Hi Guys and girls just joined the forum I have had several vintage amps and I have a question?I recently moved house and came across my old Mike Matthews Freedom Amplifier it's the 10" non battery version plugged her in and "unbelievable "it sounds as great as it did the day I bought it .It take a while vto power down but I think it always did? I took it to a friends and he loved the sound but was concerned it had a 2 pin power cable so it wasn't grounded? I know its an old amp and if I,m going to use now should I get it converted to a 3pin grounded plug? And can I do this myself I build acoustic guitars so I'm relatively practical,any help most welcombe
Many thanks
DG
PS Concerned about this switch of "death" that pervades the internet
Quote from: dg on December 03, 2009, 02:04:51 PM
Hi Guys and girls just joined the forum I have had several vintage amps and I have a question?I recently moved house and came across my old Mike Matthews Freedom Amplifier it's the 10" non battery version plugged her in and "unbelievable "it sounds as great as it did the day I bought it .It take a while vto power down but I think it always did? I took it to a friends and he loved the sound but was concerned it had a 2 pin power cable so it wasn't grounded? I know its an old amp and if I,m going to use now should I get it converted to a 3pin grounded plug? And can I do this myself I build acoustic guitars so I'm relatively practical,any help most welcombe
Many thanks
DG
PS Concerned about this switch of "death" that pervades the internet
You should be able to simply get a 3 prong cord, wire it the same except bolt the ground wire to the metal chassis somewhere.
Hi joecool85 Many thanks if I may impose on your knowledge again
Both of the wires going to the plug are black ,at my friends house he told me that the mains plug was in the wrong way round as it hummed louder ,when the guitar jack plug was in the input (but not connected to the guitar) but dangling in front of the speaker? And we put the plug back in rotating it and it did reduce the hum considerably is this correct ? as he only remembers this from distant conversation over 20 years ago and
as the two wires going to the socket are both black?
many thanks
dg
Hi DG.
Try to post a more specific title, such as "help with a Freedom amp", or it becomes impossible to find it using search.
Excellent picture, sharp and big.
Popst a couple extra ones, from the front and another showing the controls panel.
These amps were meant to be powered by 40 C cells, +60VDC.
The power supply was added later.
It *looks* like you have a side mounted male power sock, to which you plug a female 2 pin connector, is that so?
It also *looks* that the power switch handles DC (as in the battery one), and the transformer is always on.
I also don't see any "death cap", but it might be present in the power supply itself.
Neither do I see a fuse !!!!
The green and yellow seem to be soldered to the negative (ground?) lug at the power supply capacitor, but if they are ground, why does the yellow one go straight to the board, and the green one is switched?
I think you should open the black tape bundle and draw a schematic of the power supply wiring.
Take a picture there too.
This is *not* a conventional amplifier.
Hi Guys
QuoteThese amps were meant to be powered by 40 C cells, +60VDC.
The power supply was added later.
It *looks* like you have a side mounted male power sock, to which you plug a female 2 pin connector, is that so?
It also *looks* that the power switch handles DC (as in the battery one), and the transformer is always on.
I also don't see any "death cap", but it might be present in the power supply itself.
Neither do I see a fuse !!!!
The green and yellow seem to be soldered to the negative (ground?) lug at the power supply capacitor, but if they are ground, why does the yellow one go straight to the board, and the green one is switched?
I think you should open the black tape bundle and draw a schematic of the power supply wiring.
Take a picture there too.
This is *not* a conventional amplifier.
hi it is a female 2 pin connector,this is a picture un wrapped ,no fuse i can see,as to draw a schematic i dont know how sorry,Can I easily convert this back to batteries? as I would love a little portable amp
Many thanks
Dg
No idea when it was converted I have obviously been lucky not to electrocute myself (some would say a wasted chance to hasten my demise)
LOL
(//)
Quote from: J M Fahey on December 04, 2009, 04:51:29 AM
Hi DG.
Try to post a more specific title, such as "help with a Freedom amp", or it becomes impossible to find it using search.
Excellent picture, sharp and big.
Popst a couple extra ones, from the front and another showing the controls panel.
These amps were meant to be powered by 40 C cells, +60VDC.
The power supply was added later.
