No affiliation nor interest, but interested to hear the experts' opinions here. I have my reservations; interested to see how keen my eye may or may not be. Thanks in advance
1969 1987 on Reverb
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playloud
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First off, it's definitely not a 1987. Looks like a 1985 (4-input PA model).
Choke and impedance selector have been replaced for later type. 3 pots have also been replaced. Whoever has worked on this amp was very sloppy. There are insulation burn marks galore. They've also used red dye (a brighter shade) to create the appearance of originality where changes have been made - another red flag in itself. The PT primary side wiring is a mess. A cathode bypass cap has been installed on V2A.
At that ridiculous asking price, I would take the advice of the Velvet Underground and 'run, run, run'.
Choke and impedance selector have been replaced for later type. 3 pots have also been replaced. Whoever has worked on this amp was very sloppy. There are insulation burn marks galore. They've also used red dye (a brighter shade) to create the appearance of originality where changes have been made - another red flag in itself. The PT primary side wiring is a mess. A cathode bypass cap has been installed on V2A.
At that ridiculous asking price, I would take the advice of the Velvet Underground and 'run, run, run'.
I agree that it looks to be a modded Model 1985PA.
I think choke could be original (those frame type can be seen 69on). Obviously the V2a bypass cap added. The pi plate cap replaced. Interesting to see 220pF mica in tone stack (vs 256 or 250 more usual).
Is the OT original or just the wiring loom clumsily untwisted?
Didn’t clock the price but £3-3.5k would be typical in U.K. (going to look after I’ve posted this!)
I think choke could be original (those frame type can be seen 69on). Obviously the V2a bypass cap added. The pi plate cap replaced. Interesting to see 220pF mica in tone stack (vs 256 or 250 more usual).
Is the OT original or just the wiring loom clumsily untwisted?
Didn’t clock the price but £3-3.5k would be typical in U.K. (going to look after I’ve posted this!)
Typically you don't see that style choke until later in 1969. Since you don't see a residual outline on the chassis for the usual U-frame choke I would guess that the choke was replaced very early on (perhaps 1970), or else it could be original to the amp.
If my memory serves me correctly, there was a discussion regarding the odd 1 Meg pots, and it was determined that they are original...Other examples were presented.
If my memory serves me correctly, there was a discussion regarding the odd 1 Meg pots, and it was determined that they are original...Other examples were presented.
Ned B
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I used to own 10828 which was a 1987, test dated May 14, Job 35. This one appears to be April 25th and Job 13. Mine had the window selectors. This is a period when anodized and plexi panels were used concurrently. That choke never appeared stock before December 1969 from the amps I have seen.
Amp #10823 does not have a Job Number...What your misreading is actually "Tag B Kath" which means Kath (Kathrine, Katherine, Kathryn) installed the Tag Board.
Did a quick check on other 50w amps to see if I could find more examples that use the odd 1 Meg pots and came up with the following:
S/A10347 19/4/69 PA; Model 1985.
S/A10519 18/4/69 PA; Model 1985.
S/A10530 18/4/69 BASS; Model 1986.
S/A10347 19/4/69 PA; Model 1985.
S/A10519 18/4/69 PA; Model 1985.
S/A10530 18/4/69 BASS; Model 1986.
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Hello all. This is my amp listed for sale. I was pointed to this thread via a member of another forum that I frequent. Prior to listing for sale, I was trying to reach out to a forum member there for originality verification, which didn't occur, and since I needed to list it for sale I went ahead and did so with what knowledge I had. I did know of a few non original items, which I listed, but was not 100% sure of everything else, hence my request in the listing to reach out if anyone could offer pointers if anything seemed off. I had it listed as a 1987 because that's what it was sold to me as. Soon after I listed, I was contacted by someone pointing out that the amp has a few features which would point to it being a 1986 model, so I took them at their word and changed the listing with this updated information. Not long after, I was contacted by another person stating that this looks to actually be a 1985 PA model with a few glaring changes. I have since been in discussion with this person and we are putting our heads together to iron things out so that it can be appropriately described. Some things we have discussed are the impedance selector, the tropical fish cap, the choke, the desoldered OT and the pots. My opinion: the impedance selector and pots are original to the amp. The tropical fish cap has been added. The choke is a slightly later, legit replacement. The OT...I don't know. Obviously looks original, but why desoldered? I welcome any and all feedback from the experts, as I am not trying to pass this off as anything other than what it actually is. I am no tech or expert, so I'm gladly learning and editing the listing as I go.
As for the price, I don't know what it's worth. All I know is what I paid for it. If it seems ridiculous to you, here's a hint...there's a button on the listing that says "Make An Offer." If someone was actually interested in buying the amp (no one has been), then they can make an offer on what they think it's worth. If you have an opinion, other than scoffing from the sidelines, feel free to post here what you think it's worth, or "Make An Offer" if you're interested.
As for the price, I don't know what it's worth. All I know is what I paid for it. If it seems ridiculous to you, here's a hint...there's a button on the listing that says "Make An Offer." If someone was actually interested in buying the amp (no one has been), then they can make an offer on what they think it's worth. If you have an opinion, other than scoffing from the sidelines, feel free to post here what you think it's worth, or "Make An Offer" if you're interested.
There's something odd about the OT secondary wires....Why is there an additional White and Brown wire? Why is the Green and Gray wires so thick? Although not very common, I have seen the Negative wire (Orange) as a sleeved self-lead wire rather than the typical "flying lead" PVC jacketed wire. The lamination stacking looks incorrect for the Drake 784-139. It looks like someone had the endbells off so I would hazard a guess that the OT is a replacement.
Other things I noticed, some of which have been mentioned already...
The H.T Fuse holder is a replacement.
Added "tropical fish" bypass cap on the cathode of V2a.
Added screen-grid resistors on octal sockets.
The bias adjustment network has been replaced.
The Impedance selector is original.
Thank you for your insight, it is much appreciated. If there are questions that can be answered with more pictures or better angles, please let me know and I will do my best to take them and upload them. The only thing I don't want to do is poke around inside in an unsafe way.
If you can post a photo of the top of the OT which shows the lamination interleaving it may help clarify things.
As far as I'm aware, the Drake 784-139 uses a 1 to 1 interleaving for the E-I laminates as shown here.
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![SA10807[g].jpg](/data/attachments/150/150082-bdf762e86184fac95accfacfaa035832.jpg)
On your OT the laminations are thinner, and they are in groups of three...Meaning there are three 'E' laminates and three 'I' laminates per layer making up the stack. The 784-139 was made with a thicker laminate and has only one 'E' and 'I' per layer. So, your OT is a different spec, and I would be inclined to believe that it is not a 784-139...
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Ok, and you are 100% sure of this fact? I just want to be completely sure of the issues with the amp before I go back and alter the listing with the correct information.
Well, all I can say is that I looked at approximately 200 other Drake 784-139 OT's and they're all the same. The lamination difference coupled with the secondary wire differences points to a different model OT. Neikeel or Ned B may be able to offer a second opinion.
Thank you. I am heavily inclined to trust this information since almost every sign seems to be pointing towards a replacement. I really appreciate the detailed information on this, it is very helpful.
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