Low-plate Skyline

[ijedouglas]

It’s a beauty for sure, Ian! ‘80’s time capsule, and HAD construction technique showcase.

Question, have you measured capacitance/ft on those old coax types? Is the type number known?

Thanks Martin.

I haven't tested the capacitance yet but it is Columbia C-1116. HAD used Columbia C-1112 in some of his amps.

[ijedouglas]

Looks fantastic! I bet it sounds just as awesome too!
What type of speakers are you going to pair it with?
Matt J.

Thanks Matt. I have a 2x12 with EV-12Ss in it.

[didit]

It’s a beauty for sure, Ian! ‘80’s time capsule, and HAD construction technique showcase.

Question, have you measured capacitance/ft on those old coax types? Is the type number known?

Thanks Martin.

I haven't tested the capacitance yet but it is Columbia C-1116. HAD used Columbia C-1112 in some of his amps.

Astoundingly detailed work Ian.

That’s RG58 coax I believe. Should be marked.

Best .. Ian

[ijedouglas]

It’s a beauty for sure, Ian! ‘80’s time capsule, and HAD construction technique showcase.

Question, have you measured capacitance/ft on those old coax types? Is the type number known?

Thanks Martin.

I haven't tested the capacitance yet but it is Columbia C-1116. HAD used Columbia C-1112 in some of his amps.

Astoundingly detailed work Ian.

That’s RG58 coax I believe. Should be marked.

Best .. Ian

Thanks Ian. It is marked but not the capacitance.

[martin manning]

it is Columbia C-1116. HAD used Columbia C-1112 in some of his amps.

So RG58 and 59, nominally ~25 pF/ft.

[jazzbass]

hi everyone,

can someone please explain to me what is the difference between Low-Plate and High-Plate, Classic and Skyline? until now I thought that Low-Plate meant 100K resistors on the Plates of V1 and V2 (like in this amplifier) ​​while for High-Plate the same resistors were 220K and 150K.
I would like to finally understand the meaning of these terms, thanks for your help.

Franco

[ijedouglas]

hi everyone,

can someone please explain to me what is the difference between Low-Plate and High-Plate, Classic and Skyline? until now I thought that Low-Plate meant 100K resistors on the Plates of V1 and V2 (like in this amplifier) ​​while for High-Plate the same resistors were 220K and 150K.
I would like to finally understand the meaning of these terms, thanks for your help.

Franco

Hi Franco,

You are correct. Low-plate typically means 100K plate resistors and high-plate 220K and 150K. I have also seen 180K and 120K. Classic and Skyline are the tonestack configurations and are typically differentiated on the front panel by "Deep" (classic) or "Mid" (skyline) although this is not always the case as in some scenarios the "Deep" switch was updated to a Skyline "mid" switch but the chassis label remained (see #0124) Internally the the skyline tonestack has a 0.01 mid cap, 0.002 treble cap, a 390pf on the mid switch and a 0.005 over the bass pot. The pot values for the mid is 250K and the bass is 500K. For the classic stack you have a 0.05 mid cap, 270pf-330pf treble cap and a 0.01 cap on the deep switch. The pot values for the mid is 100K and bass is 250K. There are some variations to this but you can see the differences if you take a look at #0124 in its current Skyline state and what it may have been before its conversion from a classic tonestack. I hope this helps?

[jazzbass]

dear ijedouglas,

thank you.

Franco

[ijedouglas]

Cab finished, pretty pleased I didn't lose a finger

PXL_20250212_232941428.jpg

PXL_20250212_233001775.jpg

[mikeram]

Looks really good. Is that really a 3 amp fuse in there?

Mike

[ijedouglas]

Looks really good. Is that really a 3 amp fuse in there?

Mike

Yup, 6L6 with Twin iron had a 3 amp. The EL-34s had a 5 amp

[ayan]

Cab finished, pretty pleased I didn't lose a finger

PXL_20250212_232941428.jpg

PXL_20250212_233001775.jpg

Brilliant, Ian! Let me know when it's a good time to come round and pick it up.

[ijedouglas]

Cab finished, pretty pleased I didn't lose a finger

PXL_20250212_232941428.jpg

PXL_20250212_233001775.jpg

Brilliant, Ian! Let me know when it's a good time to come round and pick it up.

You know where I live

[mikeram]

I'm guessing that you have been able to turn it up by now. Any update on how it sounds?

Mike

[ijedouglas]

I'm guessing that you have been able to turn it up by now. Any update on how it sounds?

Mike

Hey Mike,

I have and it sounds really good. I had a friend over today with his Dumble ODS and Dumble 1x12 (and a Dumble-modded Marshall) and we were able to pretty much dial in the exact same tones. I am not sure what circuit is in the Dumble but I'm guessing a low-plate skyline similar to this one. The amps sounded really similar although mine was a little brighter and had lots more gain on tap. It didn't hurt that we were playing through his 'burst either