It *looks* like you have a side mounted male power sock, to which you plug a female 2 pin connector, is that so?
It also *looks* that the power switch handles DC (as in the battery one), and the transformer is always on.
I also don't see any "death cap", but it might be present in the power supply itself.
Neither do I see a fuse !!!!
The green and yellow seem to be soldered to the negative (ground?) lug at the power supply capacitor, but if they are ground, why does the yellow one go straight to the board, and the green one is switched?
I think you should open the black tape bundle and draw a schematic of the power supply wiring.
Take a picture there too.
This is *not* a conventional amplifier.
Good advice, I didn't realize we were dealing with an oddity like this.
**edit**
I merged the two threads for you.
Thanks joe cool 85 I,ve never been referred to as an oddity before LOL any thoughts of how to convert it back to a battery amp please
Thanks
Thanks Joecool and DG.
Now I understand it.
To begin with, the supply is quite amateurish, the amp itself seems to have been rebuilt, that's why asked for a front panel picture.
The original one had an L shaped chassis, to which was mounted the PCB, and the pots were direct soldered to it.
This one has a flat, presumably home made front panel, some *very* strange, home made twisted brackets, the pots are wired, etc.
The power supply clearly (now) has the transformer *always* connected to 110V (or 220V), its *secondary* is switched, is rectified by a too small W02 bridge , and filtered by an unknown, although large, electrolytic.
As I see it:
the black wires are 110V (or 220V) , no fuse, no switch, an accident waiting to happen. The *first* short there will set the amp in flames, no kidding.
So, first task is to cut a rectangular opening on the side (say, 2.5"x4"), where now the power socket rests, and mount there a somewhat larger piece of 1/8" Masonite or MDF , with 3 holes for: power cable, power switch and fuse holder (2A for 119V ; 1A for 220V)
I'll post a drawing for you to play it safe.
The transformer will have its primary switched and fused, its secondary will feed the amp.
You must also change the puny round 1A bridge rectifier for a rectangular, flat, 6Amp x 200V (or better) bridge rectifier.
Then you can use your fine amp for other 35 years.
You *can* battery power it, but buying 40 D cells every 4 hours playing will break your wallet.
You *can* use 5 x 12V 1.2 AH gel lead acid batteries in series, but better add some wheels and/or consider it the intensive workout the Doctor ordered.
In short, for a few bucks you can enjoy safely this light (for its power), very portable and attention getter historical amp; but battery powering it isn't practical for monetary reasons.
Please post the front panel pictures.
Hi j m fahey many thanks I think that's all a bit technical for me to do ,you lost me after drill three holes LOL but thank you for the help ,it really is a great sounding little amp but I prefer my limbs intact and when amateurish and fire are use together I'm usually looking for the nearest exit LOL It seems rather difficult for a novice to fix
Thanks
dg
Hi DG.
Get a friend who can work with electricity safely.
Some Pizza and a couple Beers will help a lot, but give him the Beers only *after* the job is finished. :)
Your "mods" are not Electronic but plain electrical in nature.
Buy the excellent switch/power socket/fuse holder you showed me, and post front and back pictures to indicate the exact wiring.
We're talking wiring a desk lamp complexity level here.
You can also buy separate switch-power socket-fuse holder and mount them side by side on the piece of Masonite.
I'm attaching pictures of the "official" Freedom Amp, where you'll see the L shaped chassis, with the boards securely mounted
Yet it has the same improvised power supply, although a little more complex.
I guess the amps, although advanced and excellent sounding, weren't selling because of the enormous battery expenses, so they were somewhat amateurishly converted at the factory.
You can easily correct that and enjoy your fine amp.
Your only personal task will be cutting the side slot and mounting the switches , etc. on the Masonite piece, let your friend do the wiring.
Quote from: dg on December 04, 2009, 09:07:41 AM
Thanks joe cool 85 I,ve never been referred to as an oddity before LOL any thoughts of how to convert it back to a battery amp please
Thanks
I meant the amp, not you lol.
