Tube Sockets & Tube Pins

Discussion - HT-1 amplifiers
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thephantum
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Sat Mar 07, 2015 8:27 pm

If it is, then it has to be something heat related. A clean and re-tension of the tube sockets might fix it....but it's more likely to be a bad solder joint someplace. My guess would be around the power tube socket.

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Classicplayer
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Sat Mar 07, 2015 8:54 pm

thephantum wrote:If it is, then it has to be something heat related. A clean and re-tension of the tube sockets might fix it....but it's more likely to be a bad solder joint someplace. My guess would be around the power tube socket.
It's possible, but I need to test the Gain channel too. I should think though that bad solder joint might produce other effects in the sound too. How hot do both ECC82 and 83 typically run? Is it possible that the power tube (really a pre-amp variety) has a shorter optimum life when used in the place of a power tube.

If no discernible improvement is noted after using the DEoxit 5, I will have my tech perform a check on the power tube socket. Strange that each set of tubes in this amp seems to go about 4 months or so before loss of highs is noticed.

Classicplayer

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thephantum
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Sat Mar 07, 2015 10:40 pm

All kinds of weird things can happen with a bad solder joint. It really depends on where it is and how bad the joint is.

As far as the using a preamp tube as a power tube, it's similar with the HT-5. The 12BBH7 is a preamp tube, but it's only powering a 5W ouput stage. Same thing with the HT-1...it's a 1W ouptut stage. So it's not making a whole lot of power.

I don't think I have ever seen a spec published containing operating temps. Most likely because it's sort of subjective...the cathode, the plate, the glass, etc will all be different temperatures. What's more important is the operating voltages and currents.

I think we talked about this in another thread, but I know for a fact that the HT-5 runs it's power tube right on the edge of it's specs AND runs it hot bias wise. I'm betting that the HT-1 is doing something similar with the 12AU7. That would explain it if the tube was actually wearing out....but I'm still not sure that's whats going on here.

Assuming that the HT-1 is running the tube on the edge of it's specs, then the tube is generating a lot of heat. Plus the preamp tube is going to generate heat as well. The way the chassis is oriented in the combo means that the tubes are not directly under the chassis (they are off to the side)....but they are at the top of the box. Basically making it a little oven...so it could very well be a heat related issue.

It might not be a bad solder joint either....it could be some other component that is being affected by the heat. Things like resistors and capacitors do have tolerances for their values. If something is drifting outside of that tolerance as it gets hot (like, for example, a high pass resistor in the tone stack), it could be the culprit. That's a real Easter egg hunt though...it really helps to have a signal generator and an O-scope to help track it down. I don't own the latter so even I would take it to a tech for that.

I would see what happens when you clean the sockets and put the same tubes back in. Also if it seems to be heat related or more time based.

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Classicplayer
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Sun Mar 15, 2015 7:47 pm

I'm still progressing through the test of my HT1R combo with respect to the "vanishing highs". I have not received my recommended DEoxit 5 and alcohol as yet. I have discovered though that my two Les Pauls have to have their volumes kept nearly full on to preserve this highs. Today I used a Les Paul Studio Deluxe with the 490R and Burstbucker Pro in it. When both pickup's volume were at 9 there was no loss of highs after an hour of playing time. That is to say, each pickup individually and then in the middle position. It got even better when I noticed that the guitar volume pots provided substantially more volume and highs just by moving up to 10. I need a repeat test tomorrow and duplicate the same amp and guitar setting and see what happens then. The HT1R has its's volume maxed, the gain at noon or midway and the ISF is set at 9:00 o'clock. I will also set my Classic's volumes the same way. It has a pair of Duncan '59s in it. Wish me luck.

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thephantum
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Tue Mar 31, 2015 1:55 pm

Any update on this dude?

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Classicplayer
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Tue Mar 31, 2015 3:55 pm

Thought you'd forgotten about us :D Yes, I have in hand the products you told me about, I've only cleaned tube pins on my backup pair and swapped those in.....will do the sockets next time. So far, so good. No,loss of highs as yet after extened duration practice sessions. In fact, my wrist started to ache on my fingering hand. :cry: What product similar to DEoxit is good for my guitar's pots?

I've been experimenting today with the gain side of the HT1R. I have a Les Paul with Duncan 59s and Orange Drops and the best result I have so far is to keep the guitar's volume controls on low volume numbers i.e. 2, 3 or perhaps 4. I think the Tung-Sols have so much power that I have to set the amp's gain pot about 9:30am to
10:00am and volume about 4:00pm. Between the Tung-Sols and the Orange Drops, tone adjustments happen very quickly. Also factor in the 300K volume pots on the guitar!

