This is my first post.......
If you are one who is wanting to build Pete Millett's DCPP Engineers amp......in a "hot rodded" version, there is a new power transformer available at EDCOR!
I have paid the setup and design fee for a "custom design" so the unit should be available at the standard price for all, now.
EDCOR part # XPWR246-120
Specs:
385-CT-50-385 @275ma
(2x) 3.15-CT-3.15 @4A
Only available with 120V primary
Several things to note:
There is only 1-50V tap ( Pete's board is designed for 2) but it works just fine using just this one ( see previous posts/threads). Edcor advised that room was too cramped for a second lead.
The 6.3V windings ( in parallel) will yield 8 amps ( as opposed to the 6A in the original spec'd trans).
I have built the DCPP in "stock" form and the PT starts to get hot after a while ( likely due to the fils windings, being taxed to the limit at 6A !)
EDCOR ( very cool, nice and HELPFUL people) said that in order to achieve 8A fil current, they needed to build with 2 separate windings due to space limitations.
Also due to space limitations, there was only enough room for a single (120V) primary....as opposed to a 120-220V format.
Just yesterday, I got my new, "Hot Rodded" DCPP board, up and running with this larger transformer! Still need to do some refining and tweeking but, after following what others have posted RE: component values/ changes needed for an "UP VOLTAGE" Engineer's amp, here are my preliminary test readings:
Plate voltage for the final tubes, 500V ( no load)
Screen and grid V's are dead on
Plate voltage for the 6CB6 drivers is ~200V ( I'm thinking I need to lower this a touch as it is above Pete's spec) Believe another change to R48 and R49 (?) ( original was 1K.....posts have indicated I will need ~10K.....have 11K 5W in it now).
The new transformer runs absolutely COOL to touch after 1 hour of loaded run time!!!
This trans WILL NOT support the filament current needed for the "tall bottle" sweep tubes like the 6KD6,6LR6,6LF6 etc ! They each draw 2.5A whereas the "short bottle" types that Pete spec'd ( 6JN6, 6JM6) draw 1.2A. I am using the slightly larger 6JZ6. It has a little bit higher Pdis and draws 1.5A on the fils.
You should be just fine running the JN or JM tube with this trans.
I am using the EDCOR 6.6K 50W OPT's
The volume level in this HOT ROD amp, is quite abit LOUDER than the "stock" version ( as intended) !
Hope this makes it easier for anyone who wants to make a modded version of Pete's awesome project !
CHEERS
Dan "Goose"
If you are one who is wanting to build Pete Millett's DCPP Engineers amp......in a "hot rodded" version, there is a new power transformer available at EDCOR!
I have paid the setup and design fee for a "custom design" so the unit should be available at the standard price for all, now.
EDCOR part # XPWR246-120
Specs:
385-CT-50-385 @275ma
(2x) 3.15-CT-3.15 @4A
Only available with 120V primary
Several things to note:
There is only 1-50V tap ( Pete's board is designed for 2) but it works just fine using just this one ( see previous posts/threads). Edcor advised that room was too cramped for a second lead.
The 6.3V windings ( in parallel) will yield 8 amps ( as opposed to the 6A in the original spec'd trans).
I have built the DCPP in "stock" form and the PT starts to get hot after a while ( likely due to the fils windings, being taxed to the limit at 6A !)
EDCOR ( very cool, nice and HELPFUL people) said that in order to achieve 8A fil current, they needed to build with 2 separate windings due to space limitations.
Also due to space limitations, there was only enough room for a single (120V) primary....as opposed to a 120-220V format.
Just yesterday, I got my new, "Hot Rodded" DCPP board, up and running with this larger transformer! Still need to do some refining and tweeking but, after following what others have posted RE: component values/ changes needed for an "UP VOLTAGE" Engineer's amp, here are my preliminary test readings:
Plate voltage for the final tubes, 500V ( no load)
Screen and grid V's are dead on
Plate voltage for the 6CB6 drivers is ~200V ( I'm thinking I need to lower this a touch as it is above Pete's spec) Believe another change to R48 and R49 (?) ( original was 1K.....posts have indicated I will need ~10K.....have 11K 5W in it now).
The new transformer runs absolutely COOL to touch after 1 hour of loaded run time!!!
This trans WILL NOT support the filament current needed for the "tall bottle" sweep tubes like the 6KD6,6LR6,6LF6 etc ! They each draw 2.5A whereas the "short bottle" types that Pete spec'd ( 6JN6, 6JM6) draw 1.2A. I am using the slightly larger 6JZ6. It has a little bit higher Pdis and draws 1.5A on the fils.
You should be just fine running the JN or JM tube with this trans.
I am using the EDCOR 6.6K 50W OPT's
The volume level in this HOT ROD amp, is quite abit LOUDER than the "stock" version ( as intended) !
Hope this makes it easier for anyone who wants to make a modded version of Pete's awesome project !
CHEERS
Dan "Goose"
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