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Sony C800g w/ a 7543 or non-Sony 6au6 tube? Effects Pedals, Units & Accessories
Old 13th November 2018
  #31
Here for the gear
Quote:
Originally Posted by Prince Vision View Post
Sony DEFINITELY still sells the replacement tubes for the C800G, I just purchased one for my C800G directly from sony's site about 2 months ago, and checking the site today they are still definitely in stock: Part Number 152525511

The exact tube that Sony uses is actually an obscure soviet 6AU6(A) variant, the 6J4P. Sony buys these in bulk (they are super cheap $1-5 a tube on ebay) and grades them for for noise specs or whatever, stamps "Sony" on them and marks up the price to $75 (actually as of 2017 it's $95 a tube).

This tube is partially what gives the C800G it's unique high end

If you want your C800G to sound like it's actually supposed to, I would only use the 6J4P, as normal 6AUA6's DO NOT sound the same in the C800G circuit. You will loose some high end and the microphone's character will change (in my opinion for the worse) I attempted to use multiple normal and premium NOS 6AU6A's in my C800g, and none of them sounded right.

PS: Sony's customer service is a mess, and is known for giving out bad/inconsistent info about items being discontinued, or saying something isnt available when it is. Anyone remember when the C800G was "discontinued" according to some customer service reps?

Also, changing the tube in the Sony is easy once once you do it for the first time, I would never send the mic off to Sony and wait weeks or months for them to charge a ridiculous amount to do a 10 minute job. $5 tube, 10 minute job at Sony = $400+
Guess what I found in my PSU..
Two American made 6AU6A.

Are these good?
I mean, should I change them with the Russian 6J4P or anything else?
I haven’t looked in my mic yet to see which one they used :/
Attached Thumbnails
Sony C800g w/ a 7543 or non-Sony 6au6 tube?-48c20ff2-fabc-4bf6-ba14-b3fdc5bb4c5f.jpg   Sony C800g w/ a 7543 or non-Sony 6au6 tube?-c6232a7e-3fb1-4acf-8c5b-ee2d6bbab31b.jpg   Sony C800g w/ a 7543 or non-Sony 6au6 tube?-d35b05e2-b899-4f39-9195-d1623dbd3069.jpg  
Old 14th November 2018
  #32
Lives for gear
 

Quote:
Originally Posted by Ripz View Post
... I mean, should I change them with the Russian 6J4P or anything else? I haven’t looked in my mic yet to see which one they used :/
How does the mic sound? Any "hiss"?
The PS ones aren't as "important" as the one inside the mic.
Old 14th November 2018
  #33
Here for the gear
Quote:
Originally Posted by aremos View Post
How does the mic sound? Any "hiss"?
The PS ones aren't as "important" as the one inside the mic.
The mic sounds great. But what do I know..
No hiss sound though, so the tubes are working properly.
I only had this one and never worked/listened to another Sony mic. So I have no comparison or experience with others.

What I mean is, I don’t know what it suppose to sound like. I’ve bought it second hand.
I obviously want the best, I can get out of the mic/psu, hence the possible tube change from American to Russian.

But has anybody experienced the tubes I’ve posted?
I think it says Gold Aero. Maybe someone knows if they’re better or worse than the 6J4P or 6AU6A.
Old 20th November 2018
  #34
Here for the gear
Quote:
Originally Posted by mals View Post
you still can buy Sony 6au6a tube here
1-525-255-11 Sony Vacuum Tube (6Au6a))
but price is not so good (IMHO)

or try to use tube 6J4P made in exUSSR (original cyrillic name: 6Ж4П)
6j4p tube | eBay
it full analog of 6au6 tube

but after changing tube, you will need to check and adjust voltages (please see service manual)
Hi mals.
How would I know if the tube I buy needs volt adjustment?
Could you elaborate, please?

