New Bluesmaster (Pics soon)

[tonejunkie]

Just finished a bluesmaster and now its tweaking time. First step is to get the power rail giving my the right voltages. What should I be shooting for for each preamp tube in a bluesmaster. Also I am noticing too much bass (similar problem to other bluesmaster threads and one more thing. I have built 3 Non HRM's and each have performed smoothly with the guitars volume control but this amp has a houge difference in tone when turning by guitar up from 9 to 10 on my volume knob (Gibson 335). Is there somthing that that could be attributed to? I will post pics tomorrow and ask for many suggestions. Thanks

PS. with the bass at 1 mids at 1 and teble at 7 and brite switch enguaged (as read on the face of the amp) I do like the clean tone and with scott's suggestions from another thread for the hrm board settings the overdrive is going to be nice as well.

[talbany]

Is it a high plate or low plate?

[Structo]

Also, so we are on the same page, when you give numbers for where the pots are set, do you mean 1-10 on the marks of the front panel?

Or are we talking o'clock such as a clock dial?

[tonejunkie]

I had a gig last night (late reply). Here is the schematic I used and some pics are in the next post. I would imagine this would be high plate with the 220k on CL1, I did not know there was a high plate and low plate version of a bluesmaster. Also the settings were on the face of the amp not O'clock. [/img]

[dogears]

Schematic is chock full of problems.

I had a gig last night (late reply). Here is the schematic I used and some pics are in the next post. I would imagine this would be high plate with the 220k on CL1, I did not know there was a high plate and low plate version of a bluesmaster. Also the settings were on the face of the amp not O'clock. [/img]

[tonejunkie]

Here are the pics I promised.

[tonejunkie]

You may have noticed a reversed Elytic cap on CL2. I put that in extreme excitement from a pm suggestion. I caught it before I took the pic but I thought I should show that I have done it too.

[ayan]

Here are the pics I promised.

Your build looks vey nice, congrats. As far as he schematic goes, not sure what you used exactly. As far as BMs go, I believe Dumble always used the "66 ratio" for plate/cathode resistors. A popular combination for this amp is 150/2.3K and 120/1.8K for clean, and higher than that for the OD. I used 180/2.7K and 120/1.8K for the OD, other folks use 220/3.3K, 150/2.3K for overdrive... the higher values will be a tad smoother. For cathode bypass caps I used 4.7uF across the board, some people use higher on the clean side. I use a .01uF coupling cap out of the clean channel and .001uF out of the OD1 stage, some people prefer a larger cap in the OD section.

One comment I can make, and I don't believe it will make or break an amp, is that all plate load and cathode resistors in my amp are metal film, I see you have some carbon films there as well. My pots are: 250KB treble, 50KB middle and 500KA bass. I do not have a coupling cap before the HRM board. My HRM settings have changed A LOT over the years, the latest I have is Bass = 50K (from ground lug to wiper); Middle = 10K (from ground lug to wiper) and this has changes the most... smoother sound with as low as 6.5K setting, but then the sound compresses way too much for my taste in a band setting; Treble = 110K (I think, from ground lug to wiper) and this has changed a lot too... set it for home use and it will not cut through with a band, set it for band use and it will be bright at home.

I think this is all I can offer in terms of stuff you may want to try out.

Cheers,

Gil

[Normster]

Very nice! I use settings very close to Gil's which work well even on a 50 watt BM.

For plate/cathode values, I think it depends on the iron. With Moss's M27 OPT, I can get away with 180k/120k on V2, but with his M6 OPT, it sounds much better with 220k/150k. Jelle and I have discussed this several times and it seems that the lam material makes a noticeable difference in the smoothness of the amp with M6 being more hi-fi but less forgiving.

[rmb550]

Schematic is chock full of problems.

I had a gig last night (late reply). Here is the schematic I used and some pics are in the next post. I would imagine this would be high plate with the 220k on CL1, I did not know there was a high plate and low plate version of a bluesmaster. Also the settings were on the face of the amp not O'clock. [/img]

Serious problems?

[dogears]

Serious enough that if one followed the suggested values the amp would not sound so good.....

All bypass caps are 4.7uf

cathode resistors are 66/1 ratio

As Gil suggested, V1 is 150/120 and V2 is nice at 220/150

CL2 is either .01 or .02 cap.

