NE5534 circuit. I need more bass. Help!!

[dj_holmes]

Yes. As is, the HF rolloff is 723kHz (without the input filter).
You should be able to use as much as 22pF before it's too much.
How much capacitance did you try?

I think I tried a wima 220pf was that over kill?

 

[rayma]

I think I tried a wima 220pf was that over kill?

That would be way too much, by about ten times. No wonder it sounded bad.
Do you have any 22pF polystyrene or cog/npo ceramic types?

 

[jaycee]

15dB is a lot of gain, and i really doubt you require so much if this is for a hifi amplifier, from a source such as a PC or a cd player

 

[rayma]

15dB is a lot of gain, and i really doubt you require so much if this is for a hifi amplifier,
from a source such as a PC or a cd player

Right, unless it's mainly for use with a RIAA stage of typical gain.

 

[jaycee]

Right, unless it's mainly for use with a RIAA stage of typical gain.

Quite so, but then the circuit would have extra frequency response shaping.. this is just a simple flat amp..

 

[dj_holmes]

That would be way too much, by about ten times. No wonder it sounded bad.
Do you have any 22pF polystyrene or cog/npo ceramic types?

Probably not. My daughter is sleeping I will dig trough old parts must have it somewhere.

The only reason I messed with that 1pf in the first place because it was the easiest to remove.

I did have some 5pf silver micas few months back. Will that lower it much? It may have been 3pf but I know they are superior grade caps!!

 

[rayma]

Quite so, but then the circuit would have extra frequency response shaping..
this is just a simple flat amp..

I mean that with the typical 34dB RIAA stage, you will still need gain in the line stage,
around 15 or 20DB.

 

[jaycee]

Probably not. My daughter is sleeping I will dig trough old parts must have it somewhere.

The only reason I messed with that 1pf in the first place because it was the easiest to remove.

I did have some 5pf silver micas few months back. Will that lower it much? It may have been 3pf but I know they are superior grade caps!!

To be honest I wouldn't bother with that 1pF capacitor at all. I doubt it is needed as the NE5534 is compensated with the 22pF between pins 5 and 8. Leave it out.

Then what sets your high frequency rolloff is the 220pF capacitor. Increase it to decrease the rolloff point.

 

[rayma]

I did have some 5pf silver micas few months back. Will that lower it much?
It may have been 3pf but I know they are superior grade caps!!

You could try a couple of those in parallel instead of the 1pF feedback cap.
Remember not to change the existing 22pF cap, that's necessary for unity gain stability.

Do you use phono, or CD mainly? If CD, you could bypass this stage entirely.

 

[dj_holmes]

Thats crazy so for:

: higher bass increase resistor
: lower treble increase capacitor

so if I decrease resistor and lower capacitor I will get stronger mid band?

I use mainly CD, what stage can be bypassed?

 

[jaycee]

Preamp. CD players output 2V RMS which is enough to drive most power amps so loud it'd make you deaf (and kill your speakers) without any extra gain.

What amp are you connecting this to ? You might simply want a buffer followed by a potentiometer for volume control.

 

[rayma]

I use mainly CD, what stage can be bypassed?

For CD, you don't need any gain at all, so you could bypass this entire stage.
That is, take the signal from before its input. What amplifier is this?

I've had very good results by using the CD player directly into a 10k volume control,
then into the power amp. That is, bypass the entire preamp for much better sound.
No hacking around on the circuit needed, either.

 

[dj_holmes]

For CD, you don't need any gain at all, so you could bypass this entire stage.
That is, take the signal from before its input. What amplifier is this?

I've had very good results by using the CD into a 10k volume control, then into the power amp.
That is, bypass the entire preamp section. Much better sound.

The pre amp is built in the amp itself. Its split into pre and power

 

[dj_holmes]

The problem is now I will spend all day trying different values to get the best sound and that for me is something very difficult as there are so many value combinations

 

[rayma]

The pre amp is built in the amp itself. Its split into pre and power

Right, you just add a volume control between the CD output and the power amp input jacks
of the amplifier. You use it as a power amplifier, instead of an integrated amplifier.

 

[jaycee]

If you're feeding an integrated amp's pre-out into this circuit, and then back into the power in socket, you are adding gain on top of the amp's existing preamp gain. Youll almost certainly be driving the thing into distortion...

 

[rayma]

The problem is now I will spend all day trying different values to get the best sound
and that for me is something very difficult as there are so many value combinations

I would avoid too much of that, as a mistake will happen and you will let out smoke.

 

[rayma]

If you're feeding an integrated amp's pre-out into this circuit, and then back into the
power in socket, you are adding gain on top of the amp's existing preamp gain.

I think this is the line stage in his integrated amplifier, not a separate external circuit.

 

[dj_holmes]

Right, you just add a volume control between the CD output and the power amp input jacks
of the amplifier. You use it as a power amplifier, instead of an integrated amplifier.

I get that and it probably will sound better. But its not my amp, well it is but I'm working on it for a dear friend and I just want the sound to be perfect for him.

Its old and has no name but very well built its not even worth mentioning it, I'm just really excited the mods mentioned kindly here are a real working solution and has literally opened my eyes to so many other amps that could be modded this way!! Thanks to you guys!

 

[jaycee]

I think this is the line stage in his integrated amplifier, not a separate external circuit.

Thats why i've been asking what his integrated amp is