To mod or not to mod...?

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thom
Mark II
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Re: To mod or not to mod...?

Post by thom » Thu Aug 04, 2011 2:19 pm

R_Rbnsn wrote:Okay, so recently I've started using my Lonestar plugged into a Marshall 4x12 (inspired by seeing James Dean Bradfield of the Manic Street Preachers doing the same) and really liking the tone, however to get the tone I like on the Drive channel I'm having to set the treble and presence controls all the way up, and even then wish it had a little more.

Would you say that the Reeder pot swap mod would allow me to get that extra treble and not have to set it with those controls maxed out? Like I say, I'm loving the tone but it doesn't seem right having to set the controls that high.
Where are your bass and mids? I have both around 9-10 o'clock on my LSS. The treble is up pretty high, around 3 o'clock, but the presence is quite low, 10ish and it sounds great. How old are your tubes? Could be knackered power tubes. (Sorry if this is all obvious stuff !). When I first had my LSS I struggled to get enough treble and bite but after some experimentation, it is really working for me, and a big part of that (other than getting used to having to set the eq very differently to all the other amps I ever had), was trying different tubes. I did also prefer the amp post Reeder mod. Re speakers and cabs, I currently have one C90 and one Celestion neo in my 2x12 combo. Works very well and saves some weight. I also have an old Marshall 4x10 cab that sounds great with the LSS. Love the thump a sealed back cab gives.

R_Rbnsn
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Re: To mod or not to mod...?

Post by R_Rbnsn » Fri Aug 05, 2011 4:05 am

thom wrote:Where are your bass and mids? I have both around 9-10 o'clock on my LSS. The treble is up pretty high, around 3 o'clock, but the presence is quite low, 10ish and it sounds great.
At the moment, the tone that I'm liking is with Gain and Drive around 9:00, Treble 5:00 (all the way up), Mids 8:00, Bass 7:00 (all the way off) and Presence 5:00. The settings seem totally impractical!
thom wrote:How old are your tubes? Could be knackered power tubes. (Sorry if this is all obvious stuff !). When I first had my LSS I struggled to get enough treble and bite but after some experimentation, it is really working for me, and a big part of that (other than getting used to having to set the eq very differently to all the other amps I ever had), was trying different tubes.
The tubes are the same ones as when I bought it so I think they may well be the culprit! I've been running it in 50 watt mode so does that mean I only really need to replace 2 out of 4 of the power amp tubes? (I'm sure I read that only 2 are used in 50 watt mode on the Lonestar classic).

I think I'll first change the tubes and then decide about whether to go ahead with the mod or not based on that. It's easily reversible otherwise though so I might just bite the bullet and do it.

thom
Mark II
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Re: To mod or not to mod...?

Post by thom » Sat Aug 06, 2011 4:12 am

Do you have a manual? This will tell you which tubes work the 50w mode. Make sure they are spec'd for the amp as well. I would also have a look at what pre amp tubes are in it. I found JJ pre amp tubes to be very dull and lifeless. Not knocking JJ because I often use JJ el84 power tubes. I ended up with a couple of old Brimar tubes in V1 and V2 and they made a huge difference to the amp as older tubes were made to much higher quality than most current production. These can be expensive but I found a job lot of 5 used 12AX7s on ebay, 2 brimars, 1 Mullard and 2 RFT all of which are good. This can be a bit of a risky purchasing strategy but I seemed to have got lucky....

I found the Reeder mod quite easy to do and preferred the amp after it was done. It was a bit fiddly so be patient and be very careful not to touch anything on the circuit board........lethal voltages and all that.

I don't know if you ever frequent the gear page. That has amp and technical forums and there is lots of good info and knowledgeable folk contributing. It is a tad busier than this place as well!

Hope you get things sorted soon.

Ylo2
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Re: To mod or not to mod...?

