CHAMP ELECTRONICS -" THE VINTAGE VALVE AMP HOSPITAL"

NOTTINGHAM, ENGLAND

 

OVERHAUL OF A VAMPOWER 100 Watt AMPLIFIER HEAD Mk I

(See Email from the designer of Vamp Amps at the bottom of this page.)

 

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WOW, I WAS WELL PLEASED TO BE CHOSEN TO DO THIS ONE!

OK, here’s how the story goes. A gentleman named Paul, from South Yorkshire here in the UK, rung me to see if I could possibly help him out with the “getting back to life” of a VamPower 100 watt Head Mk1? Now, I already had a Mk3 on the site but to get the chance at a Mk1 was thrilling to say the least! The Mk1 is a very rare amp; about as rare as “rocking horse dung!” In-fact between us, we know of only two other MK1s: another in the UK, and one in Australia owned by a guy named John Justin, who collects the Vamp products!!

After I had willingly agreed to do the amp for him, Paul came down to Nottingham to meet me and bring the tired old specimen too. She really was pretty tired so, after a good chat and a few cups of tea, Paul left the amp with me and headed for home. It took quite a lot of work and time to get it back to rights but hey, it was well worth it in the end. Below is a list of all that ended up being done!!


1.    Straightened rear bent chassis as best as possible.

2.    Replaced broken mains fuse holder for genuine Bulgin type.

3.    Fitted extra metal securing nut to rear mounted power switch.

4.    Replaced broken cord grip in power plug plus missing screw too.

5.    Labelled mains selector switch (be careful this doesn’t get moved, it would do a lot of instant damage!!).

6.    Repaired “non working” standby lamp.

7.    Sprayed and cleaned all valve bases and potentiometers (controls).

8.    Replaced all four main smoothing capacitors along with new mounting brackets (better than the originals now!!). Also used original hardware on these, as-in the original BA nuts/bolts.

9.    Replaced bass channel input jack sockets (2) and new components with genuine “chrome nut” type.

10.    Removed main power board, changed all faulty/tired components. Also super-glued all broken corners. Glue-gunned small bias smoothing caps - nice & solid now. Sprayed and cleaned board with special chemicals. Refitted & rewired.

11.    Removed main output board, replaced all resistors and one capacitor, sprayed and cleaned board with special chemicals (this board had many duff, tired and wrong components!). Refitted & rewired.

12.    Removed main pre-amp/drive board. Found a couple of duff components and changed accordingly. Re-soldered a lot of dry joints on this board! Sprayed and cleaned board with special chemicals. Refitted & rewired.

13.    All other hardware in the form of nut’s, bolts washers etc checked for tightness.

14.    Replaced all five speaker output jack sockets (one broken, one not working so a full new set of matching ones have been replaced).

15.    Found one ECC83 (Mullard) to be faulty. However, this turned out to be the wrong valve anyway! This has been replaced with the correct valve….ECC81, also Mullard.

16.    Supplied full quad set of used-but-very-good Mullard EL34’s (2 matched pairs).

17.    Full bias set-up and bench test.

18.    All other wiring tidied up and cable-tied where need be.

19.    Supplied/fitted missing 2BA cage mounting nut.

20.    Supplied four new brass 2BA screws and four new cabinet feet.


So now, having finished all the above, it was time for Paul to collect his baby and let me know the results. On the test gear it was superb, and I could see that it was going to sound great! This amp has a control on the second channel called “a bite control”. This is a type of overdrive and is designed around the idea of the early fuzz boxes, only using a tube (valve) to achieve the desired results rather than a transistor. To the best of my knowledge, this is the only amp of its kind to have this method/design of circuitry, and it was “way ahead of it’s time” too!

You may well be wondering why I’m making such a “fuss and interest” on this particular amp? Well for those of you who don’t already know this:-

 The VamPower 100 watt head Mk1 was the late Marc Bolan’s choice of amp both on stage and in the studio. Bolan had a short period between 1971-4, where his guitar tone was awesome. How or why he came to use VamPower amps is not known; maybe sponsorship (?). No one else of any note was using them at that time. It is known that he loved the “Bite” control. During the era circa 1971-2 he used this amp extensively, and great examples can be heard on “The Slider” album, with the track of the same name being a fantastic example of this sound with its “woody growl”. It is believed, through general photos available on the net, that he used to drive the Vamp with a HH 100 watt transistor head and also, along with both the amps, he used a “Dallas-Arbiter Rangemaster treble booster” with a Germanium transistor in it. (These are fetching really silly money nowadays!). It was the combination of these amps, the Rangemaster, and his 50’s Les Paul with its randomly wound Humbuckers and Bumlebee capacitors that gave Marc his unique sound…..the sound that Paul, the amps new owner, was seriously looking for!

So, after now having had the amp back for a few days I got the call from Paul………….. "Yes" he said….."that’s the sound!!!"

