The Trace Elliot V-type Club!!

[Wood and Wire]

Have a question about my Trace Elliot 300H,just got couple weeks ago. I am running it through GK 410SBX,8Ohm,and starting making unusually noise(would have to be there?). I was playing an active bass,and was plugged into the active input. Had gain,close to what is in the picture,and the volume. Bass at 3,mids dimed,and treble at 2. Did it couple times,figured it might be batteries in the bass guitar? So I switched basses,and it didn't do it any more? I went over to the Church this morning where amp is at and ran the bass guitar that was hooked up to it when I heard the distortion,never could get it act up? I changed the batteries,just so I would know they are fresh. Mystery to me! Any comments/suggestions welcome! Just don't appreciate sarcasm,so you will know!View attachment 3188849

The critical part of your post is a little unclear / confusing to me.

Are you, in essence, saying that the distortion returned, when used with a different instrument?

1. Is the distortion present on the D.I. output?

2. Is the distortion present on the F/X loop?

3. Is the distortion present on both passive, and active input sockets?

4. Have you tried swapping out the pre-amp tube?

5. Have you tried a different speaker cabinet?

6. Have you tried a different speaker cable?

 

[Wasnex]

It was another matched set of JJ’s, even from the same shop. But I can get how they maybe the case. I went back to the original JJ’s I had installed years ago. When I do get around to the servicing I’m gunna get the guys to check that set as well. I’ll maybe contact the techs tomorrow and see if they offer a test service.

I believe KT88 are matched on plate current and transconductance (Gm). Basically matched tubes should have about the same current and same amount of amplification. One problem is matching needs to be done at the actual operating voltages your amp uses to be very accurate...and this is rarely done or even possible. Matching is supposed to ensure the tubes perform in similar manner, but it doesn't determine how they perform. So another thing to keep in mind is grading.

Normally if you want to replace an old set of tubes without resetting the bias, the new tubes must be graded in same manner as the old tubes. If you get the same brand tubes from the same vendor, this can be achieved by telling the vendor the plate current rating and Gm rating marked on the tubes so you can get a new set with the same ratings. It doesn't work if you use different vendors because they typically use different equipment to perform their matching services. An exception would be if you bought from one of the many vendors who sell Apex matched tubes.

IMHO your still better off checking the tubes to see if they are biased properly, than trusting the new tubes with the same ratings will work perfectly in the amp. Additionally as tubes age it's usually necessary to adjust the bias to keep them in the proper current range. From what I have seen, tubes typically tend to run a bit hotter as the age, although this is not always the case.

 

[Chrome Dome]

The critical part of your post is a little unclear / confusing to me.

Are you, in essence, saying that the distortion returned, when used with a different instrument?

1. Is the distortion present on the D.I. output?

2. Is the distortion present on the F/X loop?

3. Is the distortion present on both passive, and active input sockets?

4. Have you tried swapping out the pre-amp tube?

5. Have you tried a different speaker cabinet?

6. Have you tried a different speaker cable?

Not using the D.I.,not using the F/X loop. I was plugged into the active input. Don't have another speaker cabinet. Never have tried swapping tubes. Have't tried different speaker cable. Distortion was not noticed when I switched to another bass guitar.Thanks for your input though.

 

[Wood and Wire]

Not using the D.I.,not using the F/X loop. I was plugged into the active input. Don't have another speaker cabinet. Never have tried swapping tubes. Have't tried different speaker cable. Distortion was not noticed when I switched to another bass guitar.Thanks for your input though.

So, re-reading your original post ; you switched back to your original bass, and couldn't get it to misbehave - this was after having put in fresh batteries - am I understanding you correctly?

Sounds like you fixed the problem.

If it plays up again, run through the checklist in my previous post.


One other question : when you initially encountered the distortion, was the amp connected to the same ring main (at the church) as it was the second time - or was it a different location entirely?

 

[Chrome Dome]

So, re-reading your original post ; you switched back to your original bass, and couldn't get it to misbehave - this was after having put in fresh batteries - am I understanding you correctly?

Sounds like you fixed the problem.

If it plays up again, run through the checklist in my previous post.


One other question : when you initially encountered the distortion, was the amp connected to the same ring main (at the church) as it was the second time - or was it a different location entirely?

Thank you,for your help,and advice. Yes,I did have the bass plugged into the same ring main,and I hadn't changed the batteries. I will see how it goes,this Wednesday,and play the same bass with fresh batteries. The amp in question had been on and playing for at least an hour,when I got the distortion?

 

[Wood and Wire]

Thank you,for your help,and advice. Yes,I did have the bass plugged into the same ring main,and I hadn't changed the batteries. I will see how it goes,this Wednesday,and play the same bass with fresh batteries. The amp in question had been on and playing for at least an hour,when I got the distortion?

