#1. Blues and Pro Jr amps
#2. Hotrod Deluxe and Deville amps
#3. 59 Bassman Reissue amps
#4. Prosonic and it's offspring the Supersonic
#5. Older Fender amps
#6. The Fender reissue amps including Twin's, Super's, Deluxe's and Princeton's
#7. Why don't you post on the Fender Forum?
#1. Blues and Pro Jr amps:
These are great little amps with a warm juicy tone right out of the box and the main reason for this is the bias is nice and hot. In fact with just a moderate grade on the EL84's they will usually clock in at between 85 to 95% of max dissipation so we pay special attention to grades on the EL84's for these amps based on player requirements.
I get almost daily inquiries about the VERY popular Bill M. mods for these amps so please note, the following is simply my opinion and will not be shared by everyone!!!! (Sorry Bill)
While some of the Bill M. tone mods are nice I completely disagree with his theory on correct bias for these amps. The BM bias mod will suck the life and tone right out of the amp. I can't tell you how many players have called me wanting tubes that will breath life back into their Junior's and Pro's and during the conversation they will fess up to the BM bias mod. This mod will get the bias way too low. Players like these amps because they sound good right out of the box and they are biased hot which gives them a great juicy tone with a very good dynamic response so my recommendation is to leave the bias as is and make sure that who ever you buy your tubes from knows what the tubes are for and grades their tubes. Hopefully they will also know something about these amps too.
Both the Blues and Pro Jr's are fussy about phase inverters and need a good balanced tube for V3 to get them smoothed out. Most Fender amps respond very well to the JJ ECC83S's and these amps are no exception, in fact they respond extremely well to them.
A word about "Blues Jr Disease" As these amps age we have seen more of them come in with solder issues where the sockets are soldered to the board. One of the main symptoms of "BJD" is hearing a loud overpowering hum that is intermittent while playing at louder volumes. A quick test that you can do which will almost always diagnose "BJD" is to wiggle the power and preamp tubes back and forth a little while putting upward pressure on the tubes. If there is a bad solder joint then doing this will cause the hum. Another symptom "BJD" can cause is red plating power tubes.
Visually inspecting the solder job on the board from the inside of the amp will usually not reveal the issue. We have seen boards that look great with a very nice looking cone of solder that appears to be connected to the run on the board but when you wiggle the tube with a little upward pressure you can actually see the perfect looking solder joint lift right up off of the run on the board! This happens because the copper run on the board was not heated up hot enough for the solder to bond properly with it.
In amps like the Blues and Pro Jr as well and the Hotrod and Blues Deluxe amps where the sockets are soldered right to the board and mounted in an inverted position the heat generated by the tubes goes straight up to the board and as these amps age, a marginal solder connection can become intermittent. Compound this with the fact that the severe vibrations from the speaker are pounding on the tubes, boards and components and it's a pretty good prescription for "BJD".
The cure? Fortunately it's an easy one. Just get out the soldering iron and reflow the solder joints making sure to get enough heat in the copper run on the board to make a good connection.
#2. Hotrod Deluxe and Deville amps:
I think there are more HRD amps on the planet than any other amp. A nice small package with a lot of punch. The only down side is that they are torture chambers for tubes! There is no amp where the tubes are placed closer to the speaker that in a Hotrod Deluxe. We get calls several times a week from HRD players with brand new amps complaining about rattling and "broken glass" sounds when playing lower notes so they think their tubes are bad. The truth is most tubes will rattle at certain frequencies in these amps no matter what brand they are.
Since early in 2004 I have been having special 6L6GC's being made for Eurotubes by JJ Electronic with a design change that has dramatically reduced the rattle factor. (My HRD customers know what I'm talking about) These special JJ 6L6GC's are shipped out with every retube kit for HRD's and some other select combo amps where the designers have placed the power tubes ground zero to the speakers. These 6L6GC's are also available individually upon request and the cost is still the same at this point in time.
