98 VH4 (8 preamp tubes) CH2 really low gain = normal?

[speakermouth]

Hi Guys,

I've got a question on what's to be expected of the sound & gain structure of channel 2 of an early Silverface.
It seems I have a rather lacking amount of gain on CH2 compared to younger Silverfaces, I'm wondering if this is considered normal for CH2 of a Blueface and by extension the early Silverfaces?

After reading up on the board I've come to the conclusion I've got an '98 VH4 Silverface which probably has circuit similarities with the Blueface versions: 8 pre-amp tubes, red power switch, blue 'caps', a magic unicorn trapped inside the power supply ;-)

I've watched a couple of Youtube demo's of younger VH4 amps and I noticed a rather dramatic difference in sound & gain with my CH2:
I can't seem to drive the channel to its limit unless I crank the gain well beyond 4 o'clock, and only with some of my guitars.
Even at 4 or 5 o'clock my CH2 never comes close to really saturated AC/DC, classic rock or creamy blues sounds.
Younger VH4's seem content with CH2 gain at noon to get into these kind of sounds!

It responds well at 4 o'clock to an ESP Viper with EMG81 pickups because it's a treble- and mid-heavy guitar (aka Metal Beast), but to get nice crunch tones with my older humbucker guitars I have to crank the gain AND use a boost pedal: '78 Ibanez MC300 + '80 Yamaha Super Flighter 1000, both with their original - probably medium output - pickups.

I don't have to tell you that the channel is practically useless when using a 50's spec'd Stratocaster... I've also tested a friends Telecaster with a Seymour Duncan hot rail bridge pickup, and that also needs the gain set to at least 4 o'clock to get nice overdriven sounds.

My VH4 was recently fully re-tubed with TAD EL34 power amp tubes and is running TAD ECC83_Cz preamp tubes at all V1-8 positions. These are rated 'clean, hifi, warm'. The amp sounds the same as with the previous tubes.

The amp doesn't sound broken, I've been running it on CH3 and CH4 for years, which of course sound spectacular. For reference, CH1 also seems to be a lot cleaner than newer VH4's, even with the gain at max.

Maybe it's just a matter of using a nice high gain pre-amp tube at the correct position for CH2?

PS: If my early Silverface does share the circuit of the Blueface, I can't even imagine AJ-like tones from my CH2. But maybe I've just got the wrong kind of unicorn in my power supply ;-)

Thanks for any insights.

Link to current tubes:
Pre: http://www.tubeampdoctor.com/en/shop_TA ... lected_393
Power: http://www.tubeampdoctor.com/en/shop_TA ... Valve_2829

 

[slyvren]

AJ uses chan 3 exclusively. He rolls the guitar volume down for crunch (and don't forget the Marshall).

As far as less gain than newer amps? I believe that's par for the course. Especially compared to '07+ amps. I'm no expert on the older amps though. I'm sure someone will chime in with much more experience on the topic.

 

[speakermouth]

I'm not really searching for the AJ-tones, but my amp is probably akin to how a Blueface would sound.

But I would describe it as a dramatically different gain structure on CH2 compared to what's described in the VH4 manual or Youtube clips of newer VH4's.

In the sense that if CH2 is supposed to be a blues players' dream while also satisfying classic rockers, they'd better be packing James Hetfield's ESP guitars or bring some kind of boost pedal if they want to gig on my VH4's CH2.

It just feels 'out of the ordinary'...

 

[Peter Diezel]

We never know what some "tech" did inside the amp.

 

[Sigma.Xiria]

I don't know if this would help, but back 2 years ago I had my 2007 VH4 updated and had some necessary maintenance done to it due to the previous owners mistakes. What Jens (he was our US Diezel tech at the time) had me do was take some high quality pictures of the circuit of the amp and email him them after I said that I noticed something sounded a bit "off" when compared to sound clips and other Diezels.

I am sure you could send Peter some good pictures of the circuit and he could help you out... might end up having to send the amp to Germany though haha.

Oh and I know a buddy of mine had said that his amp started sounding different and it was due to the tube socket connectors becoming loose over time

 

[jonl]

Let me see if I can help.
If Channel 2 isn't getting you to the gain level you need then go up to channel 3.
My 98 does have less gain than the 07 I had but its not a bad thing, it growles like crazy.
I am using a JB in the bridge position and a micro amp for boost as well.
Single coil pups won't get you loads of gain ether.

Did you check the bias after changing the tubes? I don't think your amp has a trimmer.

Maybe what you need is a newer VH4.
I may know someone who would trade.

 

[cardinal]

That doesn't sound right to me. I had an amp with that extra tube (it was a VH4S, so had 10 preamp tubes), and channel one could have a ton of preamp gain (also could be dialed back to be very clean). Channel 2 had less gain and more noticeably IMHO less saturation than a 2007 VH4 I also owned, but the blueface had plenty of gain and crunch to do heavy, hard rock in that channel. Way more than AC DC crunch if you wanted (particularly with moderately high output pickups and heavy pick attack).

 

[speakermouth]

If Channel 2 isn't getting you to the gain level you need then go up to channel 3.
My 98 does have less gain than the 07 I had but its not a bad thing, it growles like crazy.

I actually like the raw sound of CH2, it's just very difficult to manage gain-wise with anything but my 'designated metal' guitar.

I am using a JB in the bridge position and a micro amp for boost as well.
Single coil pups won't get you loads of gain ether.

Granted, my Strat has really low output 50's style pickups. I wasn't expecting to drive the amp with that guitar.

Did you check the bias after changing the tubes? I don't think your amp has a trimmer.

You're correct, no bias trimmer. Although the previous owner has modded it with one.
The amp tech that did the re-tube checked the bias, but we didn't do a circuit review though, mainly because CH2 sounds OK.
So unless he'd have another VH4 to compare it to, he probably didn't have reason to suspect the lower gain structure of my CH2 was anything out of the ordinary.

If I take Peter's comment in consideration it's perfectly viable the previous owner had some modifications done to it.

 

[speakermouth]

Way more than AC DC crunch if you wanted (particularly with moderately high output pickups and heavy pick attack).

Thanks, I can almost get there, but certainly not anything like you described (way more)
And I've got a very strong pick attack courtesy of the Dunlop Jazz III picks I use.

I think Peter might be right, time for a circuit/modification checkup ;-)

 

[cardinal]

In my experience with that circuit (the extra tube for channel one), you can go beyond AC/DC crunch in just the first channel (had way more gain that any silver face I played). Channel two is good up to early Tool, AiC, and Pearl Jam type stuff.

 

[MOOSEHEADS]

Isn't the TAD ECC83_Cz pres not a high gain pre?

Wouldn't it be better to put in some TAD 7025WA HG is the V1, and a 12AX7AC5 HG+ in the V2 then 12AX7-C in the rest?

I am no expert but, wouldn't that give you more gain?