 12" cabs and be amazed 😀.
I said that the AMP is small (compared to a steel chassis full of KT88s). The cab is a Barefaced 2X12 -plenty of everything but weighs about 40lb. I don't think I said "carry" either. The amp goes in a rucksack and the cab on a lightweight barrow.
No you didn't. 🙄
Actual quote above.
Thanks for nitpicking but specially for hiding essential information until the 15th post.
Side note for non British speakers:
A "barrow" as mentioned above is slang or shortspeak for "wheelbarrow" :
An externally hosted image should be here but it was not working when we last tested it.
although certainly useful and actually needed to carry a 2x12" Bass cabinet any real distance, is not what first comes to mind when the Subway is mentioned .
I'd love to see it going through typical rotating gates, or the hate in other passenger's eyes when one of these (with a 2x12"cabinet strapped to it) is pushed inside one of the crammed and small, claustrophobic London Tube wagons.
For those who think I am nitpicking, these are Merriam Webster's (part of Encyclopædia Britannica) first definitions of the word:
Yes, the third accepted meaning refers to:
which is what I illustrated above.
I bet the Subway people get very happy when they see you 😉
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The "Essential" information? I have the amp I want. That's it. Done.
The QUESTION was about exploring the changes in tone resulting in passing a signal through a transformer.
So far, other than acknowledging an effect through a OT transformer this forum has only managed to say it can't be done or that I didn't use the correct words. Carry on nitpicking. No one has produced any science.
Pbassred is putting his amp in a burial mound and is off to buy a sandwich. Once again this forum has produced no knowledge.
Bye Bye.
The QUESTION was about exploring the changes in tone resulting in passing a signal through a transformer.
So far, other than acknowledging an effect through a OT transformer this forum has only managed to say it can't be done or that I didn't use the correct words. Carry on nitpicking. No one has produced any science.
Pbassred is putting his amp in a burial mound and is off to buy a sandwich. Once again this forum has produced no knowledge.
Bye Bye.
the "science" of transformers is to make them as transparent as possible so that they don't produce audible effects. your desire to have them produce audible changes to the frequency response of your amp is a contradiction to how they are supposed to function.
would the subtle, possibly indistinguishable, difference be considered usable or worthwhile?
would the subtle, possibly indistinguishable, difference be considered usable or worthwhile?
Well said. The OP's problem is that he did not get the answer that he wanted. I feel the forum provided plenty of food for thought on the subject. Why didn't the OP just hook up a tranny and try it out? Nothing wrong with a little experimenting. I enjoy the trial and error part of rebuilding old Hammond organ and PA amps. Try hotter bias, bypass the cathode, change the coupling cap, etc. He "knew"? that the 600 ohm 1:1 was the way to go. OK, hook it up and see. Art M had an excellent response to this in post #10. I think he was never really was going to get a satisfactory answer to his liking. Tube amp sound=tube amp. His kiss-off to the forum in post #17 just exposes his ignorance. If he has the "amp he wants", why all the fuss? He already did his own research. He just wanted to pick a fight.
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