Is my new VJr head a V3?

[Duff]

I have a new VJr head. It has a solid red on off switch and a serial number 0060207xxxxxxx.

Does this sound like a V3? Just got it at GC about two months ago. A look at the power transformer shows an orange and two red wires coming out of the right hand side. It also has a code sticker on it if that would help I can add that.

Anyone able to tell if this is a V3?

Duffy
Winfield, Pa

[tunghaichuan]

I believe so. The 14-digit serial number is a dead giveaway. Another sign is that the output transformer (smaller of the two) will have a 5.2k primary. It should say on a sticker on the top of it.

The on/off switch is also indicative of version 3 amps. The version 2 amps had an I and 0 marked on the switch for on and off respectively .

Finally, if you pull the chassis out of the head cab, take a look at the printed circuit board, it will be black. It was green on versions 1 & 2.

tung



I have a new VJr head. It has a solid red on off switch and a serial number 0060207xxxxxxx.

Does this sound like a V3? Just got it at GC about two months ago. A look at the power transformer shows an orange and two red wires coming out of the right hand side. It also has a code sticker on it if that would help I can add that.

Anyone able to tell if this is a V3?

Duffy
Winfield, Pa

[Duff]

Right. Right on the sticker it says 5.2K ohms. 14 chasracter serial number, red on off switch.

Are these significantly upgraded to the previous models? Did they incorporate some of the mods you guys have been doing, during the production phase? Like the OT. Is that the more powerful one?

It's a cool head.

I have a Blackheart Little Giant head that I'm playing a lot also, but the VJr still sounds great. I won't get rid of it by any means.

You have been a lot of help. Thanks a lot.

Duffy

[tunghaichuan]

The new VJs sound pretty good right out of the box. The new 5.2k OT is the same size as the old version 2 OT, but it has a different primary impedence. The version 1 & 2 OTs had a 7.5k primary. They sound crappy in the circuit. The 7.5K OT is close to the Champ OTs and was probably a Champ-style OT meant to be used with a 6V6. The new OT sounds much better. To squeeze the last bit of performance out of the amp, you'd have to step up to the Hammond 112ESE. You'll get a little more bass and a smoother tone overall.

Epi made some changes to the power supply to get the voltages down in the amp. The version 1 & 2 amps ran the voltages too high. They made a few changes in the preamp which helps the sound.

There is still a bit of room for improvement, though. The stock cathode bias resistor is still too low, which causes the EL84 to dissipate too much wattage. I like to bump it up to a 270 ohm, 3W metal oxide resistor.

Some of the preamp values can be tweaked to improve the tone slightly. But overall, the amp now sounds very good stock.

Still when I compared the stock version 3 VJ agains the Blackheart head, the Epi had a better OD tone; more agressive, louder and more gain. The BH head had better clean headroom. The BH wasn't as loud, the tone wasn't as agressive. I'm planning on gutting mine and rebuilding another circuit into it.

tung





Right. Right on the sticker it says 5.2K ohms. 14 chasracter serial number, red on off switch.

Are these significantly upgraded to the previous models? Did they incorporate some of the mods you guys have been doing, during the production phase? Like the OT. Is that the more powerful one?

It's a cool head.

I have a Blackheart Little Giant head that I'm playing a lot also, but the VJr still sounds great. I won't get rid of it by any means.

You have been a lot of help. Thanks a lot.

Duffy

[Duff]

I noticed that the VJr sounds louder thru my 4 by 12 So. Cal. cab., and more tonefull. The Blackheart is neat though and I imagine tweaks will be coming down the line.

Thanks again.

Duffy

I wonder if there is a Blackheart forum?

[tunghaichuan]

There is a Blackheart forum on the SEwatt.com site.

One thing to be aware of is that the Blackheart's PCB has a double sided board with traces on both sides, but the holes are not plated through. So for each lead, you have to remove two solder joints. The pads are prone to lifting if you're not really careful.

tung


I noticed that the VJr sounds louder thru my 4 by 12 So. Cal. cab., and more tonefull. The Blackheart is neat though and I imagine tweaks will be coming down the line.

I wonder if there is a Blackheart forum?

[Duff]

Tung,

Therefore, this could make soldering mods into the pcb board a sensitive operation; such as using a low wattage soldering iron?

Have you modded your Blackheart yet?

Duffy
Winfield, Pa, USA

[tunghaichuan]

Tung,

Therefore, this could make soldering mods into the pcb board a sensitive operation; such as using a low wattage soldering iron?

Have you modded your Blackheart yet?

Duffy
Winfield, Pa, USA

Yes, very much so. My wife bought me a 60W Hakko temperature controlled soldering station a few years ago. I have to change tips when working on PCBs. I still managed to mess up a couple pads on the Version 2 green PCB. The Version 3 black PCB is supposed to be more rugged, but I would still be very careful. I've found the best tool for removing solder is solder wick. I didn't have much luck with my solder sucker bulb.

As far as wattage goes, I wouldn't use an iron bigger than 30 watts with a medium tip. Soldering PCBs requires a fine touch, and it is possible to cook the components.

As far as the Blackheart goes, I'm actually kind of afraid of the lifting pads. I'm seriously thinking about gutting it and building a new circuit into it. But I'll probably do some minor mods like changing out the stock Chinese tubes, setting the bias and tweaking some of component values. I just haven't had a chance yet. :(

tung

[Duff]

I should get some tubes and try adjusting the bias. I have a nice digital multimeter. I'm good around a soldering iron and have a 40 watt and a 15 watt. I got the fourty at Radio Shack a month ago for seven dollars. That fourty makes a short order of any solder I've encountered yet in a guitar. I haven't soldered in an amp yet though and am very skeptical of soldering on a pcb board. I could see burning it.

Duffy

What do you play the Blackheart on most? Three or five watts?

Bill M wrote that he thinks the SCXD is more like 20 watts based on his preliminary and incomplete tests.

[tunghaichuan]

Duffy,


I should get some tubes and try adjusting the bias. I have a nice digital multimeter. I'm good around a soldering iron and have a 40 watt and a 15 watt. I got the fourty at Radio Shack a month ago for seven dollars. That fourty makes a short order of any solder I've encountered yet in a guitar. I haven't soldered in an amp yet though and am very skeptical of soldering on a pcb board. I could see burning it.


The VJ is a good tool to learn how to set bias in a cathode bias amp. It has a bleeder resistor built into the power supply that drains the filter caps of their charge when the amp is turned off. But to be sure, I always measure the voltage with my DMM.

You may have seen this, but I have a link on my web site that explains how to set the bias in a VJ:

setting VJ bias (http://www.diycustomamps.com/valvejunior.htm#vjbias)

This can be done with any single-ended cathode biased amp like Champs, Princetons, etc.

Just remember to keep one hand behind your back or in your pocket when working on the amp.



What do you play the Blackheart on most? Three or five watts?


I like the five watt setting better. The three watt setting sounds like someone threw a blanket over the amp and it isn't that much quieter than the five watt setting.



Bill M wrote that he thinks the SCXD is more like 20 watts based on his preliminary and incomplete tests.

Wattage for guitar amps is kind of a nebulous thing. A 50 watt Marshall will put out about 60 watts clean and lots more than that when dimed. Of course that is at 20% THD levels though. Most hifi methods of testing for actual audio output are meaningless because hifi amps want to have the least amount of distortion possible. Guitar players, OTOH, like to have at least *some* distortion, even when playing clean. A small amount of distortion is percieved as "warmth."

tung