HAL PREAMPLIFIERS

[OnAudio]

The planet goes green

[OnAudio]

With a high pass filter the curves are a bit cleaner. Feel free to chip in.

[OnAudio]

Here are the curves from the latest mod.

[OnAudio]

Originally Posted by OnAudio

Here are the curves from the latest mod.

Hi all,

These curves are not bad , can be compared to Self's, small signal fig 11.8, 11.7 and 11.9, it falls in some where there. Also the B5 bass curve can serve as a reference http://www.firstwatt.com/pdf/prod_b5_man.pdf, although the B5 does more than that. Also Linkwitz has some interesting curves here Linkwitz Lab - Loudspeaker Design.

But please this is still open to discussion.

kind regards,

Harrison.

[OnAudio]

Comments welcome, also there is an interesting article in the MIX magazine Dec 2011 page 60. Seems this kinda pre amp is hot at the moment.

[stratus46]

Originally Posted by OnAudio

Here are the curves from the latest mod.

The Bass is marginal while the treble borders on useless. You will not like how it works.

G²

[stratus46]

Originally Posted by OnAudio

Here are the curves from the latest mod.

The Bass is marginal while the treble borders on useless. You will not like how it works.

G²

[Bonsai]

Originally Posted by OnAudio

Comments welcome, also there is an interesting article in the MIX magazine Dec 2011 page 60. Seems this kinda pre amp is hot at the moment.

It was hot 35 years ago too - I remember building something similar . . . with LF356 op-amps (very late 70's in my youth) . . .

Your tone control curves are looking quite good, and the return to zero is very important if you want to avoid amplifying supersonic noise etc.

[currentflow]

Originally Posted by OnAudio

Here are the curves from the latest mod.

Look at Hi-Fi Preamplifier by ESP. This design gives a more sensible and subtle tone adjustment range of +/-10dB whereas the more "traditional" designs use +/-20dB.

I built this circuit using LM4562 op amps, have used it for around 18 months and find the quality and adjustment range excellent. The gentle tonal corrections it offers seem perfect when compensating for the room acoustics.

Regards,
currentflow

[Bonsai]

I agree. For tone controls, 10 db at the frequency extremes is about right.