Express / SLO 50W hybrid

[bepone]

MODS (for the moment )
1. added grid stopper everywhere (100-220k)
2. changed 10k cold clipper res. to 4k7
3. made compression stage and fx loop driver combo from V2: in V2a 220k anode, 4k7 cathode, 220k grid stopper, 150k remain grid leak, directly followed by follower V2b, 100k-2k in cathode, from 2k 470nF to SEND terminal
4. 82k grid stopper in PI,
5. 4n7 PI input cap
6. FX loop stage recovery, 100k-2k, directly coupled with follower 91k in cathode for light compression, driving MV
7. MV because of CF before can be low as 250k so it is not ruining so much high end
8. 1nF 1kV in parallell with 91k cathode res.
9. 47nF to MV from 91k

[bepone]

Now this is very usable rock machine, ready for testing and other tweaking, working nicely on low(er) volume..
Gain is really good and vintage, not harsh, now i get litlle bit soften bass from first try because increased 47nF cap instead of 33nF to the MV , so maybe i will reduce it after, but for the moment is ok all

[bepone]

how it looks

IMG_20231204_133800__01.jpg

IMG_20231204_134025.jpg

[Reeltarded]

It looks great.. the ideas are mental. You make good stuff and I will bet it is fun.

[Guy77]

Looks beautiful. I will have to try kt66 one day. Who makes the hifi amp on the right side of your pic?

Cheers
G

[boops]

Really nice

I have the same goal with a finished train wreck express .
Vintage OD at low volume.Can you please share a schematic (with mod)

[bepone]

Looks beautiful. I will have to try kt66 one day. Who makes the hifi amp on the right side of your pic?

thx, in free time i'm doing HiFi system by side , building speakers, trying transistor amps, preamps, here is 6V6 preamp with interstage transformers in old Kenwood chassis..

[bepone]

Really nice

I have the same goal with a finished train wreck express .
Vintage OD at low volume.Can you please share a schematic (with mod)

thx, yes when will time allow i will draw schematic

[bepone]

Yesterday was amp testing day, at loud volume.. with few pedals it is killer stage amp, overdrive is special and thick, a lot of details and harmonics (altough this is not OD special topology )

I get some great results in very very low noise and hiss! Almost unbelievable, there is no any noise when the amp is turned on and master vol. low! On first powering on, i was thinking that amp is dead, i switched off , put on the lab table again, test on the scope - there is signal, just needed to open master volume

I have some lo fi videos, better not listen them on the hi fi system , there is fake bass augmentation on low side by mob mic , need to be cut on post processing but i have no time to do it. Listen on mob or laptop, those small speakers will cut this fake bass off naturally

[bepone]

It looks great.. the ideas are mental. You make good stuff and I will bet it is fun.

thx here "new" thing is master volume pot in lower impedance run by CFB from previous stage, and followed by standard PI (high input impedance, low capacitance), i think from this short testing it behaves nice, not cutting highs because is low impedance pot enough to not interfere with PI input capacitance, making useful MV, no need treble cap accross it..
i have put 250k MV but can be lower, need to refine schematic from CFB previous stage (cath. resistor lower value), if i would have time i will check 50k cf resistor and 100k master pot before PI)

[bepone]

test showed that M6 laminations with classic Drake Marshall scheme works very very nice, bass is tight even with neck pickups, i will not change OPT it is ok, details from those lams are great, nothing is smeared , cleans are special too , precise, rich, detailed..

[bepone]

[Reeltarded]

It looks great.. the ideas are mental. You make good stuff and I will bet it is fun.

thx here "new" thing is master volume pot in lower impedance run by CFB from previous stage, and followed by standard PI (high input impedance, low capacitance), i think from this short testing it behaves nice, not cutting highs because is low impedance pot enough to not interfere with PI input capacitance, making useful MV, no need treble cap accross it..
i have put 250k MV but can be lower, need to refine schematic from CFB previous stage (cath. resistor lower value), if i would have time i will check 50k cf resistor and 100k master pot before PI)

You are doing something I am doing but in a completely different way. I will sketch out the basic and send you a PM from another device, but simply put, pick a classic amp design and add an intermediate stage for a master. You can imagine it easily. Slightly (very slightly) cold biased and treated in a way that makes it sound fairly neutral. Having a driven stage be the master allows alot of tweaking for end result and exactly how you want to load up the PI.. as you describe. It's warm and smooth. I do add a 15k extention control to my unbypassed 1k8 cathode tail for more fine control of the bandwidth vs volume.

[Reeltarded]

hahaha AWESOME!!

Take that, purists! I LOVE IT!!

[erwin_ve]

Really nice sounding! Thanks for sharing!