I hope the “quit interesting” was a typo; some say I quit being interesting around post #3 😆 . Anyhoo, you’re in good company; Pete Townshend, John Entwhistle and Dave Gilmour all had Custom 100s specially adapted for them by Hiwatt to their own spec. Pete Townshend, particularly, is synonymous with Hiwatt. I think CDs of The Who “Live at Leeds” are readily available; one of the great recorded gigs with plenty of your Hiwatt to listen to. Some of the people I know at a “vintage amp” forum I’m on will be spluttering their coffees on reading that your Custom 100 gathers dust in favour of a Crate 😯 , but I know what you mean.

Incidentally, lack of use with my own favourite head has had its downside. At least one, probably two, of the filter caps have started to show white powder and I’d better replace them. Funnelly nuff, regular use keeps electrolytic capacitors sweet and prevents them drying out. Try to give the amp a monthly kerrang if you can.

Your tall. skinny tubes were EL34s (or E34Ls), much more commonly used with British amps than the big-bottle 6CA7. There’s two reasons why your previous tubes may have glowed blue. One possible is that you had the JJ Tesla E34L with blue-stained glass:
http://www.danelectroid.com/pics/e34blpl-q.jpg

or they were normal tubes and the blue glow was from trace gas fluorescence (this worries some people but it’s no harm to amp or valve). It sounds suspicious that someone should replace tubes inside a fortnight. If I had, I would’ve said “Your cruddy amp needed retubing and it cost me $50!” rather than said nothing. I’ve got a feeling they weren’t JJs, but prized and valuable old Mullards that your “friend” has lifted and replaced with cheap moderns. A working, matched quad of Mullard EL34s is worth several hundred dollars, depending on which type, condition etc.

As for removing the serial plate to fit a switch, that’s just 👿 😡 , whoever did that. Probably some hot-rod mod to give it some overdrive. What is left of the ident? Is there the plate with the factory address still present? Another photo would be interesting.

Lastly, here’s a website with a bit of Hiwatt history:
http://mhuss.com/Hiwatt/history.html

Flashback, it really is a pleasure to see a new member come in and take the trouble to post up such a lovely gem. If I could dole out prizes, you’d be #1 in line for an amp-porn lover like me. I am “Bender” from Futurama and you have a lovely Custom 100, there. Make a coffee, sit back and read. I could bore you, but it’s worth writing a lengthy about.

First, that sticker:
http://www.freewebs.com/opusmustang/tested%20sticker.JPG

At first, I didn’t take much notice. Those things are available to anybody in Blighty, and frequently used by local government employed types who test electrical equipment for safety. All it meant was that the amp was born no later than 1976. However, those initials “DR” suggest that it could have been checked over and passed by Dave Reeves, the founder and head honcho of HiWatt.

Next, that name written on the underside of the chassis:
http://www.freewebs.com/opusmustang/under%20view.JPG

Harry Joyce was the chief technician in HiWatt’s engineering, and went on to make his own valve amps after Reeve’s death in 1981. The pic also beautifully shows the attention to the wiring that is the HiWatt trademark. Look at those right angles where the critical wires pass, to avoid any impedance loop. By comparison, a Marshall Superlead or Plexi is a plate of spaghetti.

Your topshot:
http://www.freewebs.com/opusmustang/top%20view.JPG

clearly shows the Partridge mains and output transformers. Your “odd one out” is a replaced filter capacitor. Don’t worry too much about this, even though some people like to see original capacitors. The fact is, they were designed to live maybe 10-15 years and it’s amazing that originals are still in place. If your original were bubbling and/or showing white powder, it really needed to be replaced before it puffed an acrid smokebomb all over the innards.

Finally, the valves:
http://www.freewebs.com/opusmustang/valves.JPG

These look to me like the Electro-Harmonix 6CA7, a modern valve that is a copy of the “big bottle” Sylvania 6CA7 of the USA. They definitely weren’t the originals, but you don’t say for how long you lent out the amp. Valves, even more so than capacitors, wear out. If it had Mullards when you lent it out, but came back a fortnight later with these EHs, then you’ve been done. If, however, the amp was borrowed for a long time then I’m not surprised the valves were replaced. FWIW, the EH 6CA7 isn’t a bad choice out of all the modern availables and probably suits the amp well enough. I prefer the old valves, but they’re not easy (or cheap) to get hold of.

Hope some of this is useful info, thanks again for the pics and posts. I’ve deleted your pic-posts that didn’t work out 😀

[quote=”flashback”]”thanx for ya help lads”

I’ve asked for help in many guitar forums and so far the most help has come from you lads.OK the guitar has turned out to be special only to me ,but thats ok.Damn thing plays well and sounds good through a “CUSTOM HIWATT 100”,old equiptment i know.

“FLASH”[/quote]

I have a Hiwatt Custom 100, mine is a 1973, not in great condition but has the original Partridge transformers in, ive had all the large caps replaced and a few other bits and the amp was well worth spending money on, if yours has all the original parts it could be worth £500-£700, its worth a lot more than a comparative Marshall, don’t sell it cheap, those things are all point to point hand wired too, take the cover off and have a look at the skilled workmanship inside, they realy are a work of art.

My nan’s singing would sound great through that HiWatt, and she’s dead 😀 Don’t let anyone ever con you out of selling that amp cheaply; it’s worth a considerable amount. Unless the buyer’s 1bassleft; sell it to him cheaply by all means 😆

As a lot of people here will tell you. Something close and important to you, no matter what make, model or appearance, will always be more special then any top priced guitar.

Do stick around.

Hey flashback,

Here’s what Blue Book publications has to say about Opus:

Instruments previously produced in Japan in the mid-1970s
The Opus trademark is a brand name of U.S. importers Ampeg/Selmer (source: Michael Wright, Guitar Stories, Volume One).

Maybe this will get you started with your research. SB

So it’s a a bolt-on. As a general rule of thumb, the glued-in neck guitars are going to be worth a whole lot more.

But if the guitar works for you, and you like it, then what’s it matter what it’s worth?

Is the neck glued in or is it a bolt-on?