Hi J M Fahey many thanks I am gouing to try and do it my self then have it properly seviced, I don't know anyone with any electrical experience most are just like me plug in and play, but I intend to change that .I am in the UK (so its 240V) in a rather remote part of Norfolk but I am careful used to doing things properly and an eager to learn I will get the switch and is this square one in picture correct
Quote1A bridge rectifier for a rectangular, flat, 6Amp x 200V (or better) bridge rectifier
ther seems to be a lot of codes shall i just ask for a 6amp x200v?
many thanks
david
very excited
(//)
HI juan just a quick question so i can get all the bits at the same time
QuoteYou must also change the puny round 1A bridge rectifier for a rectangular, flat, 6Amp x 200V (or better) bridge rectifier.
the bridge rectifier, better in what way more amps?more volts? are there other bridge rectifier options ,i will get the one you think best.
and is there anything else i will need , specific wire or any other components ect i can buy at the same time, i have plenty of mdf but also some 6mm birch ply that might be better, stronger? and a decent soldering gun and a new found enthusiasm
many thanks and i think the panel must be the original one with the writing on?
(//)
david
ps hi joecool85 i,ve been called worse LOL
Hi DG, that's the SSGuitar spirit !!!
1) Post the link of where you shop, so I can give you a specific part number, but anyway, "6 Ampere, 200 PIV bridge rectifier" will get what you need.
It's 4X the current capacity of the one fitted (6A vs 1.5A)
The one I use is rectangular, with a diagonally cut corner to help in alignment (also 2 pins are shorter than the other 2) and all pins exit aligned on one side, but that's a minor matter.
I'm not at my shop now, tonight I may post the exact code, but it will be better to follow your supplier's.
2) If your transformer is 110/120V and you use your amplifier with an external 240>120V transformer, it might be interesting to buy an equivalent new 240V primary transformer and avoid carryinf useless weight.
I you can't do that now for "$tec$nical$ rea$on$", consider it for the future.
3) That 6mm birch will be fine.
4) Maybe your friends aren't experienced because they buy their IPods and PCs ready made, but perhaps you can find some "greybeard" with some solder smoke filled lungs who can help you.
UK has a mighty fine tradition of electronics builders.
I still have roof-high stacks of Practical Electronics, ETI, Practical Wireless and many many others where I learnt a lot.
I shouldn't even mention this, which shall send me straight to the Mummy Room at the British Museum, but I even have an old (well, it was new then) issue of "Beat Instrumental" where they talk about that "new, promising" band, called Deep Purple, who were playing for free just to show those "new, promising" amplifiers called Marshall. ;D
Hi Juan the link is http://www.maplin.co.uk/Module.aspx?ModuleNo=19088
Quote2) If your transformer is 110/120V and you use your amplifier with an external 240>120V transformer, it might be interesting to buy an equivalent new 240V primary transformer and avoid carryinf useless weight.
its 240v in the UK i dont use an external transformer ,i thought it would blow up if you plugged a 110v appliance into a 240v socket?
it seems to work? how can i tell if its a 110v or 240v?
QuoteUK has a mighty fine tradition of electronics builders.
yes I think we do but because its so cold all the time there is a general apathy towards everything LOL
Quotethose "new, promising" amplifiers called Marshall
I have had two Marshalls loved both but my mesa boogie was the most wonderful thing, heavy as hell but a sound to die for .sadly divorce left me with no Gretsch or mesa (liquidation of assets) but I got the kids so it was excellent exchange.
My son has gone over to the dark side after two years of guitar lessons he has just taken up the bass !!!!!!!!I bought him a mini
one " Smoke on the Water Bass line "great the first time by the 200th Ahhhhhhhhhhhhhhhhhh
Thanks
david
Hi DG.
I'll check the switch and answer, but there's something I don't understand by the way you phrase it.
1) Is the amp working now, meaning you plug it straight on 240V, you turn it on and play?
*or*
2) you *guess* it works, because "it used to"
*or*
3) you use it with an external transformer?
I ask all of this because any factory powered original amp, made in California, would have come with a 120V transformer, and besides that, that male power socket mounted on the amp's wall is a typical twin parallel flat blade 120V connector.
Of course, it *might* have been made in 240V for a British client *or* said client could have replaced the transformer for UK use, still keeping the original USA connector.
Please answer that before we can continue with this.
