Clean Headroom

[robinrockus]

One of those things, we have to take what the OP has said to be as what it is. A Fender BDRI, (Blues Deluxe). No mention of any changes to pickups or whether he ate a piece of pie that day. We have to assume the previous tubes were operating correctly otherwise what is the point of the thread?

I dont think so. There are 35 watt old amps that are dirty at low levels and dirty at high levels also. There are a lot of things going on.
There are 20 watt amps that are very clean.
There CAN be a relationship of power to clean, but not necessarily is.
The question here maybe is: "do power tubes have an effect on headroom or clean vs dirty sound?"
I think the answer is "yes", otherwise all this talk about great old US made tubes is bunk.
However I'm not a big proponent that the brand of tube normally makes a huge difference at all, barely audible in my book.

And it worries me that putting some Jan tubes in, and they sound cleaner than JJ's, because JJ's have a rep for sounding a little bit like 6L6's, which are normally much cleaner sounding than 6V6's.
But I think old GE power tubes often sound very clean like JJ's..

I’ve found that even JJ tubes can vary. Pre amp and/or power tubes. The JAN pre amp tubes have longer plates that occupy almost the entire length of the tube, whereas newer tubes those plates are shorter. In a different blog I read recently one gentleman stated that he had purchased old amps that had their original tubes in them and they worked perfectly. Btw I used the same guitar for each test run. No pedals. You can even get different breakup results by turning the master volume up and the drive volume down. I like to experiment, and find a “sweet spot “ and that can vary from practice room to venue and from venue to venue. Acoustics and conditions play a role as well.

 

[printer2]

Realized I was wrong about the amp being a non-master. If the master is turned down then different tubes can effect the amount of headroom in the preamp.

I dont think so. There are 35 watt old amps that are dirty at low levels and dirty at high levels also. There are a lot of things going on.
There are 20 watt amps that are very clean.
There CAN be a relationship of power to clean, but not necessarily is.
The question here maybe is: "do power tubes have an effect on headroom or clean vs dirty sound?"
I think the answer is "yes", otherwise all this talk about great old US made tubes is bunk.
However I'm not a big proponent that the brand of tube normally makes a huge difference at all, barely audible in my book.

And it worries me that putting some Jan tubes in, and they sound cleaner than JJ's, because JJ's have a rep for sounding a little bit like 6L6's, which are normally much cleaner sounding than 6V6's.
But I think old GE power tubes often sound very clean like JJ's..

But we are talking the same amp, not different amps. A 35W amp should be able to put out 35W of clean power (5% THD or there about). To say it is only a dirty amp can have use take a Deluxe Reverb which is normally a 20W amp and overdrive the output stage resulting in 30W. Is there a relationship between the amount of power to clean output? Darn rights, I have yet to come across an amp that can not clip the output section with a clean signal.

On the headroom end, how much is noticeable? Under controlled listening I would say a difference of 1-2 dB is the low end of what we can perceive as a difference in volume. How much difference can we detect after a given period of time? Since 3 dB is a doubling of power, can a tube change give a doubling (or reduction of a half) in power? As Wally said, a difference in bias current can change what an amp could put out. Bias the tubes cold and you have more "room" for the signal before the tubes red plate. My bench is a storage space for stuff I do not want to deal with at the moment so no testing, maybe I will think about it tonight. Set the bias at 50% and test clean output and then at 70% test for maximum output.

I’ve found that even JJ tubes can vary. Pre amp and/or power tubes. The JAN pre amp tubes have longer plates that occupy almost the entire length of the tube, whereas newer tubes those plates are shorter. In a different blog I read recently one gentleman stated that he had purchased old amps that had their original tubes in them and they worked perfectly. Btw I used the same guitar for each test run. No pedals. You can even get different breakup results by turning the master volume up and the drive volume down. I like to experiment, and find a “sweet spot “ and that can vary from practice room to venue and from venue to venue. Acoustics and conditions play a role as well.

