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The Official Reeves Bass Amp Thread

#242
dDaddybass said:
It has huge power and output transformers. You could have 12 power tubes but it does you no good without the right transformers. 392 watts is the number got from a very reliable source. Reeves is actually using KT120's right now. Tom Bowlus from Bass Gear Magazine commented that he saw a 12% increase when he changed to KT120's, that put the Custom 225 to 256 watts. 392 + 12% = 439. So, it is possible with capable transformers.
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I think Bass Gear Magazine actually got 256 watts from their C225 with the stock KT88's, the 12% increase was from that number.

As a side note; Bass Gear Magazine's testing procedure is hands down the most comprehensive I've ever seen in an general enthusiast publication.
It's tech journal intensive in an easy to understand reader friendly format, glossy and well composed; a "must read" for any bass gear junkie IMO.
 
#243
edbass said:
I think Bass Gear Magazine actually got 256 watts from their C225 with the stock KT88's, the 12% increase was from that number.

As a side note; Bass Gear Magazine's testing procedure is hands down the most comprehensive I've ever seen in an general enthusiast publication.
It's tech journal intensive in an easy to understand reader friendly format, glossy and well composed; a "must read" for any bass gear junkie IMO.
Click to expand...

I stand corrected. 256 + 12% = 287. Oh yeah!
 
#244
I just got off the phone with Bill at Reeves. He's been experiencing a slew of premature failures (not lasting through burn-in!) with the KT-120's here lately. I've decided to stick with the time-tested KT-88 design. Pretty quick build time on the amp - he said it should be ready to ship next week.
 
#245
spiritbass said:
I just got off the phone with Bill at Reeves. He's been experiencing a slew of premature failures (not lasting through burn-in!) with the KT-120's here lately. I've decided to stick with the time-tested KT-88 design. Pretty quick build time on the amp - he said it should be ready to ship next week.
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Interesting. This sounds like what was happening with the KT120s and the Meatsmoke. I wonder if he will abandon the KT120s too?
 
#246
spiritbass said:
I just got off the phone with Bill at Reeves. He's been experiencing a slew of premature failures (not lasting through burn-in!) with the KT-120's here lately. I've decided to stick with the time-tested KT-88 design. Pretty quick build time on the amp - he said it should be ready to ship next week.
Click to expand...

This is disappointing because the KT-120s helped with the "alleged" mid scoop. The extra power is cool too.
 
#248
Yeah, the KT120's have somewhat dodgy reliability and some quirky design specs that make me want to stay away from them. I'm sure you could tweak the tonestack to reduce the mid scoop if that's a concern.
 
#249
Bill @ Reeves and the Meatsmokers had a co-rant about the problem. Bill was telling me that he had one from each set fail out of four sets of four (4 out of 16). That's a high rate. If you get four good ones, you'd (probably) be sailing smoothly for years. Bill told me straight out that he is not confident at this point sending out amps with these tubes. I did not realize until he told me that the KT-120 is a relatively new design. It's gotta be driving up the aspirin/tums bill for amp builders relying on these.

The Custom 225 supplied to "Bass Gear Magazine" for testing had a measured dip at 400hz. Not drastic, but it was there...
 
#254
spiritbass said:
Bill @ Reeves and the Meatsmokers had a co-rant about the problem. Bill was telling me that he had one from each set fail out of four sets of four (4 out of 16). That's a high rate. If you get four good ones, you'd (probably) be sailing smoothly for years. Bill told me straight out that he is not confident at this point sending out amps with these tubes. I did not realize until he told me that the KT-120 is a relatively new design. It's gotta be driving up the aspirin/tums bill for amp builders relying on these.

The Custom 225 supplied to "Bass Gear Magazine" for testing had a measured dip at 400hz. Not drastic, but it was there...
Click to expand...

There is nothing inherently "wrong" or "quirky" with the KT120, it's just NOT a KT88/6550 despite the fact that some "engineers" try to treat it as such. The failures are almost certainly a temporary manufacturing issue.
ALL vacuum tubes have a failure rate, but IMO a 25% failure rate is too high to offset the cost, hassle, and possible negative consumer reaction involved, and would dictate switching suppliers until the OEM gets their house in order on the production level.

Except… There is currently only ONE supplier for the KT120; as has been mentioned it’s a brand new tube, just a “baby” in a world where the last previous major power increase innovation was in the 1950’s (KT88/6550).
With KT88’s and/or 6550’s if you get a bad run from one supplier there are a handful of others to replace them with at the OEM level, if Tung Sol has issues with their overseas manufacturer of KT120’s you are SOL until the situation is remedied.
And I would imagine this situation WILL be remedied, IMO the KT120 is a great sounding tube.

Of course all of this is assuming that the circuit(s) in question are actually up to the task of properly utilizing the bigger device. Although the Reeves overbuilt components are more than adequate to handle the higher current levels of the '120 over the '88, as Mr. Bowlus mentions there are significant modifications needed to the stock C225 circuit to actually utilize this additional output.
I can’t speak to the situation that Verellen was having with the Meatsmoke, but I have wailed the tar out of the C225 with just about every tube that it has ever been tested with. I would speculate that the Verellen problem was that either the component compliment or circuit design just wasn’t up to the task, or (most likely) faulty tube manufacture, which really doesn’t matter because…
The additional power is all but irrelevant.

It’s really not a race to see “whose is biggest”; although the additional headroom from the KT120 can translate to a little more SPL, I will wager that the average Joe that TB poster couldn’t tell which Reeves was running which output tube in a blind, side by side comparison.
Unless you were intimately familiar with the C225/C400 already, the differences would probably fall within the range of normal differences that exist between like amps.

It’s like those transistor amp guys that think it’s crucial to run their outputs at the lowest possible impedance to “use all the power”, you know, the players that post questions about “Where can I find a 4 ohm 410 cab?”, etc..
While it makes for amusing reading, it doesn’t really amount to a hill of beans as far as volume, other than the fact that lowering impedance is generally accomplished by paralleling additional speakers, which will indeed add SPL. Personally I would rather run transistor output as high impedance as I can get away with; it’s an audio signal amplification device, not a toaster oven. Heat is the enemy.
But I digress as usual…
 
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#257
edbass said:
Although the Reeves overbuilt components are more than adequate to handle the higher current levels of the '120 over the '88, as Mr. Bowlus mentions there are significant modifications needed to the stock C225 circuit to actually utilize this additional output.
Click to expand...

FWIW, the "modifications" were basically a pretty serious rebiasing job. Fortunately, the C225 bias adjustment options encompass a sufficiently wide range to accomplish this.
 

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