I'll let the real experts respond to your procedural questions, Matt. Just wanted to thank you for sharing info on your magnificent beast - and to welcome you to the Vintage Hiwatt Forum .
I have never seen those "finger slot" type handles used on a HIWATT. As I recall, those didn't appear on the market (in other brands) until perhaps the 80's...or 90's. Is there any chance the case itself might be a replacement?
How many studios in Australia could have supported a DR405? It seems that tracking to the studio should be possible, in this era of google. Someone must have commented somewhere about recording through a 400 watt HIWATT. Maybe even an open question posted to your local Craigslist (or whatever the down-under equivalent is) might flush out more information.
Very cool amp and absolutely worthy of returning to full song. Keep us posted!
Hi Matt,
Welcome to the Vintage HIWATT Forum and congratulations for owning the cleanest DR405 I have ever seen!
I have seen around a dozen real DR405 of the approx. 50 that were made. None had those handles, but all things considered (quite critically) I believe them to be original in this cab.
I don't think the head cab is a replacement. My reasoning: I have seen what a drop or fall can do to these amps. Both the head cab and chassis are inadequate considering the mass of the transformers. Please forgive me DR! If the amp had the sort of impact to break the cab, the amp would have had damage as well and I see no signs of that.
Recapping is a good idea, it is just maintenance.
Be very patient and careful when replacing the switch. The PVC insulation melts quickly. Tin the tip and be ready with a solder sucker!
Your plan looks sound to me. I would suggest using flameproof metal oxide resistors for the screens. I'm not a fan of EH power tubes, but that is an opinion only, and modern tube quality seems to shift with every sea change.
Thanks for the warm welcome and helpful replies, guys! I've been meaning to register here for a while now and am glad that I finally did.
Firstly in reply to Dave - you are most likely correct, it shouldn't be too hard to find out where the amp was living before I got hold of it - to be honest, I haven't really dug into it and may give the detective work a bit of crack after it's all up and running again (but one thing at a time, eh?). Fortunately I can count amongst my friends and acquaintances some local engineer/producers and studio owners. Whilst no-one's ever mentioned knowing of the amp before, I'm sure I can get folks to pass around a query in wider circles. It would definitely be interesting to know a little more about it.
Clayton, thanks for the warm welcome and your thoughts re: the head cab and handles. I tend to agree with your assessment, but it's been a while since I've had the amp out and had a really good look, so this time I will be checking very closely for any more clues. Given how clean and close to original (IEC power socket notwithstanding) the rest of the amp is, I too find it hard to believe it didn't come from the factory that way. Also, I'm wondering what KT88s you run in your amps and any opinions your might have on current production tubes (more on output tubes coming below...).
Mark, I was hoping you'd chime in and thanks for your vote of confidence in the proposed plan. Thanks also for your efforts in drawing up those wonderfully clear schematics. Regarding the choice of output tubes, I appreciate hearing your opinion. I am a little torn on the decision and tend to agree with your assessment on EH tubes in general (and especially your assessment on the varying quality of current production tubes). The other option I have considered is getting some New Sensor Gold Lions (which I am running in an old !blasphemy! 100s head and am quite happy with there), but I don't have a good source for them and would likely spend twice what the sextet of EH will cost from CE distribution. It's all hearsay, but I have read some pretty good things about the EH KT88s specifically w.r.t. bass performance, so given the the price differential and inherent uncertainty around QA, at this stage I am willing to take a punt on them. A third option are the winged-C KT88s but they are around the same price as the gold lions and I personally have no experience with them, so have discounted them at this stage. Would definitely be interested to hear if anyone's had good or bad experiences with any of those tubes here, or even better, had the opportunity to compare them in a DR201 or 405.
Anyway, I tend to ramble, so will stop for now and just say thanks again for your input and display of enthusiasm surrounding this project. I am keen to contribute to the forum in return so please send any questions/queries/requests regarding the amp my way and I will endeavour to answer them once we get stuck into things. As Emil mentioned, it'll take us a few weeks yet to get everything in order, but we will get there soon enough I hope.
I prefer JJ KT88s in mine. They are in my 1978 DR405.
I have a set of Valve Arts KT88's in my '72 DR405 and they make noise as the mica seems to hang up on the glass. I guess the precision is not there with them. Besides the mentioned noise, they sound very good.
I may try the Gold Lions some day, but I am quite content with the JJ's.
I haven't tried the EH kt88's but their 12ax7 and EL34's have scared me away from any EH valve.
Dr.HIWATT wrote:I prefer JJ KT88s in mine. They are in my 1978 DR405.
So the plot thickens... I can't say that I've been thrilled with any JJs that I've tried thus far, with the noted exception of the KT66s that live in a friend's tweed-ish bassman replica. Admittedly, the KT88 is not amongst those that I have any experience with though. Thanks for your input!
synthi wrote:Admittedly, the KT88 is not amongst those that I have any experience with though.
I'm running JJ KT88's in my DR201. Pulled the GEC's and set them aside for special occasions. Have had some issues with JJ's recently but the KT88's are still in favor. Maybe they get a more advanced production line?
I had not been EH's biggest fan, but inherited pairs of their 6L6's and 5881's in a couple of "F" amps I bought. I have to admit, they sound good there. Still not in love with their 12AX7/ECC83 tubes, but would give their KT88's a try.
I recall placing the road-case with the amp inside on the bathroom scales once. I'm pretty sure it was 42kg (~92lbs). Will check and report back once I get it out. Suffice it to say, it's really uncomfortable for one person to lift.
Dr.HIWATT wrote:one of mine in a road case weighs 119 lbs.
Mine's in the spare room upstairs and I could not carry it downstairs by myself...
In other news, I think I've decided to spring the extra cash and go for the Winged-C KT88s. Following the replies here, I was giving very serious thought to the JJs but in the end decided not to quibble over what amounts to a good feed and a few pints at the local.
Here is a link to a thread where I documented the restoration of my 1973 DR405. viewtopic.php?f=2&t=977
I replaced all of the screen resistors with sturdy metal oxide 1000 kΩ resistors from VHR.
I have been very happy with the New Sensor Gold Lion KT88 tubes. After two years of being driven hard, those tubes are still sounding great. I use my DR405 almost every day. I think Winged C =C= tubes are a good option too.
My DR405 weighs about 85 lbs in the head box, no case.
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