Krinkle wrote: Barring any mistakes or issues, I will play it for a while to try to get a feel for what it should sound like without going deaf, and then install Dana's board. I can already see that it should be fine.
WHAT??? You can still hear after that 100 watt Metro build!!!
Take care,
John
WHAT!!!
Oh yes, I've tweaked the Metroamp, I'm slaving it into my London Power Standard and I'm loving it
I'm finishing this Express and then it's a Hiwatt DR504 , as authentic as I can build it, along the lines of the Metroamp.
Shoot me an email and let me know how you're doing.
I need some educating on your VVR. If I was to build a 80 watt Meyer style express what exactly does the VVR do for me. Instead of running a master volume I would be using variable voltage on the whole amp to control the power going to the plates? I haven't had much interest because I don't know what function this has on the amp. With 80 to 100 watts on board one needs to have a master volume or your VVR I'm guessing.
I need some educating on your VVR. If I was to build a 80 watt Meyer style express what exactly does the VVR do for me. Instead of running a master volume I would be using variable voltage on the whole amp to control the power going to the plates? I haven't had much interest because I don't know what function this has on the amp. With 80 to 100 watts on board one needs to have a master volume or your VVR I'm guessing.
Mark
Mark
Unfortunatly the VVR is only designed for amps running 50 watts or less. If I ever get any time I am planning on looking into doing something for a 100 watter but for now that is the limitation. What it does is to make the voltages, either all of the voltages or just the power tube plate and screens variable. You can adjust the voltages any where from full B+ to 10% B+ or anywhere in between. It also adjusts the bias voltage on fixed bias amps so that as you turn you B+ voltage down you also reduce the bias. They track together. By changing the bias and the B+ at the same time you are shifting the operating point of the tube and keeping it operating on a linear portion of it's characteristics curve so it reacts the same, only at a reduced power level.
The theory is that if you were to crank the amp and get the tone you like you should be able to reduce your voltages and keep the same tone at a reduced volume. So in that respect it acts like a MV but unlike the MV if your amp tone depends a lot on power tube distortion as you turn down your MV you will loose that. With the VVR you don't . You will reach a point where the amp isn't producing enough power to move the speakers properly and at that point nothing is going to help. The same thing happens with an Air Brake, in that if the speakers aren't working efficiently or moving any air your tone will change.
Hey Dana,
I sent a pm about buying a vvr for an express build Im putting together and Im not sure you got it, so I decided to post. Please PM me. Thanks.
Steve
eBay: The place where a fool and their money part.
Thanks for the education. I now know that I will have to buy a kit from your when I build another amp. Also viewing your web site for release on that sweet little killer amp of yours/prices.
I don't know what sorts of sins I am committing but I have a little different layout for my first Express build. My buddy wanted Dana's VVR2 (at my recommendation) as well as a fender style jewel light (on the heater wire circuit). Combine that with the fact that I ordered the Chassis and Faceplate from Ceriatone with a MV hole pre-drilled, I did not have a lot of choice for VVR location. We shall see how it works.
Anyone else know of other sins I have committed so far that I should repent of?
I'm too dumb to know if the Bournes pots are stainless steel and I found the build guide rather confusing to understand regarding buss bar choices, so I have a buss bar connected to those big-grounding-lock-washer-with-a-lug mounted between the chassis and pots. I thought I understand the grounding scheme ideas, but maybe it is over my head. We shall see.
I don't know why my builds never look as tidy as all you geniuses' work. Oh well, I'm just a hack that builds for my friends for free. I'm hoping that he reimburses me for the parts eventually, otherwise I will have to try to sell it elsewhere.
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Dana, can you provide the specs on the cap cans please. What a great build.
The cans certainly allow for a more spacious arrangement. It sounds like this version has all the sonic quality of the original layout. Do you have a layout of this unique version??
Would that be a 120uf 500v JJ and a 60uf 500v JJ ? or Panasonic?