Can't say I dislike it at all. Plenty of highs, sufficient mids and bass too. I tend to not pile on the gain/distortion. It's not my style, but I will fiddle with the amp gain and volume and let you know. If it continues to sound this good, I may use it as my "clean"channel. Some owners do just that. This is
one gem of an amp.

Classicplayer

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thephantum
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Tue Mar 31, 2015 7:55 pm

Cool. It's good to know that it's simply a matter of degraded/dirty pins and not something with the amp itself.

You're kind of like me....I prefer to drive power tubes hard and make them overdrive...as opposed to stacking a lot of gain up in the preamp.

Are just your volume pots 300K or is the tone stack(s) as well? It's funny because I have an Ibanaez RG470 with heavily customized electronics that I'm getting ready to customize again. It has three aftermarket Dimarzio's (Neck to bridge: PAF Pro, FastTrack 2, MoJo), but the customization is really in the switching. I basically replaced the stock 5 way switch, with 3 on-off-on switches. It's wired to be able to run any pickup combination both in and out of phase. Thing is I never use the out of phase positions. So, I want to ax the switches and add two pots as individual volume controls. So I'll have a volume for each pickup and a single tone control. The point is to get more blending options, as opposed to just on or off.

Anyway...my point is, while making those changes, I'm going to play around with pot resistance. The MoJo at the bridge is very hot and very bright...I like it and it's great for the heavier stuff, but takes a little fiddling to warm it up. So I was thinking about taming it a little with a 250k and retaining one of the switches as a coil tap. I love the PAF Pro at the neck ...it's perfect and my goto pickup on this guitar. It will do anything I ask it to, so it stays 500K and I have no plans to tap it.

So in a nutshell, I want to go 500K on the neck (hb) with no tap, 250K on the middle (sc) and 250K on the bridge (hb) with a tap. Then I'd play around with 250K and 500K (as well as caps) on the tone. So yea, I'm interested in your take on humbuckers with a 300K volume pot versus 500K.
Classicplayer wrote:What product similar to DEoxit is good for my guitar's pots?
That's easy. Deoxit. :mrgreen: If you bought the little squeeze tube of Deoxit Gold, you can use that...but it can be a pain and there's is no real way to "rinse" out the pot.

The aerosol version usually works better with pots.
Image
Spray a little in, turn the knob stop to stop a few times and spray a little more in to rinse (if the pot is really "scratchy", you might have to do it a few times). Then use the squeeze tube of Gold to put a drop or two in there, which will keep the pot lubricated and prevent contaminants from building up.

Even with the little straw to direct the product where you want it, it can still be a bit messy. I usually use paper towels and/or rags to prevent over spray from getting on things I don't want it to (like guitar finishes).

I recommend getting the 5oz can (142 grams) over the 14 gram can. It's a negligible price difference and you get 10x more. Besides, you can use it on anything that has a pot. :ugeek:

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Classicplayer
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Tue Mar 31, 2015 8:32 pm

Thanks Phantum. I'm not up on blending and phasing pickups, so, I have no opinions on what you are thinking of doing with your Ibanez.

The Les Paul has the original 300K audio taper volumes and 400K linear taper tone pots. Orange Drop .022 are the caps to replace the original ceramic disk ones.

Classicplayer

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thephantum
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Tue Mar 31, 2015 9:53 pm

I was really just fishing for an opinion about a humbucker with a 300K pot vs one on a 500K pot.

While my goal with this guitar is to be able to blend it's pickups better than I can today, the first step of that is to do some shaping of the individual EQ range of each one....specifically it's bridge pup. I like the pup, it just needs to have a little more treble bled off. I can't do it with a cap on the tone since that will impact treble bleed on all the pickups.

A lot of it is "thinking out typing" too. I could use a 250K on that pickup and if it chokes it off too much, I could change the tone cap to bleed less treble off. While that would brighten up the other pickups, I would be able to roll tone back...

This is all off topic anyway. The only real answer is to set aside a day or two, record some "control" riffs, bust out the soldering iron and try/record different combinations. :geek:

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Classicplayer
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Wed Apr 01, 2015 12:04 am

I suppose my easy answer would be to lower that pickup somewhat, especially on its table side. That would be a good question to post on the Seymour Duncan forum or the MYLesPaul forum. Is it a single coils or humbucker?

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