VOX Long Tom Schematic and or layout

[michaelshadmaster]

Hi, Does anyone have a schematic for the Vox Long tom CO2 MKII. I have one that Charlie gave me but there are some discrepancies. I need help with the record amp section-12AU7 socket wiring on my unit is different to the schematic. I am getting know where searching for info on this unit.



Thanks. I would appreciate any help I can get.

[fenderplucker]

Hi Michael,

I have refurbished a number of Long Toms here on Australia (including those of Robby Januarsa and Adrian Browne) and would be happy to help out. There are often variations in the actual components used in these units and any of the circuit diagrams I have seen are at best only a guide. Ultimately you need to do whatever is necessary to get the best sound.

Regards,

Paul
TVS Specialty Products.

[michaelshadmaster]

Thanks Paul. I just want to get it going first. Tone is not even a concern yet. I see some major differences between the unit I have and the schematic. The record amp is very different on my unit. The pin numbers don't seem to be correct on the 12AU7. I need to spend some more time and draw up a schematic or layout of what I actually have. I believe this would help but it's going to take some time. There are other issues. Have you ever seen a long tom with a 1K power resistor between A+ and the wearite coil. All schematics I have show 5K 5 Watts. My unit has 1 K in there, I am sure that's wrong.There are also some 2200pf caps across tube sockets that are not on any schematics also. I don't want to break of any wiring or components and then not know where they where. I have photos to back me up. I would send you some but I doubt it would help. If you think it would let me know exactly what you need and I will snap a few hi res pics for you. Thanks in advance. I am being cautious until I get a schematic that makes sense./ I am sure you agree it is a good idea.

Thanks Regards Michael.

P.S I have also been a shads fan since I can remember. Saw them twice at St George's League's club in Sydney 1st time in 1985. Never forgot it. I have some photos I would like to post online but not sure where I stand legally with that. Do you think hank would mind. My son is also a big fan he is 13 and going well. He is using a Q2 with J patches. I plan to by EFTP soon. I would love one of your units but a little expensive considering I am not playing much at the moment. Such a small world. I cant believe I am communicating with you. I have admired your system for some time. I used to fall asleep with a guitar in hand and dream about jamming on stage with Hank.

My son Chris playing peace pipe and wonderful Land at age 12. Enjoy. Maybe you can forward this to the man him self. imagine the look on a 13 year old boys face knowing hank heard him play.

Thanks again.

Peace Pipe- soundcloud.com/christopher-david-anthony/peace-pipe-cover-by-christopher-fenech
Wonderful Land - soundcloud.com/christopher-david-anthony/shadows-cover

[sandra]

Two nice versions by Chris there Michael, I am quite envious

[michaelshadmaster]

Thanks Sandra I will pass it on. He is still learning. He  has a way to go. I cant teach him everything. Some things just need to come with time & experience. 

[fenderplucker]

Hi Michael,

Christopher is definitely on the right track, I wish I could have played that well at 12 years old!!

From what you have said so far, it seems to me that someone has tried in the past to increase the level of the recorded signal. This probably because many Long Toms barely have enough loop gain to cause regeneration (i.e. oscillation) when the feedback control is fully up. However, driving the record head harder will change the sonic quality significantly and, in my view, not the right way to go. When you have a schematic I would be happy to have a look and make some suggestions. It would also help if you could record the voltages at some key points, like B+'s and valve pins.

I am sure that there would be no problem with you posting the photos of the Sydney Shadows gig, the web is already awash with similar ones from other public appearances.

Best Regards,

Paul.

[rosemary]

Hi Michael
That was excellent playing and sound on both songs from young Chris! I'm guessing you're in Sydney from your message. We have a Shadows Club in Brisbane with another very talented young guitarist like Chris. His name is Ben and he's 12 years old so much the same age as Chris. If ever you're up this way we'd love to see you. This is our website where you can get in contact.
www.brisbaneshadowsplayers.com/
Best wishes
Rosemary

[michaelshadmaster]

Thanks Paul. I would like to return the unit back to its original configuration and then make some tonal assessments based on what I here. I would assume that the power resistor should be 5k. In nay case it's safer than 1 K. so I think I will fix that. Just got the EZ80 Tubes today but I am not game to power it up yet as I need to go over it a little first. There is a cap with a broken lead. All electros need replacing anyhow. I will do that first. The power supply section seems to match all schematics that I have seen. I am still waiting on new 12AX7, 12AU7, & eL84 Tubes. I plan to replace all electro caps and check resistor values, look for shorts, leads contacting Chassis soldering iron damage if any , things of that nature. as soon as i feel comfortable applying HT I will let you know what I find. Some resistors are 60% or more of the values marked by colour code. That cant be good. i expect 10 to 20% not much more than that. I assume the original designers were well aware of the tolerance's of the day and made allowances for that.



I will send you more info when I have some. Thanks again.

[michaelshadmaster]

Thanks for your Kind words. Chris is not here at the moment but I will pass it on to him. I doubt we will get to QLD any time soon but we may swap some video's and sound files soon. He is a little distracted with computer programming at the moment but i am sure all he needs is a little inspiration and he will be back on track. I may take him to see hank with his gypsy jazz band. They are plying in Sydney in November.

I will have a look at the website soon.

Thanks again.

[sandra]

Sept 21, 2015 3:04:41 GMT fenderplucker said:

Hi Michael,

Christopher is definitely on the right track, I wish I could have played that well at 12 years old!!

Paul.

I still can't

[fenderplucker]

Hi Michael,

Sounds like you are on the right track. It is not unusual for some of the old cracked carbon resistors to be way out of spec, particularly the anode resistors that can be way high (60% is not unusual), also the 12AU7 cathode resistors.

Regards,

Paul.

[michaelshadmaster]

Thanks Paul. I figured as much. I have some more schematics that are very different from anything I have seen so far. I will draw up the unit as it stands and send you a copy. when I get time. Thanks very much for your help so far. My EZ 80 came yesterday and the other tubes are due tomorrow so hopefully I can power it up soon.

Thanks again.

[darren]

Sorry to resurrect an old thread here!

New member, I have been searching in vain for a schematic for the vox "long Tom" echo deluxe, can anyone help with this? I'm trying to understand the function of this amazing echo. I must confess my reason is because Jimmy Page used one a lot for recording!!

[Charlie Hall]

Hi Darren,
I have sent an email to your registered email address.
Regards,
Charlie

[jyrki3101]

Hi, I'm building a tube tape echo and I'm planning to use the Vox long tom circuit with just one instrument input.I have the tape transport system copied from a Pearl echo orbit 302 unit and have almost all parts for that. Tape bias oscillator is based on Dynacord echocord S65 because I have a few original transformers for that 12au7 push pull oscillator.

Could I have a schematic and a layout for that Vox unit.I'm not sure how to organize the circuit on tagboards. For example , the grounding scheme must be quite critical and what amplification stages(playback-,rec.stage, input-and output) to put on each tagboard.I have only built basic tube amps and other effects so far. I could also use the oscillator circuit from the Long tom echo but unfortunately I don't have that wearite? coil for that.
 I would greatly appreciate your help !
With Kind Regards,
Mr Jyrki Telila

My email is : [e-mail]