Now, here’s where the story takes a possible unexpected twist! Paul had bought the VamPower head from an Australian collector of Vamp products named John Justin, whom I mentioned previously, although it had actually been stored in a London recording studio where it had apparently stood in a corner, untouched for many, many years. However the mind boggles….. As Marc did most of his recording in London studios, could this have been Marc’s actual amp from back there in the seventies?……Who knows? Another thing that makes me wonder about this is the fact that this amp has an unmarked slave in/out socket on the back panel, yet it did look factory fitted, whereas the photo of the other one in Australia doesn’t have this socket. Maybe Marc had this factory fitted for the use of linking in/out his HH head? If any more information on this surfaces I will post it herewith.

The amp is presently being recovered back to original by a great guy for doing this……James Payze (Click HERE for James' Website). When it has been finished, Paul is going to send me some photos and I will be posting them herewith.

I have made some useful comments on the photos' captions. I really enjoyed doing this one. Thanks for your interest in the site. Cheers, John.
 


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Finished & ready to “Rock ‘n’ Roll!!


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As received. Note the two “non original” black nylon jack sockets on Channel 2.

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As above, no output tubes & smashed fuse holder.

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The output board…….Cooked, charred, burnt, many duff components, dreadful soldering & incorrectly replaced/bodged components too!


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The pre-amp/drive board……not as bad as the output board but still needing attention!

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The “non-labelled” slave in/out socket which certainly looks factory fitted. It is the same branded jack socket as all the others & is wired with the identical type shielded cable as-is used throughout the rest of the amp!

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The output board removed.

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The rebuilt output board.

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All re-soldered & chemically “cleaned-up” underside of the output board.

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The output board back in place.

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The power supply board, all the resistors were well tired or duff! Also, note the broken corners where the mounting bolts locate. These circuit boards were so bad all those years ago. They are made of a very brittle & cheap type of bakelite, which one only needs to look at them & they break! These were already broken on removal of the various boards/panels.

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Underside of the power board, all re-soldered & chemically cleaned too.

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The power board back in place with all new resistors. I have also super-glued all the broken circuit board corners & glue-gunned all the wire-ended capacitors - the trendy, sensible, & good way to secure them nowadays!!

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The four new smoothing capacitors in place; better than the originals! Tightening up the HT supply on any tube amplifier improves the “bottom-end” & “kick” without effecting tonal quality.

  vamp1q.jpg

The voltage selector switch - this is not a good design/idea!! It can easily be “knocked” and if so……..would cause a possible/immediate amount of damage! I had advised Paul (the amps owner) to be very aware of this, although once in its case & with the back grill in place it is very unlikely that this would actually happen. Nevertheless, still worth noting!

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The incorrect black jack sockets that had at some point been replaced have now been changed for the correct “chrome-nut” type. Plus a “close-up” of just two of the four new, main smoothing caps.


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Underside of pre-amp/drive board; prior to any commencement of work.

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After all work & chemically treated.

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One of the output jack sockets was smashed, and another wasn’t working. As I didn’t have the same brand, it made better sense to simply change all five to a different brand…….but still of the chrome nut type, as the originals.

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Both pre-amp & output boards back in place.

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I just love this last photo! What you are looking at is the “above chassis heater fuses”. I am not aware of any other amplifier manufacturer way back there in the seventies that actually fused their tube (valve) heater supply. The ironic thing is that nowadays this is a compulsory/law issue and all amps have to have this! It is now done however by using standard fuses rather than two pieces of fuse-wire across tags, but hey…..the Vamp products were all “well before their time! Another point  worth mentioning here is the fact that not only does this amp have the “heater fuses”, a “bite” (fuzz) control, but also it has four individual bias controls (one for each output tube) plus the facility to check each tubes’ bias via the four additional, individual cathode “bias check” resistors! This amp (and in-fact all the Vamp products) was “way ahead of its time! 101% bravo for this!

PHOTOS OF THE AMP AFTER RESTORATION WORK CARRIED OUT BY JAMES PAYZE:

(To visit James' website, click HERE.)




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Front & back of the amp as she is now.

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Paul's complete set-up, all recovering compliments of James Payze.

 

POSTSCRIPT:

I have just (February 2008) been contacted by Dave Roffey who was the actual person who designed the Vamp amps in the 1970's. With his permission, I have added his email below because it offers a fascinating insight into the history of these great amps, and the Marc Bolan connection:

"Hi John,

As the ‘old timer’ who designed the Vamp amp, seeing your restoration has just given me a warm smile and good memories, (those that are still available to my brain!).

That amp was made at Triumph Electronics in Purley, where I first started work in music electronics. Triumph made stuff for VOX and their own Tranny amps as well as valve stuff. Made by a guy called Roy I believe, ex drummer of the then Ram Jam Band. Great guy, and excellent wirer. (judged by the artwork doodle).

The ‘bite’ control brings back memories of the rows I had with the purists. Being in a rock band at the time, the overload control was a definite requirement for me, but it took the wisdom of the MD, Geoff Johnson, to see it should go on.

Marc Bolan frequented a music shop in Lewisham, South Eastern Entertainment. This was run by Frank Taylor, who approached Triumph to make the Vamp amp for him. Frank Taylor then went on to manufacture the amp himself, along with me as the designer. I left after a while, leaving the music side of the industry.

Anyway, thanks for the memories,

Dave Roffey" 



 

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