Anvil Amplifiers

31/08/2024

Hilarious Again!

Bradley Walsh FINALLY meets F***y Chmelar 😂 ***yChmelar and 🔔 to the BBC 👉 https://bi...

21/03/2024

But are they Kosher?

Sky News host Chris Kenny reveals another example of how Christianity is “under fire” after a supermarket chain in the UK decided to get rid of the cross fro...

19/02/2024

Moved out of Auckland last year.
Now located in a small town called Paeroa.
I have made a downsized workshop in a 2 car garage.
Still unpacking stuff.

05/06/2021

65 Fender DRRI Hiss removed.
Stripped out PCBs And rewired point to point using high quality components.
Made Tremolo as 6G16 type bias Trem.
Owner is pleased with the result.

21/07/2020

Another scratch build Stereo Amplifier.

This one uses a small ex computer chassis/box.
Locally made Beacon radiometal Ultra Linear OPTs, PP EL84 topography again.
I used a new grounding idea, the aluminium bar in the centre is isolated from the chassis.
The PI stage is ECC82/ 12AU7, the first socket on the chassis is for EF86 phono stage borrowed from Quad 22.
My friend auditioned with Lowther speakers and was stunned by the lack of noise and the dynamics of the power amplifier.
He said he would buy it if he did not have so many amplifiers already.
The phono stage needs some high spec capacitors for the RIAA network which I am at present sourcing.
I had originally planned to used GZ34 recto but went with solid state and used the space on the chassis to mount a smoothing choke.
Photos tell the story.

21/07/2020

Had a pair of QUAD 2 mono blocks for repair. Someone had made a dismal attempt at repairing earlier, Wrong filter capacitors installed with sticky tape Clunking around under chassis!
I made some mountings from aluminium bar to support tag strips for replacement filter caps and also replaced the cathode resistors/ bypass caps and the signal caps with more correct types.
One of the amps had two 330uF filter caps loading the GZ34 rectifier, luckily the tube had survived this overload.
The other one had a dual 16uF which was loose inside the chassis. I fitted a bracket (pictured) but later decided to make the setup the same as the other amplifier.
The owner is very pleased with the result after auditioning them on his Lowther high efficiency horn speakers.

08/12/2019

Thanks to everyone who liked my page.
I just reached 100 likes.
I will have more time to put up more interesting repairs and projects in the near future.
Cheers Alan.

19/11/2019

1976 Fender Twin Reverb Rebuild. (SOLD).

I acquired this Amplifier from a client who did not want to proceed with what would be a very expensive repair.

The main problem was a very conductive eyelet board.
The pots had lots of DC voltages leaking in from the component board.
The board was so bad that I could measure 100 Volts 30mm away from the preamp HT and plate resistors with my meter probe just by touching the black crud board!

I decided because the amp needed a replacement board and would never be "original" again that rather than procuring a new black cardboard piece of dung I would make a Turret board instead.
I further opted to use high grade components to populate the new board.

16/10/2019

1960s GIBSON MAESTRO COMBO.
I was presented with what appeared tp be a tidy example of a desirable vintage amplifier for repair.
When I removed the chassis I was shocked by the butchery which had taken place inside!
All resistors and capacitors had been replaced with miniature types apart from 6 resistors on the input jacks.
The “Output Transformer” fitted with duct tape was actually a power transformer with 2 110V primaries and 6V secondary.
A fluorescent light ballast had been installed as a power supply choke.
(This amp originally had a 2K dropping resistor.)
The 3 octal sockets had been replaced with some dirty second hand ceramic types which I recognised as the type used in 1970s NZ GUNN Amplifiers.
The speaker fitted was a NZ assembled by Plessey which I recall were actually Rola.
Obviously the Amp will never be what it once was but I decided to make it work anyway.
I fitted an old output transformer which seemed more suitable for the job, a dropping resistor instead of the light ballast and fired it up via a lamp load.
Got a little audio out but discovered that the shared cathode resistor fitted on the 6V6s was 700 Ohms.The the schematic showed a 250 Ohm so I fitted a 270 which I had.
Monitoring the cathode current with my Bias probe showed 10 mA thru one 6V6 so I paralleled another 270 to get 22mA which I calculated from the Plate voltage would dissipate 9 watts per Tube “cough” Valve.
After cleaning all the pots the amp was operating OK.

25/07/2019

Stereo Valve Amp Scratch Build.