John Curl's Blowtorch preamplifier part III

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Yes, it is interesting. I'm experimenting successfully with an IB subwoofer in the corner of my room (supposed to be bad place?) I'm getting a smooth response except for my ever present peak at 40Hz, easily cut and no nulls. What do you do bass wise? Another useful test Sine Burst Tones (20-200 Hz)
I have RCA fed powered sub centrally between two floor standers (1"x1, 6.5"x2) and I find the LR position and depth position of the sub to be critical and surprisingly so for good and coherent overall sound and imaging.
The sub has level and LP controls and I find these adjustments to be critical and according to the mastering of the programme.
The other usage of these controls is deliberate bass remastering of tracks according to taste....and circumstance etc.
So, according to my experience I am curious that such corner placement does not 'unbalance' the stereo experience ?.
If the music purpose is general background music then I suppose it is not so important, for 3D hi-fi imaging I expect the imbalances would be a nuisance.
Tell us what you find longer term ?.

Dan.
 
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I have two u-frame subs positioned near my mains and have used delay to get them more time coherent. My plan was to use the IB for the bottom octave to take the load off the u-frames, I don't like boost and excursion if I can help it. I haven't got them all going together yet, but have been pleasantly surprised using the IB below ~100Hz. It's not as house and neighbour friendly as the OBs though :)
 
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IME the series inductors marked in the pic cause unnatural subjective mayhem and need to be removed...... wire bypasses will not do but could be tried as a first experiment in hearing stage by stage changes.
First experiment is to fit a couple of non directional links flat bridging or high looping across the vacant inductor pads.........a length of stripped Cat5 wire looped back and twisted is plenty of conductance for the purpose and in this environment is said to be non-directional conductance.
Enameled wire of similar gauge similarly implemented is also perfectly suitable and is indeed another subjective experiment.
Those non directional 'naked' wire loops are open to application of all kinds of modifiers, that's part of what Goop is about.
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Wire bypasses will not do?
What would be best....I do have a 18gauge air core inductor I could strip but what would be best to start with?
 
Wire bypasses will not do?
What would be best....I do have a 18gauge air core inductor I could strip but what would be best to start with?
No because the ferrites are still 'in circuit' despite short circuit wires across them.
A stripped strand of Cat5 folded back on itself and twisted......long enough to make two links that replace the ferrite links.
Make the links long enough to come vertically up off the board 15/20mm or so and loop over and go vertically back down to the other pad....this looping is for later experiments/tweaking.
Bare Cat5 strand (24AWG/0.51mm) doubled back versus enamelled 24AWG doubled back will make a fine difference......if you have suitable enameled wire preferrably use that, diameter is not critical except for physical size restraints....two 18 AWG (1.0mm) wires might not fit into the pcb holes.
24AWG links will not present as any bottleneck but will cause a different sound to that of the ferrites and let the amp 'open up' with different tonal and dynamic characters.
Once the AC power input is sorted we will go to the other end of the amp.


Dan.
 
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