So, next project will be a small valve amp in a 60's record player. I am getting a broken Bush valve record player (rather like the popular UK brand Dansette, but cheaper to buy). It will need some modifications to sound good.
Look away now if you are of a nervous disposition.
I plan to remove the autochanger deck and all inner woodwork, cut the lid and fit a 10 inch Celestion and re-use the original controls for volume and tone.
You carry the amp by the side handle on stage like you brought your old record player, but you stand it up with the controls at the top and the lid/speaker facing forwards.
The existing chassis has two B9A sockets so it could be 12AX7 and EL84 perhaps. This thing dates back to the "live chassis" era - so I can't re-use the mains transformer 'cos there ain't one.
Ah, those were the days 🙂
Pete
Look away now if you are of a nervous disposition.
I plan to remove the autochanger deck and all inner woodwork, cut the lid and fit a 10 inch Celestion and re-use the original controls for volume and tone.
You carry the amp by the side handle on stage like you brought your old record player, but you stand it up with the controls at the top and the lid/speaker facing forwards.
The existing chassis has two B9A sockets so it could be 12AX7 and EL84 perhaps. This thing dates back to the "live chassis" era - so I can't re-use the mains transformer 'cos there ain't one.
Ah, those were the days 🙂
Pete
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Fascinating idea! I think there'll be enough space to add a 35 to 50 VA mains transformer plus silicon bridge.
Best regards!
Best regards!
He he..
There's a sneaky trick I have planned. You remove the horrible elliptical speaker and the hole acts as a cabinet port.
Then you reverse the way the lid opens by moving the hinges from the back to the front. Now you can partly open the "record player" to increase the inner volume and also point the speaker slightly upwards. Some woodwork issues to consider but I think that is worth trying.
Yes, exactly. I am still considering where the power switch goes. The original design has it as part of the bass control but I don't want to bring mains power that close to the tone stack....
Maybe you don´t even need to cut much woodwork, if at all.
Start by removing the record changer and show what´s inside.
Will you keep the original 1 to 2W power level (meaning you can use the original OT) or add full PT and OT complement?
A single EL84 + 12AX7 let you make a tasty VOX AC4 clone ; or if using a couple ECL82 you have 2 pentodes, 2 triodes which can provide up to twice the power with the same number of bottles.
Not much power in any case so choose a nasty biting speaker to cut through the stage mud, such as a Celestion G 10 25 or whatever they call it now (whatever the old Marshall Lead 12 used) or Jensen MOD10-35 or similar.
A heavier bassier speaker like Celestion Tube 10 or similar needs more power than you´ll have available and in any case you already forfeited powerful Bass by choice of enclosure, something chimey will use it better.
But please show what´s inside 🙂
Start by removing the record changer and show what´s inside.
Will you keep the original 1 to 2W power level (meaning you can use the original OT) or add full PT and OT complement?
A single EL84 + 12AX7 let you make a tasty VOX AC4 clone ; or if using a couple ECL82 you have 2 pentodes, 2 triodes which can provide up to twice the power with the same number of bottles.
Not much power in any case so choose a nasty biting speaker to cut through the stage mud, such as a Celestion G 10 25 or whatever they call it now (whatever the old Marshall Lead 12 used) or Jensen MOD10-35 or similar.
A heavier bassier speaker like Celestion Tube 10 or similar needs more power than you´ll have available and in any case you already forfeited powerful Bass by choice of enclosure, something chimey will use it better.
But please show what´s inside 🙂
This model, as in the Dansette range, uses the motor with a tap for the heaters.
Why not fit a small horn, similar to a Leslie Cab, running off the motor.
You will need isolation from the mains of course, as you have already mentioned.
As all venues nowadays have a house PA, mic up the speaker and you won't need any more extra power.
Why not fit a small horn, similar to a Leslie Cab, running off the motor.
You will need isolation from the mains of course, as you have already mentioned.
As all venues nowadays have a house PA, mic up the speaker and you won't need any more extra power.
Let's type that all again shall we..
I like the idea of using the turntable as a Leslie. I wonder if that has been done before.. However I need the internal space to fit the Celestion 10-30 speaker I have for this project.
Likewise I can't use the valves as they are series heater types run off that motor tap (brilliant corner cutting by some sixties engineer). So it's either a single EL90 or EL84 and 3 to 5 watts, which I know is just about enough even if you are next to the drum kit in a small gig.
I like the idea of using the turntable as a Leslie. I wonder if that has been done before.. However I need the internal space to fit the Celestion 10-30 speaker I have for this project.
Likewise I can't use the valves as they are series heater types run off that motor tap (brilliant corner cutting by some sixties engineer). So it's either a single EL90 or EL84 and 3 to 5 watts, which I know is just about enough even if you are next to the drum kit in a small gig.
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...but scarce and hence ultra expensive 😱!
By economical reasons I'd prefer two ECL82's, as yet suggested. Roughly representing half a 6SL7, this tube's triode isn't that bad at all.
