fun with amp gurus ( amp identification post)

[24 track]

this could be a fun game

I have the absolute pleasure to work on this work of art and its bigger 100 watt brother
look closely at these 5 pics and see if you can tell me what amp it is , I know you guys will be all over it
its a work of art literally

what a beautiful design

enjoy

24

 

[Dacious]

Some sort of Marshall. Four hole JMP 50

 

[beyer160]

Hi, what?

 

[Powdog]

Hi, what?

Yea. Custom 50.

 

[sudogeek]

Yep, I’d guess Hiwatt Custom DR504 - very similar to the 100W DR103.

And, yes, I’m a big Townsend fan.

 

[24 track]

Hi, what?

you win,
Yes Sir a Hiwatt custom 50, DR505 ,
my gawd this is 96% original even all the tubes are period specific, ( 4 caps replaced and a EL34 tube socket replaced)
I had never seen inside one of these , totally reminescent of DR Z amps in quality construction .

 

[24 track]

that wont take long, did it? LOL

 

[beyer160]

you win,
Yes Sir a Hiwatt custom 50, DR505 ,
my gawd this is 96% original even all the tubes are period specific, ( 4 caps replaced and a EL34 tube socket replaced)
I had never seen inside one of these , totally reminescent of DR Z amps in quality construction .

If you got to play with that amp, I think YOU win!

 

[SnidelyWhiplash]

Hiwatts are so impeccably wired. Great loud cleans.

 

[24 track]

If you got to play with that amp, I think YOU win!

I also have the 100 watt matching unit as well , the owner is crazy concerned I'm going in there to mess it up , because of its condition , I'm only going to clean it and report any concerns, its worth more to a collector original than modified.

but what a gorgious build!

 

[loopfinding]

Lol yeah was gonna say some british something that isn’t orange. I think I’ve seen one hiwatt in my life, never mind played or worked on one.

 

[codamedia]

I can spot that Hiwatt build quality from a mile a away. There is nothing like it.
I've seen builders replicate it... but Hiwatt (in particular "Harry Joyce") is where the inspiration came from.

The first "quality" amp I owned was a Hiwatt DR105 (100 watt)... as a 16 year old at the time I though that's how amps were always built. I never saw quality like that again until I found a DR505 (50 watt) 20 years later. I wish I had kept one of those amps.

BTW... the bottom few pics has a purple and green wire that are NOT to Hiwatt Standards. Without the right angle bends and straight lines - someone has been in there.

Yes Sir a Hiwatt custom 50, DR505 ,

Most people outside of Canada don't know what a DR505 is.... It is the 50 Watt Custom DR-504, with the voltage selector removed to meet Canadian Import Standards. The DR105 is the 100 Watt DR103 with the voltage selector removed.

The Canadian Imports are identical to the models the rest of the world saw other than the missing voltage selector, however the importer did something called a "Canadian Mod" to "some" of the amps, giving it a cascading gain. I believe this was only done on the two input models (late 70's) to match what Marshall was doing with their JMP Master Volumes which soon became the JCM 800.

When a Hiwatt has the Canadian mod applied.... if you plug into the bright input, the normal volume cascades into the bright channel volume providing a lot more gain.

 

[24 track]

I can spot that Hiwatt build quality from a mile a away. There is nothing like it.
I've seen builders replicate it... but Hiwatt (in particular "Harry Joyce") is where the inspiration came from.

The first "quality" amp I owned was a Hiwatt DR105 (100 watt)... as a 16 year old at the time I though that's how amps were always built. I never saw quality like that again until I found a DR505 (50 watt) 20 years later. I wish I had kept one of those amps.

BTW... the bottom few pics has a purple and green wire that are NOT to Hiwatt Standards. Without the right angle bends and straight lines - someone has been in there.



Most people outside of Canada don't know what a DR505 is.... It is the 50 Watt Custom DR-504, with the voltage selector removed to meet Canadian Import Standards. The DR105 is the 100 Watt DR103 with the voltage selector removed.

The Canadian Imports are identical to the models the rest of the world saw other than the missing voltage selector, however the importer did something called a "Canadian Mod" to "some" of the amps, giving it a cascading gain. I believe this was only done on the two input models (late 70's) to match what Marshall was doing with their JMP Master Volumes which soon became the JCM 800.

When a Hiwatt has the Canadian mod applied.... if you plug into the bright input, the normal volume cascades into the bright channel volume providing a lot more gain.

first off thank you some great info here !

you are correct there were 2 mods done to this amp
1) the EL34 V1 socket has been replaced hense the purple wires
2) impedence selector cover is the Voltage selector ( wierd Mod)

inspection of another Custom 50 showed 4 Ohm at 105 volt marker, 8 Ohm at 115 Volts, 16 Ohm at 225volts , so I labled this accordingly the output schematic shows only 8-16 Ohm Output transformer Feed but the photo I found also includes a 4 Ohm out , not quite sure which is correct

this unit uses the TH7551 O/T

this an image showing the non canadian unit but the output markers show a definate 4 Ohm out

 

[codamedia]

2) impedence selector cover is the Voltage selector ( wierd Mod)

So it's still the impendence selector, but has the voltage plate.... and it's riveted? My first thought is an error in production since the plates are the same size. But I find it hard to believe that would slip through Hiwatt quality control.

I'm sure you have found it already, but the best resource I have come across for original Hiwatt info is the Mark Huss page.

Mark Huss Hiwatt Amplifier Pages

hiwatt.org

 

[24 track]

So it's still the impendence selector, but has the voltage plate.... and it's riveted? My first thought is an error in production since the plates are the same size. But I find it hard to believe that would slip through Hiwatt quality control.

I'm sure you have found it already, but the best resource I have come across for original Hiwatt info is the Mark Huss page.

Mark Huss Hiwatt Amplifier Pages

hiwatt.org

too cool , thanks again

 

[teletimetx]

2) impedence selector cover is the Voltage selector ( wierd Mod)


*********

I can only guess about the concept, but if you were touring regularly between countries with different voltage regimes, wouldn’t it be handy to have a built in selector, if you would prefer not relying on back line choices?

 

[24 track]

I can only guess about the concept, but if you were touring regularly between countries with different voltage regimes, wouldn’t it be handy to have a built in selector, if you would prefer not relying on back line choices?

I am repairing these units for a customer , like I stated even the tubes are period specific , sylvania El34's etc. obviously this guy is a collector so complete authenticity is paramount , these will never hit the road again ,I suspect

 

[Bobbyoso]

Was gonna say, either a DR Hiwatt, or a TopHat. Both amps built to very high standards. Haven't seen anything else handbuilt with that level of attention to detail.

 

[24 track]

Was gonna say, either a DR Hiwatt, or a TopHat. Both amps built to very high standards. Haven't seen anything else handbuilt with that level of attention to detail.

I worked on a DR Z , came very close, very,very close,
Dr Z takes each component and sands down the leads to remove all oils and coatings to ensure soldering to solid metal contact , bends the leads at the same 90 degree angles , clean and beautiful lines , another engineering work of art.

 

[Wally]

The only vintage amp that I have had open that is as visually impressive as a HiWatt was a Sano….immaculately constructed. Every bend of a wire or lead was a 90 degree bend.