My 1970 SAP DR103 #749

Maxwedge413 · Post by **Maxwedge413** » Wed Jan 23, 2008 4:31 am

It's finally alive....

Replaced some bad coax, fixed some pretty bad butchery of input wiring and power tube sockets, and cleaned up a river of rust. Also installed two proper short-bat Arrow mains/standby switches, a gen-u-ine Bulgin pilot lamp. The IEC mains connector was there when I got it - it stays for now.

Circuit looks alot like the other posted Jimmy Page Hiwatt (DIY), and other SAP amps seen, except has the V2 tube setup with a cathode follower like V1. I've seen pix of one DR201SAP that was also wired this way - same era.

The input jacks are wired exactly as the Page DIY amp and the SAP schematic on Mark H's website. The Hi gain input goes straight in and bypasses the 68Ks - like a 2 holer or a CP103. From the tone stack on it's pretty much standard 1970 DR103.

The 1K 5W resistors on the power tubes are a concession to late model tube - it helped a lot.

I thought it needed a cap job, now I don't think so.

Has a TON of gain - way more than my 1969 DR201 or 77 DR505. I think only the OL103 would out drive it.

Balance control is super cool - can give a big volume and drive boost.

I still have to fix the case, which literally fell apart. The thin HIWATT badge is intact thankfully.

[image links broken 8-2015]

Post by **OldSchoolDave** » Wed Jan 23, 2008 12:28 pm

Cool amp, Max! I'd love to hear it.

Is it the photo or are those pots the smaller diameter versions? From my limited experience, the larger diameter pots were typically used until the mid-late '70s.

Do you have any history on this SAP or did it just arrive, orphaned, on your doorstep?

Dave

Dr.HI-TONE · Post by **Dr.HI-TONE** » Wed Jan 23, 2008 12:46 pm

Very Nice! Great work Max!

Those pots are made by dubilier. I wasn't sure who made that type. I will buy you a beer if you bring that beauty to the Convention in June! I would love to hear it too!

Dr.HI-TONE · Post by **Dr.HI-TONE** » Wed Jan 23, 2008 1:57 pm

OldSchoolDave wrote:Cool amp, Max! I'd love to hear it.

Is it the photo or are those pots the smaller diameter versions? From my limited experience, the larger diameter pots were typically used until the mid-late '70s.

Do you have any history on this SAP or did it just arrive, orphaned, on your doorstep?

Dave

Those are the same type of pots used in my late '60-early'70's HIWATTs.

I have seen '72 and later amps with the larger RS pots.

-CC

Post by **OldSchoolDave** » Wed Jan 23, 2008 2:27 pm

Dr.HIWATT wrote:Those are the same type of pots used in my late '60-early'70's HIWATTs.

I have seen '72 and later amps with the larger RS pots.

Ahhhhh, so, they started with smaller diameter Dubilier pots, moved to the larger RS ones for awhile and then changed back to smaller ones?

Learn something new every day

!

Dave

Dr.HI-TONE · Post by **Dr.HI-TONE** » Wed Jan 23, 2008 2:31 pm

I am pretty sure that the smaller ones circa '76 and later are Ohmite pots.

I am dealing with some serious remorse seeing this beautiful amp! I wish I hadn't got cold feet during the auction!

Maxwedge413 · Post by **Maxwedge413** » Wed Jan 23, 2008 2:36 pm

Dr! So you do remember this one.

Yes the auction looked a little dodgey, especially when some other guy pirated the picture for another scam auction - while I was waiting delivery of it - thought I'd never see it for awhile.

It came out of Scotland - it smelled like only a Scottish basement can..

I have a little history on it somewhere - only recent stuff - I had the name the band it was associated with on the 80's (I'll dig it up).

I'd really like to know who it was built for - The serial number is right around one of Page's (#618) and some of Townsends CP103s (#-715, 742, #852, #892). There are also at least two SAP DR201's (#674, #755). Lots of cool things happening at that time.

Of course, if you add up the numbers, there were quite a few amps built in that period, so many were probably church PAs and amps built for nobody with a name - which is OK - I've definitely got something as good as they came.

Yes - the pots are Dubilier - I posted something on that on the Plexi site.

All my heads have them - they are all early.

I've seen pics of the Hylight built Sound City 100 (DR114) that has the same pots.

The pots are hard to find - I am missing one on my 200, but I am expecting a small shipment of them shortly.

I've vever has an amp with RS pots, so I'd guess they are used somewhere between 1971 and 1976, when they went to the tiny Ohmite pots.

Wrung it out last night - My ears are still ringing.

