Ts808 modified question!!!

[astley]

I just finish my clone Ts808 , but i feel that middle boost  not enough , so i want to increase the middle boost. but how can i increase that ? or increase three band EQ circuit , any one can help me ?
thansk so much~^-^

[markm]

I can't really help you with the problem but, every 808 I've heard is mid-heavy right outta the shoot.
Maybe reversing some of the mods as there are quite a few on the net that actually cut some of the mids.
   MarkM

[JHS]

Use a JRC4558D, KA4558 or BA4558 chip, those have decreased bass and highs or in other words have a natural mid hump.
If that is not enough, wire a small ceramic cap 2,2-5,6n between the normal (+) and inverted (-) input on the OD-stage to increase the mids a bit (I saw this trick in the HAO Rumble Mod).

JHS

[oldrocker]

What website did U get the schematic from?  I got mine from Tonepad.  There is a slight difference if u use General guitar gadgets.  From pin#2 above the diodes the 4.7K and the .047uf trail off to different places.  Tonepad goes to ground which is what I did and GGG goes to Vr.  I haven't tried going to Vr so I don't know how this effects the sound if at all.

[JHS]

Connecting the 4,7k/47n RC-network to ground is less middy, but give a softer tone w tweed like distortion and better response to pickung dynamics. Connected to VREF, the tone is louder, stiffer w tight bass and more middy.

All in all it depends on the IC-type, 'cos both methods have an effect on the internal BIAS of the IC.

I prefer connecting to VREF if the IC has low slew rate (JRC1458,4558/-58/-60), and to ground if it has higher slewrate like a TI 072 or OPA. A Mitsubishi TL 072 for ex. seems not to like connecting to ground at all, but the internal circuit is slightly different from the TI 072 and has a very low slew rate for a 072.

I think there's no prob to add a switch to the RC-network to have an option.

JHS

[oldrocker]

OK thanks.  I have the TL082 in mine so I don't know how close that is to the TL072.  Maybe I should just leave it connected to ground since it seems to working good.  I'm always curious to try different things just to check it out and see how it sounds.

[Ge_Whiz]

Use a JRC4558D, KA4558 or BA4558 chip, those have decreased bass and highs or in other words have a natural mid hump.

[scepticism] I've never heard that claim before. Seems contrary to good op-amp design to me. [/scepticism]

[JHS]

Acc. to my experience no cheap op amp amplifies really linear, the TI 071/72/74 are close to linear, good OPAs are even more close.
The NE5532AN is close too but has a sterile tone with artificial highs, I don't like it in ODs but otherwise it's a cheap, good low noise IC for all around purpose use.

All 4558 have more or less a midrange hump, due to a weak bass and reduced highs to defeat the treble hiss.
I think the JRC, KA, and BA are the middiest sounding ICs I have used so far, the JRC is the softest of those, sometimes so compressed sounding that raising the deep frequencies in the circuit produce nothing but low end mud.

I do not like checking ICs in actual FX-devices but I have a small signal booster and a TS-copy on perfboard for testing op amps and trannies. The active devices are mounted in sockels and the units have some switches, so I can swap them very easy to make a preselection for the actual use.

Those cheap op amps stray a lot in sound and output due to manufacturing tolerances, even if they come from the same lot, some are strong, some are weak, some are crap.

JHS







JHS