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Messages - julio daniel


Hello everyone. I come with you to ask for help, in this case for a bass amplifier ALESIS BASS 125EQ, which has an output amplifier similar to the HH-IC-100, after some measurements and having not detected any damaged component, I come across an oscillation at the output of (12.8 Khz), with an amplitude of 23.5 Volts, after checking the power board and components, I did not detect any anomaly, I even changed the input integrated one LM741, for a NE5534, the result was same.
I don't know what else to do, the components appear to be OK, but then the result is disastrous.
I thank you in advance for your precious help.
Best regards

Julio Daniel

Hello everyone. After several months waiting for ordered material and several attempts, to reach a definitive result, "some failed", I can already present the results of the change "or upgrade" of my Torque T12. The changes I made, after some time of reflection, and some suggestions that you sent me, turned out not to be difficult to execute, that is: I added a reverb line like MOD 9EB3C1B, the result was good but I didn't stop there , as I had already done several experiments with lines built by me, using a small loudspeaker of 8 omhs, as an exciter and as a receiver a piezo unit, normally used in acoustic warning devices. I placed the two lines in parallel, with the appropriate impedance adaptations, made a little randomly and after a few attempts and experiments the final result paid off, in my humble opinion. The result was achieved with a Fender T-bucket 350-E NAT Acoustic guitar, crafted in Indonesia, with Fishman preamp. The audio file was recorded with my old man, already 10 years old, Compaq CQ61SP100, maybe there is a background noise that is not noticeable when the amplifier is used, only for the guitar. Greetings to all and thank you very much for your cooperation. J.B.

Hello everyone
Thanks dmeek for the suggestion, as for the input resistance of 47K, it is what is mounted, however I will try to change the value to about 1M, as well as the capacitor, I will test with 0.022, but it all depends on the arrival of the reverb tank, which is delayed due to the current situation.
Best regards.
Hello everyone
Thanks dmeek for the nice work.
Any suggestions to optimize this circuit?
Best regards.
Hello everyone
I will try to answer the dmeek's comment, but the photos, although sharper, are limited to my Samsung camera, which is not the best.
best regards

Hello everyone
in particular I respond to the observation of the dmeek, in fact the diagram had inaccuracies, the annex follows the corrected version, and also a detailed version of the transistores part.
I think I will try to reformulate this preamp, keeping the rest of the components, I have plenty of time, so I will start to elaborate a new board with a new circuit, even if it is limited by the amplifier panel.

Hello everyone
I will try to reply to your posts.
Finally and after a long time, I found encouragement there to remove the amplifier's scheme, because because of confinement (covid-19), we have to occupy time, otherwise we go crazy.
The scheme is already on the question of using the TDA2050, as I mentioned in a previous post, this aims in the medium term to replace the transformer with a more powerful one with an AC voltage output between 17 and 17.5 Volts. On the other hand, even using the current transformer, the TDAxxxx circuits, available on the market, are not original, since the manufacturer considers them obsolete.
Thanks to everyone, suggestions are accepted to optimize the existing circuit, if possible.


P.S. The driver scheme for the tank reverb is just to complement, as this circuit is already built and tested, I just need the MOD line 8EB2C1B, which should arrive on Monday

hello, good morning
by the time here.
Thank you for your answer Joecool85, the amplifier is quite simple: 1st stage with a TL072, between the operational ones, there is a limiter / compressor made up of two BC182 transistors and two 1N4148 diodes, for some cut, then and after the second of the TL072, is the tone control, only with bass and treble and very simple, the tone control output directly attacks the output amplifier in the case of a TDA2050, which is not original, originally had the TDA2030, the power is consisting of a transformer with symmetrical 13.7 volt outputs, rectifier bridge and 2200 micro farad filter capacitors, the whole set is very simple. My goal is to add a reverb line and maybe in the near future change the power transformer, for a higher voltage, in the 2x17 volt range, which would allow to get about 30watts in the output, which is the reference power of the loudspeaker that I have installed a Celestion Tube10, which I recovered from a ZOOM amplifier, after it was replaced by EMINENCE of 75 w.

To identify the Torque 12 amplifier, I add some photos, the speaker you see, is already the Celastion tube 10.
best regards
Hello everyone
This is my first post and I am in need of help, to make some changes to an Acoustics Torque 12 amplifier, I need the diagram. I've already made some changes such as: I changed the original 8 "speaker to a 10" Celestion Tube 10, I replaced the TDA2030 output chip with a TDA 2050, I intend to include a MOD 8EB2C1B reverb line, the driver for this line already it is built and tested, all that remains is to reach the line that is already ordered.
In addition to the scheme I am open to all suggestions.
My thanks in advance.
Best regards