If you would like to see an actual video of how to bias a HRD amp go here! http://www.eurotubes.com/eurotubes-how-to-bias-video-probe-Pro-One.htm
It's common knowledge now for most net surfers that we have been using the JJ 6V6's in HRD's since December of 2003 and the most common question I get about this is "does this work and will it harm my amp". The answer is yes it will work and no, it won't harm your amp or I would not recommend it... I have LOTS of HRD customers that have been using the 6V6's for over three years now with no ill affects what so ever. There are no mods necessary to do this. The transformers do not need to be changed nor do the screen grid resisters need to be changed. The only thing necessary is to bias the amp for them.
The bias on HRD amps will rarely get the 6V6's as hot as they can be run which would be between 40 to 45mv at the test points for Hotrod Deluxe's and 30 to 35mv for Hotrod Deville's, but the JJ 6V6's have the ability to sound VERY good at lower bias settings clear down to 25 to 30mv. You will probably be very happy with the tone anywhere from 25 up and if your Hotrod Deluxe will not get the tubes up to 40 ( some will & some won't ) and you want to get them up higher then you can change the 100K resister ( R77 ) that is in series with the trim pot to a 70K and then you will be able to use all grades of 6L6's and get the 6V6's up to maximum levels.
Now these will NOT turn your HRD into a bedroom quiet amp but it will cut the power down from about 40 watts to around 28 to 30 watts so it will still be plenty loud but it will have that cranked Deluxe Reverb vibe. For you HRD players still after maximum headroom stick with the JJ 6L6GC's.
#3. 59 Reissue Bassman:
Quite a bit different from the original but a nice amp none the less. We have lots of 59 RI customers but there are three main types of players seem to gravitate towards this amp and Blues players lead the pack. For this application a good hot grade of the JJ 6L6GC's and a hotter bias setting up around 42 to 44mA per tube along with replacing the solid state rectifier with a GZ34 will do the power section up nicely for a greasier tone with more breath and a little earlier breakup. The ECC83S's and a good balanced ECC83S for the phase inverter in V3 round it out. I also have quite a few players using the JJ 6V6's to drop the power which work great in these amps too.
The second most popular setup for these is for Country and Jazz players. A more moderate grade on the power tubes and biasing to about 32 to 34mA per tube and leaving the solid state diode in place will get the twang and headroom necessary. I will sometimes drop the V1 tube to an ECC81 for even more headroom.
Third on the list is Harp players. For power I use the same lineup as I do for Blues players and then I drop the V1 and V2 tubes to ECC81's and the use an ECC832 in V3. To make a good harp amp the phase inverter tube needs to be unbalanced which is the opposite from the way a good guitar amp should be which is with a nicely balanced PI tube. For some odd reason harps just sound good with an unbalanced PI tube, this is the preamp tubes that's right next to the power tubes ( V3 ). By going with an ECC832 ( 12DW7 ) tube which is one half of a 12AX7 and one half of a 12AU7 this puts the power tubes way out of phase and it sounds good and cuts down the feedback for harp. On the other hand it does not sound good for guitar
#4. The Prosonic and it's offspring the Supersonic:
I confess, I love my Prosonic! These are of course hated by Fender Purists and received a bad wrap because their drive channel was ahead of it's time. These amps are a Zinky design and even Bruce admitted that the bias was a bit off the deep end in the class A mode, so it takes a cooler grade for the power tubes to come in right but with cooler tubes and a good GZ34 and preamp tubes these amps are really quite nice. I often sub an ECC832 in V2 in mine to drop the gain a bit. They are adjustable bias in class A/B which was also set hot from the factory. These are easy to bias and if you only play in class A then no bias is required when using the proper grade for the power tubes. I've seen the Prosonic Combo's go for as little as 450.00 and the heads for 400.00 and personally I think these are one of the best sleeper deals out there.
The Supersonic is a knock off of the Prosonic as far as the drive channel is concerned and the clean channel has two voices which is nice for a more varied set of tones and designed to emulate a Vibrolux and a Bassman. The GZ34 rectifier is missing which I feel was a mistake but all in all a nice amp.
