Search found 40 matches

by azrael
Fri Aug 03, 2012 7:26 am
Forum: Technical Discussion
Topic: Hammond "JCM800 Replacement" choke
Replies: 14
Views: 3675

Re: Hammond "JCM800 Replacement" choke

Well, it was literally just installed in place of R5. Just replaced it.


Mounted improperly? Like, mounted to the chassis improperly? This is possible?
by azrael
Thu Aug 02, 2012 6:26 pm
Forum: Technical Discussion
Topic: Hammond "JCM800 Replacement" choke
Replies: 14
Views: 3675

Re: Hammond "JCM800 Replacement" choke

Oh, of course. I was thinking there was a day to do it theoretically, hehe.

I'm not always by my amp, so ya. :)
by azrael
Thu Aug 02, 2012 6:06 pm
Forum: Technical Discussion
Topic: Hammond "JCM800 Replacement" choke
Replies: 14
Views: 3675

Re: Hammond "JCM800 Replacement" choke

This is the reason why I asked to add the pics of the choke installation. Have you measured it's 420Ohm? Have you seen R5 is 400Ohm? Then it could not be 330V instead of 470V. It's 140V drop for something around 20mA (screens and preamp), the choke should be 7k4 Ohm. 50-60mA choke is ok for a 50W a...
by azrael
Thu Aug 02, 2012 3:18 am
Forum: Technical Discussion
Topic: Hammond "JCM800 Replacement" choke
Replies: 14
Views: 3675

Re: Hammond "JCM800 Replacement" choke

Well, the original dropping resistor in the VTM is a 400 ohm one. But it shouldn't be a big different anyway.
by azrael
Thu Aug 02, 2012 12:18 am
Forum: Technical Discussion
Topic: Hammond "JCM800 Replacement" choke
Replies: 14
Views: 3675

Re: Hammond "JCM800 Replacement" choke

No one has modified this amp except for me, I have not moved the B++. And yeah, I meant R5, sorry. :) Pics of all the mods? Kind of a hassle with all the multiple circuit boards. Again, if I reinstall the original resistor, the amp functions normally, sounds great. I don't think any of the additiona...
by azrael
Wed Aug 01, 2012 7:21 pm
Forum: Technical Discussion
Topic: Hammond "JCM800 Replacement" choke
Replies: 14
Views: 3675

Hammond "JCM800 Replacement" choke

I ordered this a little while ago, thinking it would be okay for my Peavey VTM60. The VTM is a close relative of the JCM800. http://www.tubesandmore.com/products/P-C194C However, when I received it, I found out that it was 40H and rated for 50mA. Still, I thought, if it's marketed as a JCM800 drop i...
by azrael
Sun Jul 22, 2012 6:29 pm
Forum: Technical Discussion
Topic: Power Transformer
Replies: 3
Views: 1098

Re: Power Transformer

You sir, are a gentleman and a scholar.
by azrael
Sun Jul 22, 2012 5:10 pm
Forum: Technical Discussion
Topic: Rebuilding my 2204 clone - looking to have 2 channels
Replies: 4
Views: 1884

Re: Rebuilding my 2204 clone - looking to have 2 channels

I prefer unbypassed 2nd stages in 2203 like configurations. You can use a plexi-2203 like switch (to go directly from 1st stage to 3rd), with a dual gain pot and a dual master (or using the master volume only for the 2203 circuit). I've seen people do this before with Peavey VTMs, an amp very close...
by azrael
Sun Jul 22, 2012 4:59 pm
Forum: Technical Discussion
Topic: Power Transformer
Replies: 3
Views: 1098

Power Transformer

Looking at buying a new transformer so my amp will be able to make the switch from 6L6s to either EL34s or KT88s. The current power transformer can't supply enough current to the heaters. 4 12AX7s, two octal power tubes. Now, my options are: - to either replace the current one completely, so I figur...
by azrael
Mon Nov 14, 2011 7:08 am
Forum: Technical Discussion
Topic: Fender Hot Rod Deville
Replies: 9
Views: 6028

Fender Hot Rod Deville

I had an HRD on my workbench this weekend, had to do a few repairs for a friend. While it was there, I did a few mods. I wanted to: increase the treble on the cleans tighten up the bass improve the reverb usability improve drive, make it less harsh, more usable and thicker So here's what I did: -rem...
by azrael
Thu Jul 21, 2011 11:41 pm
Forum: Technical Discussion
Topic: Getting DC Crackle from VVR?
Replies: 11
Views: 3470

Re: Getting DC Crackle from VVR?

Okay guys, I put the 100nF cap after the 33k grid stopper, but before the 1M resistor.

Still crackles when i roll down my guitar volume! ideas?


when I had it open, I modded it for tighter bass and more gain, totally worth it.
by azrael
Wed Jul 13, 2011 6:54 pm
Forum: Technical Discussion
Topic: Getting DC Crackle from VVR?
Replies: 11
Views: 3470

Re: Getting DC Crackle from VVR?

Okay, cool guys. I'll try switching it around and seeing what happens. Should have time tomorrow.

In the meantime, I fixed up my Peavey VTM and am playing through that. :D
by azrael
Wed Jul 13, 2011 12:40 am
Forum: Technical Discussion
Topic: Getting DC Crackle from VVR?
Replies: 11
Views: 3470

Re: Getting DC Crackle from VVR?

The 1M resistor is after the 100nF cap, but before the grid stopper.

I have the directions from Hall, but it's rather invasive, as the Baby Will 18W project uses a PCB and also uses two triodes in parallel.
by azrael
Tue Jul 12, 2011 5:09 pm
Forum: Technical Discussion
Topic: Getting DC Crackle from VVR?
Replies: 11
Views: 3470

Getting DC Crackle from VVR?

Hey, I'm getting some DC crackle from my 18W on my guitar's volume pot.
I put a 100nF coupling cap from the input jack to the grid stopper to block DC, but it didn't help. Any ideas?
by azrael
Wed Feb 02, 2011 5:56 pm
Forum: Technical Discussion
Topic: Modifying a Traynor YCV40...
Replies: 4
Views: 4748

Re: Modifying a Traynor YCV40...

Good point on capacitors! I noticed a significant tonal difference when I upgraded the caps in my Peavey VTM to Sozos.
I'll open it up and take notice of cap material.

Any ideas for thicker OD? I was going to try some coupling cap changes, maybe double the value of C17 to 22nF.