Listens2tubes
New Member
Both mine and my Dad's 8B's came stock with Seimens EL34's.
Marantz 8B - hints and kinks?
- Thread starter kkib
- Start date
Check the power cord carefully. I have an earlier 8. When I got it (last year) the cord was cracked in a few places and brittle as could be. It snapped under finger pressure when bent.
I've used the Phillips tubes that it came with, JJ E34Ls and new issue Mullard EL34s and I can't tell the difference. I'm no expert, they all sound good to me. They do have help from a 6 pack of 10m's in a Model 7 though.
Thanks Grandma.
I've used the Phillips tubes that it came with, JJ E34Ls and new issue Mullard EL34s and I can't tell the difference. I'm no expert, they all sound good to me. They do have help from a 6 pack of 10m's in a Model 7 though.
Thanks Grandma.
Attachments
dieseldude
New Member
Freds or no Freds??
Great thread!! :thmbsp:
Question is does the amp now sound as good as before? I'm a bit nervous about upsetting the orginial voicing. Considering diving into my 7/8b and installing freds along with new ps filters. Anyone know of a source for oem filters?
Thx,
DD
Great thread!! :thmbsp:
Question is does the amp now sound as good as before? I'm a bit nervous about upsetting the orginial voicing. Considering diving into my 7/8b and installing freds along with new ps filters. Anyone know of a source for oem filters?
Thx,
DD
Hello,
Normally, I would be as minimally invasive on a Marantz 8b as possible. When I got mine one of the voltage doubler caps was leaky and had to be changed so I changed all of them. Also the goodalls showed signs of leakage.
In my Model 5's one section of a can was open and bad. So I changed both, also changed the bias supply caps as this is absolutely crucial. In the Model 1's I'm currently working on. The first section of the first high voltage can in both units was way leaky... I restuffed them. There's a thread on how I did it here.
So, while we try to keeps things authentic, you have to be safe unless the units are unused on a shelf.
I include a shot of my 8b with caps from VAC who did the reissue and claim the voicing of these is as close as can be to the original Goodalls. I also include a shot of what can become of bumblebee caps in these units and how dangerous they can be to sound and in key coupling locations . Leave them in at your peril.
Good luck with it.
Normally, I would be as minimally invasive on a Marantz 8b as possible. When I got mine one of the voltage doubler caps was leaky and had to be changed so I changed all of them. Also the goodalls showed signs of leakage.
In my Model 5's one section of a can was open and bad. So I changed both, also changed the bias supply caps as this is absolutely crucial. In the Model 1's I'm currently working on. The first section of the first high voltage can in both units was way leaky... I restuffed them. There's a thread on how I did it here.
So, while we try to keeps things authentic, you have to be safe unless the units are unused on a shelf.
I include a shot of my 8b with caps from VAC who did the reissue and claim the voicing of these is as close as can be to the original Goodalls. I also include a shot of what can become of bumblebee caps in these units and how dangerous they can be to sound and in key coupling locations . Leave them in at your peril.
Good luck with it.
Attachments
Pio1980
AK Member
6BH6 follies:
I've never been all that fond of the sonic performance of my 8 which doesn't really draw me in, tho I love the idea of having it around.
So, it's been periodically rotated in and out of the system that turned out to have other problems bearing on the impression. Last time in yielded a notably feeble 'A' channel that biased properly, so it came out for measurements. When I acquired it, it had NOS vintage tubes in the front end and splitter, and new EH 6CA7s, so no worries, right?
So I eventually got around to flipping it over and making resistance and voltage measurements around the 6BH6s and found unexplainable measured discrepancies between channels. Replacing the pair with another NOS pair fixed the resistance discrepancies but there remained voltage disparities again in the A channel. After numerous tests and measurements, I swapped the tubes across channels and the faulty measurement followed the suspect, what are the chances of replacing a faulty NOS tube with another faulty NOS tube in the same socket location during diagnosis.
Lesson learned is that it wouldn't hurt to use a socket extender to measure actual plate drop when matching tubes in the front end of these amps.
Dont trust, verify.
I've never been all that fond of the sonic performance of my 8 which doesn't really draw me in, tho I love the idea of having it around.
So, it's been periodically rotated in and out of the system that turned out to have other problems bearing on the impression. Last time in yielded a notably feeble 'A' channel that biased properly, so it came out for measurements. When I acquired it, it had NOS vintage tubes in the front end and splitter, and new EH 6CA7s, so no worries, right?
So I eventually got around to flipping it over and making resistance and voltage measurements around the 6BH6s and found unexplainable measured discrepancies between channels. Replacing the pair with another NOS pair fixed the resistance discrepancies but there remained voltage disparities again in the A channel. After numerous tests and measurements, I swapped the tubes across channels and the faulty measurement followed the suspect, what are the chances of replacing a faulty NOS tube with another faulty NOS tube in the same socket location during diagnosis.
Lesson learned is that it wouldn't hurt to use a socket extender to measure actual plate drop when matching tubes in the front end of these amps.
Dont trust, verify.
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