The Supersonic 22 is a departure using a pair of 6V6's for power and is a great alternative for players who want to get more towards a Deluxe Reverb but also want a pretty decent drive channel. It's quite a bit of tone in a small club size package.
#5. Older Fender amps:
I re-tube more Fender amps than any other brand. I must say that one of my most favorite amps is a 65 Super Reverb. Almost all of the old amps are adjustable bias and I will typically set the JJ 6L6’s up pretty warm in these amps. In a super which usually has about 450 plate volts I will start at about 40mA of plate current draw at idle and if the player wants a little greasier tone for blues I will go as high as 55mA.
The JJ 6L6’s are built like a tank and they will dissipate a whopping 30 watts!
I tortured a quad in my twin reverb for over a year running at 50mA with 485 plate volts with no ill effects and they sounded great. The only reason I pulled them was to try a quad of the JJ KT88’s which have been in the amp now since the middle of 2002 running at 65mA and they sound great, very thick.
I have also been using the JJ 6V6's in a couple of my old Bassman amps (one 65 and one 66) at 460 plate volts so for Bassman's, Bandmaster's, Super Reverb's the JJ 6V6's are a cool tone alternative!
I also highly recommend the long plate JJ ECC803S's in Bassman and Bandmaster amps. These are a great fit and really thicken up the tone and sparkle.
#6. The Fender reissue amps including Twin's, Super's, Deluxe's and Princeton's.
The things these amps all have in common is that they all do a very nice job of getting pretty close to their original counterparts and they are all adjustable bias amps. Just as the originals, the reissues can be biased without removing the chassis. We have a "How To" bias video that we did on a Deluxe reissue over on the "How To" bias page here; http://www.eurotubes.com/eurotubes-Fender-Deluxe-Reverb-How-to-Bias-Video-Probe-Pro-One.htm and the bias access hole which looks just like a 1/4" jack is where you will find the adjustment screw. You can use this video as reference for all of these amps. A small screwdriver will allow you to turn the adjustment screw and all you need is a bias probe and a multimeter to do the job. We typically bias the JJ 6V6's in Deluxe's to between 22 to as high as 28mA. Super's and Twin's have a higher plate voltage so with the JJ 6L6GC's we see them come out of crossover distortion at about 34mA but we typically like to bias them between 38 to 44mA and most players like them best at 38 to 40mA.
The Reissue Twin and Super Reverb amps also have a hum balance pot located down underneath the chassis in front of the transformer on the pilot light side of the amp. The access hole looks just like another 1/4" jack hole and can be adjusted to minimize the amps hum simply by turning the screw with a small screwdriver. Here is a pic of bias trim pot and hum balance pot from inside the chassis.
All of these amps respond extremely well to the JJ tubes which will give them a lot more of a vintage sound than the stock tubes. If you want a real smooth and rich sound you can use the JJ gold pin preamp tubes but if you like a bit of grit in your sound then the standard non-gold pin pre's would be better.
#7. Why don't you post on the Fender forum?
I get asked the question
all the time "why don't you post or participate on the Fender Forum?" so I guess
it's time that I answered this question here rather than explaining it over the
phone all the time ( although it's fun to tell the story! ). The answer is I
did, once... One of my customers sent me an email asking why I had not answered
a question. I promptly emailed him back asking "what question?" He responded and
told me that someone had posted a question on the Fender forum directed to me
and JJ Electronic. Since I had not posted before I signed in, received my
password and posted an answer. I started with a disclaimer stating that I was a
re-seller for JJ but I did not advertise my name or url. I then answered the
question. Within thirty minuets I received a scalding email from chris greene
accusing me of spamming the forum and then he banned me for life from the forum.
I was a bit set back by his attitude because I didn't know him from Adam so I
returned his email asking him what part of my post was spam? He promptly
responded saying "all of it" and then proceeded to swear at me and call
me names... So there you have it, that's why I don't post on the Fender forum.
(Not that I have the time...) chris will of course allow other tube venders
including "blue strat" who is mike at kca to post whatever spam he wants and
accuse me of insider trading, but the reason for this is obvious, he lines
chris's pockets by sponsoring the page. A little payola still goes a long