Any good Class A(B) power amp kits?

[Pio1980]

Excessive screen voltages, continuous or peak, or both.

 

[deltalight]

My friend has designed a very high end Class AB Power amp. The rated power is 75W/ channel. It's the best sounding amp I have heard so far. The build is fairly easy, there are soldered modules with heatsinks mounted on PCBs. The Amp is based on Toshiba BJTs. The modules have all the high quality parts. The Amp has onboard power supply, protection circuit etc.The user has to only connect a transformer. Here are some pic

He has also designed a Class A preamp/Headphone amp

Regards
Sachin

Is there a weblink or address? I like what I see!!

 

[sachu888]

Hi,
I have posted it on lencoheaven.net , but only registered members can see that. The build is fairly straightforward, theuser only need to do wiring for signal and transformer.
below are the specs of stereo amp:

Power output : 70~120W into 8 ohms, 110~180W into 4 ohms.(continuous avg per channel.)
THD : <0.03 % at rated power 20-20000Hz, 0.003 % @ 1kHz half power
Signal to noise ratio : 112dB
Frequency response : 3Hz-250kHz.(-3dB)
Input impedance : 25k ohms
Input sensitivity : 1V rms for rated power
Damping factor : 200, @ 8 ohms, 20-500Hz
Power supply : 30-0-30 for 70W, 40-0-40V AC for 120W 300-500VA, 9-0-9V AC for protect
1. 70W PC

Bjts: Toshiba 2SC5200N/A1943N
Power caps , 4 X 6800uf, 50W

2. 120W pc

Bjts: Toshiba 2SC5949/A2121
Power caps , 4 X 10000uf 63W
PCB size is approx 304MM X 125MM. Ther are two heatsinks mounted directly on PCBs.

He has also designed a pure class A with onboard power supply and can also be uses as headphone amp.

I have built no of Class A amps like Amp camp(still using) Pass F5, Jean Hiraga Lemonstre, but this one is special and much more cheaper to build.

Regards
Sachin

 

[triode17]

I'm pretty sure I can fix my tube amps....I just can't figure out why I've had so many 6V6 failures. They'll work fine then one day they want to make a light show. They were rebuilt at some point. I cant find any bad parts. I did run a different rectifier so I suppose the lower voltage say due to higher current handling may have played a role....in which case why the hell is the B+ that high to start with? Typically units like this we're designed to have a homeowner replace tubes....so they shouldn't care about non non matched tubes.

It basically all started when the JJ tubes had one suffer a screen failure....they've been issues ever since. I don't know whats up with them. But I'm kinda done throwing money at them for the time being. I need to get the money saved up for the move.

Did you try replacing the power tube sockets and adding 100 Ohm screen grid resistors yet? That may cure your problem and won't cost much.