don't know opt's output

[bnew63]

Hi first post on this site
I have an  OPT off an old organ amp.
I was told it was a hammond organ but there is no identifying marks or numbers to tell me what it really is.
How can I test to see what the output would be.

Thanks Brian

[tubesornothing]

Get out your ohmmeter.  Use it to determine pairs of wires - write down the wire colors and the resistance between them.  The primary will measure  about 100-900k, the secondary will measure very low. Any taps will be a smaller resistance between the larger resistance.  If you have lots of wires, it will take a bit to figure it out.

The get out your signal generator or variac.  Put in 1V AC into the secondary (100-500Hz is good if you can).  Measure the voltage on the primary (15-60V).  This will be the turns ratio.  Square the turns ratio and you will have the impedance ratio. 

If you put on a 8ohm output load, multiply it by the impedance ratio and you will get the primary load.

[andrew_k]

In a nutshell, you disconnect the OT and put a small AC voltage across the secondary (I often use the ~3V of half a centre-tapped heater winding), then measure what comes out across the primary. Divide primary AC Vout by secondary AC Vout and you have your winding ratio; eg: 25:1. Square that (eg: 625:1) and you have your impedance ratio. Now you can work out the reflected impedance for various speaker loads.

Using the above examples, an 8 ohm load through a 625:1 imp. ratio would be a ~5k primary.


[edit]: should have realized someone else would reply while I was typing this 

[Dave]

I think he is asking about the power output of the OT.
What the other guys told you is good for knowing, generally what kind of speaker load you can match to what kind of tubes.
As far as how much power, I think it would be much harder to say with any degree of certainty.
In other words, you could measure a Twin Reverb OT and come to the conclusion that it is used for one PP pair of 6L6's into 8 ohms when in fact, it is for 4 6L6's into 4 ohms.
So, electrically, it would be hard to answer your question with any degree of certainty.
The best you can do, that I am aware of, is use the electrical readings and add that to the physical size of the OT and make your determination based off prior experience.

Dave

[tubesornothing]

If he wants to know the power output - weigh it.  Go to the Hammond transformer web site and look up similar OTs and the weight.  THat'll get you close.

[Dave]

That's a great idea. Kudos to you sir !!!!

Dave

Also, I would add that there were oodles of Hammond organs that had built in power amps and the majority of them used either a PP pair of 6V6's at a wattage somewhere in the teens or a PP pair of 6BQ5's also somewhere in the teens.
The 6V6 organs typically had a "chassis thru" type OT that was particularly small and the 6BQ5 ones had an OT that was mounted upright.

When I say teens, what I really mean is 11 or 12 watts. But those are organ watts and also have to power bass frequencies, so they are probably good for a little more than that in a guitar amp.

Most of the bigger power amps were not in the organ, but in a Leslie.

[bnew63]

Thanks for the quick answers.
The amp I took the opt of off had 4 6v6's so I was hoping it was above the 30 watt range.
It weighs in at 4 lbs.
Is there a way to tell in appearance if it is a SE or PP OPT.

Brian

[Dave]

If it had 4 6V6's, it is almost definately PP.
The primary side should have 3 leads (or 2 if it is SE).....
Probably (most likely but not for sure) Red Blue and Brown. If that is the case, then Red should be the CT that connect to B+ and the other 2 are ends that connect to the output tube plates.
The other side will have all the speaker taps (probably a whopping two / black and green).
If the OT was running 4 6V6's, it probably is a 25-30 watt OT (again, for guitar, a little more than that can be squeezed out).

Be sure that there is not another OT in there, and if this OT was running all four 6V6's and they were cathode biased (most likely) then you could probably use it for 30 watts in a guitar amp. If you wanted to be surer, it would help to know what the B+ voltage was, and if it was in fact cathode biased.

Dave

[Shrapnel]

It may as well be about 30w with 4-6V6 tubes. I'd also find a manual on that organ and see what they claimed output power was.