Dr.HI-TONE · Post by **Dr.HI-TONE** » Wed Jan 23, 2008 3:03 pm

A large percentage of the amps built in New Malden were custom builds for Artists. It was Dave, Daphne and Doug Fentiman building the amps and they could only produce a limited number.

I am glad to see that you have got "her" running like a champion again!

You may have to share some of you sourcing secrets for NOS pots etc..!

Maxwedge413 · Post by **Maxwedge413** » Wed Jan 23, 2008 3:39 pm

Ah, if only it could talk...when I'm awake.

I source parts the same way you all do - eBay and the web.

I fact, I think we've battled over a few amps and bits - I'm sure we've driven the price up for each other a few times.

The Dubilier pots can sometimes be found as "DCC pots", as the body is ink stamped DCC. They are marked "Dubilier" in small print on the front face in the bakelite.

I get a kick out of these early amps - pot shafts roughly cut off with a hacksaw, potentiometer holes in the chassis ovaled out with a file to fit the faceplates that were probably came in a little off - all original, but very much testament to a handbuilt, garage operation it was then.

My 103 and 201 both have this kind of thing in them.

The circuits are also both different to what has been published (Mark's site included), so I'd bet that the electrical design was evolving rapidly at the time too.

Clay - I'd bet that your non-master volume 103 (that you skunked me on! - no offense taken..) is a bit different electrically from the classic 1973ish DR103. Probably 8+8uF filter caps on the front instead of 16+32uF etc..

Dr.HI-TONE · Post by **Dr.HI-TONE** » Wed Jan 23, 2008 8:31 pm

Maxwedge413 wrote:Ah, if only it could talk...when I'm awake.

I fact, I think we've battled over a few amps and bits - I'm sure we've driven the price up for each other a few times.

Clay - I'd bet that your non-master volume 103 (that you skunked me on! - no offense taken..) is a bit different electrically from the classic 1973ish DR103. Probably 8+8uF filter caps on the front instead of 16+32uF etc..

I hear you! I would love to know who owned them and where they have been.

Yes, I think we have been after the same item a couple of times..

Aren't these old HIWATTs Great!

I think #420 has an 8uf + 32uf cap, but I can't remember for sure. I do think it was an odd value! ( the seller offered me a BIN that I could pass up!)

Maxwedge413 · Post by **Maxwedge413** » Wed Jan 23, 2008 9:07 pm

( the seller offered me a BIN that I could pass up!)

No harm, no foul.

The case on that amp was differnt too - the vents seemed different.

Oh, the oldies are great - I still want a DR508....I'll trade a 509 for it!!

Funny thing tho' - the 73 4 holer is the classic one, right?

It seems that Page, Townsend and Gilmour all found the standard fare to be wanting in some way...

Dr.HI-TONE · Post by **Dr.HI-TONE** » Wed Jan 23, 2008 9:24 pm

It does seem that way, but Page and Townshend used amps that pre-date the "classic" 4 input DR series amps. Their amps were like links in the evolutionary chain that some would argue peaked with the 4 input DR's of the mid 1970's.

Gilmour's were the classic 4 input DR504 and DR103's with the jacks internally linked.

I think the mid 1970's DR amps are the most flexible tonally, but I am really excited about possibly building an SAP.

Hiwatt Bob · Post by **Hiwatt Bob** » Thu Jan 24, 2008 1:42 am

very cool!

i'm quite envious of you bastards with your old hiwatts...but i suppose i should probably count my blessings and be happy with my '72 DR504.

Dr.HI-TONE · Post by **Dr.HI-TONE** » Thu Jan 24, 2008 2:07 pm

Hiwatt Bob wrote:very cool!

i'm quite envious of you bastards with your old hiwatts...but i suppose i should probably count my blessings and be happy with my '72 DR504.

Absolutely! That is a great DR504! I would take it in a heartbeat!

Maxwedge413 · Post by **Maxwedge413** » Thu Jan 24, 2008 2:45 pm

I'd have to agree that your 72 4-holer probably represents the amp that the breed is most significant for.

It's the desert island amp for sure -

I've tried to collect some of the "best of the breed" for several amp makes/eras,

ie;
Magnatone 280
Ampeg Super Echo twin
AB763 style Fender
Fender Super Champ

wanted;
Marshall 1959 Super Lead
Orange OR120
Laney Supergroup
Traynor YBA-1
Garnet Sessionman
National Glenwood 80
Supro Big Star
Fender Tweed Deluxe

Like those, the 4 hole Hiwatt is the "definitive" Hiwatt.

But hell, one of the 'watts at the top of my list to get is a Biacrown Lead 100! What do I know...