Or you go for series heated tubes (PCL86, PCL82, UCL82, whatever you want), get an isolation tranny as the PT, tie the heaters in series and drop the superfluous heater voltage over a suitable capacitor.
Best regards!
By economical reasons I'd prefer two ECL82's, as yet suggested. Roughly representing half a 6SL7, this tube's triode isn't that bad at all.
Or you go for series heated tubes (PCL86, PCL82, UCL82, whatever you want), get an isolation tranny as the PT, tie the heaters in series and drop the superfluous heater voltage over a suitable capacitor.
Best regards!
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Ah yes. My most recent project -
The one valve guitar amp is dead, so ....
- did in fact use a pair of ECL82s (though in a slightly unusual arrangement). It proved to be the best sounding amp I have made so far. However it didn't quite have the power output I wanted and it is now in a studio as a recording amp. It does sound great though.
I haven't done an EL84 design, and I have some old examples that I could use in this. It will be a single ended design, as I have a reasonable sized output transformer also available.
You know how it is with a new project. Once you have a plan you just want to start, but I won't get the record player until next week. Patience...
and best regards!
In my high school days (late 60's), I had an old Baldwin organ that used a bunch of 6SN7's for the tone generator. Lots of heat, very heavy, and no Leslie!
What does a cash strapped kid do, with parts from the local trash dump.....I built the paint can Leslie.
Parts list:
An old turntable ripped from a console HiFi with a heavy metal platter (for momentum). I kept most of the wood base that it was mounted on, and the spinning stuff. It was an old one with 4 speeds, 16, 33, 45 and 78 RPM. The tone arm and everything else in the HiFi went back to the trash dump, except the tubes and transformers.
A one gallon round paint can.....it took 3 or 4 to get the hole right.
A small sealed back speaker cabinet with a 6 or 8 inch speaker. I don't remember the exact size, but I actually used a complete dead guitar amp, just for the speaker.
The turntable base was mounted in a crude box. I connected a foot pedal from an old sewing machine in series with the motor and the line cord so that the TT spun when you hit the pedal, and coasted down when you didn't.
The paint can was screwed to the platter open end up. I cut a large partial hole in the side with a jig saw, bending the metal inwards to form an angled reflector to bounce the sound out through the hole. This was not easy for a 15 year old kid to get right but a can with lots of dried paint on its side worked the best.
The speaker was mounted above the can facing downward into the original lid opening with a small gap for clearance using 4 short legs made from wood 2 X 2's.
I would feed this thing with one of my trash dump Fender Champ clones for guitar use, or directly from the Baldwin's built in amp. It was far better than no Leslie, but obviously not up to "B3 with big Leslie" standards. All of it would be scrapped by my parents a few years later.
Fast forward about 50 years. My wife are shopping in a Goodwill store and I find THIS (see picture).
Yes, this is an original Hammond M3 drawbar organ made in 1958 in perfect working condition for $39.99. After playing with it for a few days, my first thought was "paint can" but now I'm rethinking this a bit.
The paint can did pretty good for a kid who played his guitar at one setting, full heavy metal racket. It's dimensions matched the frequency range of the guitar amp and speaker. The organ would like something bigger. Someday......
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Congratulations on the old times construction project.
Congratulations on the incredible find.
Congratulations in advance on the future Leslie[tm]
Congratulations on the incredible find.
Congratulations in advance on the future Leslie[tm]
Here 's the progress so far. I have an old Bush record player which I have stripped ready for it's new life. The woodwork is pretty flimsy so I have put in some reinforcing to improve the acoustics of the box.
I cut the lid for four 6 inch guitar speakers and moved the hinge and clips so the lid opens the other way. It will sit with the controls at the top and I plan to cover it in red and cream vinyl eventually, so it has that Dansette look.
I test fired the speakers, and they sound better than expected. However they are new so will need some playing in. Hopefully it will be a bit more mellow.
Next I have to build the amp using the stripped chassis plates. This time it will be a three valve design. I'm using two 12AX7s and a 6V6GT. (That configuration is set by having a pair of B9A sockets in the chassis and a hole for an octal socket). So that's a gain stage + cathode follower. Then a driver stage and cathode follower, then the single output valve. So it's a bit like a Champ on steroids..
Pete
I cut the lid for four 6 inch guitar speakers and moved the hinge and clips so the lid opens the other way. It will sit with the controls at the top and I plan to cover it in red and cream vinyl eventually, so it has that Dansette look.
I test fired the speakers, and they sound better than expected. However they are new so will need some playing in. Hopefully it will be a bit more mellow.
Next I have to build the amp using the stripped chassis plates. This time it will be a three valve design. I'm using two 12AX7s and a 6V6GT. (That configuration is set by having a pair of B9A sockets in the chassis and a hole for an octal socket). So that's a gain stage + cathode follower. Then a driver stage and cathode follower, then the single output valve. So it's a bit like a Champ on steroids..
Pete
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