I've got one sitting here that I may or may not use from an old Lowery DSA. The manual said it was 30 watts of power out. It probably is too since it had 7591 output tubes.  It also helps to know what the operating conditions of the power tubes were, what voltage, what bias voltage if fixed bias, or the cathode resistor value. Knowing all that can help give a ballpark for the power handling of that power transformer. 6V6s can be pushed to upwards of 20w a pair (as fender has claimed a few times) so 4 could give, probably at most, 40 watts output, if they weren't looking for the lowest THD, or distortion in general. My guess was an abundant supply of cheap 6V6 valves were available and the organ designed around those for the PA. 30 watts is reasonable for a good hi-fi clean and tonal range from those tubes in organ use.

We have a weight on this transformer of 4 lbs, which suggests it's one OT for 4 power tubes. What are it's measurements too? I know that these can vary by core density and all, but it *can* be used also in ballpark guesses.

IF, bnew63, IF that transformer is still wired into the original circuit (hasn't been pulled yet), trace where the wires go. One wire will probably be red, if the colors are still readable, and lead to a capacitor. on a push pull you will have two others leading off to the 6V6 tubes. IF only one transformer (like I suspect) one wire will go and connect to two tubes on pins 3 (a direct connection probably between the two tubes in question) and the other wire will connect to the other two tubes. IF they only connect to one tube each, it may be time to look for a second power transformer. On the secondayr side, you should have one wire tied to ground, and at least one other wire running off someplace to where a speaker would connect, and also a resistor (maybe a capacitor too) running back toward some other tube like a 12AX7. It will probably only have the two on the secondary though as already mentioned. REMEMBER those connections if at all possible, as it will help keep how it is supposed to be connected in some other circuit easier.

[bnew63]

Thanks
Dave your spot on the wiring colours.
The amp only had one OPT
Unfortunately the amp is already disassembled.I may be able to trace some of the wires as there is some of the wire still left behind.
The diamensions are 3.5" tall,3" wide by 3.5 deep.
I will look into the b+ voltage

Brian

[sluckey]

Look on the chassis for a model number. There are many schematics available on the net.

[PRR]

Generally, when you remove an OT you should keep the PT with it, and some notes about what power-bottles it used.

This "package", PT, tubes, and OT, can be dropped into another plan and is sure to work well.

> Hammond ... had 4 6v6's

That narrows it down a lot. Hammond ran tubes conservatively (not over-volted like Fender). It would have been worked at 280V-300V (though maybe more total for bias and field-coils) to make 20W-28W down to 50Hz.

An OT's "power rating" depends are much on lowest frequency as on "Watts". The same OT will work well for 6W at 25Hz or 100W at 100Hz.

For guitar you can raise the B+ to 350V-450V and expect 30W-50W. At the low end you can use four good 6V6, a sweet rig. At 400V you should use a pair of 6L6GC/EL34, ala Fender/Marshall "40W-50W" plans (like Bassman).

The real issue is finding the output taps.

[bnew63]

The B+ voltage is 388
I can't find any identifying # on the old amp so I'm including some pics

Thanks Brian

[Dave]

That doesn't look like a Hammond to me. But it makes little difference.
I assume you measured the B+ by firing it up unloaded.
That probably means that the operating voltages were around 350 VDC, so the numbers that PRR gave you should ring true enough.
Looks like pretty standard iron. Should be good stuff.
You could use a 5AR4 / GZ34 rectifier and get a little higher B+ if you wanted, or use a diode rectifier and get a little more yet.
Like PRR said, a quad of 6V6's or El84's would make you a nice little amp out of this thing.
Or you could use the same transformers and go the 6L6 or EL34 (1 pair) route.
Lots of possibilities there.
Anyway, you are right where you want to be as far as wattage.
Get your OT measurements and see what speaker load you need, and have at it.

To recapp,

Apply a small AC voltage to the blue and brown wires on the primary side (ignore the red)
measure the result accross the secondaries.
divide the supply voltage by the voltage you get out of the secondaries. The secondary voltage will be a lot less than what you put in.
this gives you your turns ratio.

