PTP boards for Bluesbreaker RI's

Post by **VelvetGeorge** » Tue Jun 28, 2005 3:50 pm

I have added the listing for these to the store:

http://www.metroamp.com/store/product_i ... cts_id=329

Anyone who's interested should know that I don't have the normal step by step, color by numbers type instructions for them. You'll need to be able to read the schematic and correlate that with the layout diagram and high res pics included with the board.
It's really not too difficult, basically the normal JTM 45 board with the added components. But there are a few parts right on the tube socket for the trem.

If there is enough demand for these, I'll spend the cash to do a full layout ect. For now, we'll see how the techs (and more electronically inclined) do with them.

George

5150loveeddie · Post by **5150loveeddie** » Tue Jun 28, 2005 10:23 pm

Cool, Those Allen Bradley pots do they come other than 1M?

Ricky Lee · Post by **Ricky Lee** » Fri Jul 01, 2005 2:41 am

Here's what the Bluesbreaker RI PTP looks like. I just did this one today, went all out and back to the original values on everything, including the valves, filters etc... End results "BEANO". This amp sounded great with just a change to the KT66's & Mullard RI's. The valves they come with are GARBAGE. In my opinion, this is Marshalls best sounding reissue, even in its stock form. It doesn't take much with this one to get a great tone. I first recapped the PCB and went to the original B/B values on everything, and what a difference that made. Since it sounded so good, I figured it deserved the PTP. This amp is a 1993 and it looks NEW, infact, it probably is new, since it sat in a warehouse un-played since 1993. The Bluesbreaker makes for an excellent small club amp, with only 30 watts and breaks-up really sweet without making your ears bleed.

McGoogle McDougal · Post by **McGoogle McDougal** » Mon Jul 04, 2005 1:28 am

I installed one of these boards in my Bluesbreaker and it really does sound great. I ran some Groove Tubes KT66's in it for about 4 or 5 months but ended up back with JJ 6L6's after the bias drifted so far off on one of the KT66's. I am still going to try a set of the Valve Arts or Shuguang KT66's one of these days. I've been thinking about trying a plug in solid state rectifier to see if I get a little more headroom (not sure if I want that or not - gotta try). The Bluesbreaker is great since you can crank it without killing anybody, but I think I also need a head and 4x12 setup for times when I need to push a little more air.

I did have some problems when I did mine, but they all were a result of my mistakes. Plenty of folks on this board (and George) gave me help in troubleshooting, but for the most part I just had to do what I should've done in the first place - read the schematic! I had some problems with periodic weird noises/distortion etc. but they all went away when I went back in and cleaned up my wiring. I'm embarassed to say I never got the tremolo working, but the amp sounds so great I've just been to lazy to troubleshoot the tremolo. It shouldn't be too hard to track down what's wrong, I just need to get to it (I'd love to get some sample voltage readings for the tremolo tube, if anyone's got 'em).

I would encourage anyone who gets one of these boards for their Bluesbreaker to also get one of George's Heyboer JTM45 output transformers. This is really worth it.

Eamon
p.s. the attached picture is from before I went in and cleaned up my wiring.