There is not or ever will be a cap before the HRM!!! No .01 or .001. This is wrong and I wish it would disappear from schematics.

OD 1 is a .001 or .002 cap. I use .002. More growl texture. .001 is smoother but is too smooth for me and a bit lacking if you are a bridge pup solo player like I am. I tried the .001 for a while before moving up to .002uf. I also tried .0012, .0015, and .0018.

If .002 is used, set preod trimmer to about 20K to ground. This is key, otherwise the schematic 40k recommendation will be really bad. With no 47pf cap and a .001, then the 40K maybe ok. I tried both and preferred the .002uf with 20K setting.

FET simulator is 150K and not 120K. Adjust this to get 180V on V1 and close to 200V on V2.

With the recommended values, using the .002uf OD1 coupler, the stack sounds nice at treble 45% on, bass at 70K, and mids at 4K or so. Any higher and it gets very aggressive in the mids and not RF like at all. The real Bluesmaster I was in was set at under 3K on the mids.

Use an OD master bright cap only if you use the loop. I use 47pf on both masters and use 6 foot loop cables to my rack.

I use an unpadded megaboost. 22M to lift stack. That was in the real BM I had here.

Schematic is chock full of problems.

I had a gig last night (late reply). Here is the schematic I used and some pics are in the next post. I would imagine this would be high plate with the 220k on CL1, I did not know there was a high plate and low plate version of a bluesmaster. Also the settings were on the face of the amp not O'clock. [/img]

Serious problems?

[tonejunkie]

Hey guys thanks for the help! I have gone to V1 is 150/120 and V2 at 220/150 with corresponding 2.2/1.8 and 3.3/2.2 cathode resistors. The coupling cap on CL2 is .01 and no cap before the HRM. I am going to wait to fool with the OD1 cap and trimmer till I get the voltages in the right range and the clean channel working to my satisfaction.

Here are some issues I am having:
1. This think is really bass and mid heavy, I changed the mid pot to a 10k and the bass pot to a 100k with a 400k tail to try and change and obtain a larger "sweet spot ". I still with this set up have the bass turned down to 3 and the mids around 3. (These settings are the readings on the face of the amp). This leads me to believe that I may have a circuit problem. Also to get the right amount of highs I have to turn up the treble to 8. I have a tendency to have a darker tone also.

2. Is there a large tonal difference between 5uf and 4.7uf bypass caps. This may take some of the bass frequencies away but I was wondering if it would be that drastic.

3. When I'm in the clean channel to get to gigging volumes I have to turn the clean master up to around 7 or 8 to get there with the preamp volume at around 5 or 6. Is this because the tone-stack is turned down so much that there is very little signal left?

4. The overdrive in this amp has much more note separation and clarity than my Non HRM's which I love but I am used the Non HRM singing or sustain thing happening. What would be tricks to getting just a little more of that attribute in this amp.

5. I am going to search the megaboost thing in a minute but does the schematic I have shown here not have the megaboost?

Thanks for everyones time!

[tonejunkie]

I found this Ayan thread with good info on mega boost.https://tubeamparchive.com/viewtopic.ph ... =megaboost
The schemo that I have does lift the mid pot with a 22m but the other 22m is not in the circuit like it is in the megaboost schemo below. Which one is corect?

[Normster]

Running a 100k bass pot with 400k tail is taking you in the wrong direction. Keep in mind that a passive tone stack works by blleding off frequencies to ground.

At the risk of straying to far from "established" values, here are my recommendations for taming a bass-heavy bluesmaster. I'd also recommend doing them in this order. Assuming you already use a .01uF coupling cap on V1b:
1. Go back to the 1uF bypass cap on V1b.
2. Increase the value of the slope resistor. Try 56k but you may need to go as high as 100k to hit your sweet spot.
3. Change the treble pot to 250KB. (250KA sounds too dark to me.)
4. Last resort, change the bass pot from 500KA to 250KA. (Shouldn't be necessary after the above changes, but can help things along.

OK, gotta go duck outta sight before dogears lambasts me.

[tonejunkie]

I don't know what to call it but the 400k "tail" is on the other side of the pot. The 100k pot controls how much of the 100k goes to ground. Should we call it a "head". I feel like others have experienced this bass heavy thing and still others have not so why would this be? Just components? Iron? A jackass tech wiring it up wrong? Normster I will try your suggestions after I get the voltages situated and play this thing some more.