A fixed ac voltage of 10 or 20 volts will work fine, but the easiest way is to use a variac. If you use a variac, run the voltage up on the variac until you see 1 volt on the secondaries. Then divide primary voltage by 1.

multiply turns ratio by itself and mulitply the result by 4  and then 8 and then 16 until you find a number that is somewhere around 4000 - 5000.

Whichever number (4 / 8 / 16) gives you something reasonably close to 4000 - 5000 is your target speaker impedance.

Have fun

I just noticed that I told you a different way to get your turns ratio than the other guys. No matter. They skin the cat starting at the tail and I do it from the head. Both ways leave you with a skinned cat. What the heck you gonna do with a skinned cat anyway?

Dave

[Dave]

Here's a couple of thoughts.

Judging from the way you spelled color (colour) I figure your either European or Canadian. If you are in Europe I might double check that power transformer just to make sure it wasn't designed for 115 mains. If you are Canadian I don't know what you are going to do, but that amp will not work in Canada at all. You should just mail it to me here in Texas where I know it will work.

The other thing is, it only shows a spot for 1 preamp type tube (presumably a phase inverter). So, it must have had a preamp module elsewhere. When it comes to organs (assuming it did come from an organ) it could have supplied juice for anywhere from a few to 50+ preamp tubes. Who knows?

But, say it was designed to run 4 6V6's and 4 or 5 preamp tubes. That's pretty much what you'll be doing with it for guitar, so all is well. However, EL34's add quite a bit of heater load and I might be a little paranoid about going that route.
On the other hand, if it ran 50 preamp tubes, then you could build whatever you could dream up.

None of that has any thing to do with the OT, that's just me yammering.

Dave

[bnew63]

I'm Canadian and yes are mains are 110 also.
And no we do not live in Igloo's and use dog sled's.
I remember being in Texas years ago and gave a waitress a Canadian two dollar tip.
She though I had given her Monopoly money.

I need some advice on which amp to build.
I looking for an 2 channel amp that will deliver clean sound at high volumes
on one channel and the other channel be for lead etc.
30 watts of power is plenty for me
I have an addrenalinn 3 that I use for effects so it need to be pedal friendly.

[Dave]

Ah Canadian. I would never accuse you of living in igloos. Everybody knows Canadians live in windmills.
Given the target wattage and the type of iron you have, you might look over on 18 watt.com
have a look at the 36 watt TMB amp and look at the 18 watt Plexi.
I think a Plexi or a Bassman front end married to a 36 watt 4 x 6BQ5 power amp might be just what you are looking for.

Also, if you needed a little more gain, you could rewire the preamp to have a hot switch (Doug Hoffman's added gain stage can be found on the main page).

I would have a look at those circuits and read up on them and then start figuring out from your own perspective where you want to go from there.

P.S. That's what we use for monopoly money down here.
If I'm not mistaken, I seem to remember when I was living in Canada, 2 dollars was a coin. If that's true, then your waitress was a little on the Big Dummy side.

Dave

[Shrapnel]

Here's a couple of thoughts.

Judging from the way you spelled color (colour) I figure your either European or Canadian. If you are in Europe I might double check that power transformer just to make sure it wasn't designed for 115 mains. If you are Canadian I don't know what you are going to do, but that amp will not work in Canada at all. You should just mail it to me here in Texas where I know it will work.

The other thing is, it only shows a spot for 1 preamp type tube (presumably a phase inverter). So, it must have had a preamp module elsewhere. When it comes to organs (assuming it did come from an organ) it could have supplied juice for anywhere from a few to 50+ preamp tubes. Who knows?

But, say it was designed to run 4 6V6's and 4 or 5 preamp tubes. That's pretty much what you'll be doing with it for guitar, so all is well. However, EL34's add quite a bit of heater load and I might be a little paranoid about going that route.
On the other hand, if it ran 50 preamp tubes, then you could build whatever you could dream up.

None of that has any thing to do with the OT, that's just me yammering.

Dave

o_O U wanna his Amp?!?!?

