original 670 poor version DIY
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SUPERMAGOO
Well-known member
is a funny name. ;D
and it really is a monster.
I wish I could count on his knowledge to give a good refinement. :
and it really is a monster.
I wish I could count on his knowledge to give a good refinement. :
lewilson
Well-known member
- Joined
- Aug 9, 2005
- Messages
- 218
I got my 660 type comp done. It works great.
I had to buy one Sowter for the control amp output. All else I had here. I went with the 6ba6 type remote cutoff tubes. Actually the russian version of that tube ,the 6k4p which work nice .
Side chain has 6973 output tubes. I was trying to make it as compact as possible, so I used solid state regulation and rectifier.
The time constant and bias supply circuit is attached by multi pin connectors/cables and are located under the main chassis.
Its a little funky looking because its built on a blank guitar amp chassis. I'm going to make some sort of front panel for it. I learned a lot anyways.
I had to buy one Sowter for the control amp output. All else I had here. I went with the 6ba6 type remote cutoff tubes. Actually the russian version of that tube ,the 6k4p which work nice .
Side chain has 6973 output tubes. I was trying to make it as compact as possible, so I used solid state regulation and rectifier.
The time constant and bias supply circuit is attached by multi pin connectors/cables and are located under the main chassis.
Its a little funky looking because its built on a blank guitar amp chassis. I'm going to make some sort of front panel for it. I learned a lot anyways.
SUPERMAGOO
Well-known member
wooow is a guitar amp!.
great job!!
I have considered using 6ba6 in my next version.
you could make recordings for rock drums and upload to the internet?
appreciate that!
great job!!
I have considered using 6ba6 in my next version.
you could make recordings for rock drums and upload to the internet?
appreciate that!
SUPERMAGOO
Well-known member
Lewinson. I am waiting for your recordings!
simonsez
Well-known member
I love those knobs, where did you got that?
.. fighting .. hard .. not .. to .. do .. one .. of .. these ...
A losing battle .. can feel myself .. starting to buy parts ...
----
Thinking of :
8x 6SK7s with UTC signal traffos.
pp EL84 control amp , around 10W or so with Edcor traffos, no tertiary winding
Poorman PSU (reg 135, 245V), 6A of filtered unreg 6.3V
Yet another project - 700us or so
Aaarrrrgggg!!!
god help us .. (us)
A losing battle .. can feel myself .. starting to buy parts ...
----
Thinking of :
8x 6SK7s with UTC signal traffos.
pp EL84 control amp , around 10W or so with Edcor traffos, no tertiary winding
Poorman PSU (reg 135, 245V), 6A of filtered unreg 6.3V
Yet another project - 700us or so
Aaarrrrgggg!!!
god help us .. (us)
OK - so started buying. Couldn't resist anymore. Yet another poor 660 version
A few UTC A15s 10K:500 for in/out traffos and a pile of 6K4P remote cutoff pentodes.
Seems like the curves are pretty reasonable for the task and they are cheap enough to have an initial go.
I'm hoping to use Analag's PSU from the Poorman 670 - done a couple of them and have been happy with the
performance and robustness.
A couple of mods for whatever B+ values I go for the signal amp and control amp driver stage.
May not be possible, depending on my PSU traffo choice.
I think I'm going to need around 300mA of HV - 8x 25mA for the signal amp and around 100mA for the
EL84 based control amp. Maybe I don't need as much for the 64KPs. Not sure yet.
Next up, find a control amp output. Probably use the Edcor 8K:600 10W or similar. I figure that should be enough juice
to drive 8 grids and the timing network to a reasonable speed. I think 1ms at the fastest is plenty.
I'll use one of the 2 1/2 watt 600:10K for the input here.
I may see if they can make me a custom with a tertiary winding of some sort.
No idea yet of the turns ratio for a tertiary.
Lotsa fun and games!
A few UTC A15s 10K:500 for in/out traffos and a pile of 6K4P remote cutoff pentodes.
Seems like the curves are pretty reasonable for the task and they are cheap enough to have an initial go.
I'm hoping to use Analag's PSU from the Poorman 670 - done a couple of them and have been happy with the
performance and robustness.
A couple of mods for whatever B+ values I go for the signal amp and control amp driver stage.
May not be possible, depending on my PSU traffo choice.
I think I'm going to need around 300mA of HV - 8x 25mA for the signal amp and around 100mA for the
EL84 based control amp. Maybe I don't need as much for the 64KPs. Not sure yet.
Next up, find a control amp output. Probably use the Edcor 8K:600 10W or similar. I figure that should be enough juice
to drive 8 grids and the timing network to a reasonable speed. I think 1ms at the fastest is plenty.
I'll use one of the 2 1/2 watt 600:10K for the input here.
