Why preamps have high outputs

[@janinapalmer8368]

It's the equivalent of audio comfort zone !

[@searchiemusic]

me looking at the 24V rails i'm soldering for my preamp right now: UHHHHHH BETTER TO BE SAFE THAN SORRY

[@stimpy1226]

Long ago and far away I sold my first great preamp, a Mark Levinson ML -1 to my good friend and replaced it with an Audio Research SP3A-1. He has never regretted his purchase and I never regretted mine. Looking back, I wish I never sold the AR but that’s the way it goes over many years of buying selling and trading.

[@jeremyhughes6485]

I don’t agree - it is extremely useful! Higher operating voltage means you can keep S/N to be as low as possible. The higher you operate above thermal noise the better. You should always try to run line level as high as possible in each line level stage in order to keep S/N as low as possible. It is simple enough to add a selectable resistor pad at the output of your active electronics or input to the next stage so as to handle the next gain stage - but once you accept to operate at low voltages anywhere in the chain then S/N will suffer. Pro audio runs at 1.2 volts and consumer audio is 316 mV - this is a factor of 4 - consumer audio has less headroom and inherently higher S/N. There are very good reasons to design gear that can operate internally at much higher voltage because lowering the noise floor is very difficult - so the best way to get better S/N is to raise the operating level even higher above the noise floor.

[@tomterrific9459]

Sounds 100% logical to me. Good answer

[@stuartshort1745]

Hey there thanks for the great content! I have a slightly unrelated question, please excuse me. Do you know if I can connect my REL Storm sub with the RCA connection to the tape out or preamp out connection on an amplifier? Thank you so much, Stuart

[@Paulmcgowanpsaudio]

Yes, as long as you are using the RCA outs and ins there's no restriction to what you can connect.

[@seanmangan2769]

The Benchmark amp can be set to need 9.8 volts for full output. ( Or 4 volts or 2 volts)

[@saiprasad8078]

Think like this if the source puts in 2v you get 16v (18 db gain) Your amp is at 1v sensitivity. What happens if the source material peaks at -6 db? In order to compensate for these irregularities outputs are designed in such a way.

[@salvadorrodenas3071]

I remember the titan series of musical fidelity and I observed with astonishment why that brand used final stage power transistors in the output stage of their preamps. I don't think that that kind of devices give their best linearity feeding an input power amplifier. I agree with Paul and I guess they use sensible parts for that kind of usage. No one uses an sledgehammer to hang a picture, isn't it?

[@DDSRacer01]

Would this also be the reason why amps should be more powerful than what the speaker can handle? For headroom?

[@searchiemusic]

exactly

[@ssks1979]

I think Paul skipped some details here. I agree that a preamp circuit should have lots of headroom but consider the typical situation where a CD player, tuner, etc. output 1V and the power amp outputs maximum power with 1V in. Any preamp with lots of gain will have its volume control close to minimum in normal situations. What's the point of having the volume control go from whisper quiet to frying speakers in just a few degrees of rotation?

[@tomterrific9459]

@Douglas Blake I have been in electronics all my life, and I still cannot understand this particular issue. How much sense does it make to manufacture a preamp that is capable of producing voltages capable of driving an amplifier into clipping ten times over?????

[@DDSRacer01]

@Douglas Blake is this why having an amp that is more powerful than what a speaker is rated to handle is better? For headroom? For example, the mono block amps I’m considering will supply 600watts each, but the speakers are only rated to handle 300w max. Is this good? I see a lot of hi fi setups do this, - big amps with more power than the speaker is designed for. Isn’t this bad for the voice coil. My belief is that the speaker will never see this much power, especially at one time, so it should be safe. Would like to know your opinion. Thx!

[@goransalomon5783]

It uselly stands 1.5v to 10V. What is it with the lowest number? I wonder if it starts wth lower 1V is it more ease to regulate the volumeat low sound? sorry I beleive it has to compare between preamp and amps ohm?

[@ThinkingBetter]

Having some dynamic headroom is great...but a too high output voltage of preamps yield an increase in accidents (too high volume) causing smoke from tweeters due to too much clipping, especially when the power amp doesn't have soft clipping.

