Choke for a 5150

[JacksonRR]

What are you guys finding is the best price/performance choke available for a 5150? I know of Mercury Magnetics and Hammond, just wondering if there are any hidden jewels. Thanks.

[JacksonRR]

http://www.blueguitar.org/new/schem/...kmaster_91.jpg

The diodes between V2A and V2B.... noise reduction? Can I add this idea to the 5150 circuitry and kick that hiss in the nuts? What else? Swapping carbon comp for metal film resistors? I'm already doing the bias mod, hehe. I know you guys just helped me with that Krank problem. New amp, new goals.

[Steve Conner]

I don't see the point in putting a choke in a 5150 personally. It works fine without one. Mercury tell you it needs one, but their goal is to sell chokes.

The two back-to-back diodes are Peavey's ghetto noise gate. Some people call it the "coring" circuit. The trick works in any high-gain amp, but only in the lead channel. They just make a clean channel sound bad. I think the 5150 has them already.

If you can hear the hiss, your drummer isn't loud enough.

[Enzo]

Like Steve says, that cheap and dirty noise reduction only works on lead channels. I does reduce noise, but it also adds distortion. In something as distorted as a 5150 overdrive channel. that is OK, but on a clean channel it is obtrusive.

The 5150 and 5150-2 did not have that feature, but the Ultra amps do, and the XXX and JSX amps. Due to the great similaruty between ALL those models, comparing circuits side by side between the haves and have nots should make it real clear where to add one.

There is a resistor in parallel with the noise diodes. In the JSX< they turned the resistor into a pot, so now the amount of the effect is adjustable.

[JacksonRR]

Cool. That's good to know about the choke. I was just listening to FJA mods on YouTube and thought it was pretty nice. Yeah the XXX schematic Peavey was nice enough to send me this morning has the same diodes in the same spot between V2a and V2b, but has a 1M resistor in parallel. I'm going to e-mail peavey ONE more time for a 5150 schematic. They sure are easy with those things. No wonder Bugera took off with em.

I was wondering about the extra distortion thing, cuz that's the kind of design I'd stick in the NFB loop of an opamp for an overdrive, or afterwards for a distortion.

And Steve... My drummer is a maniac.

[Enzo]

Well, make that 1meg a 1meg pot and you have an adjustable noise reduction.

Did you search here for the 5150? We may already have it posted somewhere.

[JacksonRR]

Wow. Sorry. I will use the search engine next time before posting. The thread I found was almost a carbon copy of the info here. The diodes used to solve the hiss were mentioned, but not described as well.... So if I had found that thread, but still had questions, is it cool to bring it back from the dead? Some forums are dicks about that even if it is relevant.

I'm digging the 5150 a lot. Never had one. Its winning against my Bugera 333XL by 2 pts out of 10. Bugera has more clarity in the top end, but the 5150 is meaner, tighter and has more sustain. Me thinks for future recordings I'll quad track with the 5150 tracks panned hard and the Bugera tracks sitting 80% both ways.

Well thanks for indulging me even though it's been discussed. This is my new favorite forum. You guys are great.

[JacksonRR]

Wait. It just clicked. If I use the 1M pot instead, am I installing the FJA mod that costs $145?

[Enzo]

I have no idea what Jerry is doing in his mod. If he makes the noise limiter adjustable, then I'd say yes, he is doing that, but that doesn;t mean he doesn't also do a lot of other things in the course of his mod. What does the mod description include?

And remember, You can go to the store and buy a 24oz can of beer for $1.59. Or you can go to a bar and pay $3.50 for one half that size. You do it yourself it costs less, you have someone else buy it, chill it, serve it, provide the table and chair for you, and take care of cleaning the glass and taking the empty container away, it costs more.


The diodes are just diodes, 1N4148 would be my choice. Says "1N4148" right next to each diode on teh XXX schematic, so I feel safe in suggesting them.

[JacksonRR]

Oh, I wasn't thinking along those lines.... I'm well aware of the expertise he has and that it should be rewarded. I put the price on there as an extra identifier, not to slyly say his price was inflated. I meant no harm.

Yeah I was gonna use the 1N4148 diodes. Both the Rockmaster and the XXX are using them so it does seem safe to me as well.

Side note: Beer costs more in both time and money if you make it yourself.

[Steve Conner]

Jerry seems like a cool guy, he used to post here. But I don't know how people can possibly judge mods by listening to them on Youtube. They compress the audio to hell, it barely sounds like a guitar any more.

I think $145 for opening your amp and drilling a hole in it for a pot is reasonable.

If you try dropping the Bugera and the 5150 down a flight of stairs, you'll appreciate the Peavey even more. No, I'm just kidding, don't really do that

[Enzo]

It's true, but don;t do it.

[JacksonRR]

So guess what guys? I went to Fry's. Bought a pair and 1M pot. Also bought a 10K trim and did the bias mod with the 4.7K resistor. Soldered it up and the noise gate functions exactly the same as the vid I saw of the FJA mod and exactly the same as the noise gate on my Bugera 333XL. Then I threw down some stairs. Best mod ever. The stairs really opened the gain up for me and made it seem more alive. Maybe that was bringing the bias up to proper level.... Nah I'm goin with the stairs mod. Stairs mod for life.

[nashvillebill]

Hope the Peavey didn't break the stairs.

[JacksonRR]

Hehe, no. But I was wondering about trying a pair of KT88s in this thing. One pair on the outside sockets is safe on things, right? I called Bob at Eurotubes and he said yeah, but he does some funny configurations.