Im thinking about getting the 6J4P from eBay.
I don’t see anything about voltage and I don’t know how many volts it suppose to be.
It is it the mic/psu that needs adjustment?
I’ve looked through the service manual and nothing caught my eye.
Attached Thumbnails
Sony C800g w/ a 7543 or non-Sony 6au6 tube?-d718a8af-47a1-400e-b057-10046a9981fb.jpeg   Sony C800g w/ a 7543 or non-Sony 6au6 tube?-6a0fc3e6-878f-425e-a73f-a266408e3b5c.jpg  

Last edited by Ripz; 20th November 2018 at 12:00 PM.. Reason: Added pics
Old 20th November 2018
  #35
Gear Maniac
please download
SONY AC-MC800G Service Manual download, schematics, eeprom, repair info for electronics experts

and see from page 2-1(E) (page №9 in PDF),
Section 2
Electrical Alignment

you not need Dummy Load, use connected microphone

and page 2-2(E)
--------------
In case of using C-800G
Caution: The following steps 1 and 2 should be executed
with power switch OFF.
1. Connect C-800G to MIC IN connector with Micro-
phone cable.
2. Connect digital voltmeter across R111/PS-295 board.
3. Turn the power switch ON.
Adjust after 40 minutes from turning the power switch
on.
4. Adjustment
Specification: dc voltage across R111 = 1.150 V dc
Adjusting point: 1RV101/PS-295 board
5. Check the specification on the item 4 is satisfied 10
minutes later.
When it is not satisfied, adjust again.
6. Confirm that the voltage between pin-3 and pin-4 of
connector CN108/PS-295 board, is in the range of
+4.0 V thorn +5.0 V dc.
7. Turn the power switch OFF.
--------------

AND REALLY: Adjust after 40

as I checked, only 30-40 minutes after turning on this voltage will be stable
Old 20th November 2018
  #36
Here for the gear
Quote:
Originally Posted by mals View Post
please download
SONY AC-MC800G Service Manual download, schematics, eeprom, repair info for electronics experts

and see from page 2-1(E) (page №9 in PDF),
Section 2
Electrical Alignment

you not need Dummy Load, use connected microphone

and page 2-2(E)
--------------
In case of using C-800G
Caution: The following steps 1 and 2 should be executed
with power switch OFF.
1. Connect C-800G to MIC IN connector with Micro-
phone cable.
2. Connect digital voltmeter across R111/PS-295 board.
3. Turn the power switch ON.
Adjust after 40 minutes from turning the power switch
on.
4. Adjustment
Specification: dc voltage across R111 = 1.150 V dc
Adjusting point: 1RV101/PS-295 board
5. Check the specification on the item 4 is satisfied 10
minutes later.
When it is not satisfied, adjust again.
6. Confirm that the voltage between pin-3 and pin-4 of
connector CN108/PS-295 board, is in the range of
+4.0 V thorn +5.0 V dc.
7. Turn the power switch OFF.
--------------

AND REALLY: Adjust after 40

as I checked, only 30-40 minutes after turning on this voltage will be stable
Awesome, thanks a lot MALS

It looks like I need an electrician to do this for me. But is it important and necessary, if I buy these from eBay:

6J4P 10pcs LOT (6AU6/EF94/6P2/CV2524)HF SOVIET PENTODE SOVIET TUBE UNUSED FONON | eBay

Or

8pcs 6J4P ( 6AU6 EF94 ) High-Frequency russian pentod tube ussr soviet tubes | eBay
Attached Thumbnails
Sony C800g w/ a 7543 or non-Sony 6au6 tube?-00f93ed6-5d6e-4c55-9139-25757cfdaf21.jpeg   Sony C800g w/ a 7543 or non-Sony 6au6 tube?-a1038528-8105-4811-b696-07ed2d35d2bb.jpg  

Last edited by Ripz; 20th November 2018 at 12:13 PM.. Reason: Added pics
Old 20th November 2018
  #37
Gear Maniac
as i see, both of these lots can be good
Old 21st November 2018
  #38
Gear Maniac
 
Prince Vision's Avatar
Quote:
Originally Posted by mals View Post
please download
SONY AC-MC800G Service Manual download, schematics, eeprom, repair info for electronics experts

and see from page 2-1(E) (page №9 in PDF),
Section 2
Electrical Alignment

you not need Dummy Load, use connected microphone

and page 2-2(E)
--------------
In case of using C-800G
Caution: The following steps 1 and 2 should be executed
with power switch OFF.
1. Connect C-800G to MIC IN connector with Micro-
phone cable.
2. Connect digital voltmeter across R111/PS-295 board.
3. Turn the power switch ON.
Adjust after 40 minutes from turning the power switch
on.
4. Adjustment
Specification: dc voltage across R111 = 1.150 V dc
Adjusting point: 1RV101/PS-295 board
5. Check the specification on the item 4 is satisfied 10
minutes later.
When it is not satisfied, adjust again.
6. Confirm that the voltage between pin-3 and pin-4 of
connector CN108/PS-295 board, is in the range of
+4.0 V thorn +5.0 V dc.
7. Turn the power switch OFF.
--------------

AND REALLY: Adjust after 40

as I checked, only 30-40 minutes after turning on this voltage will be stable
Thanks Mals for instructions on how to adjust the voltage after installing another tube. I always wondered how to do this.

