fun with amp gurus ( amp identification post)

24 track

Doctor of Teleocity
Ad Free Member
Joined
Nov 6, 2014
Posts
19,994
Location
kamloops bc
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

P1010011.JPG



P1010014.JPG



P1010015.JPG



P1010016.JPG


P1010018.JPG



what a beautiful design

enjoy

24
 

24 track

Doctor of Teleocity
Ad Free Member
Joined
Nov 6, 2014
Posts
19,994
Location
kamloops bc
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 .
 

beyer160

Poster Extraordinaire
Joined
Aug 11, 2010
Posts
5,231
Location
On Location
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!
 

24 track

Doctor of Teleocity
Ad Free Member
Joined
Nov 6, 2014
Posts
19,994
Location
kamloops bc
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

Poster Extraordinaire
Joined
Jun 19, 2011
Posts
5,023
Location
europe endless
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

Poster Extraordinaire
Joined
Apr 4, 2009
Posts
6,052
Location
Western Canada
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.
 
Last edited:

24 track

Doctor of Teleocity
Ad Free Member
Joined
Nov 6, 2014
Posts
19,994
Location
kamloops bc
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

P1010025.JPG
P1010023.JPG


output.png


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

Screen shot 2022-07-02 at 1.09.11 AM.png
 
Last edited:

codamedia

Poster Extraordinaire
Joined
Apr 4, 2009
Posts
6,052
Location
Western Canada
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.
 

24 track

Doctor of Teleocity
Ad Free Member
Joined
Nov 6, 2014
Posts
19,994
Location
kamloops bc
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.
too cool , thanks again
 

teletimetx

Doctor of Teleocity
Joined
Jul 25, 2011
Posts
14,828
Location
Frontrangia CO
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

Doctor of Teleocity
Ad Free Member
Joined
Nov 6, 2014
Posts
19,994
Location
kamloops bc
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

TDPRI Member
Joined
Aug 22, 2008
Posts
88
Age
70
Location
Bellevue WA
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

Doctor of Teleocity
Ad Free Member
Joined
Nov 6, 2014
Posts
19,994
Location
kamloops bc
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

Telefied
Ad Free Member
Joined
Mar 17, 2003
Posts
41,966
Location
Lubbock, TX
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.
 




Top