Dave, his e-mail provider is in Canada (BC), and now he's admitted to being Canadian.

bnew63, Texas is too far south to see much Canadian money (and so is Arkansas for that matter,) even the old Canadian pennies with the birds on them, or even the older ones, let alone the newer ones, Michigan on the other hand, as I imagine any of the other "border" States, is another story.


bnew63, If at all possible, try to draw out a schematic from what's left. You said the connections still had a bit of transformer wire connected, so if the rest is still intact enough, it still may be possible to see what was input, and output, and what kinds of output. (i.e. power from the power transformer, and what was used for a power switch, etc) It's an exercise that will also help you with your understanding how that specific amp is set up to work. PRR has recommended this in the past, IIRC. It will definitely help to discover if that amp supplied DC and filament power or just switched AC to the rest of the organ. (If DC and filament power, you should have plenty of power for a guitar amp.) Stopping by 18watt.com isn't a bad idea, BUT if you converse over there, remember it has to be specifically about the 18 watters, or generic enough that it could be about an 18 watter.

[bnew63]

Dave
I'm talking over 30 years ago when we still had a two dollar bill.
Thanks for all the info I've got some reading to do.

Brian

[Dave]

How's it coming Brian?

Dave

[tubesornothing]

I played a gig up in Canada once.  I think it was in Vancouver, Canada.  Anyways, here is a pic of the hotel we stayed in.  It was cold, but I guess they are used to it.  We traveled to the gig using the Canadian SUV (the dogs), it was fun.  I guess they don't have gasoline there.  On the way across the border, we got stopped by one of the mounties on horse back.  I think he was actually on the US side, because there was no snow on the US side, just on the Canada side.  He wanted to make sure we weren't trying to bring any US bacon into Canada,  I think that's a pretty important export to there economy.

It was a little strange because everyone spoke french.  No one spoke American - really weird.  But we figured it out anyways.  The US dollar goes along way.

They didn't have any electricity there, so we couldn't use amps, so we had to play acoustic.  The beer made up for it.  I drank one and was buzzed all night and the next day.


Strange but true.  Ask psychonoodler.

[Dave]

I ordered a pizza once in Ontario. I wanted it with Canadian Bacon. The guy said, "Up here we call it ham."
What was his problem?

Dave

[bnew63]

I looked at a North American map once from a public school in Detroit and it was blank above the US border.
Have you looked at the exchange rate lately(I think we've caught up)

Dave I have been looking at the 36watt TMB(by the way what does TMB mean)
I think this will be a good project for me.
I'm trying to do this with parts I have already,having the iron will save me the biggest amount.

I still haven't checked the OPT for it's impedence.I figure I've got lots of time before I need to worry about that.I do have two 10" Legends I'm going to use until I can afford better drivers
Thanks for all the help

Brian

[Dave]

TMB stands for Treble Middle Bass. The project is derived from the Marshall 18 watt amp. Some folks were dissatisfied with the "one knob" tone control so they bent the circuit to accomodate more tone shaping possibilities.

The reason I suggested a tweed Bassman frontend was because you had mentioned that you wanted a nice clean channel.

Take care and good luck with it. Keep us posted.

Dave

PS... I was in Ontario thru a couple of winters. I can assure you that during certain parts of the year, most of the country is indistinguishable from what you saw on that map.

[bnew63]

Dave
I took your advice(even if your from Texas)and looked into the Fender bassman.
The clean tone is what seems to stand out about this amp.
The problem I would have is trying to marry bassman preamp with a different power amp.There are so many schematics out there it's hard to know which one to choose
Does anyone have a schematic (or better yet a layout)of a similar project,as I have limited skills in this area.

Thanks Brian

[tubesornothing]

So you want clean 2 channel with 4-6V6.  You are in Fender territory.  Use the PI and power stage from a Deluxe circuit (with small mod for 4 6V6) and marry it to your favorite preamp.

Like you say, there are lots of preamps.  You want two channel, do you want reverb or trem?

[Dave]

That's what I was getting at earlier on.

Take a look at the 18 watt Plexi schematic on 18watt.com (Plexi and Bassman are almost the same thing)
That will give you your basic design.