Yes tubes vary, I have no experience with JJ's though, have enough old stock tubes and only bought one 12AY7 as the one I had went out with an amp (I did get it back years later). I can see different sets of tubes needing a different amount of drive to produce the same output. This can change where the controls are set on the panel to find the sweet spot. Do not mean to be contrary (and I'll bow out as I never meant to be here this long) just question perceptions about listening to a 40W amp at full output at home. Heck, used to do sound and used a SPL meter as our hearing shifts and loud is subjective. With our ears hearing a distorted signal sounding louder than a clean one it can be tough to really know where you are. At least to the point of I would not bet money on our perceptions over time. Sorry for all the commotion. (I just get triggered when I see Clean Headroom).

 

[scottser]

Fastest way to clean headroom is a more efficient speaker.

 

[middy]

I think we read that all the time "clean headroom". Two 5W amps have the same power; one is dirt all the time, the other plays clean all the way up the dial. The second one has more clean headroom.

No. Whichever one is louder when clean has the most clean headroom. The dial position means nothing.

 

[robinrockus]

Realized I was wrong about the amp being a non-master. If the master is turned down then different tubes can effect the amount of headroom in the preamp.


But we are talking the same amp, not different amps. A 35W amp should be able to put out 35W of clean power (5% THD or there about). To say it is only a dirty amp can have use take a Deluxe Reverb which is normally a 20W amp and overdrive the output stage resulting in 30W. Is there a relationship between the amount of power to clean output? Darn rights, I have yet to come across an amp that can not clip the output section with a clean signal.

On the headroom end, how much is noticeable? Under controlled listening I would say a difference of 1-2 dB is the low end of what we can perceive as a difference in volume. How much difference can we detect after a given period of time? Since 3 dB is a doubling of power, can a tube change give a doubling (or reduction of a half) in power? As Wally said, a difference in bias current can change what an amp could put out. Bias the tubes cold and you have more "room" for the signal before the tubes red plate. My bench is a storage space for stuff I do not want to deal with at the moment so no testing, maybe I will think about it tonight. Set the bias at 50% and test clean output and then at 70% test for maximum output.


Yes tubes vary, I have no experience with JJ's though, have enough old stock tubes and only bought one 12AY7 as the one I had went out with an amp (I did get it back years later). I can see different sets of tubes needing a different amount of drive to produce the same output. This can change where the controls are set on the panel to find the sweet spot. Do not mean to be contrary (and I'll bow out as I never meant to be here this long) just question perceptions about listening to a 40W amp at full output at home. Heck, used to do sound and used a SPL meter as our hearing shifts and loud is subjective. With our ears hearing a distorted signal sounding louder than a clean one it can be tough to really know where you are. At least to the point of I would not bet money on our perceptions over time. Sorry for all the commotion. (I just get triggered when I see Clean Headroom).

No commotion! Just discussion, that’s what this forum is for! Cheers!

 

[FenderLover]

No. Whichever one is louder when clean has the most clean headroom. The dial position means nothing.

No. you seem to be talking about volume regardless of the character of the signal. <any>Watts of all clean has more clean headroom than <any> watts of all dirt.

 

[middy]

No. you seem to be talking about volume regardless of the character of the signal. <any>Watts of all clean has more clean headroom than <any> watts of all dirt.

Nothing is "all dirt" you can always dial back gain somewhere. I'm not even sure what your point is.

Understanding Headroom in Guitar Amps

Headroom is a term used to denote and describe how much power your amp can provide before the sound starts to break up.

www.fender.com

 

[robinrockus]

Fastest way to clean headroom is a more efficient speaker.

Absolutely! Any amp, tube, solid state, hybrid, will sound better with a great speaker. I have a fondness for Celestions.

Nothing is "all dirt" you can always dial back gain somewhere. I'm not even sure what your point is.

