euro-m

Before I even get started here i need to address the MOST asked question about all Marshall DSL and TSL 50, 60 and 100 watt amps. Even though we always state right on our customer invoices that the V4 phase inverter tube is the closest preamp tube to the power tubes, our inbox and message machine continue to overflow with the following question.

"are you sure the PI tube is closest to the power tubes? because there is a cover on the tube farthest from the power tubes so that must be it!"

The answer? YES! Yes, without a question of a doubt!!! We are sure! V4 is closest to your power tubes!!! The reason the V1 tube has an RF cover on it is to help shield it from noise and radio frequency interference because it is the most susceptible tube for these things.

We re-tube almost as many Marshall amps as we do Fender amps. We see quite a few old ones but mainly we see 800's, 900’s and 2000’s. We do still see a few of the old 60’s and early 70’s Marshall's along with the mid 70’s Mark ll Master Volume amps. We will usually load them with the E34L's to get a better low end but we have also been using a lot of the JJ KT77's which sound great. For the front end we almost always go with high gain ECC83S's and balanced phase inverter tubes but another real nice option is using the ECC803S in V1. If you're looking for a real fat sound from a 50 or 100 watt Mark ll the JJ KT88’s will do it! We’ve re-tubed a lot of them with KT88’s biased up to about 60 to 65mA and the tone is very thick and fat.

The 800 series amps that come stock with 6550’s will really come to life when fitted with JJ KT88’s and ECC83S's. 6550’s are very sterol and glassy sounding compared to a real KT88. The best sounding Marshall I’ve heard to date was an old Marshall Major P.A. head that came in with RCA 6550’s ( you can see pic’s of it in the gallery). I installed a quad of JJ KT88’s and some JJ pre's in it and it had the biggest, warmest sound I’ve ever heard!

The 900 series Marshall's are my least favorite (sorry 900 owners). So now I want to elaborate on this, I did not say I hated them, I did not say they were junk in fact they have a very good clean channel, but compared to most all other Marshall's they are just not my favorite.

Almost all of the 900’s that we re-tube locally leave with 6L6’s in place of the stock EL34’s. We always ask the owners if they would like to compare the tone of the JJ 6L6 with the JJ E34L or Winged C EL34. We don’t sell the =C=-’s because we like the JJ’s better but we keep them on hand along with every other brand for comparison purposes. I’d say 99% of the 900 players like the more balanced tone that the JJ 6L6’s provide. The KT77's are also a nice option because of their increased low end.

The 2000 series Marshall's are a step up from the 900’s in my opinion and I almost always use the JJ E34L’s in them. The KT77's are also an option once again but because the 77's have more sizzle (presence) on the top end it's sometimes a bit too much if you're playing single coils so you will have to roll the presence back, with humbuckers the KT77's ROCK!

The ECC83S's do very well to tame the shrill high end and thicken up the mids and low end and a good balanced ECC83S in V4 for the phase inverter really helps these amps. Another option in the head versions of the DSL and TSL amps is to use an ECC803S which is slightly lower in gain but thicker in the mids and a little brighter in the highs. This does real well for humbuckers.

As for the 201 and 401's they use the same front end and we use the JJ EL84's for power which will tighten up the low end and makes them real punchy and less boxy than the sovtek/EH tubes.

The hand wired X84 amp is a nice addition but boutique pricy! These are biased real hot so cooler grades are necessary to get much tube life from them.

We get LOTS of questions about biasing these amps and lots of players tell us they are going to take the amp in to get it biased. Our response is "don't waste your money!" These are very easy to bias and all that's necessary is a cheap simple multimeter. We use bias probes to bias these but the test points and a multimeter will do just fine. If after you read all the info below, you still don't get it or have the courage to bias the amp yourself then head on down to your local grade school and find a fourth grader to give you a hand, that's how easy it is!

Now, since we put up the original info on bias we have still been getting emails and phone calls from you total newbies out there that don't know what a multimeter is, or you're just positive that you will die from electrical shock, so here is a new and improved description of biasing these amps.

This is a multimeter! You can buy a cheapy at radio shack for about 15.00 to 20.00 and that is all you need.

The bias trims on the DSL/TSL amps are VERY different than all of the past Marshall's. Once you remove the back screen cover you will find three gold plated wire prongs poking out from the back of the amp with two bias screws, one on each side. Don't see them? Careful, they'll BITE you! OPEN your eyes! For you combo amp owners you will find these prongs under a black rectangular plastic plug on the back panel.

The center tap is ground and the left tap measures the two left tubes in a 100 watter and the right tap measures the two right tubes and a setting of 80 to 90 DC Milivolts is good. Marshall recommends 90 per side. Don't worry if you temporarily have the bias hotter than 90 while adjusting to a final setting. For instance if both sides are reading at 100 and you turn one side down to 80 the other side will hit about 110 so when you turn this side down, kick it down to about 75 and when you go back to the first side which will probably be at about 100 by now, back it off to about 90 and both sides will probably be very close. After you do this a couple times you will be able to hit it on the first or second adjustment.

In a 50 watter the single tube on each side is adjusted by the respective trim pots and a setting of 40 to 45 is good. Marshall recommends 45 and it's the same scenario, when you adjust one side higher it makes the other side go lower so you have to jockey back and forth to get both sides the same.

Now the biggest question I keep getting is "will I get electrocuted?" Why of course you will! It wouldn't be any fun unless you got electrocuted! So ok, I lied... No, you're dealing with Millivolts here so there is no possible way to get a shock of any kind period. Stop shakin in your boots and bias that amp!

Just clip the black negative lead to the middle prong with the meter set to DC millivolts and then touch the red positive lead to the left prong to test and adjust the left side and repeat by touching the right prong to test and adjust the right side until both read about the same as explained above. This is done with the amp on and in the play mode with a speaker load on the amp. This does not mean that you set a speaker cab on top of the amp to put a load on it, it means plug a speaker cab into the amp!!!

The only issues that we have encountered with the 2000 series amps have been cold solder joints where the sockets meet the board and where the trim pots are soldered to the board. Either of these can cause a tube on one side of a 50 watter or a pair of tubes on one side of a 100 watter to run away and red plate!

The bias trim on the TSL 60 is very different and much simpler to adjust than the DSL/TSL 50's and 100's which have two trim pots. The center tap on the TSL 60 is ground and the left tap measures the left tube and the right tube and a setting of 80 millivolts is good. Just set your multimeter to DC millivolts and dial in the tubes.

You guys with 201 and 401 amps have to take the amp apart to get the test points and trim pot. Here is a pic. Marshall recommends a setting of .675 volts for the 201 and 1.375 volts for the 401, I feel that the 1.375 is way too hot and recommend a setting of between .8 to 1 volt if you are using the test point and for the 201 .375 to .400 to .500 is good.

401

In the right pic you can see three test prongs, the middle one is ground and you can measure the left or right prong to measure the bias.