Reduction Too Quiet

[tjessen]

Hello,

I've completed my Reduction build and have come across a problem. My Reduction is not putting out a line level signal, but one that is much quieter. All of my voltages are good and the LEDs and tubes light up well. I have checked my solder connections on the output components of the amplifier circuit, and everything seems well. It is connected to a MM cartridge and I have tried it with my receiver and headphone amp, and compared it to another phono preamp. It just seems way too quiet.

Any ideas?

[Chris65]

The Reduction has 36dB of gain, which is at the lower end for phono stages. So you may well find it quieter than another phono stage, as I did. If it works fine just accept that a higher volume is needed on your amp. Also depends on the output of your cartridge.
 

[tjessen]

I have my Reduction plugged into my Crack, a combination I was told is suitable. Do I need a preamp?

My cartridge outputs 5mV.

[Chris65]

Reduction into Crack is fine, where is the volume knob at your normal listening levels? Btw, the Integration kit adds more gain, about another 4dB.

[tjessen]

I cannot get to my normal listening volume when the pot is turned completely, and by then there is too much noise in the system.

[Doc B.]

What is the nominal output level of your cartridge?

[tjessen]

What is the nominal output level of your cartridge?

As in 5mV +-2db? I'm fairly new to this. It's the music hall tracker.

[Doc B.]

That should be giving you pretty close to 1/2 a volt of output. Which will sound lower than a typical digital source, but still be able to play pretty loud on most gear. If the level is just somewhat (I dunno, maybe 1/4-1/3 turn of the volume control?) different then it is probably working as designed. The gain is 36dB which is lower than some other phono preamps. If it is way too low, like you turn the volume up all the way and you can barely hear it, then there is probably a miswire in the preamp.

A lot of this has to do with what gear it is working with and what kind of gain the other components have. What preamp, amp and speakers are you using?

[tjessen]

I'm going to check everything in the amp in the morning, and I'll get back. I truly appreciate the help. I've noticed one channel is currently dead. Better get to work!

[Chris65]

I cannot get to my normal listening volume when the pot is turned completely, and by then there is too much noise in the system.

That doesn't sound correct, as Doc says, there many variables but you should get more volume than that.
Yes, check over the wiring, parts in the correct place, etc

[tjessen]

Ok, I've found that I soldered the one lead of a filter cap to 10L instead of 11, and will fix that asap.

[tjessen]

So I've fixed my capacitor and both channels are good to go, however the amp is still too quiet. Hmmm.

If this is identifiable in both channels and my voltages are checking in, where might I find the problem? Also, the small capacitors are .22uf 250V, unlike the specified .01 uf 400V specified in the manual. Come to think of it that's quite a difference, is this the source of my problem? All 8 are .22uf 250V.

[Grainger49]

Just to put it in perspective, what source have you used before the Reduction and where on the volume, i.e. 9:00 or 12:00, did you listen to it?

[fullheadofnothing]

The .22µFs are a packing error. We will send you the correct parts. It would help to know who you are (see rule 1 http://bottlehead.com/smf/index.php?topic=3.0 ).

[tjessen]

Just to put it in perspective, what source have you used before the Reduction and where on the volume, i.e. 9:00 or 12:00, did you listen to it?
Err6tt

Before the Reduction, I would run my DAC with volume at 30%.