Ah, right, so it didn't have fresh batteries on the 2nd (yet successful) test, but you have since replaced the batteries.

If it again returns after an hour, run through as much of that check list as you possibly can - but if it's consistently exhibiting this problem, I'd get it serviced, as it could be a capacitor dying, so replacing the pre-amp valve could be a waste of money, until the real fault has been diagnosed.

 

[Chrome Dome]

Ah, right, so it didn't have fresh batteries on the 2nd (yet successful) test, but you have since replaced the batteries.

If it again returns after an hour, run through as much of that check list as you possibly can - but if it's consistently exhibiting this problem, I'd get it serviced, as it could be a capacitor dying, so replacing the pre-amp valve could be a waste of money, until the real fault has been diagnosed.

Just got this amp couple weeks ago,and previous owner said it was just serviced,and it had an iffy solder joint,but everything else checked out good. Course it was shipped to me from the west coast,to Ohio. So hopefully nothing got shook loose,from the bouncing around during shipping? I have been playing it quite a bit since receiving,and nothing unusual until the other night? Which I had a different bass guitar I used when it happened?

 

[Bigbri]

The V4 has a pair of variable resistors to set bias in each pair of tubes. They are adjusted through the top of the chassis. See the image below for the location.

View attachment 3182039

The tubes do not have bias sense resistors or test points to measure/set the quiescent current. I use bias probes on my V4 and V6 that insert a milliammeter inline between the cathode and ground. There are also probes that insert 1 ohm bias sense resistor between the cathode and ground. A meter is used to measure the voltage drop across the resistor, so you can easily calculate the current. Basically since resistance = 1, voltage = current.

My V4 has 698V on the plates, so be careful and make sure any bias probes you may buy are rated for the voltage. Some of the digital probes are only rated to about 500-550V. You could easily fry an expensive probe with the V4.

If you buy a set of bias probes, it's a good practice to check the bias every year or so. As long as the amp sounds good and makes good power, I would check/reset the bias and continue running the same tubes.

Could wrong biasing cause tubes too run too hot? I put new Mesa 6L6's in The B15 and they just seem to very hot and brighter than they should be. No problem with power or sound quality. It han't been biases in 20 years because it's had the same tubes. still has the original Ampeg branded 6SL7's.

 

[Wasnex]

Could wrong biasing cause tubes too run too hot?

Yes. If the bias is set too hot the plates will heat up and glow pinkish orange. Red plating basically means the metal is getting hot enough to melt so the tubes are being destroyed. Sometimes the glass envelope can melt down as well.

Here's a video:

 

[Chrome Dome]

Just got this amp couple weeks ago,and previous owner said it was just serviced,and it had an iffy solder joint,but everything else checked out good. Course it was shipped to me from the west coast,to Ohio. So hopefully nothing got shook loose,from the bouncing around during shipping? I have been playing it quite a bit since receiving,and nothing unusual until the other night? Which I had a different bass guitar I used when it happened?

Hello,Wood and Wire,started getting distortion last night? Checked the speaker cables,and they were little loose on both ends? Tightened them up,and played bass for about half hour,or so never did distort. Been thinking about open the amp and see if anything got shook loose,in shipping?

 

[Chrome Dome]

Just got this amp couple weeks ago,and previous owner said it was just serviced,and it had an iffy solder joint,but everything else checked out good. Course it was shipped to me from the west coast,to Ohio. So hopefully nothing got shook loose,from the bouncing around during shipping? I have been playing it quite a bit since receiving,and nothing unusual until the other night? Which I had a different bass guitar I used when it happened?

Started getting distortion again last night. Bass guitar is passive,no battery. Check the speaker cables,and they had loose ends,and I tightened them,and played the bass about half hour,and never distorted? Thinking about open the amp up,and see if anything is loose,after it being shipped?

 

[Wood and Wire]

Hello,Wood and Wire,started getting distortion last night? Checked the speaker cables,and they were little loose on both ends? Tightened them up,and played bass for about half hour,or so never did distort. Been thinking about open the amp and see if anything got shook loose,in shipping?

Having tightened the ends of the cable, why not wait and see if it distorts again, before opening it up?

In any case, I'd be inclined to try another cable that is known to be reliable, prior to opening the amp up.




BTW I have to admit to finding your use of question marks a little confusing, so I'm sorry if I've answered a question you weren't asking, or missed the point of one you were.

 

[Chrome Dome]

Having tightened the ends of the cable, why not wait and see if it distorts again, before opening it up?

In any case, I'd be inclined to try another cable that is known to be reliable, prior to opening the amp up.




BTW I have to admit to finding your use of question marks a little confusing, so I'm sorry if I've answered a question you weren't asking, or missed the point of one you were.