Post by Ylo2 » Sat Aug 06, 2011 10:55 am

The Gear Page contains some information on modifying the LSS that also apply to the Lone Star. Aside from swapping pots, these boil down to this:

1. Eliminate or reduce the 120 pF snubber cap in the PI. This is across a 100 k resistor on the plate of V5A. This brightens both channels by maybe 2 dB at 2.5 - 4 kHz. I actually returned mine to stock after a couple of months; the amp was just a little too fizzy and bright using OD pedals on the drive channel with the Weber ceramic Blue Dog I've got in the amp.

2. Reduce the potentiometer bypass capacitor across the presence controls. This shifts the maximum presence to "brighter," but leaves the minimum unchanged. You can do this on either or both channels. This is a keeper, IMHO. It just adjusts the range of the presence control a little bit.

3. Bypass the 220 k resistor that feeds stage 2 (drive stage) of Channel 2 with a 470 pF capacitor. This copies the Channel 2 "Edge" mode of the Mark V, if you happen to like this sound, which is a brighter distortion useful for on-the-verge of breakup sounds. I think this is a keeper too, at least for the styles of music that I play, sort of blues oriented, low distortion.

These mods are easy to do if you understand schematics and can solder, and they are easily reversible. They will nullify your warranty, so you might want to do them only on an older amp. Whether you will like them depends on the kind of speaker you have in the amp and the sounds you are going after. If you find the amp dark sounding with humbuckers and you have already tried a variety of speakers, these mods are a good direction to pursue, IMHO.

Chris
Last edited by Ylo2 on Fri Sep 27, 2013 1:53 pm, edited 2 times in total.

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plan-x
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Re: To mod or not to mod...?

Post by plan-x » Sat Aug 06, 2011 11:16 am

^^ Hey thanks for those mods. I don't have an LSS but it's great to have some more mods around here, cuz it is the Boogie board. Can't have TGP exclusively hoarding the mods. :lol:
Fillmore 25 head
Lonestar Classic (LSC) 2x12
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Plan-x
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thom
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Re: To mod or not to mod...?

Post by thom » Sun Feb 05, 2012 5:13 am

Ylo2 wrote:3. Bypass the 220 k resistor that feeds stage 2 (drive stage) of Channel 2 with a 470 pF capacitor. This copies the Channel 2 "Edge" mode of the Mark V, if you happen to like this sound, which is a brighter distortion useful for on-the-verge of breakup sounds.
Chris (or anyone else!), do you know what the circuit reference is of the 220K resistor, or could you help point out where it is? I would quite like to try this mod but don't know which resistor it is. I am actually pretty happy with my LSS but still curious to try it anyway.

Thanks

Tom

Ylo2
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Re: To mod or not to mod...?

Post by Ylo2 » Thu Mar 15, 2012 4:55 pm

Hello Tom. Sorry for the slow response. I have not been visiting the Boogie Board very often lately and just saw your message.

Find the schematics for the Mark V and Lonestar on the web and compare the CH 2 signal paths. They are almost identical in the preamps. The EDGE mode in the Mark V adds a 500 pF capacitor across the 220 k resistor that feeds the additional tube stage used for drive in CH 2.

In the Lonestar or LSS, locate the center pin (wiper) of the CH 2 Drive pot. Trace the wire to the circuit board, and follow the trace to the 220 k resistor. The opposite end of the resistor connects to a .005 (input) coupling capacitor. Carefully solder a 470 pF (500 pF is close enough) capacitor across the 220 k resistor. Do this carefully so you can unsolder or clip it without making a mess of things if you do not like the sound. I think this mod sounds great for blues!

Chris

thom
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Re: To mod or not to mod...?

Post by thom » Fri Mar 16, 2012 2:49 pm

Ylo2 wrote:Hello Tom. Sorry for the slow response. I have not been visiting the Boogie Board very often lately and just saw your message.

Find the schematics for the Mark V and Lonestar on the web and compare the CH 2 signal paths. They are almost identical in the preamps. The EDGE mode in the Mark V adds a 500 pF capacitor across the 220 k resistor that feeds the additional tube stage used for drive in CH 2.

