Crate V5 mods... anyone?

[Tarin]

Hello mark, mexican buddy here.
Just read your bio and can't manage to clos my jaw... that must be the shortest/best explained/interesting and surprising bio i've read in a long time (people at Myspace could learn how to get a message thru).

[Tarin]

Now back to the main concern: upgrading the V5.

Deafelectro... That's some great task you've acomplished in the little amp. i might catch you up on sending the board to get modded and be the first one to review and experiment with your findings.
I already got your email so i'll get in touch with you next week to make this happen.
Now for the speaker issue... is there any way of including one of your leftover Eminence's in the picture?

[deafelectromark]

Hello mark, mexican buddy here.
Just read your bio and can't manage to clos my jaw... that must be the shortest/best explained/interesting and surprising bio i've read in a long time (people at Myspace could learn how to get a message thru).

Thanks C.
Your last line is cryptic- what do you mean concerning Myspace? That they can't speak succinctly? It is a skill after all. I do become quite long winded (see first post above), but last night you (and the rest of us) got lucky. I was passing out from lack of sleep. I just HAD to say what I said. That said- let the music begin!
M

[jim p]

I bought a V5 from Musicians Friend for 80 bucks and have started modifying it. I have two Epi valve Jr. Amps one that I added reverb, triode pentode switch, and Alnico Weber speaker to and the other with FET input high voltage regulator and 6V6 installed. I saw the schematics for the V5 on the web and can see right away they have an amplifier with a solid state preamp (TL072) and tube output not what most people want but easy to fix. Getting the amp found the stock speaker is probably not a guitar speaker so first thing was playing it through the valve Jr speakers also a pair of Jensen 10 special designs made a big difference. So ordered a new speaker from Ted Webber (they have 15% off right now so 43 bucks total with shipping) they make the stock speaker in the old valve Jr. I think. For circuit mods so far I did not remove the Op Amp because it is used for high frequency bypass (above 100Hz) and pre emphasis (boost the highs so the tone control can take them out or pass them through). So I removed R13 to change IC1-A to unity gain and use as a high impedance buffer to not load down the guitar pickups. Next removed C26 changed C24 to 47nF (Note this should be 100nF) removed C27 and installed a 33k resistor in its place removed the 250k pot to use as a volume control after the tone stack. Lifted the 100nf C25 at the node connecting it to R2 and R1 putting a 33k resistor with a 10 nF cap accost it in series (this is now the pre emphasis for the tone stack) With these changes if you over drive the amplifier input with overdrive instead of the OP Amp clipping (awful noise) the first stage tube will clip (as man and god intended when tube amps were created) Next on the tone control changed C6 to 25 nF removed C5 (not sure where a frequency this high is going to come from) and removed C4 (so when you turn the tone control all the way up it does not go to no highs) Now to install the volume pot removed R15 and R27 connected the 250K pot CW1 that was in the Op Amp feedback to ground on the wiper full CCW side connected the wiper to junction of R15, R27, R7 and the grid of J2-A and the third terminal of the pot to junction of R29 C28. Now the tone is set to flat at a quarter turn (9 o’clock position). Then checked the output of the amplifier with a frequency generator and scope and found that it did not clip equally at high volume and started to oscillate. Fixed that by lowering the cathode bias resistor to what the data sheets call out for 270 ohms. Also changed R22 the resistor in series with the power indicator to 150 ohms but it is still to bright will probably go to 220 ohms also it is a light bulb not an LED.
As always if you do mods to a tube amplifier be careful of the high voltages in this case a plate voltage of 316 volts. There is a bleeder resistor R24 so that helps but use a volt meter. And always remember the one hand rule do all your probing with one hand make sure no other part of your body or your other hand is tied to ground.
I changed the value of C24 above found lowest frequency from guitar to be 82Hz not 190Hz.

[Tarin]

Wow, that's some major modding. Unlike what Deafelectro achieved with his more simple mods.
I've been in touch with Deafelectro for him modding my V5 since he's is the only mod i've come up in the internet.
But now that you have accomplish another one...it's only fair to take in consideration, any clips? pics?