NAME THAT VINTAGE AMPEG

[t7mackie]

Alright guys, what is this thing?

Got this in an amp lot. The seller said he thought it was a Rocket. I've modestly scoured the internet and I just can't find anything that matches it. The tube chart says it's a, "MODEL 6015" for which I could find nothing. The closest match is a late 50's M-12 Mercury but from what I've seen Mercurys have only one chassis and four input jacks. This has two input jacks, a footswitch jack, and an, "ULTRA HIGH" knob. I have yet to see a photo of an amp with the same grill cloth and silk screened logo as this example never mind the previously mentioned input section.

Unfortunately it appears someone unceremoniously cut the bottom chassis out which held the transformers and the power section. The seller said he's going to check his basement to see if he can find it but I'm not holding my breath. Worst case scenario I could scratch build the lower chassis but I feel this amp deserves to be made whole again with original stuff. Plus, without having a proper schematic - not even knowing what the heck this is - I'm at a loss.

Help me Obi Wan, you're my only hope!!

[t7mackie]

I was able to find this short video that appears to be the amp. Not much help though...

https://www.youtube.com/watch?v=2V1X7Cns0fw

[xtian]

Why, it is a 6015! I can even guess the serial number.

Kidding aside, there are very few Google hits for "Ampeg 6015". Look very cool. Is it playing?

[t7mackie]

It's got half the chassis so, no, it's definitely not playing anytime soon.

The youtube video comment says it's a Dolphin and I think that's it. Now I gotta find a bottom chassis for this that won't cost a small fortune...

Here's a Reverb ad for one that looks the bill:

https://reverb.com/item/7079371-ampeg-d ... blue-black

[sluckey]

I think this is the preamp schematic...

https://el34world.com/charts/Schematics ... olphin.pdf

[thetragichero]

not so much the guts but the cabinet looks very "sano" to me. interesting!

[Phil_S]

I don't know if this will help with respect to the lower chassis (power amp.) I believe Ampeg was at the Woodside, NY location until 1962, when it moved to Linden, NJ. It was first the Ampeg Bass Amp Company, with the name changed to the Ampeg Company in 1956. This makes the possible years of production from 1956-1962. You have a model 6015, a/k/a Dolphin II, which was made from 1956-1959 or maybe into 1960. So, you are looking for a very old schematic. You may need to find another of this amp to obtain the information you are seeking. If that doesn't happen, you might consider building something that is "good enough."

There were three later models that used 6SL7-6SL7-6V6-6V6-5Y3 configuration. These were R-12 Rocket, J12B Jet, and M-12. Schematics are available for all of these. The power amp sections of these amps are all very similar...nearly identical from what I can see at a glance. My thinking is that the 6V6/5Y3 sections are likely to be just right along with the transformers (if you can identify them.) I suggest the 6SL7 is the 5751 (12AX7-ish) of octal tubes and the 6SN7 is nearly identical to the 12AU7. If you can't find a schematic, you might consider building one of these, modifying the circuit for components that are better suited to the 6SN7, or 12AU7. Check the tube sheets for 6SN7 and 12AU7 and I think you'll see there's virtually no difference, so you can use either one.

Mercury Magnetics sells transformers for the Jet with a pair of EL84's. Those should work equally well with 6V6's. Regrettably, these will probably cost nearly $400 for the pair.

I have a feeling this post is disappointing, but there you have it, FWIW. Good luck.

[thetragichero]

^^^^^ that post has a lot of good information, don't sell yourself short

[Stevem]

That’s also the schematic i found for it on my Groovetubes book on page 313,

So it looks like if it’s two channel it’s called a model Duette, if it’s single channel is a model Dolphin II.

Power supply and output stage wise it likely uses the section from the 1962 model R-12, or M-18.
Actually now that I think about the M-18 is more likely since the R-12 was made in Linden NJ and those two models where made in NY.

[Stevem]

After snooping around more I am 100% wrong with what I posted.
The Duette model had a 15” speaker and used a 5U4 recto and El-37 output tubes.

The Duette and Dolphin models where both part of what was the Guitatamp line which was silk screened on some control panels, and yes spelled out as Guitaramp!

This line of amps first appeared in 1957.

[t7mackie]

Thanks everyone for the help - awesome suggestions & info!

I reached out to Ampeg and they were great. Per the serial number it's a 1958 Dolphin II model 6015. They said the schematics / wiring in those days were, "wily-nilly" so, "good luck!" They forwarded a couple of links:

https://www.bluebookofguitarvalues.com/ ... AMP_MODELS

https://leightonamplifiers.blogspot.com ... ecial.html



I still have my fingers crossed the seller comes up with the lower chassis. If not, what would be proper transformers - period correct or modern equivalent? I started to do a little research and it looked like it was gonna be a challenge just to figure that out.

[Stevem]

It's no challenge at all!
The power and output transformer that you want to build with are from a R12R model.

These can both be had from The fliptops site for a total of like 200 bucks.

The only difference is that the PT for the R12R model is not a stand up type like the original, I guess you can add L brackets if you do not want to take the time to jig saw out a square transformer bell hole in your chassis.

You will also need a Amphenol Octal male plug which can be had from tubes and more / AES.

A Hammond 272DX PT would be a good choice also!