Then take a look at the 36 watt TMB.
Use the power amp section off that. It will be very similar to the 18 watt power section but with two more tubes.

I know that sounds kind of complicated, but it won't be.

The idea is, those guys already came up with a way to marry a 18 watt power section with a Bassman front end.
They also turned an 18 watt into a 36 watt. You just want to make a hybrid of those two.

Here on this site, you will find a Hot switch mod designed to take the Bassman/Plexi front end to a whole new level that could also be incorporated.

It seems like a lot of mixing and matching, but all the information is there all you have to do is put it together.

If you get stuck, just ask questions, we'll help you out.

Dave

[Dave]

I just had another look at the 18watt plexi. As it stands over there they have already incorporated a "hot switch". So, that's kind of taken care of. I also looked at the Power section. I don't see any reason why you couldn't build the 18 watt, but just use 4 power tubes.
You would only need to look at the 36 watt schematic to make sure that when you wire up the 4 power tubes, you see how it should be done.

Dave

[PRR]

> marry bassman preamp with a different power amp.

What different power-amp?

Build the 5F6A. Except where it has two 6L6/5881 bottles on 432V, put four 6V6 bottles on 370V. Expect 30W, which isn't much less than a true 5F6A. The 5F6A's -44V grid bias may have to be a bit less for the lower voltage. The rest of your amp, the driver and preamps, will run slightly lower B+, but that's OK because we aren't trying to smack the big 6L6es, just a team of 6V6.

There is a small silliness here. Hammond (or whoever) ran four power bottles mostly for church-type reliability. If the bride is walking up the aisle, and one of a 2-tube team goes fttzzzz!, the bridal march will be very weak and distorted. And nobody in the church can change a tube no matter how long the preacher drones-on about love and honor. With a four-tube team, the organ plays on, just a little down on power. OTOH, on electric guitar the distortion of one-tube working may be "different, not disaster", or the other players can cover you. And if you build an amp, clearly you could change a tube during the next drum solo. So you could use that iron to build a 30W 370V two-6L6 "3/4 Bassman".

Oh: Canadian Dollar passed the US Dollar a week or two back. No more 30% differential. Makes a big difference up here in Maine. Usta be, someone slipped me a Canadian coin, I felt ripped. Last week I found a Canadian penny in my pocket and realized I'd come out a few milli-Cents ahead.

[Dave]

The reason I suggested a different power amp was because I thought it would be easier for him to copy an existing design with cathode biased power tubes than to try to derive negative voltage off of his power transformer that isn't (presumably) equipped with a bias tap.
This is his first build and my suggestions were intended to meet his needs and not be too complicated.

Brian,... PRR is exactly right, you could easily do what he said, but you would have to dig a little deeper to derive your negative voltage for the bias circuit. Its up to you.
I still think your easiest and best band for the buck is to build a "36 watt plexi" circuit. Its cathode biased and a great amp (based on the 18 watt version).

Dave

PS. just to avoid any confusion. It doesn't matter really whether you use 6V6's or 6BQ5's both are perfect for your PT and OT.

[tubenit]

I looking for an 2 channel amp that will deliver clean sound at high volumes
on one channel and the other channel be for lead etc.

I don't think of the 18-36watt amps as a clean tone.

I personally think you would find a pair of 6L6's cleaner toned than a quad of 6V6's. I say that based on what I have heard people comment comparing a 5E3 quad 6V6  to a 5E3 with a pair of 6L6's.

It doesn't matter really whether you use 6V6's or 6BQ5's both are perfect for your PT and OT.

Please look at the max plate ratings for the amps.  Most 6BQ5's max out at 350v and JJ 6V6's are rated for 500v.

If you want to consider a pair of 6L6's for about a 27watt amp, you might consider one of these ideas. All three of them can do either a reasonably clean or overdriven tone.

With respect, Tubenit

[Dave]

Tubenit, you're right about the 18 watters and 36 watters not being recognized as clean amps, but with a Bassman front end, I think, it would be a different story.

There are lots of modern amps designs out there running 6BQ5's at well over 400 volts and claiming 50 watts out of a quad.
Peavey, Carvin, Mesa Boogie come to mind.