I may see if they can make me a custom with a tertiary winding of some sort.
No idea yet of the turns ratio for a tertiary.
Lotsa fun and games!
Lot's of reading later .. and quite a bit of part ordering later ... my current thinking ...
... following belatedly in the wake of the creators, redesigners and info trailblazers
----
Decided on UTC A15 600:10K for signal input (an A24 or so if I have to have a higher ratio)
Still trying to decide on a signal output - trying to find one for 10K:600 or 15K:600 at a 5W or so.
An LS series UTC would be nice but not very likely.
Probably the Edcor 8.6K:600 10W PP out traffo would work here.
Perhaps even a custom one with 10K or higher primary.
Using an Edcor 600:10K 2.5W for the control input, and a Hammond 1645 for the output, as suggested by DaveP.
Hopefully I can get it work with a standard 660 style sidechain with a low enough output impedance.
Thinking about 10W of side chain power.
Still learning and understanding the issues (thanks to those individuals who are awesome contributors!)
So far, I like the choice of 8x 6k4p for the channel, at around 125V and 8mA per tube quiescent.
That keeps my B+ within the 65mA I have available. And heater to 2.4A or so.
Another 135mA of B+ for the sidechain amp and I need 200mA of B+ total.
Another 1.8A or so of heater for a total of 4.2A.
Which means I can use the psu pcb from the Poorman 670 and an Edcor XPWR063-120/240
for a 660 channel. Along with a diode rectified L-C-R filtered unregulated 315V B+ for side chain finals.
Bias voltages and a utility voltage are available as well as the 2 regulated HVs and filtered heater DC.
GR grid biasing scheme as per original 670
GR cathode biasing scheme as per original 670 with the dual balance trimmer.
DC threshold and standard 660 sidechain
So - starting to drill holes now!
Again - thanks to all the great contributors in helping me get to the point where it is feasible to even
entertain the notion of a making myself a version of this
It's going to be real interesting.
... following belatedly in the wake of the creators, redesigners and info trailblazers
----
Decided on UTC A15 600:10K for signal input (an A24 or so if I have to have a higher ratio)
Still trying to decide on a signal output - trying to find one for 10K:600 or 15K:600 at a 5W or so.
An LS series UTC would be nice
but not very likely. Probably the Edcor 8.6K:600 10W PP out traffo would work here.
Perhaps even a custom one with 10K or higher primary.
Using an Edcor 600:10K 2.5W for the control input, and a Hammond 1645 for the output, as suggested by DaveP.
Hopefully I can get it work with a standard 660 style sidechain with a low enough output impedance.
Thinking about 10W of side chain power.
Still learning and understanding the issues (thanks to those individuals who are awesome contributors!)
So far, I like the choice of 8x 6k4p for the channel, at around 125V and 8mA per tube quiescent.
That keeps my B+ within the 65mA I have available. And heater to 2.4A or so.
Another 135mA of B+ for the sidechain amp and I need 200mA of B+ total.
Another 1.8A or so of heater for a total of 4.2A.
Which means I can use the psu pcb from the Poorman 670 and an Edcor XPWR063-120/240
for a 660 channel. Along with a diode rectified L-C-R filtered unregulated 315V B+ for side chain finals.
Bias voltages and a utility voltage are available as well as the 2 regulated HVs and filtered heater DC.
GR grid biasing scheme as per original 670
GR cathode biasing scheme as per original 670 with the dual balance trimmer.
DC threshold and standard 660 sidechain
So - starting to drill holes now!
Again - thanks to all the great contributors in helping me get to the point where it is feasible to even
entertain the notion of a making myself a version of this
It's going to be real interesting.
Hammond 1645 specs with
http://www.hammondmfg.com/1608.htm
I haven't tried this but I will as soon as mine gets here.
I'm using Digikey to purchase Hammond stuff.
International USPS is very reasonable even for heavy item all the way down here!
There is a 1645A with no seperate 70V coil, just an additional tap.
edit-
OK - I see what you mean - the Digikey listing doesn't mention the 70V explicitly,
but it does reference the correct Hammon part no. and the catalog link has the
schematic with the seperate secondary coils.
I think it is the one required.
Cheers
http://www.hammondmfg.com/1608.htm
I haven't tried this but I will as soon as mine gets here.
I'm using Digikey to purchase Hammond stuff.
International USPS is very reasonable even for heavy item all the way down here!
There is a 1645A with no seperate 70V coil, just an additional tap.
edit-
OK - I see what you mean - the Digikey listing doesn't mention the 70V explicitly,
but it does reference the correct Hammon part no. and the catalog link has the
schematic with the seperate secondary coils.
I think it is the one required.
Cheers
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