But did the OP not say he would make a tube amp but just the transformers will cost close to $200. And some of us are not suggesting wonky tubes and untested designs (the ones thought of as boring). NOS 12V6's can be had for $7.00, hardly wonky tubes.
https://www.tubesandmore.com/products/vacuum-tube-12v6gt-tetrode-beam-power
Wish I had time to read the rest of the posts, tomorrow.
I find it stunning no one probably even looked at the pictures of that little 6BQ5 P-P Hammond amp I suggested off ebay. (No affiliation with the seller)
$100 free ship and still for sale...with its I'd say more than adequate power tranny and how easy can it be Fender style point to point wiring underneath.
Looks like it even has the reverb tank driver / circuitry in there; just get the springs for it and you have that part 95% done too - probably have to add the control pot - and label it "Reverb".
$100 free ship and still for sale...with its I'd say more than adequate power tranny and how easy can it be Fender style point to point wiring underneath.
Looks like it even has the reverb tank driver / circuitry in there; just get the springs for it and you have that part 95% done too - probably have to add the control pot - and label it "Reverb".
Direct radiators can be around 1 to 3% distortion for " Hi Fi" so depends what you consider " distortion"
And pedal distortion can be, say a tube screamer full tilt around 15 to 22 % distortion.
Speaker can move so far forward and back before it reaches 10% distortion often rated as " Xmax " or linear travel
lots of standards. But usually 70% of speaker BL. So how far forward / back a speaker can move before reaching 10%
is considered Xmax. Basically the magnet only has so much control to move it a certain distance before distortion climbs
knowing fundamentals of open strings good place to start, lets just look at lower frequency wound strings. Of course depending if you use a wound G or not
with string gauge. Im rounding to non decimal for simplicity
Low E 82 Hz
A 110 Hz
D 146 Hz
G 196 Hz
Lets look at a typical underhung 150 watt guitar speaker in a sealed box, which is super fair to it not open back so it actually has more cone control.
Xmax rating as discussed before is .8mm some go to 1mm. Once cone travel reaches .8mm you are at 10% distortion or Xmax or linear travel.
Look at the red line straight across measuring .8mm =10% distortion cone movement above that is far far more than 10%
Yellow line = 15 watts already exceeded xmax by almost twice
Green line = 30 watts
Red line = 60 watts
Your other question is below , amplifier bandwidth or AC analysis of very simple amplifier and bandwidth is close enough to 5 Hz to almost 1 Megahertz
is far far far wider than the guitar pickups, strings or speaker
Bass is no problem for a amp. Again Voltage depending how many volts your putting into a 4 ohm load the current goes up.
Transistor can only do so much current and gain drops. So depending how many volts you wanna put into 16 , 8 , 4 or 2 ohms
That requires so much current. So again the transformer needs to be big enough to provide that current and you need enough output
transistors to also pass that current and not overheat using a heatsink. So flappy weak amps use penny pincher small transformers and
could use more output devices, instead of hammering a single pair of transistors. often done with many amps. Pushing parts count low
and using small cheap transformers. So driving difficult loads like 4 ohms using more transistors and bigger transformers for more current
will keep bass healthy. Then of course a speaker or more like multiple speakers sealed back for bass response
for serious drop D even C I wouldn't use the typical underhung speakers, something with real bass and excursion
Last edited:
Not too bad, in my teen years we would find fully abandoned organs at the Salvation Army donation station on weekends.
Since the trailer wasn't open on weekends. People filled the parking lot with junk / donations.
I built a few 30 watt tubers with basically free organ amplifiers. Many of them with working tubes.
And had a good collection of reverb tanks and rotary speakers with foam horns found in organs.
All free sitting on the street. One organ had all tube oscillators so that gave me 88 free 12AU7 tubes
and a 6V6 push pull power amp. Wurlitzer and others had pretty big amps.
That all tube oscillator organ had a transformer big enough to run 88 tube filaments
So was a massive massive huge transformer, and I got a lot of high voltage coils to build tube Theremins
Last edited:
Yeah - those were the days. There was a restaurant in Yelm WA that had these 3 big tone cabs. I asked about them and they just said "take 'em - get 'm out of here". Couple of nice amp chassis in those, 15" field coil speakers...
My proof that I've parted out an organ or two is one remaining part I still have, a mercury filled tilt switch on a lever, used to turn the thing on. Apparently, ordinary dry switch contacts would not do, for the AC line current the thing took.
Really !! as in the big Hammond tone cabinets
Nice! love those things.
Leslie speaker was the " cool" thing to have
So the big tone cabinets got sold cheap. But would blow away a Leslie for sound output
Always wanted one for that reverb tank its basically the mother company for Accutronics.
My friend Roy bought a C3 tone cabinet. It had the early reverb patent from Hammond
Often called "Necklace" type spring it went from top of cabinet to bottom. Insane
More speakers in that thing than imaginable, we were laughing like children when he bought it.
Anyhoo...Dont wanna be too off topic... but Hammond tone cabinets are amazing.
How lucky to get 3 of them.
Maybe should post a picture of the necklace reverb spring.
And why I thought people were insane back in the day and underrate the tone cabs
cause they weren't spinny winny overpriced Leslies.