I'm not trying to sell the 36 watt idea. I don't care what he builds. It was just something to look at to start the ball rolling.

Dave

[tubenit]

There are lots of modern amps designs out there running 6BQ5's at well over 400 volts and claiming 50 watts out of a quad.

Good point. And I owned a Carvin Bel Air once.

Physconoodler has done something similar with low voltages on the screens and I think fixed bias?  He reports they sound good.  So if you went that route, then there would be numerous options available.

With respect, Tubenit

[PRR]

> try to derive negative voltage off of his power transformer that isn't (presumably) equipped with a bias tap. This is his first build...

Good point.

If the amp is mostly-together, he might just leave the power section as-is. The organ amps are not guitar amps but can be very "musical". Add any simple guitar guitar preamp (it will be tight). While it won't be "a copy of a specific amp", it may be a fine player and a useful educational process.

Bias-voltage from the HV winding is found in many amps; steal one and trim to voltage. I don't like those plans (especially in the hands of novices); a rarely-seen alternative is to power a teeny 120V:12V transformer backward from a 6V winding to make 60VAC. But again that's not novice-friendly.

[bnew63]

Boy if you miss a day these thimgs take on a life of there own
I started looking at some of the 18watt variants.Mark Durhams Vajra I noticed had a PP to SE switch.Am I correct that you need a different OPT that is gapped to run single ended amp.
Reverb and trem is not high on the list for me,I just want good tone.
I noticed that the 36 watt TMB has a feed back switch,is this used for creating feedback?
It will take me a little time to figure out the joining the 36 watt variant to the plexi  front end,But I do love a learning curve.
Thanks Brian

[Dave]

Yes you would need a different OT to switch from PP to SE.
The feedback switch is for control Global Negative Feedback NFB. NFB is a small portion of the complete signal that gets routed back to the preamp. It helps with stability and balance and tends to reduce ugly distortion.

Keep at it. Knowledge is never wasted.

Dave

[sluckey]

I started looking at some of the 18watt variants.Mark Durhams Vajra I noticed had a PP to SE switch.Am I correct that you need a different OPT that is gapped to run single ended amp

That amp does not have a PP to SE switch. It has a pot labeled PP/SE. All it does is vary the grid drive to one side of a PP power amp. You use a standard PP OT as specified in the schematic. You do not need a SE OT.

[bnew63]

Can you use oversized iron in an amp with no ill effect,as long as voltages are within reason.

ON the 18watt plexi there is a y/cascade switch is this a gain stage?

Brian

[Dave]

That is the "hot switch" I was telling you about. It cascades two gain stages for some growl.

Oversized iron, yes, I guess so.... What are you thinking of doing? If you are thinking of just building the 18 watt plexi, the 36 would only require you to include 2 more power tubes, it won't be hard. I promise.  Well, it won't be any harder than putting the rest of the amp together.

Dave

[bnew63]

I guess I was worried about two many watts(volume) to be able apreciate the tube sound.
Ya hear about people spending extra money on attenuators to be able to appreciate there amps tone.
A friend phoned me up the other day,he had just bought a twin reverb and was asking about the very same thing.
I popped into a local music store and tried a 18watt locally made tube amp and was blown away by the volume this thing put out.
I still would like to do the 36watt,I will draw a schematic and post it here for the approval of you much more experienced builders

Thanks Brian

[Dave]

The beauty is, if you build the 36 watt, you could always pull the two outside tubes and run it at 18 watts.
I like 4 power tube amps for that reason.
The trick is that you have to double your speaker impedance when you do it.
There was a recent thread about it on this forum we discussed it quite a bit.

Dave

here it is

http://www.el34world.com/Forum/index.php?topic=9229.0

[tubesornothing]

Put in VVR or if its cathode bias, you could have separate cathode caps and life the caps to get a good 1/4 power system (a la Carr, documented by geezer).

[Dave]

There's an idea too. VVR for getting your wattage down. But, that's something you could look into after you get the amp built.

