First Kaiju: Slight hum and somewhat low volume

[Alex.podaru]

Ok, so I hope I did this right... I fed in a 60hz tone (from http://www.szynalski.com/tone-generator/) from my laptop into the Kaiju and with the Kaiju powered off i took the following measurements for max AC voltage (i only did this on the left channel as both channels seem to behave identically at this point).
From the middle of the left input to the ground tab next to E: 1025mV
From the middle lug of the left trim pot (with the trim pot in its lowest position) to the ground tab next to E: 170mV
With the Kaiju powered on from B3 to he ground tab next to E: 403V
In the speaker terminals with the trim pot in its lowest position: 8mV
In the speaker terminals with the trim pot in its highest position: 6.28V

 

[Doc B]

OK, this helps. 1.025Vrms of signal in is quite a bit less than the 1.56Vrms the Kaiju needs to see for full output power of 8W. Assuming 8 ohm output transformer secondary wiring into an 8ohm speaker, 6.28Vrms output is only about 5 watts output. So a preamp to boost that input signal a bit may be the best solution to get the Kaiju cookin'. Even a Quickie would do the job.

 

[Paul Birkeland]

From the middle of the left input to the ground tab next to E: 1025mV
From the middle lug of the left trim pot (with the trim pot in its lowest position) to the ground tab next to E: 170mV

You've lost 20dB through your trim pot, are you sure it's all the way up?

With the Kaiju powered on from B3 to he ground tab next to E: 403V
In the speaker terminals with the trim pot in its lowest position: 8mV
In the speaker terminals with the trim pot in its highest position: 6.28V

Yeah, turn the trim pot all the way up and start again.

 

[Alex.podaru]

OK, this helps. 1.025Vrms of signal in is quite a bit less than the 1.56Vrms the Kaiju needs to see for full output power of 8W. Assuming 8 ohm output transformer secondary wiring into an 8ohm speaker, 6.28Vrms output is only about 5 watts output. So a preamp to boost that input signal a bit may be the best solution to get the Kaiju cookin'. Even a Quickie would do the job.

So, if I'm understanding this correctly, the Kaiju is working within norms, I just have to increase the input.

You've lost 20dB through your trim pot, are you sure it's all the way up?

Can you explain to me, if it's not too complicated or time consuming, how you've obtained the 20dB value? I will run those tests again with the trim pots all the way up.

 

[Alex.podaru]

You've lost 20dB through your trim pot, are you sure it's all the way up?
Yeah, turn the trim pot all the way up and start again.

Tried it again with the trim pot all the way up and was getting near 1mV between RCA and middle lug of trim pot.

 

[Alex.podaru]

Alright!! So I tried running the Kaiju through my Emotiva UMC 1 and boy can it get loud!! Still crystal clear and with its natural warmness and cohesion.

I couldn't help but to do the same with the S.E.X and I was again amaze how loud it got before showing signs of distortion. It really is a great little amp! 

 

[Paul Birkeland]

You reported about 1000mV of signal at the RCA jack, but only 100mV at the middle lug of the trim pot.  This would indicate a measuring error or that the pot isn't turned all the way up.  If the pot is all the way up, the middle lug of the pot and the center pin of the RCA jack will show the same AC voltage. (With the remote possibility of a wiring error, but I looked over your photo and couldn't see anything)

-PB

 

[Alex.podaru]

My apologies! I was measuring the wrong thing. The reading i gave you of near 0mV was from RCA input to middle lug on trim pot. From trim pot to ground I am getting 1,009mV (with and RCA to ground of 1,010mV).

 

[Paul Birkeland]

Try pin 3 on each 4 pin socket again.  With 1V (1000mV) of signal coming into the amp, you should see more like 20-30V on pin 3.

 

[Alex.podaru]

Ok, i’m getting 29V and 29.9v in the left and right channels respectively

 

[Paul Birkeland]

Ok, so far that's a well balanced amp.  Now you should see somewhere between 4V and 8V when you measure AC voltage between the black and red post on each speaker output.

 

[Alex.podaru]

Ok, i’m getting ~6.2V in both channels with the trim pots fully open. Should I conclude the Kaiju is operating exactly as it should?

 

[Doc B]

It all sounds about right. Try a preamp if you have one.

 

[Alex.podaru]

Ok, I'll give the preamp a try!

I realize this might not be the best thread to discuss the topic, but what would be the pros and cons of the Smash vs the Bee? I realize that you recommend the Bee as a great pairing for the Kaiju, but if I don't have $1200 burning a hole in my pocket, what would be the drawbacks of the more cost conscientious choice of the Smash? 

 

[Doc B]

The BeePre has more resolution and of course it has the 300B body and weight. With the upgrades the Smash has a similar Bottlehead house sound, just a little bit less refined. It's always surprising to me to listen to a Quickie, Smash and BeePre in sequence. They are different, but since they are all DHT the differences are not as extreme as one might assume.

Now the Neothoriator as a preamp, that's a whole 'nother level.