Guest · Post by **Guest** » Mon Jul 04, 2005 2:59 am

My trem doesn't work either and I'm having other problems, as well. The thing with the JTM is that all the wiring is under the board and you really can't see how things are supposed to be wired-up. For example, the black wire from the OT isn't mentioned in the Metro CD for the B/B, so I connected it to the yellow wire on the 32uf can and it works but sure is noisey. The wire that goes to the trem pedal jack, I haven't a clue where on the board that connects. According to the Metro pics there is a resistor that goes on the intensity pot, but I can tell what the color codes are for the resistor. I also had a bad hum noise until I grounded the # 3 terminal on the intensity pot. And there is no pics on the CD that shows how the trem section is wired and I can't read schematics, I'm a paint by numbers guy. When I turn my volumes all the way up I get this noise like a tv without an antenna, you know the snowy picture sound. I seen a colorized layout of an amp somewhere on the net and it showed (Schematics For Dummies) so to speak, where every wire, resister, cap, you name it, went to in that amp. I think what's confusing with the Metro CD is that, it references tranny changes and not the stock B/B layout. I think George is waiting, and rightfully so, to see how these things will sell before commiting to a full blown Instructional CD. I've been taking lots of pics, so when I get this thing figured out I'll sort thru the ones that are correctly connected and make my own CD to share with others. I'm also one who sticks with the OEM color codes to keep things from getting confused. Like the green wire going to the trem pedal jack, I kept the OEM pink wire there. When I did my 69 circa, I had an original 1969 SLP, so I followed all the color codes to a "T", right down to the pink wire. But then agagin, Marshall wasn't that consistant with layouts either. Have you figured out the double pot at the trem speed yet, mine is a single pot? You can follow the JTM 45 layout on the Metro CD and it will get you close but there are some changes even without the trem section, like choke wires, grounds etc... I know things would be much more simple if I could read schematics. I've tried and tried, but there's got to be an art to doing that.

Ricky Lee · Post by **Ricky Lee** » Mon Jul 04, 2005 3:03 am

Sorry, keep forgetting to log-in. I noticed you don't have the extra grid resistor at V4, or is it tucked under the board some where? You also mentioned your bias kept drifting, I'm having bias problems myself, only not with tubes but with the bias sweep itself. I can't get full ma. This amp usually runs best at about 42ma, but I'm limited to about 36ma since changing the board.

McGoogle McDougal · Post by **McGoogle McDougal** » Mon Jul 04, 2005 12:12 pm

Hi Ricky,
To get the bias into the right range, you'll need to swap out the resistor that is in line with the bias adjustment pot. If it's currently a 68k (for example) try putting in a 56k and that ought to get you in the right range. My problem with the bias drifting was just with one of my KT66's. I had them at abotu 41-42 ma, but after a few months I checked the bias and one of them had dropped to about 33 ma (if I remember correctly), which is getting pretty cold for a KT66 with around 420 volts on the plates. I had to use a 33k resistor to get mine in the range for my JJ 6L6's. The rated maximum dissipation of these is 30 watts (as opposed to 24 or so for the KT66's), so I am running them at around 50ma.

If you want to see if the noise you're getting is caused by the tremolo circuit, just test this by disconnecting the wire that runs from the mixer resistors to the intensity pot (should be a long shielded wire). My amp has the dual pot on the speed knob - I just left it as is. I attached another picture which shows where the wire to the footswitch attaches.

Eamon

Ricky Lee · Post by **Ricky Lee** » Mon Jul 04, 2005 1:07 pm

That's the green wire I have going to the trem tube itself. Had that been the OEM pink wire I would have known it went to the pedal jack. That's what I mean about color codes. The green wire you have soldered to the turret there is where I have the trem pedal soldered. That was my next change including a different bias resistor. THANKS A BUNCH. As soon as I get this wired right I'll get some voltages of the trim circuit. All my voltage readings for the remainder of the board are dead-on specs. Are those piggyback resistors on the trim circuit 1 meg each = 500k? I didn't get those with my kit so I just stuck what I could find in there.

Ricky Lee · Post by **Ricky Lee** » Mon Jul 04, 2005 1:54 pm

I switched the wires around and still the same thing as before. The intensity pot is nothing but one big hum and the speed pot is totaly dead. My volume pots still have the snowy TV sound at high volume. What year is your B/B? Mine is a 1993 and doesn't have that dual speed pot, that's got me curious! Also, that insulated grey wire originally connects as well to the number two volume pot terminals, NOT directly from the intensity pot to the board as shown on the Metro CD. I'm still wondering about that second grid resistor on V4 what that's for. I'm thinking about dumping that resistor and going directly to the choke wire as original.

Guest · Post by **Guest** » Wed Jul 06, 2005 12:58 am

worked on tremelo circuit all night, no luck all I get is a loud hum from the intensity pot.