In the Lonestar or LSS, locate the center pin (wiper) of the CH 2 Drive pot. Trace the wire to the circuit board, and follow the trace to the 220 k resistor. The opposite end of the resistor connects to a .005 (input) coupling capacitor. Carefully solder a 470 pF (500 pF is close enough) capacitor across the 220 k resistor. Do this carefully so you can unsolder or clip it without making a mess of things if you do not like the sound. I think this mod sounds great for blues!

Chris
Thanks Chris. Much appreciated. I have actually, just two weeks ago, soldered bright caps (250pf Silver Mica) across the drive pot and both channel gains. Probably a bit OTT, (may substitute the 250pf for 150pf) but its great having to tame the highs rather than to try to coax them from nowhere. I also find myself playing just on the clean channel with a bit of compression quite a lot now, sounds very good, but then I always did like a bright sounding amp! Anyway thanks for the info, I will surely try it out at some point.

Tom

ja22y
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Re: To mod or not to mod...?

Post by ja22y » Fri Mar 23, 2012 3:48 pm

thom wrote: Thanks Chris. Much appreciated. I have actually, just two weeks ago, soldered bright caps (250pf Silver Mica) across the drive pot and both channel gains. Probably a bit OTT, (may substitute the 250pf for 150pf) but its great having to tame the highs rather than to try to coax them from nowhere. I also find myself playing just on the clean channel with a bit of compression quite a lot now, sounds very good, but then I always did like a bright sounding amp! Anyway thanks for the info, I will surely try it out at some point.

Tom
I've haven't been here lately but came across this. There's a 120pF bright cap on each channel already, controlled by a 82k resistor. By adding a 250pF (or other value) in parallel, all you're doing is extend the lower end of the bright bypass. In other words, it won't be brighter but rather you get more 'high-mid'. And the effect diminishes once the pot is at 2:00 and higher. But when you open the amp, trace the circuit board and you'll see that Channel 1 actually has 3 caps in its bright bypass. I think it's done to get somewhat of a stepped brightness, very unique and I think it's quite nice. Just some foods for thoughts.

thom
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Re: To mod or not to mod...?

Post by thom » Sat Mar 24, 2012 6:19 am

ja22y wrote:
thom wrote: Thanks Chris. Much appreciated. I have actually, just two weeks ago, soldered bright caps (250pf Silver Mica) across the drive pot and both channel gains. Probably a bit OTT, (may substitute the 250pf for 150pf) but its great having to tame the highs rather than to try to coax them from nowhere. I also find myself playing just on the clean channel with a bit of compression quite a lot now, sounds very good, but then I always did like a bright sounding amp! Anyway thanks for the info, I will surely try it out at some point.

Tom
I've haven't been here lately but came across this. There's a 120pF bright cap on each channel already, controlled by a 82k resistor. By adding a 250pF (or other value) in parallel, all you're doing is extend the lower end of the bright bypass. In other words, it won't be brighter but rather you get more 'high-mid'. And the effect diminishes once the pot is at 2:00 and higher. But when you open the amp, trace the circuit board and you'll see that Channel 1 actually has 3 caps in its bright bypass. I think it's done to get somewhat of a stepped brightness, very unique and I think it's quite nice. Just some foods for thoughts.
Interesting. I realise the effect of the bright caps diminish as you turn the pot up. I like to use lowish gain and push the amp with drive pedals. The 250pf caps make the amp pretty bright in my experience. It also makes the amp work very well with humbuckers which it didn't really do well, (for the sounds I like), before this mod. Anyway it's an easy mod to do and easy to reverse and I am enjoying the amp more than ever. I still find I run the bass very low and the mids almost off.

I did also try Chris' 'edge mode' mod but ended up taking it out. It sounded a bit 'raspy' to me, possibly too much with the other caps I already added.

As an aside, for anyone wanting to try any of these mods, please ensure the filter caps in the amp are drained. I found a very effective way is to play the amp, and then switch it off using the power switch only, and leaving the standby in the play position. I always then measure the caps with a volt meter just to make sure.

Tom

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