2nd Gen hybrid

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erwin_ve
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2nd Gen hybrid

Post by erwin_ve »

Hi, Just started a 2gen hybrid build.
Using 71 Twin iron for both Ot and Pt.
Ce chassis. External dlator is going to be used.
I'm not familiar with the ins and outs of this 2nd gen hybrid circuit so I'm looking for some input for this build.
Erwin
Some pics:
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jelle
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Re: 2nd Gen hybrid

Post by jelle »

Looks good!
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M Fowler
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Re: 2nd Gen hybrid

Post by M Fowler »

Is this the 2nd generation #40? or the 183 hybrid?
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erwin_ve
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Re: 2nd Gen hybrid

Post by erwin_ve »

M Fowler wrote:Is this the 2nd generation #40? or the 183 hybrid?
2nd gen hybrid. It is somewhere in the files section: circuit close to#40.
Charlie Wilson
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Re: 2nd Gen hybrid

Post by Charlie Wilson »

:)
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erwin_ve
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Re: 2nd Gen hybrid

Post by erwin_ve »

some progess:
The PT wasnt a fit in this chassis(first batch ce chassis). Some work on this.
THe PT and Ot are used old silverface twin trannies.
Hope to finish it this month.
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erwin_ve
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Re: 2nd Gen hybrid

Post by erwin_ve »

Progress! Only heater wiring and net wiring to do.
Had some trouble with the fet relay. It's looking like a tower heist, next time it will be installed at the side of the chassis.
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erwin_ve
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Re: 2nd Gen hybrid

Post by erwin_ve »

It's finished.....almost.
The amp is working with clean/od and pab.
2 things I got to troubleshoot; the fet isn't working(dead quiet, no hum) and the rock/jazz switch behaves like a PAB when the jazz side is on.

Voltages;
B1: 440v
B2: 437v
B3: 413v
B4: 283v
B5: 276v

V2b: 180v
v2a: 181v
v1b: 173v
v1a: 169v

bias: 30mA

Does this look good to you guys? v1 and v2 seems a bit low to me.

First impression: cleans have a nice chime! Od is very suitable for strat. Outer foil positioning pays off in this build again; very quiet amp!
The OD master with 1M is maybe too much; Maybe a 500k/250k or even a 100k is a option, what do you think?
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dreric
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Re: 2nd Gen hybrid

Post by dreric »

Nice Build!
Eric
1949 Zenith, Zenith Toggle Recoil, Zenith 55 & 440
Bombacaototal
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Re: 2nd Gen hybrid

Post by Bombacaototal »

Very nice built indeed. Nice NOS resistors, they look like pre 70s Piher?

Why do you call it 2ng gen hybrid?

Have you built other versions like classic, skyliner, etc? I am wondering how do those compare to your 2ng gen so far, on a stratocaster angle

For reference sound source an Overdrive Reverb 2nd gen with amazing sustain: 100watts, 6L6. 2nd Generation

https://youtu.be/WHrU9RZ8ud0

https://youtu.be/9SYHgOz9Mls
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erwin_ve
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Re: 2nd Gen hybrid

Post by erwin_ve »

Thnx!
The NOS resistors are carbon film beyschlag. Got them at a army dump for very little money 8yrs ago.
The carbon comp resistor at v2a is a Allen Bradley.
The cathode resistors I got from a student of mine who used to be a service technician for control units at power plants etc. Whenever there was a upgrade he snipped out quality parts that would have ended at the junkyard. So the metal films at the cathodes are maybe 30 yrs old used, but perfectly on spec, I just had to made the leads a little longer.
The bias resistors are sovcor mil spec I got from the same student.

The 2nd gen hybrid is based on on 70-ies 2nd gen Dumble(something in the line of #40, pre classic tonestack) but with additions you find in later generation builds, such as Pab, seperate masters, switchable FET(not sure if Mr Dumble ever used that one it in a build). When Bludotone build something like this, AG Borders made a layout based on that Bludotone.

Yes I have built several amps. Multiple: #102, hrm, blues master without the hrm stack and a few dumblelators.
Wether you like a amp with a strat is based on personal taste. I think any of the amps I mentioned is suitable for a strat, some need maybe a small modification; fe. #102 with a 0.05 mid cap and a switchable lnfb (only lnfb when od is engaged) is imo very suitable for strat.

Erwin
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ToneMerc
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Re: 2nd Gen hybrid

Post by ToneMerc »

erwin_ve wrote: Sun Mar 12, 2017 12:00 pm
The 2nd gen hybrid is based on on 70-ies 2nd gen Dumble(something in the line of #40, pre classic tonestack) but with additions you find in later generation builds, such as Pab, seperate masters, switchable FET(not sure if Mr Dumble ever used that one it in a build). When Bludotone build something like this, AG Borders made a layout based on that Bludotone.



Erwin

The main outstanding feature that made it a "hybrid" was the use of the 90's high precision power supply verses than standard power supply.

TM
Bombacaototal
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Re: 2nd Gen hybrid

Post by Bombacaototal »

Hi Erwin, thanks for the detailed post. Amazing collection of NOS parts, I bet it sounds amazing. I am building mine with Piher carbon(1w or 2w), dale rn65d for the plates and mepco mf7c for the cathodes. Cannot wait to hear it in action

Noted with thanks regarding the upgrades on the normal 2nd gen and hence the hybrid denomination

Regarding you comment on the #102 upgrade did you leave the 150k slope and 250k middle pot jist changing the mid capacitor to .05uf? Regarding the LNfB, when on clean, removing it, did you add the 56k grid stopper?
Last edited by Bombacaototal on Sun Mar 12, 2017 6:47 pm, edited 1 time in total.
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erwin_ve
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Re: 2nd Gen hybrid

Post by erwin_ve »

ToneMerc wrote: Sun Mar 12, 2017 12:55 pm

The main outstanding feature that made it a "hybrid" was the use of the 90's high precision power supply verses than standard power supply.

TM
You're right! However I used 'normal power supply'.
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erwin_ve
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Re: 2nd Gen hybrid

Post by erwin_ve »

Bombacaototal wrote: Sun Mar 12, 2017 1:14 pm Hi Erwin, thanks for the detailed post. Amazing collection of NOS parts, I bet it sounds amazing. I am building mine with Piher carbon(1w or 2w), dale rb65d for the plates and mepco mf7c for the cathodes. Cannot wait to hear it in action

Noted with thanks regarding the upgrades on the normal 2nd gen and hence the hybrid denomination

Regarding you comment on the #102 upgrade did you leave the 150k slope and 250k middle pot jist changing the mid capacitor to .05uf? Regarding the LNfB, when on clean, removing it, did you add the 56k grid stopper?
Still troubleshooting, finetuning will start when that's done. First thing for finetuning to try is lowering the 1m resistor after v2b.
On #102: only change the mid cap. The lnfb doesnt alter the grid resistor 220k//500pF so I cant follow your thoughts on this.
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