Bray mods ?

[Harold]

I never played much with the normal channel jumpered before, as it just added bass, and the treble channel sounded full to begin with, so we will see how it goes.

Me neither, until I lowered the bypass cap to 4.7uF instead of 200uF/330uF. Now it's my favorite channel!

Do you have the 4.7 uf bypassing an 820 ohm or different value resistor?

2k7/.68 and 820R/4.7uF. Now I can open up the normal channel without it being too muddy!

[SteadyEddie]

I tried this on my 50 watter, with the exception of the 150k resistor on V2, and the .68 presence cap, and while it definitely gains things up, in my case it was too much gain, and the amp got a little too aggressive, in kind of a harsh way, and the overall EQ became distinctly more midrangey. It lost that sweet plexi vibe, that I fell in love with to begin with.

I do like the internal jumpering, and really always liked the way the treble channel alone, sounded cranked up a bit (no bright cap for me). So what I am going to do is put the treble channel cathode and mixer values back to stock, and play with the normal channel a little bit at a time to get it to more of a complimentary second lead specs, starting with just keeping the 500pf cap bypassing the normal channel mixer resistor. I never played much with the normal channel jumpered before, as it just added bass, and the treble channel sounded full to begin with, so we will see how it goes.

Yeah, I'm not set on my values yet. I think I'm going to try a 330k mixer, that is what Ben said he had IIRC. I might go to a 2.7k cathode on one channel too.

[hdahs]

Well, I put channel 1(Treble) back to stock Metro specs (2k7/.68 and 500pf/470k mixer) and for channel 2(Normal) bypassed the 820 ohm with a 4.7uf per Harold's suggestion, and left the mixer same as Channel 1 with the 500pf/470k setup, channels still jumpered internally, and I like this a lot better. I got the treble channel back the way I like it, and channel 1 blends in and compliments channel 1 nicely, and all of the exaggerated mids are gone. Channels 1 & 2 now each sound really good on their own, and blended.

Thanks for all of the tips gents
Harold

[Harold]

Well, I put channel 1(Treble) back to stock Metro specs (2k7/.68 and 500pf/470k mixer) and for channel 2(Normal) bypassed the 820 ohm with a 4.7uf per Harold's suggestion, and left the mixer same as Channel 1 with the 500pf/470k setup, channels still jumpered internally, and I like this a lot better. I got the treble channel back the way I like it, and channel 1 blends in and compliments channel 1 nicely, and all of the exaggerated mids are gone. Channels 1 & 2 now each sound really good on their own, and blended.

Harold, I got the 4.7uF tip from someone else on this forum (in the 1986 rocks! topic?) so no credits for me

Are you using a brightcap on the bright channel pot? And why did you jumper internally, is that any different from externaly? (other than the 15cm of wire?)

Harold

[SteadyEddie]

External jumpering adds input resistance. Dulls the sound out a bit and reduces sensitivity.

[hdahs]

Hi Harold. No brightcap for me. The amp is bright enough for me without one. I did try a 1000pf just for fun during some of the recent mod testing, and promptly removed it. Not my cup of tea.

I jumpered internally for 2 reasons. One reason is that is one of the suggestions in this thread. The other is that I had previously removed the Normal channel jacks to accommodate the pot and toggle switch used for the 2 in 1 2204/1987 mod I had tried. I just reinstalled the jacks without connecting them, and jumpered at the tube (pins 2&7).

That being said, I agree with Steadyeddie about the differences between internal and external jumpering. Internal goes through 34k ohms of resistance and that is it. It is gainier than external and a bit sharper/brighter as well. So much so that I reconnected the Normal channel jacks this morning and removed the internal jumper. I will play it like this for a bit to determine which I like better, and leave it that way. I like the crunch, but I want to keep that Plexi "sweetness" too, if that makes any sense.

Harold

[Did J]

I wonder what wiring do you use for internal channel jumpering, I would go for this one I found:
viewtopic.php?f=7&t=33772&p=332841&hilit=internal+jumping+sdm#p332841

Du you have any experience with it?

[SteadyEddie]

Here's a clip I just did, amp at super low volume. You can hear someone putting dishes in the sink in the next room and hear me hitting strings, the volume is so low.
At higher volumes, the sound "opens up" so to speak, but this is a representation of my version of the dual lead channels, internal jumpering thing.
At high volumes, it turns into a firebreather.
It's not exactly VH, but that's not my aim. I can play VH on here easily, the gain is there for the tapping, the tricks, the legato, etc. It's probably a bit middier than the average VH sound. If I turn down the mids, it sounds a lot more VH.

[Did J]

Nice playin', so you get a bright only high channel and both channels high...

[SteadyEddie]

Nice playin', so you get a bright only high channel and both channels high...

Both channels are bright. They're voiced slightly different, but they both have a cap over the mixer resistor, so to me, that makes both channels bright.

[Did J]

Thanks for the info SteadyEddy, so I'm going to give a try to this wiring posted by SDM:

Internal Channel Jumpering - 1959 custom inputs SDM.jpg (46.61 KiB) Viewed 844 times

[Tone Slinger]

Bray uses a different type of PPIMV than the Lar/Mar type. I think Bray uses the EXACT ppimv as Trainwrecks 'type 1', which is what certain Marshalls had. I think this ppimv (type 1) is slightly more aggressive than the Lar/Mar, which seems to excell with a cascaded front end, ala Mod5 (Like What I currently have).

[harddriver]

The PPIMV really seems to resemble the RIch MOD PPIMV which is a ken Fischer Trainwreck derivative as is the Lar/Mar. All the clips of the Rich mod seems to be more aggressive sounding to my ears as Tone Slinger pointed out. I just don't like how the PPIMV limits your NFB inthe circuit although Mr. Brays does sound good.

[antosimoni]

I have pics of a couple amps modded by Bray (found 'em on internet forums some time ago couldnt remember where)
They seem to me basically the same mod performed twice, can you please guys help me draw a schem for this mod ??
Heres the Link to the photoalbum where I put them :
http://s101.photobucket.com/albums/m45/antosimoni/Bray%20Mod/