But I have an issue: R111 is reading 4.3 V after warming up, I tried to reduce the voltage by turning the trim on RV101, but the lowest the voltage will go is 2.3. What kind of issue do you think this may be, and how would I go about solving this problem?
Old 21st November 2018
  #39
Gear Maniac
Sorry, I don’t know.
Maybe your AC-MC800G are set to 100v not 120v.
Check this voltage selector at the power supply near the power connector.
Old 25th January 2019
  #40
Lives for gear
 

Quote:
Originally Posted by afessel View Post
... I tried to order JUST the tube again from Sony- THEY WON"T SELL IT - they said I have to send in the Mic and emailed me an order form (see attached) - $135 diagnostic fee>??? the last time i bought the tube in 2017 it was $118, it's probably more now... And I can't even imagine the shipping cost ...[/COLOR]
Wow, that sounds very strange! I know their customer service is really BAD but for the last 25+ years they've never asked to send mic in or sent an order form.
In the last 2 years the tube went from $75. to $95. I believe.
There's another thread where I put the correct link to the Sony info per ordering C-800G tubes. Do a search & it should easily come up.
Calling them directly & ordering is the best way.
Old 19th March 2019
  #41
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I've been having this same problem for years... I've had 4 SONY C800G's since 1998 and they all 4 break down after a year or two. All of them. I used to send them to SONY, then I would buy the bulbs from SONY and change them myself, and now I buy them on ebay from Ukrainians or Russians by bulk and test them one by one to find the good ones. It's usually 1 or 2 in a pack of ten. The other ones are noisy (soft white noise) and usually have a low hum. Even the Waldorft ones aren't that good. I had 2 good ones out of 4. So a better ratio. I just checked again for SONY and they now sale them on amazon for $500!!!
What happens to us in 20 years?
Old 19th March 2019
  #42
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Another thought... would the low hum I get be because I'm not calibrating the voltage maybe?
Old 19th March 2019
  #43
Lives for gear
I purchased used a C800 (non-g). Used it for four years, then sold it. Never had to deal with the tubes.
Old 19th March 2019
  #44
Here for the gear
 

Quote:
Originally Posted by chezpaul View Post
I've been having this same problem for years... I've had 4 SONY C800G's since 1998 and they all 4 break down after a year or two. All of them. I used to send them to SONY, then I would buy the bulbs from SONY and change them myself, and now I buy them on ebay from Ukrainians or Russians by bulk and test them one by one to find the good ones. It's usually 1 or 2 in a pack of ten. The other ones are noisy (soft white noise) and usually have a low hum. Even the Waldorft ones aren't that good. I had 2 good ones out of 4. So a better ratio. I just checked again for SONY and they now sale them on amazon for $500!!!
What happens to us in 20 years?
I’ve been waiting for this post. thanks chezpaul. Well said
Old 19th March 2019
  #45
Lives for gear
 

Quote:
Originally Posted by chezpaul View Post
I've been having this same problem for years... I've had 4 SONY C800G's since 1998 and they all 4 break down after a year or two. All of them. I used to send them to SONY, then I would buy the bulbs from SONY and change them myself, and now I buy them on ebay from Ukrainians or Russians by bulk and test them one by one to find the good ones. It's usually 1 or 2 in a pack of ten. The other ones are noisy (soft white noise) and usually have a low hum. Even the Waldorft ones aren't that good. I had 2 good ones out of 4. So a better ratio. I just checked again for SONY and they now sale them on amazon for $500!!!
What happens to us in 20 years?
I've had the same 2x C-800G's since before 1998 & still use them just about every day & have never had any problem at all.
Can probably count on each hand the amount of tubes I've changed for each mic.
And have only changed the tubes in one of the power supplies once!

Will look into Sony to see what's really happening per the cost & availability of the tubes.
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