tube cricket type recording amp

[sickbend]

ok so I've been messing around with small recording amp circuits but have a few questions I tried wiring the fetzer ruby but it motorboats and squeals like mad so I double checked my work the fetzer works by It's self fine the jrc386 amp works by its self if I run both of them off of separate batteries and feed the input and output it works if I try to run them off of the same battery it won't work if i try running it off a power supply it also won't work also i think the schematic is wrong the 100k bias trim is way to high a 10k works alot better to dial in a better bias voltage anyway here is my idea I thought of trying to use a valvecaster as a preamp to a higher watt chip power amp maybe a  lm380 or 2 cascaded 386s I'm looking for 1 to 2 watts at most  and a better tone control then the tube cricket has so how does this sound vavlecaster to a passive eq amz with presence control? with a fixed makeup gain opamp buffer fed into a low watt power amp like a lm380 sound? will tying all three circuits to one power supply be hard to do? the goal would be that the makeup gain after the tone stack would be even with the volume knob before the tone stack so everything could be controlled with just the volume knob on the valvecaster feeding into the power amp section of the amplifer

[Fuzzmaster Zero]

ok so I've been messing around with small recording amp circuits but have a few questions I tried wiring the fetzer ruby but it motorboats and squeals like mad so I double checked my work the fetzer works by It's self fine the jrc386 amp works by its self if I run both of them off of separate batteries and feed the input and output it works if I try to run them off of the same battery it won't work if i try running it off a power supply it also won't work also i think the schematic is wrong the 100k bias trim is way to high a 10k works alot better to dial in a better bias voltage anyway here is my idea I thought of trying to use a valvecaster as a preamp to a higher watt chip power amp maybe a  lm380 or 2 cascaded 386s I'm looking for 1 to 2 watts at most  and a better tone control then the tube cricket has so how does this sound vavlecaster to a passive eq amz with presence control?

Not to be too critical but you typed that as one sentence, and it is extremely hard to follow.

If I'm following you correctly though, try a different 386. There can be some variations among them. The JRC386 (NJM386) is probably the most stable of them though.  As for the trimpot, there are HUGE variations in jfets, even amongst the same type and production run. A 10k will not make some jfets work. A 100k is used to insure proper biasing for a much wider range of jfets. For some interesting reading, search "jfet bias" here on the forum.

As for the Valvecaster, I haven't built one, but there are a lot of threads here. You might look into the TDA2003. IIRC it is about 2 or 2.5W into a 4 ohm load at 9 V, so it would be a good choice for power.

[sickbend]

ok so I've been messing around with small recording amp circuits but have a few questions. I tried wiring the fetzer ruby but it motorboats and squeals like mad. I double checked my work. The fetzer works by It's self fine and the jrc386 amp works by its self as well if I run both of them off of separate batteries and feed the input and output it works, but If I try to run them off of the same battery it won't work. If i try running it off a power supply it also won't work so anyway Here is my idea. I thought of trying to use a valvecaster as a preamp into a higher watt chip power amp maybe a  lm380 or 2 cascaded 386s. I'm looking for 1 to 2 watts at most with a better tone control then the tube cricket has. How does this sound a vavlecaster circuit into a passive eq possibly a amz with presence control then into to a fixed makeup gain opamp buffer then fed into a low watt power amp like a lm380? Will tying all three circuits to one power supply be hard to do? My goal in using the makeup gain buffer would be to even the volume before and after the tone stack so the volume could be controlled with just the volume knob on the valvecaster "preamp" feeding into the power amp section of the amplifer

[sickbend]

As for the trimpot, there are HUGE variations in jfets, even amongst the same type and production run. A 10k will not make some jfets work. A 100k is used to insure proper biasing for a much wider range of jfets. For some interesting reading, search "jfet bias" here on the forum

i had two mpf102's and both fell in the 10k and the rest of the travel of the trim pot was useless so I figured it was a schematic error my bad live and learn sometimes you really don't see how tired you are at 5 am when your posting here sorry for the run on sentence

[suprleed]

If you're wanting to power a project involving tubes, you need to start looking at datasheets.  Some tubes need a substantial amount of Amps or milliamps in addition to their voltage requirements to run properly, so you need to make sure your power supply can handle all of that along with your normal chip/analog requirements.

[sickbend]

If you're wanting to power a project involving tubes, you need to start looking at datasheets.  Some tubes need a substantial amount of Amps or milliamps in addition to their voltage requirements to run properly, so you need to make sure your power supply can handle all of that along with your normal chip/analog requirements.

1amp at 12 volts i think im good with a 12au7 from what i can tell

[sickbend]

progress report I might have to box this fet version up as well. I found a good balance between a fetzer and a ruby bassman got a short demo  on youtube http://www.youtube.com/watch?v=RD82Xw293Ck my ruby amp vs. my valve jr both fully cranked I'm really digging this lil amp so far what do you gys think stop or keep going with it? lol  

[Ripthorn]

I think it sounds good, but I notice a distinct difference between the valve jr. and the ruby.  Not to say that one sounds better than the other, they just sound different.  There are similar quailities, but the valve jr. seems a little warmer and the ruby has more of a "Fender-y" sound to it.  Just my opinion, but I think the ruby sounds good.  If you wanted to really do something fun, you could build a tonemender tonestack into it and have yourself a full blown little amp going on.  Hmm, I may have to do that now too.

[sickbend]

looks like a posibility for sure but only dual opamp  have rigt now is a lm833 it sound very clean as a op amp switch to a tube screamer but how do you think it would fair with a ruby tone control?

[sickbend]

ok so I breadboarded the valvecaster and it lasts like 15 mins of battery life  but anyway my power supply is making all kinds of noise so much it's hard to breadboard it out and play around with it. Is it cause the circuit is out of a box you think or do you think I could filter out the power comming into it better? or should i look for a new power supply?