People can see the huge reverb tank in the rack wrapped in cloth
and maybe see why me and old Roy laughed hysterically when he got one
The amp inside was a pretty large rack had countless tubes, multiple rectifiers
if I remember
Last edited:
I have no idea what you are trying to say. I am guessing that the lower scale is in Hz and the other axis is distortion. I see the yellow at 1.4, green at 2.0, red at 2,8.
On the low frequency response I was asking in response to your saying a guitar speaker flubs out at 15W. I was not asking about the SS amp needs, but you have to back up through a few posts to remember what my question was. I will ask it again, how do the doom metal guys get the low end for dropped tuning if the speakers can only accept 15W in the low end? I would guess your graph should tell us but as shown, the red line shows what would be great distortion in a hifi system (red at 2.8).
Either I am a little slow or your graph does not match up to what you are saying. But I am at the point where I do not care as it does not further the OP's desire for an amp.
Now there's a box I'd like to set my amp on top of. Did you build it - how did you make the dovetails?
Box joints. I made a sled that runs on top of a router table with wood rails that slide along the outside of the table. A number of box joint jigs on Youtube. The little square at two o' clock from the bit is a indexing 'pin' for the routed slots to slip into.
Another view at the magnet heavy Hammond.
Still need to pretty it up though. Currently dismantling my workshop in the basement and gutting the rest so the house can be lifted up and basement blown away and replaced. Otherwise I would jump into a SS amp with both feet. Picked out the lightest spruce/pine I could find, there can be a 50% difference in the weight of the board. Now days making all my amps with a 70+ year senior in mind. No 4 lb PT, switching supplies (hopefully). Now what to do with all the PT's I have?
Grill material is four Dollar Store mesh place mats. I made a panel to convert it to a sealed enclosure after taking the picture. The speakers ended up sounding like crap. But then when selling a 2x12 last week I plugged a '68 Bassman to the speakers. Sounded fine, aint life funny.
Last edited:
Good fun working with pine shelf boards
Always liked building form factors like so.
The bars across the top and bottom
give it the late 50's bassman style cabinet look.
Just took apart a huge shipping crate for glass.
was all large pine boards.
likely enough wood for a few 1x12s
or maybe a pair of 2x12s
Good to see, its been awhile since ive done
a pine board fender cab.
Just thinking as well of making a sled
to do the finger joints
Always liked building form factors like so.
The bars across the top and bottom
give it the late 50's bassman style cabinet look.
Just took apart a huge shipping crate for glass.
was all large pine boards.
likely enough wood for a few 1x12s
or maybe a pair of 2x12s
Good to see, its been awhile since ive done
a pine board fender cab.
Just thinking as well of making a sled
to do the finger joints
The unit in the picture came from an Ebay auction. I had one just like it in my teens. I drove it with a single ended 6V6 amp which worked out about right. I tested the Ebay unit with a Parts Express chip amp. Some of those reverb cabinets did use KT88's to drive all those speakers. The speakers that I got out of a reverb cabinet didn't last long with my DIY Guitar amp made from an old Stromberg Carlson PA (4 X 6L6G). I made a lot of science fiction movie type sounds as a kid with an old tape deck, the reverb tank and a kitchen butter knife and spoon to work the springs.
The cabinet seen to the left of the big reverb tank in post#131 was made from 3/4 inch pine. it is coated with Duratex from Parts Express. It's like roll on Tolex. It has a 12 inch Eminence driver inside.
Doom metal guys dont use 1x12 cabs because = fart city.
They hit distortion at 15 watts, as mentioned low end gets pretty flabby around 30/60 watts
depends how well the suspension is worked out. There underhung so they wont hit damage
like a common overhung speaker does when it starts going past linear distortion
Been in heavy bands since the 90's most my older friends / associates invented it lol.
4x12 minimum most of use full stack or = 2,3 ...4
We ran 50 watt Hiwatts or Laneys into 8x or 16x speakers so do the math how much power they are getting
to even touch drop tuning at Doom levels.
Funny story
When Lewis bought all of matamps old stock
he slapped together a bunch of old GTs and wrapped them
in Green Tolex.
Matt got like 60 grand from london records when sleep got signed.
Didnt realize that was travel money for the whole tour.
They bought every amp/cab lewis had and were completely broke
and stranded in Europe with a wall of green amps.
My bandmates ended up buying bunch of Hiwatts and laneys from
him so he would have money out there in never never land.
Anyways used that 50 watt Hiwatt all over the bay area through numerous cabinets.
And killed quite a few old Ampeg V4 4x12s with it.
they dont like low end for too long.
Ebay and Reverb is almost like the 90's again.
You can buy old stuff dirt cheap now.
Like stacks of stuff.
Mesa's are always overpriced and sold all of my sponge amps
years ago. Guys resale high because they paid to much in the first place.
I just buy end of month when people need to pay rent.
Better to go for old Soldano Slos or 51/50s for beef.
Single rec is actually better buy and easier to fix.
Since youll be doing it often lol
Did you look on reverb yet?
there is tons of fender factory speakers/ eminence legends
Here I am trying to save someone a little work and - I dont even know what work is...
That's almost like a stock trading strategy! Know the mind of those other "share" holders.