Dennis Had Inspire Amps

[OldTube Guy]

Originally Posted by Isaacc7

Like I mentioned before I also use Chinese adapters from ebay and they're fine. So if you want to save a few bucks that's an option. I think Deyen's connector is a little gentler on the top cap. One of the caps on my Cossor/GEC 807 got stuck in the cap of the Chinese adapter. So that tube is out of commission until I figure out how to fix it.

Which 807 are you ordering?

Try getting some dielectric lubricant into the top cap. I've had no issues with the Chinese adapters so far.

[OldTube Guy]

Originally Posted by khashmi

Thanks Isaacc7! Lots of good reviews. I just reached out to him. Now to figure out the 5Y3 rectifier for the Fivre’s…

Just get a 5Y3G and be happy. There is a nice Silvertone 5y3G on the auction site for $22.95, $7 shipping.

[Isaacc7]

Originally Posted by khashmi

I ordered the Ferranti 807’s that OldTubeGuy recommended. They were cheap enough to give them a try. I havn’t given up on Deyen yet. Just evaluating options. I looked at another source and they were selling one for $30, so his price isn’t necessarily outrageous.

Those Ferranti’s are a steal! Sound great. I think I have bought my last 807s, at least for a while lol. I now have the Ferranti, Cossor, Mullard, and just today I got in some Fivre and Mazda as well. Also have some funky loctal 807 from STC that needs an adapter. I will definitely get some more 6bg6ga tubes in the future though. They are related to 807.

[Analog Addict]

Originally Posted by Isaacc7

Do tell, I don't have a clue how to do it.

First off a disclaimer.

Tube amps that are powered up contain LETHAL voltages. One must always be very careful when sticking your hands or tools attached to your hands inside one, even one that has been powered down. The big power supply capacitors can maintain lethal charge for quite some time, especially if the power supply has no bleeder resistor to drain off the accumulated charge. Always better to stick one hand in your pocket when working on one, and to wear shoes with rubber soles, even flip-flops. Bare feet on a concrete floor like my workshop is asking for it. I would also wrap any needle tipped probes with some shrink tube so that only the most distal tip of the probe is uncovered. Shorting out components under full operating voltage may very well let out the magic smoke.

Can you read a schematic? Solid State schematics differ somewhat from toob schematics due to different types of components used. Anyway, to measure the power transformer output, you measure the high voltage output leads as they connect to the rectifier socket. This will be ACV.

Then you measure the output voltage, either at the socket or the + terminal of the first capacitor after the rectifier. This is DCV, and measured w.r.t ground, i.e., measure with the red meter lead on the positive terminal and the black lead on the negative . That will give you the voltage drop of the rectifier. Simple, no?

[jsbw]

Is it ok to use a 5Y3GT rectifier with 6V6GTs?

[Isaacc7]

Originally Posted by Analog Addict

First off a disclaimer.

Tube amps that are powered up contain LETHAL voltages. One must always be very careful when sticking your hands or tools attached to your hands inside one, even one that has been powered down. The big power supply capacitors can maintain lethal charge for quite some time, especially if the power supply has no bleeder resistor to drain off the accumulated charge. Always better to stick one hand in your pocket when working on one, and to wear shoes with rubber soles, even flip-flops. Bare feet on a concrete floor like my workshop is asking for it. I would also wrap any needle tipped probes with some shrink tube so that only the most distal tip of the probe is uncovered. Shorting out components under full operating voltage may very well let out the magic smoke.

Can you read a schematic? Solid State schematics differ somewhat from toob schematics due to different types of components used. Anyway, to measure the power transformer output, you measure the high voltage output leads as they connect to the rectifier socket. This will be ACV.

Then you measure the output voltage, either at the socket or the + terminal of the first capacitor after the rectifier. This is DCV, and measured w.r.t ground, i.e., measure with the red meter lead on the positive terminal and the black lead on the negative . That will give you the voltage drop of the rectifier. Simple, no?

Instead of taking the bottom of the amp off and poking around a live amp, could I use something like this?

https://www.amazon.com/Nobsound-Vacu...ps%2C77&sr=8-4

If that gives me the bias current couldn't I use that number to figure out the voltage somehow? Isn't this built into the current Firebottle amps now?

[khashmi]

Originally Posted by OldTube Guy

Just get a 5Y3G and be happy. There is a nice Silvertone 5y3G on the auction site for $22.95, $7 shipping.

3 for 3 now. I just bought it even though I was contemplating other more expensive alternatives. Brent Jesse was very high on Bendix, Mazda, and Brimar all at $99 each.

Messaged Dennis as well. He said, while the Bendix would work, he isn’t a fan. So there’s that. He had suggested a coke bottle shaped RCA of GE 5Y3G and the Silvertone (is that a manufacture or relabel) fits that criteria and seemed in line with the price I paid for the Fivres.

Oh this just occurred to me, which rectifier for the 807’s (still finalizing the adapter)—the 5U4G or the just bought 5Y3G?

[Isaacc7]

Originally Posted by khashmi

3 for 3 now. I just bought it even though I was contemplating other more expensive alternatives. Brent Jesse was very high on Bendix, Mazda, and Brimar all at $99 each.

Messaged Dennis as well. He said, while the Bendix would work, he isn’t a fan. So there’s that. He had suggested a coke bottle shaped RCA of GE 5Y3G and the Silvertone (is that a manufacture or relabel) fits that criteria and seemed in line with the price I paid for the Fivres.

Oh this just occurred to me, which rectifier for the 807’s (still finalizing the adapter)—the 5U4G or the just bought 5Y3G?

You can use either. The 807 can handle more voltage. Giving it less with the 5y3 is bound to change the sound but it won't harm anything.

I use an RCA 5y3 and 5u4gt. Also have a Japanese 5ar4 and a Russian one along with the one that came with the amp. I don't use the 5ar4 though.

[OldTube Guy]

Originally Posted by jsbw

Is it ok to use a 5Y3GT rectifier with 6V6GTs?

Yes, you can use a 5U4G or 5Y3GT. Let your ears decide.

[jsbw]

Originally Posted by OldTube Guy

Yes, you can use a 5U4G or 5Y3GT. Let your ears decide.

That's why I'm asking. 5U4G sounds great...5Y3GT sounds sublime!