Which capacitors should I order for a 1978 OR-80?

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Delicieuxz
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Which capacitors should I order for a 1978 OR-80?

Post by Delicieuxz » Sat Dec 15, 2018 7:56 am

I want to bring my my 1978 OR-80 to a tech for a recap, but I want to first order the caps myself to make sure they're the right values and a good brand (probably F&T). I'm not sure what values of caps I should be ordering for it, though. Is there a list of all the caps that I should be replacing?


Here's a 1976 OR-80 combo amp that had its caps replaced. Would they be the same ones I need to replace in my 19787 OR-80 head?

https://reverb.com/ca/item/2423945-oran ... 1976-model

They say they only replaced 4 caps, while in this thread:

https://www.thegearpage.net/board/index ... e.1887500/

It looks like the OR-80 has 7 to replace on the inside of the chassis, and then another 2 on the outside.

Does anyone know a definitive list of the caps to replace?

Les Paul Lover
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Re: Which capacitors should I order for a 1978 OR-80?

Post by Les Paul Lover » Sat Dec 15, 2018 4:51 pm

There isn't a definitive list..... because OR80/120 Have varied quite a bit throughout the 70s.

The best thing would be to open yours up, and (if it is original in terms of circuit - something which you may or may not know) hopefully you can still read the capacitors value on them and order like for like.

Obviously, voltages inside your amp could kill you, even when switched off..... so be careful and read up on safety precautions and cap discharge.
Ant

Orange Gear: RV50 MKI, R30, AD15, AD5, PPC212
Past Orange: Orange AD30TC Combo, Tiny Terror

Guitars: Gibson Les Paul Standard Faded, Vigier Expert Retro 54, Gibson SG 70s Tribute, Aria Pro II RS X80, G&L ASAT Special Tribute

bclaire
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Re: Which capacitors should I order for a 1978 OR-80?

Post by bclaire » Sat Dec 15, 2018 6:40 pm

I would think a good tech would work with you to order what you want - and they would be better at seeing what you need overall.

Delicieuxz
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Re: Which capacitors should I order for a 1978 OR-80?

Post by Delicieuxz » Sun Dec 16, 2018 5:05 am

I opened up my 1978 OR-80 OD and made a list of the capacitors.

Outside of the chassis:

2x 100 uf 450 VDC

Inside of the chassis

2x 32uf 450 VDC
2x 10uf 160v
2x 47N 1KV
2x 47uf 25 WVDC
2x 15uf 450V


Here are pics:

Image

Image


The layout and number of caps in my amp is slightly different than this OR-80 that looks like it's also an OD version:

Image


From the caps that I can read in that picture, my amp is practically identical in values:

32uf 450V - same as my amp.
2x 16uf 450V - instead of 2x 15uf 450V in my amp.
10uf 100v - instead of 2x 10uf 160v.

These are the caps in my amp that I can't compare to the other pictured OR-80:

2x 47uf 25 WVDC (coloured gold in my amp) - there are 2 grey caps in the other OR-80 that are likely these same caps, but I can't see the value on them in the other OR-80.
2x 47N 1KV - these are the large yellow ones in my amp. There is only one of them in the other OR-80, and it's smaller. I can't tell what value it is in the other OR-80.


Now, in this 1976 OR-80 combo amp that had 4 of its caps replaced, the caps listed as being replaced are 2x 100 uf 450v replaced with 100uf 500 V, and 2x 15uf 450v replaced with 33uf 450V.

Will replacing those 15uf caps with 33uf caps make a noticeable difference in the sound? That looks like a pretty large increase in value. If I can't find the exact uf value for other caps, should I replace them with a larger uf value?

Les Paul Lover
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Re: Which capacitors should I order for a 1978 OR-80?

Post by Les Paul Lover » Sun Dec 16, 2018 10:18 am

To my untrained eye, your amp looks unmolested - but some other forum members know a lot more than I do (I don't own this amp) and have refurbished repaired a number if them, so I would wait for them to chime in.

I'm surprised to see radiospares (rs) branded caps and resistors, but it doesn't mean they aren't original to the amp.

Try and Google the Orange amp field guide. One of our forum member has dedicated a lot of time to get this web site going, and has lots of schematics in it that should verify original values for you.

At the moment i would say.... if you like the way your amp sounds, and it hasn't given you any problems, simply replace like for like. I can increase the voltage tolerance of the caps without issue (never reduce it though!) But respect the capacitance.
Ant

Orange Gear: RV50 MKI, R30, AD15, AD5, PPC212
Past Orange: Orange AD30TC Combo, Tiny Terror

Guitars: Gibson Les Paul Standard Faded, Vigier Expert Retro 54, Gibson SG 70s Tribute, Aria Pro II RS X80, G&L ASAT Special Tribute

LD50
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Re: Which capacitors should I order for a 1978 OR-80?

Post by LD50 » Sat Dec 22, 2018 11:27 am

The 100uF mains cans can be 450v or 500v, they are wired in series for mains so even the 450v handle 900v with wriggle room.

The 32uF screens cans can be 32 or 33uF and similarly are in series so 350v will suffice (rated at 700v combined)

I like to go 10uF 200v for the bias caps as they are a little larger physically so fit better in old amps spaces.