Remember that attenuators, VVR, and such are all ways to allow you to get mean tube overdrive without breaking windows.
But if you want a nice clean channel too, you have to either make some compromises, or allow for pulling a pair of output tubes, or installing a VVR, or buying an attenuator.

At the end of the day, I would build it with four output tubes to ensure you've got plenty of clean, then if you find you need less wattage when running angry, then pull the outer two power tubes. If that doesn't get you where you want to be, then you can find instructions on this forum for building in a VVR circuit.

Just take it a step at a time, be safe with it, and see where the next step leads.

Dave

[Shrapnel]

The STANDARD 18watt (1974 circuit) is a clean amp until you drive the EL84 bottles, (or the 6V6 bottles on the variants that use 'em,) which isn't too hard as they normally don't incorporate NFB. All the overdrive is developed in the PA. The Plexi has a little more gain, and some variants will have a switch to combine the channels. Then there are 18watters built around the 2204 circuit or a HiWatt circuit (or a combo: the MarWatt,) or even a bit of the Vox AC30 preamp. Those 18watters are definitely small-medium size stage ready, but show that if you don't need to fill the AlamoDome, SilverDome, or some other arena, 18 watts is plenty of power.

{ Now back to our regularly scheduled opt output query. }

[Dave]

I guess power is subjective. But to say that 18 watts is plenty of power is limiting other people's subjectivity.
I have a BF Twin Reverb. I like sparkling cleans. My Twin starts to break-up at around 6 and sometimes I wish I had a little more clean headroom.
So in certain instances, for me, my Twin Reverb (recognized king of clean) is not big enough.

It wouldn't make a whole lot of since to build an 18 watter with 36 watt iron when you could build a 36 watter and use it at 18 watts. It would just limit his possibilities.

Dave

[bnew63]

I just looked at an amp layout from ceriatone and it seems to be a good candidate for me
Its 36 watt and has a half power switch.It looks similar to the 36watt from 18watt.com.Has anyone heard or seen one of these.

Brian

[Shrapnel]

I guess power is subjective. But to say that 18 watts is plenty of power is limiting other people's subjectivity.
I have a BF Twin Reverb. I like sparkling cleans. My Twin starts to break-up at around 6 and sometimes I wish I had a little more clean headroom.
So in certain instances, for me, my Twin Reverb (recognized king of clean) is not big enough.

Yes Power is subjective, BUT it is also objective. 50,000 watts of power is more ideal for outdoor and the largest arenas, 50 watts is more than plenty for most use. 5 watts can be ear-splitting in a bedroom. One has to remember that doubling the power leads to only about 3 dB of increase in volume (barely noticeable to most ears) to get double the perceived volume requires a 10x boost in power. PRR has also pointed out in another thread, that the smaller the area (volume of the space,) the less power is needed before destroying your hearing more completely than the current hearing condition of the retiring {again} Pete Townshend.

As you are referring to headroom, that is a little different, as it's a dynamic change that returns to some other lower level (usually.) Headroom is a different beast than full-out power. I agree that when playing clean, headroom is important, and a 36 watt amp, while barely perceivably louder, does allow for momentary peaks to happen, without distortion.  One way to guage how much power can also be looking at your current volume settings, speakers used, and power available. If you have the volume up as far as it can go before it distorts, just to be heard in your venue, you may need to double your power, just for the cleans to stay clean. But if you are operating your amp with a volume level of one or two, you can probably cut your power in half without sacrificing clean performance. The drawback to the lower powered amp though is less headroom at the higher volumes.

When referring to an overdriven power amp (for the distortion) the 18 watter is loud enough to have owners told to turn down. This is a case where clean headroom isn't as important. That's the other side of the coin though.

It wouldn't make a whole lot of since to build an 18 watter with 36 watt iron when you could build a 36 watter and use it at 18 watts. It would just limit his possibilities.

I don't disagree. It does make sense to go ahead and build the 36 watter, especially if more clean headroom is needed than the 18 watter can deliver. And, since he (apparently) does have everything he needs to build the 36 watter, it won't hurt to build it as a 36 watter anyway.