It would add the 11MS8 tube as a third choice..........🙂
ps they are still available at $5.70 each
So I should be fine going dual monoblock K-501's with the tubes that come with and still get just fine fidelity (i.e. no obvious complaints, but obviously everything could always be modded)?
2 volume pots controlling dual mono are a PITA. I would suggest running wire from the pot input on the boards to a centrally loacated stereo pot. The low cost leader is the Radio Shack (Alps) 100k pot (something like $4). Beyond that one you get into an area filled with landmines. The PEC are highly regarded, and do sound good, but so far 2 out of the 2 we have tried have gotten very noisy when being rotated.
The tubes used in these are similar to 6BM8/ECL82. The reason they are using them, and one of the reasons that the kits are cheap, is that these guys ran into a big stash (likely 10,000 plus for a dime or less each).
Make sure you lay in spares.
dave
The tubes used in these are similar to 6BM8/ECL82. The reason they are using them, and one of the reasons that the kits are cheap, is that these guys ran into a big stash (likely 10,000 plus for a dime or less each).
Make sure you lay in spares.
dave
$240 for a pair of K501's plus maybe another $100 for a pair of output transformers plus the cost of other mods and maybe shipping - things are getting expensive!
If I had to do it all again I would get an old EL84 PP console or Jap amp and listen to it. When I knew enough I would gut it and turn it into a Baby Huey or any of the other excellent EL84 based designs created by the talented people on this forum. Just my two pennies.....😀
If I had to do it all again I would get an old EL84 PP console or Jap amp and listen to it. When I knew enough I would gut it and turn it into a Baby Huey or any of the other excellent EL84 based designs created by the talented people on this forum. Just my two pennies.....😀
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Fair enough but for all the reasons layed out before...this may be it. Turns out the K-501's are already made with Hammond OPT's and PST's anyway 😀. Should I upgrade the tubes? Being that I will already have Hammond tranfo and decent components and the tranfos will give plenty of power...I think a stock build will do just fine. My only remaining question is still the pot or attenuator. Also, upgrade tubes or no?
Update: Final verdict in favor of upgrading the K-502. I'm going to upgrade PS tranfo and OPT. There is already a chassis made for the K-12G and I'm fairly certain that the K-502 will fit in just nicely. The tubes in the K-502 are nice. I'm tired of reading and not building.
I built an K-502 some time ago that I gave away as a present to a friend later.
Dave's comments are spot on: The original PT is quite small and runs very hot in the stereo version (too hot for my taste).
The stock configuration sounds actually quite nice but don't expect wall shaking bass (that's the weak spot).
Upgrading the OPT might help to increase LF or the use of a subwoofer.
An upgrade of the coupling caps is an improvement but does not need to be expensive: My recommendation would be WIMA FKP1 if you can fit them on the PCB.
I also changed the PS caps to higher voltage, low ESR types paralleled with a good film cap (again, not necessarily expensive).
Most likely you will go down the same route as I did and this will not be your last amp. These small kits are quite dangerous... Once you start the journey, there is no way back. 😀
My second amp was Gingertube's Baby Huey - still my favorite and main system.
At the moment, I am working on a small SE EL95 with Schade feedback and a larger SE KT-88. Not because there is anything wrong with the Baby Huey, just because I enjoy the building process and somehow feel the urge to try out things 😀.
Martin
Dave's comments are spot on: The original PT is quite small and runs very hot in the stereo version (too hot for my taste).
The stock configuration sounds actually quite nice but don't expect wall shaking bass (that's the weak spot).
Upgrading the OPT might help to increase LF or the use of a subwoofer.
An upgrade of the coupling caps is an improvement but does not need to be expensive: My recommendation would be WIMA FKP1 if you can fit them on the PCB.
I also changed the PS caps to higher voltage, low ESR types paralleled with a good film cap (again, not necessarily expensive).
Most likely you will go down the same route as I did and this will not be your last amp. These small kits are quite dangerous... Once you start the journey, there is no way back. 😀
My second amp was Gingertube's Baby Huey - still my favorite and main system.
At the moment, I am working on a small SE EL95 with Schade feedback and a larger SE KT-88. Not because there is anything wrong with the Baby Huey, just because I enjoy the building process and somehow feel the urge to try out things 😀.