Speaking of Great Britain climate, my family comes from County Cork, Ireland, where it's shorter to state that it does *not* rain for 5 days a year.
That's not that bad, considering all that warm seawater thar runs by the "Emerald Island" provides a very humid climate but quite softer winters.
Hi Juan its option 1
Quoteplug it straight on 240V, you turn it on and play
yes I just Plug it in works great, takes a while to power down ,
surely it wouldn't work if it had the US 120v transformer in it ?
My folks are originally from Garrynagree "we do get about us Irish LOL" My mother has never fully settled here 40 years on ,she still occasional mentions the "hard water, no decent bread ,different sunlight, the cold ,the heat, the cats appear to be different here as well LOL and how washing always dried quicker at home ,she cant explain the physics of it, but I will keep asking LOL
Have a good day
thanks
david
Its nice to see someone using one of these amps ,and you are in good hands with JM guiding you.
I stumbled across the original Marketing for one of these amps when I was looking for something else, and they had ads with topless woman they were going to run but didnt in the USA.
Ah yes it was some research on an EH pedal that led me to it.
Anyway the "Freedom Amp" was part of my motivation for getting into SS DIY.
When you are done could you post some more pics?
Maybe some sound clips too?
I love going back in time with this kind of vintage SS gear.
Good Luck,it sounds like you almost have it sorted.
Hi Brymus ,Juan really seem to know his stuff and I'm very keen to get the amp safe and working as it should, and he is being most helpful and informative
I'm keeping a little log that I will post with pictures on the forum when its finished and will update as I work on it
I am absolutely staggered at the sound quality, my friend played through it and is now looking for one (This man with a collection of vintage valve amps!!!!!!) he said it was the most percussively responsive transistor amp he had ever played (he's also a staggeringly good guitarist)
I have had a looked inside and can't find any topless woman LOL
Thanks
david
Hi DG. I've been checking the Maplin catalog.
Order
1: "Fused Snap-In IEC Chassis Plug with Switch" Order Code: N94CZ
1:"Bridge Rectifier" KBPC606
1: Pack of 10 fuses, they call them " 20mm Glass Quickblow (F)" and the full code is:20mm QB 1A 10 PK GJ90X
1: mains cable that suits you, with a female IEC connector and a 3 pin grounded male mains connector.
When you get it , put the switch and bridge on a sheet of white paper (to get a clean background) and take a couple pictures, legs-up and legs-down.
Also a couple real close up pictures showing from different angles the original round bridge and its connection to the filter capacitor.
You'll replace it with the new bigger one trying to keep everything as "original" as possible, to make errors difficult to happen.
I trust you can solder well, have a good 40 to 60W soldering iron, good tin, long nose pliers and a sharp wire cutter, plus some good PVC electrical tape.
Good light and glasses, if necessary, help a lot.
Hi DG.
Just to know what your amplifier would look like if you turned it into the battery powered version:
http://electroharmonix.ronsound.com/index.php?option=com_content&task=view&id=62&Itemid=45
No, it's not a Panasonic Battery ad, although it might.
No wonder they converted them into AC powered units !!
The amp design itself is lovely.
I will build its preamp (to be used with one of my regular power amps and speaker), to see if it has as much "bite" as they say.
I guess I'll like it.
Talking about 40 D-Cell batterys that's about $80.00 dollars not so free.
Hi Juan I have got the parts ,HeHe and I found a piece of hard 3mm black plastic I could use to mount the switch or I have some aluminum tread plate?
Are the positions in relation the the + the same on all Bridge Rectifiers?
+ s2
s1 -
if so
(1)The + is connected to the three center prongs then out via the white with a stripe to the circuit board
(2)to the left of the + (s1) is orange (and goes to the transformer?)
(3)to the right (s2) green goes to the top panel switch
(4) The - goes to the outer prong on the aluminum tubes case then via a yellow wire to the circuit board
(5) picture of the back of the switch(//)
thanks
garry
Hi Juan thought I would add a picture of the large silver thing that the bridge rectifier it attached , also there are two identical black wires going to the old two prong plug socket you can plug
the mains lead can be connected in either direction (up or down)
how would I know which one goes to the live and which to the neutral ? my friend told me that the correct way to put the mains plug in and to connect a guitar lead to just the amp and hang the other ends jack plug in front of the amps speaker and then disconnect the mains plug reverse it and the position with the least hum coming from the amp was right?
he said he did this many years ago with his two prong amp lead ,but was not sure if its correct and he has less knowledge of electronics than me (if that's possible LOL)
many thanks
david
PS the silver thing and the transformer? Are mounted on the bottom of the amp with bolts that can be touched from the outside should I re mount them on a block of ply inside?