The pre-amp cans affect the feel of the amp and 32/33 can be a bit stiffer and if you go from tired 15/16uF cans to 33 you may not like it.

Last one I recapped I used F&Ts:
https://www.tubeampdoctor.com/en/shop_C ... 5x50mm_500 (wire the two +ve terminals together for 100uF)
https://www.tubeampdoctor.com/en/shop_C ... _105_C_513
https://www.ebay.co.uk/itm/1pcs-BC-PHIL ... :rk:4:pf:0

fiveightandten
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Re: Which capacitors should I order for a 1978 OR-80?

Post by fiveightandten » Thu Dec 27, 2018 4:06 pm

Delicieuxz wrote:
Sun Dec 16, 2018 5:05 am
I opened up my 1978 OR-80 OD and made a list of the capacitors.

Outside of the chassis:

2x 100 uf 450 VDC

Inside of the chassis

2x 32uf 450 VDC
2x 10uf 160v
2x 47N 1KV
2x 47uf 25 WVDC
2x 15uf 450V


Here are pics:

Image

Image


The layout and number of caps in my amp is slightly different than this OR-80 that looks like it's also an OD version:

Image


From the caps that I can read in that picture, my amp is practically identical in values:

32uf 450V - same as my amp.
2x 16uf 450V - instead of 2x 15uf 450V in my amp.
10uf 100v - instead of 2x 10uf 160v.

These are the caps in my amp that I can't compare to the other pictured OR-80:

2x 47uf 25 WVDC (coloured gold in my amp) - there are 2 grey caps in the other OR-80 that are likely these same caps, but I can't see the value on them in the other OR-80.
2x 47N 1KV - these are the large yellow ones in my amp. There is only one of them in the other OR-80, and it's smaller. I can't tell what value it is in the other OR-80.


Now, in this 1976 OR-80 combo amp that had 4 of its caps replaced, the caps listed as being replaced are 2x 100 uf 450v replaced with 100uf 500 V, and 2x 15uf 450v replaced with 33uf 450V.

Will replacing those 15uf caps with 33uf caps make a noticeable difference in the sound? That looks like a pretty large increase in value. If I can't find the exact uf value for other caps, should I replace them with a larger uf value?
The 47n are phase inverter coupling caps, and not electrolytics in the B+ rail. They look to have been replaced, and were likely 68n (.068 mfd) WIMA caps from the factory. The 47n value shaves a little low end off in comparison. Some of the tone stack caps look to have been replaced as well, but I can't see the values printed on them.

For the electrolytics, I like to use Sprague Atoms for all the axial lead ones on the PCB. F&T are good for the 100 mfd can caps mounted on the chassis, or JJ are fine for those as well.

Some of the earlier PCB's have small holes in them which aren't big enough to accept the thick leads on some modern electrolytics. I had to VERY carefully use a small drill bit to widen the holes in the PCB on my '71 head. This needs to be done at high speed with very minimal downward pressure. The bit has to do the work. You don't want to put downward force on the traces and wind up separating them from the wafer board.

Just FYI, as something to look out for.

-Nick
Image
'71 GRO100 || '96 OR-80 || AD30 || '64 AC-50 || AC-30TBX || Hiwatt DR504 || HI-TONE HT30
LP Standard || LP Studio || LP Custom Lite || Ric 620 || Ric 360 || MIA Tele || SG 61 RI

Delicieuxz
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Joined: Sat Dec 09, 2017 5:21 am

Re: Which capacitors should I order for a 1978 OR-80?

Post by Delicieuxz » Fri May 24, 2019 1:44 am

fiveightandten wrote:
Thu Dec 27, 2018 4:06 pm
The 47n are phase inverter coupling caps, and not electrolytics in the B+ rail. They look to have been replaced, and were likely 68n (.068 mfd) WIMA caps from the factory. The 47n value shaves a little low end off in comparison. Some of the tone stack caps look to have been replaced as well, but I can't see the values printed on them.

For the electrolytics, I like to use Sprague Atoms for all the axial lead ones on the PCB. F&T are good for the 100 mfd can caps mounted on the chassis, or JJ are fine for those as well.

Some of the earlier PCB's have small holes in them which aren't big enough to accept the thick leads on some modern electrolytics. I had to VERY carefully use a small drill bit to widen the holes in the PCB on my '71 head. This needs to be done at high speed with very minimal downward pressure. The bit has to do the work. You don't want to put downward force on the traces and wind up separating them from the wafer board.

Just FYI, as something to look out for.

-Nick

Hi Nick. I just caught your reply. That's some great information there, thanks for sharing it!

LD50
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Re: Which capacitors should I order for a 1978 OR-80?

Post by LD50 » Tue May 28, 2019 5:04 pm

:D

bclaire
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Re: Which capacitors should I order for a 1978 OR-80?

Post by bclaire » Tue May 28, 2019 11:33 pm

For the record, if you've never done any electronic repair before you should know that the voltages stored in caps can send you flying across the room and what you land on could kill you.

Again: could kill you.

My personal advice is, take it to an amp tech and let them decide what may or may not need to be replaced. Don't mess around with the amp if you don't know what you're doing, and if you might inadvertently change things that don't need to be changed.

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