HoSo56 & 5879 OD

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TUBEDUDE
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Re: HoSo56 & 5879 OD

Post by TUBEDUDE »

I'll have lower voltages over all as my power xfmr is really designed for a deluxe reverb type amp. So i'll have to design the supply rail accordingly. Unfortunately Geoff, talented lad that he is, moved to Nashville last year to make it in the Big music scene. i'll record something. if nothing else, I have a pal here that is talented, even if he plays too much SRV. :roll:
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10thTx
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Re: HoSo56 & 5879 OD

Post by 10thTx »

Any update on this build?

:?

With respect, 10thtx
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TUBEDUDE
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Re: HoSo56 & 5879 OD

Post by TUBEDUDE »

I have done some more wiring, drilled holes for the grounds, and mounted the board.
I redesigned the circuit a little. I have the effects return from the rear panel going through the gain stage then to one side of a pot on the front panel, and the output of the channel switch going to the other side of the pot. The wiper then goes to the PPIMV, making it a balance control of sorts between the effects level and the raw preamp out level.
I've been a little too busy with wedding stuff to spend much time on it. My stepdaughter gets married May 21st. and I get married May 22nd. So currently my energies are addressing and managing the Bridezilla factor.

I did manage to score a transformer from rj and have a 4 6V6 amp to design next! So many projects, so little time.
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10thTx
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Re: HoSo56 & 5879 OD

Post by 10thTx »

OK, I did some sound clip samples

http://www.soundclick.com/player/single ... i&newref=1

Most of this is with the clean channel.

The "boost/OD" is on the lead riffs from 1:30-2:35

& on the boogie rhythm from 2:49- 3:35

With respect, 10thtx
10thTx
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Re: HoSo56 & 5879 OD

Post by 10thTx »

Just a quick update. I changed the cathode and grid values on the 5879 OD tube to the same values on the V1 clean preamp tube.

330k grid resistor and 1.2k cathode resistor to
470k grid resistor and 470 ohm cathode resistor.

I like the way this sounds on the OD more. The OD sounds a little more pushed and has a little more warmth to it.

with respect, 10thtx
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TUBEDUDE
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Re: HoSo56 & 5879 OD

Post by TUBEDUDE »

Thanx for the update on the modded Dist.channel. Yes, driving them hard enough to get crunchy goodness is key. I like mildly warm clean channels and crunchy hot channels. That long sustaining mellow sound is ok, but brighter, odd harmonic rich chording makes me firm.
The wedding schedule is accelerating and we are running out of time. But after the honeymoon, (DURING), I'll make some progress on this amp!
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TUBEDUDE
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Re: HoSo56 & 5879 OD

Post by TUBEDUDE »

Well it's been a.while, sorry 10thTx, with the weddings and having to rebuild my back deck, I've been time and physically crunched.
I've built the amp, had some issues, fixed several, have more. The clean channel sounds great! Amp is fairly quiet, but I can get even lower hiss with some ground, and or wiring changes. I still have to break out the 300w weller to ground the pots (I wish I had tinned them before installation). The dirty channel has some issues, and I may have killed the second 5879. I decided to leave the effects loop drive and recovery as you originally posted, and I'm glad I did as it will make it easier to troubleshoot. But I am still using a balance pot to vary the effects rtn with the pre signal, making it a variable parallel loop.
I'll post some pic tomo, but they aren't for the faint of heart , (crime scene photos).
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TUBEDUDE
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Re: HoSo56 & 5879 OD

Post by TUBEDUDE »

Scene of the crime.
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Re: HoSo56 & 5879 OD

Post by TUBEDUDE »

Got the hot channel working, the 5879's are ok. Turned out to be a bad joint on one of the heater pins. There is not any real distortion from it, just louder than the clean channel. So I replaced the 82k feeding the drive pot (I used that to replace the 100k pot and 50k feeding the drive pot) with a 33k.
The amp is dead quiet unless I remove my hands from the Strats strings.
I haven't tested the effects loop yet either. And I'll have to find room for some relays to allow footswitching the channels and mid boost. All this is with a 5U4GB (I don't risk my NOS GZ-34's until all is safe). Hopefully with the GZ I'll get some additional gain into the hot channel, and all else will remain wonderful.
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10thTx
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Re: HoSo56 & 5879 OD

Post by 10thTx »

Thanks for the update and posting the pics! Looking forward to a tone review after you get it all working the way that you want.

I view having a delay pedal in the FX loop as an essential part of "the" tone so I hope you will try that out.

With respect, 10thtx
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Re: HoSo56 & 5879 OD

Post by TUBEDUDE »

I'll play the amp for a short bit dry to demo the straight tone from both channels, then pop in a delay for some musical masturbation..
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TUBEDUDE
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Re: HoSo56 & 5879 OD

Post by TUBEDUDE »

The GZ34 upped all my voltages about 20V. It had a little HF oscillation if certain controls were in certain positions. That was solved when I relocated both 100nF caps grounds from the 5879's screens, to the cathodes where they should be, (I didn't look over the schematic close enough before following the layout). It shouldn't have made a difference AFAICT but it did. I wish the board was straight, but I was using a previous hole to mount the board and doing it that way left me room to mount the last 3 power filters locally, but it's ugly as home made sin. Small chassis require some compromises I guess. I'll try to get some clips done this week.
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10thTx
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Re: HoSo56 & 5879 OD

Post by 10thTx »

Thanks for sharing the update! Look forward to the soundclips!

With respect, 10thtx
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TUBEDUDE
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Re: HoSo56 & 5879 OD

Post by TUBEDUDE »

Greetings 10thTx, and all for that matter,
I have finished the amp, well, all but the front and rear panels.
And it sounds too good for words! Now I have realized that cell phone video will not cut it.
What do you use to capture your amp samples? I have a few mics, a mixer and recently got a Presonus Audio box 44VSL, but have had no time to play with it. And I'm not sure the file type it generates will be compatible for this purpose. I have a Mac and want to insure I am using the right sample rate and bit depth.
What do you use, and what is a good file type to use for uploading here, or to Soundcloud? Thanks in advance for your wisdom.
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TUBEDUDE
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Re: HoSo56 & 5879 OD

Post by TUBEDUDE »

Here's the schematic. You can see it's rather different from the schemo you shared. I didn't use any exotic parts. Caps are 716P, ceramic or silver mica, depending on value or what I had on hand. Except for the 10uF in the effects send, and the PA cathode reservoir caps which are metalized film.
Last edited by TUBEDUDE on Sun Oct 02, 2016 6:34 pm, edited 1 time in total.
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