Martin
Well, there's that route and it seems like a good one. However, outside of the upgrade the hell out of my K-502 or buy two K-501's and rig them together and do some moderate upgrades...I've stumbled upon this bad boy.
DIYTube Dynaco ST35 Tube DIY Amp Kit Great for iPod
Seems to have amazing reviews and all the mods already done for me 🙂
DIYTube Dynaco ST35 Tube DIY Amp Kit Great for iPod
Seems to have amazing reviews and all the mods already done for me 🙂
I just ordered from Dynakit. I was kind of up in the air about it then called Dynakit to ask a really quick question and he was incredibly knowledgeable and very helpful with talking me through a number of points. It's on the way (Along with EL84's and JJ ECC832 /
12DW7's)! 😀
12DW7's)! 😀
The Dynakit is in a whole nuther class from the K-amps.
And if, at a later date, you want to take it to the next level, it has all the bits in place to make a Red light district (or with more work, Baby Huey, or an Allen Wright style differential amp (what i'm doing with my original ST35/SCA35 iron))
dave
And if, at a later date, you want to take it to the next level, it has all the bits in place to make a Red light district (or with more work, Baby Huey, or an Allen Wright style differential amp (what i'm doing with my original ST35/SCA35 iron))
dave
Great choice! You won't regret EL84 PP amp sound. Plus lots of in production tubes to pick from and you'll have a neat looking amp!
I am new to the forum and tube amps so I tend to bump old threads when I am searching for information. I bought a K-502 kit but I want to build a second one point to point just for fun.
What is the specs on the power transformer? I found the specs on the Output transformer but I am not sure about the main power Supply. Thats the only part I don't have the information on to duplicate this kit as point to point
What is the specs on the power transformer? I found the specs on the Output transformer but I am not sure about the main power Supply. Thats the only part I don't have the information on to duplicate this kit as point to point
I built my K-502 Stock and have been enjoying listening to it as it. I decided to put a $100 shine on a $3 pair of shoes so I designed a housing for it.
As far as the transformers from browsing the forums I found the following suggestions for a K-502 AMP
Output Transformer options
$17 EDCOR XPP10-8-10K, no bell covers
$28 EDCOR GXPP10-8-10K, Nice Blue Edcor covers 10W
$38 EDCOR GXPP15-8-10K, Nice Blue Edcor covers 15W
$66 EDCOR CXPP60-8-10K, 60W seems way overkill
$68 EDCOR CXPP30-MS-10K, Multiple resistance taps 30W
Power Transformer Options
$56 XPWR025 180 VAC @ 200 mA and 11.6VAC CT @ 2A:*
As far as the transformers from browsing the forums I found the following suggestions for a K-502 AMP
Output Transformer options
$17 EDCOR XPP10-8-10K, no bell covers
$28 EDCOR GXPP10-8-10K, Nice Blue Edcor covers 10W
$38 EDCOR GXPP15-8-10K, Nice Blue Edcor covers 15W
$66 EDCOR CXPP60-8-10K, 60W seems way overkill
$68 EDCOR CXPP30-MS-10K, Multiple resistance taps 30W
Power Transformer Options
$56 XPWR025 180 VAC @ 200 mA and 11.6VAC CT @ 2A:*
Attachments
From this side of the pond those output transformers look a bargain. I would go for at least the EDCOR GXPP15-8-10Ks as later on you might want to build an EL84 based design. 🙂
The Poddwatt EL84 transformer package sold at EDCOR part # DAP-202 ($122) includes the following transformers
1 x XPWR236 (EMO719)
2 x CXPP10-MS-10K (EMO750)
It looks like a perfect match if I add a LT1086 voltage regulator to drop the heater voltage to 10.6V.
It looks like I could gradually upgrade the K-502 until I would have enough parts to make a Poddwatt EL84 amplifier, then rebuild the K-502 with the old parts and have 2 amps 🙂
1 x XPWR236 (EMO719)
2 x CXPP10-MS-10K (EMO750)
It looks like a perfect match if I add a LT1086 voltage regulator to drop the heater voltage to 10.6V.
It looks like I could gradually upgrade the K-502 until I would have enough parts to make a Poddwatt EL84 amplifier, then rebuild the K-502 with the old parts and have 2 amps 🙂
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