New to working with transformers, simple help

[orangecountylumbertruck]

Hey Everyone, I'm working off this schematic for my spring reverb tank:

http://gaussmarkov.net/layouts/springrev/springrev-schem.png

My question is in regards to the input of the tank itself.  Do the pins for 4 & 6 from the transformer both go to the input of the tank?  I get that the output from the tank goes to C11 and ground, but I was assuming there would be a single input to the tank, as well as a ground, and it looks to me like both 4 & 6 go "to the tank".  First time working with transformers, hopefully someone can help.  Thanks!

OCLumbertruck

[mth5044]

Correct, it connects to both sides. Looks to me like you need a tank that has an isolated I nput and grounded output. With the common accutronics numbering system, your fifth digit in the code needs to be C. Check out the chart on this page: https://www.amplifiedparts.com/tech_corner/accutronics_products_and_specifications

[orangecountylumbertruck]

Awesome, I'm still waiting for my tank to get here (ordered a 4AB3C1C so I should be good).  The other tank I have here on hand is a Type 247 OC Electronics, which appears to not have the isolated input, it has an input and ground, which is what had me questioning.

Thanks so much for the help!

[PRR]

> Looks to me like you need a tank that has an isolated Input

No.



Because the transformer secondary "floats", it may be grounded anywhere. This can be (would be) the grounded RCA jack on the tank.

[orangecountylumbertruck]

Ah-ha, so pin 4 goes to ground, as with the shielded / ground wire on the input.

[mth5044]

Thanks for the correction, PRR. Are the figures 5 and 6 isolated inputs in this ESP post?

http://sound.westhost.com/articles/reverb.htm

[PRR]

> this ESP post?

Yes.

There's no floating transformer. Rod is taking the current *through* the coil as a correction signal. There are other ways to do this, but (on paper) it is easiest to just take the return current through a small resistor to get a voltage proportional to current. There are ways to sense the current in the "hot leg" but they are more complicated a prone to needing matched resistors or added amps.

[orangecountylumbertruck]

Im struggling with this circuit and I think it has to do with the transfomer...maybe.  I swapped out for a 42TU013 via smallbear.  I get dry signal, and I have biased the input and reverb trim pots to 6v, but I still get no reverb.  If I thump the spring tank *hard* i can hear some clanging, but not even as much as I would expect.  The clipping circuit is working, if I slam on the guitar, the leds flicker and the sound cuts out for a moment.  So with a 4AB3C1C tank, and that transformer, ping 4 on the transfomer should go to ground, as should the shielding on the input of the tank, then pin 6 should connect to the input of the tank correct?  And I am assuming the P on the side of the transformer indicates thats the primary side, with pins 1-3?

[mth5044]

> this ESP post?

Yes.

There's no floating transformer. Rod is taking the current *through* the coil as a correction signal. There are other ways to do this, but (on paper) it is easiest to just take the return current through a small resistor to get a voltage proportional to current. There are ways to sense the current in the "hot leg" but they are more complicated a prone to needing matched resistors or added amps.

I see! Thanks!

[PRR]

Try this:

http://oi67.tinypic.com/zufbc4.jpg

No transformer.

[orangecountylumbertruck]

hmmm no dice, still the same result.

[amptramp]

The Univox U65RN is an amplifier with tremolo and spring reverb incorporated:



You don't need precise impedance matching - it just has to be good enough to deliver adequate signal.  I have a U65G that uses the same schematic.

[orangecountylumbertruck]

So I was able to trace the signal and I can hear the reverb off the tank, and even louder after the reverb amp stage at Q2.  The reverb tone gets lost in the mix round R5 & R25.  It seems like If I crank the input to hear the reverb at a decent level, it starts clipping.  Any thoughts on that, or additional ideas on driving the reverb stage / spring harder?  The reverb is there, but very very subtle, even with the matched transformer (42TU013).

[PRR]

> gets lost in the mix round R5 & R25

Then Q3 stage has a problem.

And Q3 stage doesn't even do much.

Take signal from R5 R25 junction right to your guitar amp. Does that play?

[orangecountylumbertruck]

Yeah it plays, but definitely the volume from R5 is much, much louder than R25.

[Vitrolin]

a small note on the isolated or grounded input/output:

the difference lies in whether the Phono connector ground is connected to the tank itself.
its a small wire that can be removed if isolated is needed.

that's the way it looks in the ones i have lying around, anyway...

[orangecountylumbertruck]

Like these:

Input:


Output:


Where the output looks like there is an additional jumper....

[Vitrolin]

yes

on first pic add some solder and you will have a grounded connector, second pic remove solder jumper for a isolated connector.

[orangecountylumbertruck]

So probably total noob question but : Is that required for the circuit I had posted?

[Vitrolin]

what you posted is isolated input and grounded output

the point was if you have wrong connector its very easy to change this