Sorry,about question marks. I think I put question marks,out to say,I have doubts about or question the results. Thank you,for your help,and advice.

 

[Chrome Dome]

Sorry,about question marks. I think I put question marks,out to say,I have doubts about or question the results. Thank you,for your help,and advice.

Thought I would check the effects loop,and see if I get any distortion. Dumb question,but on my particular amp where should I plug into the effects loop? Here is a picture of line out,send,and return. Thanks for any suggestions.

 

[Microbass]

Thought I would check the effects loop,and see if I get any distortion. Dumb question,but on my particular amp where should I plug into the effects loop? Here is a picture of line out,send,and return. Thanks for any suggestions.View attachment 3199133

@Chrome Dome, the FX loop is the 'send' and 'return' sockets. Sometimes, due to lack of use, the jack sockets can be corroded inside and just need cleaned. This can be as simple as just plugging a jack cable a few times, or putting some de-oxit on the tip of a jack.

What you can also test is where your distortion is coming from. The FX loop is between the preamp and power amp sections. The chain looks like this:

Instrument>Preamp>[send]>[receive]>power amp>speaker outs

If you plug your bass straight into the receive socket, it'll be really quiet but you can control volume with the master volume. If you're still getting the issue, suffice to say it'll be in the poweramp section and get this thing serviced! if no issue, then it's localised to the preamp. Using the 'send' output into an interface into your computer, if possible, will let you test this, you can also test the DI this way as well.

 

[Chrome Dome]

@Chrome Dome, the FX loop is the 'send' and 'return' sockets. Sometimes, due to lack of use, the jack sockets can be corroded inside and just need cleaned. This can be as simple as just plugging a jack cable a few times, or putting some de-oxit on the tip of a jack.

What you can also test is where your distortion is coming from. The FX loop is between the preamp and power amp sections. The chain looks like this:

Instrument>Preamp>[send]>[receive]>power amp>speaker outs

If you plug your bass straight into the receive socket, it'll be really quiet but you can control volume with the master volume. If you're still getting the issue, suffice to say it'll be in the poweramp section and get this thing serviced! if no issue, then it's localised to the preamp. Using the 'send' output into an interface into your computer, if possible, will let you test this, you can also test the DI this way as well.

Thank you!

 

[Wasnex]

@Chrome Dome, the FX loop is the 'send' and 'return' sockets. Sometimes, due to lack of use, the jack sockets can be corroded inside and just need cleaned. This can be as simple as just plugging a jack cable a few times, or putting some de-oxit on the tip of a jack.

What you can also test is where your distortion is coming from. The FX loop is between the preamp and power amp sections. The chain looks like this:

Instrument>Preamp>[send]>[receive]>power amp>speaker outs

If you plug your bass straight into the receive socket, it'll be really quiet but you can control volume with the master volume. If you're still getting the issue, suffice to say it'll be in the poweramp section and get this thing serviced! if no issue, then it's localised to the preamp. Using the 'send' output into an interface into your computer, if possible, will let you test this, you can also test the DI this way as well.

Not quite. The effects loops comes very early in the V-Type. It's located between the two triodes of the first tube in the preamp.

Here's is the signal flow:

Input Jack>V1a>Send>Return>V1b>Tone Controls>Gain Control>V2a>V2B>Volume Control>Power Amp

The DI is taken switchable from the output of V1b or V2b. This gives pre/post EQ with the effects loop in both.

 

[Microbass]

Not quite. The effects loops comes very early in the V-Type. It's located between the two triodes of the first tube in the preamp.

Here's is the signal flow:

Input Jack>V1a>Send>Return>V1b>Tone Controls>Gain Control>V2a>V2B>Volume Control>Power Amp

The DI is taken switchable from the output of V1b or V2b. This gives pre/post EQ with the effects loop in both.

Thanks for the correction! Is it normal, in your experience to have the FX loop before the EQ? I always thought they ran at the end of the preamp on all amps.

 

[Wasnex]

Thanks for the correction! Is it normal, in your experience to have the FX loop before the EQ? I always thought they ran at the end of the preamp on all amps.

All of the schematics I have seen of Ashdown tube preamps have the effects loop early like the V-Types. My Sadowsky and Aguilar tube amps place the loop after the tone controls. So, it varies from amp to amp.

 

[Chrome Dome]

In regards,to the amp I have been asking questions on distortion problems. Have come to conclusion to open up the amp,and check to see if tubes may be loose. Don't have another speaker enclosure to see if is the cabinet causing the distortion. Does anyone have any instruction on taking the amp out of the cabinet? I watched a video,and looks like there are 4 screws that have to be removed,and the amp just drops down to be removed? Any comments or help would be appreciated. Thanks!