Understanding Headroom in Guitar Amps

Headroom is a term used to denote and describe how much power your amp can provide before the sound starts to break up.

www.fender.com

My original post was in regards to antique tubes vs. newer ones. I find tone and output of different brands varies as well. The aforementioned BDRI came with Groove Tubes, preamp and power. They were loud as all get out, but had almost no sweetness to them at all. JJs have good tones, and were not quite as loud. The JAN Phillips/Sylvania are loud, clean and have some sweetness to them. To my ears, 12ax7s can vary. And when I compare loudness, I’m referring to the same guitar on the same amp settings. Biasing the amp was also mentioned.Per Eurotubes website, I experimented with different bias as well. I didn’t detect much of a difference in the range they recommend (70-90) at the test point. I returned it to the original factory setting which was about 68. With those JAN tubes, the amp seemed louder at certain points in the range but breakup didn’t (to my ears) change that much. I like the amp a lot, irrespective of tubes or bias. I just audibly notice differences between tubes and brands.

 

[telemnemonics]

I thouht the BDRI used 6L6?
Blues Deluxe?

Not going to bother arguing that the amp must be louder to be cleaner, just not my concern and in some cases the max volume is distorted with a smallish OT saturating so that full volume situation may not apply to turned way clean down volume.
Or maybe it does.
Also clean vs headroom, two different things we may interchange.

@robinrockus are the JAN Philips 6v6, black plates?
I have a couple of pairs that are which is odd since the ones I have are 1980s production when black plates were really not made any more.
But they are very clean bright clear 6v6 tubes in any amp I have put them in.
Sometimes too bright!
Of course if the amp is cathode biased we hear the bias as well as the tube itself, but my sense is that the 1980s JAN Philips black plate 6v6 is a clean bright tube. If that is what you got.
Not sure about more watts.
Sometimes a perceived cleaner sound is as much an eq thing as a lack of clipping.
I think of the JJ 6v6 as clean and bright too, but never compared them, not really using those. Could be a brighter 12ax7 or fresh PI is part of what you hear.

These?

 

[Wally]

Biasing the amp was also mentioned.Per Eurotubes website, I experimented with different bias as well. I didn’t detect much of a difference in the range they recommend (70-90) at the test point. I returned it to the original factory setting which was about 68.

and what was the plate voltage at those settings? Different tubes will operate very differently and with different plate voltage compared to other tubes. It is surprising sometimes to see the difference. Without knowing the plate voltage, one cannot ‘now what the plate dissipation is, and plate dissipation is the important number.

 

[peteb]

So the amp makes more power now?

No, just more clean headroom.

The amps power didn’t change, just how much louder it can be before natural breakup(distortion) begins. That would be my definition of clean headroom.

does a higher power amp have more headroom?

does a higher power amp have more power?

compare 2x6V6 versus 2x6L6

which one has more power and which one has more headroom?



I see a positive correlation between output power and clean headroom.

YMMV.

 

[robinrockus]

I thouht the BDRI used 6L6?
Blues Deluxe?

Not going to bother arguing that the amp must be louder to be cleaner, just not my concern and in some cases the max volume is distorted with a smallish OT saturating so that full volume situation may not apply to turned way clean down volume.
Or maybe it does.
Also clean vs headroom, two different things we may interchange.

@robinrockus are the JAN Philips 6v6, black plates?
I have a couple of pairs that are which is odd since the ones I have are 1980s production when black plates were really not made any more.
But they are very clean bright clear 6v6 tubes in any amp I have put them in.
Sometimes too bright!
Of course if the amp is cathode biased we hear the bias as well as the tube itself, but my sense is that the 1980s JAN Philips black plate 6v6 is a clean bright tube. If that is what you got.
Not sure about more watts.
Sometimes a perceived cleaner sound is as much an eq thing as a lack of clipping.
I think of the JJ 6v6 as clean and bright too, but never compared them, not really using those. Could be a brighter 12ax7 or fresh PI is part of what you hear.

These?
View attachment 1075387

Yes indeed, they look very similar. Plates in the ones I have are more grey, but that could be lighting. And yes, the amp is louder with the JAN 12ax7s. As stated previously, the plates in them are twice as long as any newer 12ax7. Highs are not harsh, at least for my ears. I use the rule of 6s, except for bass and mids, which is set around 2.5. BDRIs have a ton of bass irregardless of tubes. I was kinda surprised at the lack of change in tone occurred when adjusting the amp’s bias had. Thanks

 

[telemnemonics]

