Metropoulos Forum

jnew wrote:Kabaam! And just like that, we're off and running.
Yes, it works well and I prefer it over the other line out I was using. Just sounds better but in a very difficult way to describe. Like it's all guitar and amp now without anything else. Like a cleaner guitar/amp signal. Had it roaring pretty good too and didn't seems to have any shielding issues. I'm liking it. The pot works much better too. The other one went from quiet to raging in a sneeze. Probably the wrong taper pot.

What are you running it into? Avoid the temptation to use the pot as a volume knob! I use this out of the load box -> the tranny/250k pot -> Line level Reverb unit -> Plexi modified to have a "power amp" input. The reverb unit has an LED readout that shows when its input is too hot (clipping). That is reading is handy for adjusting the pot.

The other way I use it is to push a clean reamp track into a plexi: Computer lineout -> tranny/250k pot -> Plexi.
You should plug a guitar into the target amp, listen to the overall volume it produces... then (when using the computer/tranny) adjust the pot to get a similar level.

The schematic for this thing is from one that was floating around on the forum. The more I think about it, this might be better: 2k to 5k resistor between the input and the tranny input (blue wire), then lower the pot from 250k to something smaller (10k to 50k)?

Good to know. I'm doing it much the same way you are. First plexi w/one speaker out, to the load. The 2nd speaker out to the little deelio I just built with the Jensen. From there, I go to a cheap little floor reverb then on to the 2nd plexi modded to power only. It does have a volume control so like you say, should just set the Jensen's 250K pot to optimal and use the power amp's volume. I can see how the reverb would stay more consistent that way. When I get after it, the reverb increases. It has to be really really loud for the reverb to get that "too hot" signal or clipping thing going on but, it is inconsistent with different levels of volume. I like your way better and will do that from now on.

So the only difference is that I am using a rack reverb (line level), and you are using a floor reverb which is probably a lower (instrument) level. The plexi modded to a power amp would be happier with line level... but if you increase the the volume on the tranny pot, you will likely introduce clipping/distortion from reverb unit. Unless the reverb can hand line level, you might want to get one that does. I have had good results with the old digitech TSR24(S), they have the input volume, Input clipping meter and output volume.

This little bro of the TSR24 should do the job:
http://www.ebay.com/itm/DIGITECH-TSR-12 ... 3cd8a55030

Yeah, I've wondered about that. When the Jensen line out is going straight to the power amp plexi, there seems to be something just solid and present about it. When going through the reverb pedal, there seems to be a little bit of a loss of that initial impact or "HIT" if you will. It's like the dry signal is weakened a bit to mix with the reverb instead of the reverb being added to an unaffected dry signal. Like I said before though, according to my ear, it seems to be able to take quite a bit before it degrades somewhat but maybe I'll look into a more higher end reverb unit. At least one that has a direct and effect mix separate from one another and a level LED would come in handy too. Since our last post about setting the Jensen pot and using the volume on the Power Plexi, this works much more consistently. However, I am back to the problem of the volume pot on the Power Amp Plexi going from zero to real loud in a sneeze's breeze. Should this be a linear taper pot for smoother transitioning?

The pedal may not have enough bandwidth and/or there could be an impedance issue between the signal and the input of the pedal ...?

That could be a true statement. A better reverb unit will be in order.

The schematic for this thing is from one that was floating around on the forum. The more I think about it, this might be better: 2k to 5k resistor between the input and the tranny input (blue wire), then lower the pot from 250k to something smaller (10k to 50k)?[/quote]

This is interesting to me. Can you describe how or why this might be better?

vh junkie wrote:The schematic for this thing is from one that was floating around on the forum. The more I think about it, this might be better: 2k to 5k resistor between the input and the tranny input (blue wire), then lower the pot from 250k to something smaller (10k to 50k)?

jnew wrote: This is interesting to me. Can you describe how or why this might be better?

I think it makes the pot less sensitive so it doesn't go from nothing to raging so easily.

The raging volume in the power amp is probably because of a linear pot instead of an audio pot on the power amp.
The reason for changing the tranny/pot box input and output is:
1) It is seeing the same 70vac that the load box is... might be good to make it less of a current target by putting a resistor on the input... current chooses the path of least resistance... we want the little tranny to look less attractive than the 16ohm load.
2) Rule of thumb is that boxes should have high input impedances(weighs down driving signal less) and low output impedances (provides stronger signal thru cord lengths)...notice how other lineouts use a smaller pot? Perhaps the higher impedance is a mojo thing? The EP-3 also has a relatively high output impedance (perhaps why Ed kept them so close to the amp inputs?)

I like it. I think I'll do it.

I done do'd it, and I like it. I put a 2.2K resistor at the input (blue wire) and a 10K pot and it works very smooth in comparison to just the 250K pot. I think the resistor was a 1/2 watt resistor. Is this OK?

Also, I don't know if my ears are playing tricks on me but there seems to be a hint of more shimmering highs this way. Would there be any reasoning to this?

I got the lineout thing covered. I posted pics of this c.a.e. lineout with a transformer waaay back in like 09-its in the "slaving a plexi" thread. But the transformer bradshaw uses is square so I doubt it has to be a jensen. I think it just has to isolate.

How do the different loads sound?? What are your findings with the what tap to what ohm resistance load???
I know some are balls deep on the reactive deal but I can almost guarantee if Ed was loading it was a non reactive static load. 1978 was NOT sophisticated at the slightest
Blix made that clip with the 300w 16ohm single resistor and I thought it sounded tits. But wonder if he ran 8tap to16 resistor?

I run my amp on 8 ohms and my load is 300 watt, 20 ohms.

Awesome!
Keep 'em comin. I want a consensus here on what everyone is doin.
For me I am stuck in between. 8-16 sounds tighter and less flub but too much fizz and 16-16 almost sounds flubby with a decent top end that doesn't stab you in the ear.
I know the feedback deal is a huge article as well here regarding the tightness. Maybe we can get a roll down in one thread goin for statistical purpose?