Many thanks
And thanks for the link I see what you mean about using lots batteries LOL
(//)
Hi Juan (starting to get the hang of this posting LOL)
sorry should have read
(1) there are two identical black wires going to the old two prong mains plug socket but it can be connected with the amp mains lead in either direction (up or down)
how would I know which one goes to the live and which to the neutral on the new switch?
(2)you metioned grounding (pic two) is the new switches earth going to the twisted arrowed bolt?
(3) bolt at the bottom of the amp should i put it all inside?
many thanks
david
(//)
Hi juan I have mounted the switch /mains socket on a hard plasitc plate ,routed a larger hole (to cover the old one) but conected the Original mains one back as it was and its inside the amp (see pic) When I know the correct way to wire the new mains switch should I use crimped connectors or solder them?
many thanks
david
I am very excited and really looking forward to using the amp safely
Hi DG.
You have shown a good intuitive grasp of what had to be done.
Since (as they say), an image is worth 1000 words, here go 7000 words equivalent.
The main thing here is that the new green/yellow wire must be firmly soldered to the earth pin on the switch back, to a solder lug clamped at one of the transformer bolts, to ground its frame, and to one of the front panel bolts, to ground the rest of the amp.
After you have done that, be creative with a piece of string and tie those long hanging wires forming some "pack" to avoid wire cutting because of unnecessary flexing during transport.
You must also use some hot glue to attach that floating rectifier to the silver filter capacitor for the same reason.
The new bridge goes exactly the same as the older one, pin for pin.
Post some pictures of your work of art, and, more important, some MP3 to hear it.
Feel free to clear any doubt.
JMFahey
Hi Juan many thanks for the pic and help just a couple of questions
QuoteYou must also use some hot glue to attach that floating rectifier to the silver filter capacitor for the same reason
PICTURE (1)filter capacitor has a bolt on bracket i just removed it for the pictures
PICTURE(2) there are two identical black wires going to the old two prong mains plug socket from the Transformer but it can be connected to(//) the amp mains lead in either way(up or down) this is the bit i,m worried about!!!!
how would I know which one goes to the live and which to the neutral on the new switch? is my friends suggestion correct?
many thanks Juan i will add an mp3 and more pictures when shes up and running
david
Hi DG
Very short answer, I'm going to sleep.
1) The capacitor has a bracket, what I want you to fix it somehow to the bridge which is floating in the air, with two red wires pulling it.
Hot glue those red wire solder points to bridge body and reinforce bridge pins to capacitor.
Even snap a small piece of wood between bridge and capacitor and glue it to both.
What you don't want is any "play" there which might crack some pin.
2) One black wire to Live, one black to neutral, they're floating so it's the same. Grounding is now achieved through the Earth pin.
Solder everything.
As an extra safety check, a neon screwdriver to the chassis must not light at all, never, with amp on or off.
Post the pictures of your work.
Hi Juan I couldn't get any specific earth wire so an electrician at the shop said to strip the 3 core from standard mains cable and use that(is that ok?) I bought a neon screwdriver and have tested the top panel ,I bought a new soldering iron and soldered everything I will make some wood blocks to hold the wire and bridge steady .it all seems to working great I have enclosed a couple of pictures the solderings getting better , no dry joints just a little to much solder tell me what you think
Many thanks for your help
Garry
Congratulations, Garry.
Excellent work.
Now your amp is safe and you can enjoyed it.
You showed a very good level of craftsmanship and commitment.
Juan Manuel Fahey
Hi Juan thankyou so much for all you help, the amp may have languished in the loft forever but nows shes up and running
I will make a soundfile and post
thanks again
David
Ps onto my next project I make acoustic guitars and buy in preamps now to make my own they have a kit as a starter in maplin !!!!