Yes indeed, they look very similar. Plates in the ones I have are more grey, but that could be lighting. And yes, the amp is louder with the JAN 12ax7s. As stated previously, the plates in them are twice as long as any newer 12ax7. Highs are not harsh, at least for my ears. I use the rule of 6s, except for bass and mids, which is set around 2.5. BDRIs have a ton of bass irregardless of tubes. I was kinda surprised at the lack of change in tone occurred when adjusting the amp’s bias had. Thanks

FYI those 12ax7 plates being so long is not better or worse. Those are called long plates, and later we got the short plate design do reduce feedback squeal microphonics by reducing the size of the plates which can actually resonate from being attached to the box with the speaker in it.
Long plates can still resist squeal but are more prone and may develop squeal as they age if used in a box that vibrates like a combo amp.

 

[zhyla]

Probably means you can turn the knobs farther without it distorting. I know it's not the correct definition, but many people on forums consider it as such.

Ding ding ding.

There’s slight variation in amplification factor (“mu”) which can change the output volume a bit.

I have a hard time believing there is enough variation in tubes of the same type as far has where they enter cutoff to noticeably impact headroom. The specs are clear for these parts.

No offense OP, I think your methodology isn’t sufficient to draw the conclusion you drew. But glad you like the tubes.

 

[Burning Fingers]

Everyone is always talking about clean headroom. I recently bought some antique tubes on EBay; JAN Sylvania 12ax7s and JAN Phillips 6V6s to go in my Fender BDRI. Lemme tell ya, it’s super clean now even on the Drive channel. I have been using JJs. They’re fine, but the tone and clean headroom from those old US made tubes is remarkable.

The JJ 6V6 tubes you replaced...how long had they been in use ?

I usually hear a difference when I replace old power tubes with new ones... clearer , tighter bottom end and more volume.

 

[howardlo]

Reading this thread makes me very glad that I am into tube amps.

People say of solid state modeling amps that they don’t like having to spend time tweaking settings, etc. That sounds much easier (and cheaper) than tweaking with tubes, bias settings, etc.

 

[Brent Hutto]

Reading this thread makes me very glad that I am into tube amps.

People say of solid state modeling amps that they don’t like having to spend time tweaking settings, etc. That sounds much easier (and cheaper) than tweaking with tubes, bias settings, etc.

Yeah, it always slays me when someone who has spent years rolling tubes any time they want to tweak the sound of their tube amp (or even having their "amp guy" swap out caps or clip leads inside the amp) refuse to consider buying any amp lets you plug a laptop into a USB port and tweak settings.

 

[howardlo]

Yeah, it always slays me when someone who has spent years rolling tubes any time they want to tweak the sound of their tube amp (or even having their "amp guy" swap out caps or clip leads inside the amp) refuse to consider buying any amp lets you plug a laptop into a USB port and tweak settings.

My Fender GTX50 is easier yet. I can use the app on my phone through Bluetooth to tweak settings, change amps, cabs, add or remove effects and save and recall as many presets as I like from wherever I happen to be sitting. You can save the presets into playlists.

 

[robinrockus]

Ding ding ding.

There’s slight variation in amplification factor (“mu”) which can change the output volume a bit.

I have a hard time believing there is enough variation in tubes of the same type as far has where they enter cutoff to noticeably impact headroom. The specs are clear for these parts.

No offense OP, I think your methodology isn’t sufficient to draw the conclusion you drew. But glad you like the tubes.

I find brands of tubes can be hugely different. Groove Tubes are LOUD. But not pleasant sounding. The JAN tubes are loud too but retain good tonal quality. JJs are not quite as loud but they’re reliable and always sound good. Electro Harmonix are fair on both accounts, and breakup quickly. So far, the best combination is JJ 5881s (Fender manual recommended for this BDRI) with the JAN preamp tubes (all AX7s). BDRI is solid state rectifier so it can handle most anything. JJ 6V6s are rated for the plate voltage, so I might try a pair of those when the 5881s wear out…who might be a while. Guitar and pickups also have an impact on breakup (of course). Thanks for everyone’s input!

 

[robinrockus]

Aaand on a different note, it sure seems like a Fender Super Sonic would be a cool amp to try. I mean the thing has five preamp tubes!