Menu

Show posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Show posts Menu

Messages - swt

#1
Preamps and Effects / Re: Aion lab series l5
January 15, 2019, 09:09:43 PM
Yes sir! C37...no wonder why ot wasn't working
#2
Preamps and Effects / Re: Aion lab series l5
January 15, 2019, 09:01:26 AM
Solved. The 100p that was suppossed to be a multilayer was in fact an inductor. Bad supplier. Thanks a lot.
#3
Preamps and Effects / Re: Aion lab series l5
January 14, 2019, 09:57:50 AM
Thanks for the replies. R76 reads ok at 99.8k. It must be something with ic 11 or q1.
Schem at aion site.
#4
Preamps and Effects / Aion lab series l5
January 13, 2019, 11:19:02 PM
Hi. Just finished this project and i am having problems with r76. Before it, i have audio probe and tested the 4.40 ac volts as per calibration. Right after it, audio is almost lost and ac volts drops down to few millivolts. Any clues?
#5
Amplifier Discussion / Re: paging j m fahey
August 16, 2015, 10:33:17 AM
great juan!! i'll be in buenos aires in a month or so. i'll contact you before to tell you the precise date. i'll try a couple of amps if possible. thanks a lot buddy...
#6
Amplifier Discussion / paging j m fahey
August 06, 2015, 08:36:39 AM
hey juan. I'm also from argentina but i'll follow the forum rules so i'll speak in english.
Do you have a contact phone or web page or email?.
i build tube amps and fxs, ss amps, etc, but just as a hobby in the quest for good tone. i'm an ee but have dedicated my life to music and martial arts.
the reason for this message is to open your eyes to a new market in argentina. i play jazz and blues, and i think it could be a goal to build a polytone pre with a lm3886 or tda 7293 amp, with fx loop. also a desirable amp could be a fet preamp like the old roland cube with a chipamp, or with irp250 fets. i have lots of friends that can buy that type of amps in a head form, not only from the place i live (neuquen, patagonia), but have friends in bs as, mar del plata, rosario etc, that play jazz and would be really interested in buying a polytone type of amp or aimed sound, at a reasonable price. let me know what you think of this or tell me how to contact you by phone. thanks a lot!!
PS: it could also be nice to have some well built tl 606 or tl 806 cabinets to pair with those amps...
PS2: irp250 would also be nice...i'built a polytone pre with a lm3886 and it sounds good, also built a roland cube pre with tda 7294 and had good results, my friends like them a lot, but i'm not a builder...i do that for myself...and build most of the fet preamps on perfboard...
#7
forgot...the soft clipping power amp i was talking about is implemented in the vox busker, with diodes in the feedback loop of a tda 2040 chipamp. But it has a high resistor fb, and a lower series resistor with the diodes...so i don't think it will have so much headroom.
#8
thanks a lot for the replies!. very useful info. The reason i asked, is because although the power is working fine, i tried to use it in a rehearsal situation, with rog pedals as pre, but the volume needed for, was overdriven the subsequent pedals, such as univibes and delays, and when used at the correct vol, it was too low. I think my soution to this will be: use a fet buffer from, say +-18volts, and a jfet return boost similar config, as a loop. THen run the preamps at normal vol into the loop, and pedals in there. OR might try the tut ultimate fx loop, as the loop, and pre before it.
will be reporting, if anything works. thanks a lot.
#9
HI!. although i read past threads, and used the search function, i still have some questions.
I've built the LM3886 power amp from ggg. Changed the 33k feedback res to 22k, the input imp res to 100k and 10uf fb cap to ground to 22uf as in the datasheet.
SO here i go:
do you guys use buffers in front of the power amp?. i think it's useful to use them to adapt the preamp to the power amp. but useful it's not always better.
i've tried a couple of rog circuits, and also the bsiab, and unless i crank the vol, i don't achive gain and volume from the power amp....so: should i use a booster, buffer, or maybe just go up with the feedback resistor to get more gain?
Can i add a couple of diodes ala tube screamer to get soft clipping?. ( maybe through a series resistor to limit them).
Are the single rails preamps enough to excite the power amp?. Because i'm using a bipolar supply of +-25v for the chip.
Thanks a lot for your replies!
will be reporting as i make further advances.
PS: i build tube amps and fxs....so far this is my first transistor amp.
#10
Amplifier Discussion / good mosfet power amp schem??
October 15, 2006, 10:30:46 AM
can anybody suggest a good and simple mosfet power amp for the 20w to 45w range?. i'd like to try one...or find a good use for irf 520 or similar mosfets...thanks a lot!!
PS: maybe a single class A small power amp too...like ne irf 520 or 820 and components...
Thanks a lot!
#11
Amplifier Discussion / Re: Gibson LabSeries L5 (pics)
August 24, 2006, 12:34:47 PM
hi. first time in here. usually the problems you're refering to can be, bad solder at big resistors, usually ceramic, as these are large, they usually crack the solder from vibration, and also, bad caps, or bad resistor. check the ps cables too, because sometimes turning on and off, can be caused by the voltage going out, in the output section of the amp.
80% of the times it's the resistors. check them and let me know.
if your amp is dissipating heat, then check the value of those resistors too, might be a shorted one, and also shorted caps...