[@jamesplotkin4674]

Well, that's the price you pay for having children ;-)

[@tristanjones7735]

Headroom does not beget a good amplifier. A good amplifier begets a lot of headroom. IDK where all this stuff about wanting headroom in excess of 10 times the output is coming from. You can simply figure out your load line, plot 2v worth of swing against the load line, and visually check to see where that swing would achieve the most linear response. Sometimes you will end up with a situation where your preamp will put out 20v. Other times you will end up with more or less than 20v. So long as your desired output is playing over the most linear region you can possibly play over, the headroom really doesn't matter.

[@thomass.9167]

I suppose this is the equivalent of asking why an exotic sports car puts out 1,000 hp when you can only go 70 mph on the highway. Headroom.

[@hugobloemers4425]

Because Germany

[@csabakereszturi945]

930 hp headroom? No, that’s just for today’s greedy plutocracy.

[@net_news]

acceleration, response, torque, ecc

[@HareDeLune]

@@hugobloemers4425 Au-to-baaaaaaahn!

[@briansimmons5363]

So let's see. Amp reaches full volume at 2 volts, preamp puts out 20 volts. Does that mean if you move the volume up 10% (2 volts) or a couple of clicks the amp is now at full volume?

[@paulstubbs7678]

That would mean the pre-amp innards are now being driven to near 100%, so it no longer has any head room, the very thing they were using to give them a 2V 'sweat spot', so while the amp is technically not being overloaded, it is being driven to it's non-linear-ish extremes, and as such will sound far from optimal. i.e. potentially quite horrible. A 'normal' source will not have enough level to do that, it will probably drive it somewhat over 2V out, if you crank the volume knob all the way, but that is just to allow for weak/soft sources.

[@InsideOfMyOwnMind]

Paul did great. I would have been an ass and just said "Because reasons."

[@limitlesssky3050]

Or maybe you don't actually know the reasons.

[@laurentzduba1298]

Its all in the name of headroom - my ECC88 tube based preamp puts out 125 volts at no load condition when measured with a high impedance voltmeter but falls to 20 volts once connected to a power amp with a 150,000-ohm input impedance.

[@hugobloemers4425]

The ECC88 is an RF TV Tube designed to run at 90V anode voltage. It works well for HiFi but is typically still running around 90V and has quite a high bias current for a pre-amp triode (5 times the ECC83 so it should have a much lower output impedance). If you get a 125V signal out of it then it must be a real oddball design. And if it collapses with a 150kOhm load, I would harvest the tube and find an other amp for it.

[@michaellee6654]

snr optimization and pro power amps

[@tonelab]

I wanna send a question in 🤓

[@hugobloemers4425]

Make sure the question matches what Paul wants to tell us about his gear.

[@jimsregaturntableshifijukebox]

@@hugobloemers4425 brilliant! 😂 😂 😂 😂 😂 😂 😂 😂 😂 😂 😂 😂 😂

[@googoo-gjoob]

youre a baaaaaaad boy

[@NoEgg4u]

Consider a 4-cylinder car that can reach 60 MPH in 7 seconds, when floored. But you can feel the engine making the effort. Compare that to a Corvette, just accelerating to 60 in 7 seconds (it can do it faster -- but for this example you gave it just enough gas for it to take 7 seconds). Well, that Corvette will not feel like it is making an effort. The Corvette will be in its comfort zone, while the 4-cylinder car will be at its design limit. And so it is with pre-amp voltage output. You want your pre-amp to be at ease, all of the time. You want it to be well within its comfort zone. Cheers!

[@josefbuckland]

Mmm but there is not as much headroom in the corvette damn sports cars don’t work for tall people like me 😅

[@mkashiff1]

Finally a question from Pakistan.

[@googoo-gjoob]

hahahahaha

[@johnsweda2999]

What's at 20 ppv

[@traveler9573]

About 7.07 Volts RMS....................PP/2*.707

[@johnsweda2999]

@@traveler9573 there's a misleading figure for you typical overhyped engineer bs lol

[@petermartin9494]

It is useful for advertising.