ENGL Screamer 50 - older chrome face Vs black face sound different? Solved!

[tmjohn]

Has anyone had the same experience;

For the past 8 years or so I have gigged using an ENGL screamer 50 head into a Marshall 4x10 cab, and love it!.

The overall sound and versatility suit me perfectly. I own a few amps, and have bought and sold many more over this period including Mesa Rectoverb, Lonestar, Line6 HD150, HD100, DT50, Tech 21 Trademark 60, Marshall TSL601, Badcat Hotcat 30R, Peavey classic, Fender Hot Rod deluxe, etc etc…Nothing has been as well suited as a gigging replacement for the screamer.  It has been ultra-reliable, never let me down and other than the normal re-tubing has had no repairs necessary.

Due to the fact that I like it so much and that it was getting quite old now, I decided to purchase a new (black face) version as a replacement/backup, which I have done.

To my great surprise, I found that the two amps sound completely different, when all settings are the same, and regardless of which channel is selected. The new amp had much more bass and mid’s and less treble.

Thinking the obvious, that it must be the valves causing the difference in sound/tone I swapped all the valves between the two heads (and set the bias to suit). This made no difference, they both sounded different as they did before swapping the valves. I checked numerous other things like input/output resistance/impedance, plate voltages (both were the same, and both higher than the spec says at 462v not 450v), output transformer primary resistance and volt drop, and B+ voltage, all were the same or VERY close.

Subsequently I tested to see if the issue was in the pre-amp or output stages, by sending the pre-amp output of one amp (via the effects loop send), into the return of the second amp (and visa-versa). From this it is apparent that the issue is within the pre-amp stages and not the output power section.

So, my question is; has anyone else experienced this difference between older chrome face and newer blackface screamers? I did note that that there are some obvious minor changes i.e. they have now included 2 fuses on the circuit board to protect from power tube failure, so there may well be more revisions, but without removing the circuit boards completely and measuring every component on both I can’t see how else to diagnose the cause.

Have they changed things in addition to the control panel colour that would change the tone response, or is one or other of the amps suffering from a fault or faulty component(s)?

I haven’t yet tried the new amp with the band yet, to see if I like it more or less than my original, but I do know that it will sound different, even after tweaking the tone controls to get them sounding as close as possible.

My original amp settings are normally in this area;
Clean – 5/10 (bright switched off)
Lead - 3/10
Bass - 5/10
Mid - 5/10
Treble - 4/10
Lead Presence - 4/10
Reverb - 2/10
Lead Volume -4/10
Master Volume - 5/10

New amp settings to get similar (but still not the same) tone etc:
Clean – 4/10 (bright switched off)
Lead - 2/10
Bass - 3/10
Mid - 4/10
Treble -6/10
Lead Presence - 5/10
Reverb - 2/10
Lead Volume -5/10
Master Volume - 5/10

The above settings get close, but the new amp still sounds fuller somehow, as if the tone section reacts differently and has different range of control. Also the new amp appears to have slightly more gain/volume in the clean channel at least.

So, apologies for the long post, but again I am particularly interested to hear if anyone has had the same issue between old and newer screamer amps, or if anyone knows of any revisions or can suggest an easy way to diagnose and pin point the cause, without having to completely dismantle the various circuit boards from both amps.

My immediate though is that maybe the slope resistor in the tone stack is different, either through design or fault. It is also possible that my original amps tone (bass/mid’s) has slowly changed/deteriorated over the time, such that I hadn’t noticed??

[Dave Sloven]

Capacitors?

[tmjohn]

Yes, quite possibly one or more caps, the problem is how to easily find the potential culprit(s)??  Also thought that it may be something to do with negative feedback circuit, but again I'm unsure (bearing in mid that the problem appears to originate in the preamp) whether this is relevant?

[Toe-Knee]

Most likely they will have revoiced the preamp as there were common complaints about the old ones being too abrasive and fizzy.

They did the same with the powerball & fireball too.

[gordiji]

I wouldn't be surprised if it's re-voiced as toeknee says. I've got the chrome combo, and did think it was on the bright side with the stock tubes but have now replaced them twice with jj's. Putting the first new set in i was surprised i had to go fully counter clockwise with the trimpot which was fully clockwise with the stock tubes. The latest set even on fully counter clockwise only gave a reading of 31mv while i wanted 37-40. It sounds great though and assume it's cold biased. The other thing i noticed was the difference in sound for the better with the breaking in of the speaker.V30.
If i were gigging i'd be hard pushed to find a better sounding amp, especially for the money and 50w is still the perfect size if you want some good cleans. 
I hope this completely irrelevent reply is of interest. 

[Nadz1lla]

Actually this is good news as I tried the Screamer 50 once (chrome face) and found it a little too shrill, even when dialled back in the highs. Might look into the Screamer 50 head again and see how it has changed. I was always impressed with Engl but never managed to buy one. Maybe next year. 

[tmjohn]

Since my original post I have now tried the new (blackface) amp at rehearsals with the band.
Firstly, I should say that at home I actually love the tone of the new head, compared to the older (chrome faced) one.
At gigging levels with the band, I did (as expected) found it to be very different in character than the old one, not necessarily better or worse.

But...I found it so far difficult to get the settings of levels and tone etc. dialled in so that I have the best balance and overall tone (volume and tone wise) between all 4 channels.

With my old one, with settings I previously posted, it was pretty much plug in and play, with (for me at least) the most ideal combination of drive/volume levels and tone. I hardly ever had to do much if any tweaking of the amp, and it worked well with both single coils and humbuckers.

The new amp appears to have more gain for the same settings, and the balance between channels is different, so it may take some time to get it all dialled in, but it may not be possible? This is obviously a very subjective thing, as my settings and tonal preferences will not necessarily suit everyone else, and I have used the old amp for so long it has become the basis of "my sound", and something that I didn't have to think about, if you know what I mean.

I will persevere for a while and see if I can get the sounds and balance that I like and am used too.(or grow to like the differences), although I may not happen, if only that I have become so accustomed and reliant on the old amp and what I am used to hearing from it.

It is of course possible that my old amp has over time changed with use and now has some "out of spec" components, or that the new amp head has some unusual anomalies?

I would have hoped that if ENGL have changed the design/specification of the amp, that they would have made us aware of any such "improvements"? and called it the Screamer 2 or whatever.

[Alex]

That is odd, have you tried contacting ENGL customer service about this?

Somewhat OT, but I really dig the ENGL RETROTUBE amps. The sound samples I've heard sound great.

[tmjohn]

Ok...
With regard to the difference is sound between the older chrome face ENGL Screamer 50 and the newer black face version:
I have contacted ENGL technical support and they have confirmed my suspicion.
They have indeed made changes to both the power valves fitted as standard from pseudo 5881's to 6L6WGC's, because they say these valves suited the screamer better, but have also changed the EQ "a little bit".
This would explain to why the two amps sound different, and will probably be good news for many who perceived the original chrome face version as a bit harsh or had to much high end or treble.

So anyone who was not overly happy with the original should perhaps have another try of the newer black face model, which as I have found has much more bass/middle available, appears to have more output and "pop" or "punch" to the sound, if you know what I mean. (It just sounds fuller and more powerful in the bass and mid's). 
 
   

[dave_mc]

^ That's interesting, thanks for letting us know :)

[Telerocker]

The only Engl I played for a while was a Classic with 2x10's. Especially the cleanchannel with a light breakup sounded particularly good. It also took pedals well.